George Coukos

Activating the immune system for therapeutic benefit in cancer has long been a goal in immunology and oncology. After decades of disappointment, the tide has finally changed due to the success of recent proof-of-concept clinical trials. Most notable has been the ability of the anti-CTLA4 antibody, ipilimumab, to achieve a significant increase in survival for patients with metastatic melanoma, for which conventional therapies have failed. In the context of advances in the understanding of how tolerance, immunity and immunosuppression regulate antitumour immune responses together with the advent of targeted therapies, these successes suggest that active immunotherapy represents a path to obtain a durable and long-lasting response in cancer patients.

Although tumor-infiltrating T cells have been documented in ovarian carcinoma, a clear association with clinical outcome has not been established.We performed immunohistochemical analysis of 186 frozen specimens from advanced-stage ovarian carcinomas to assess the distribution of tumor-infiltrating T cells and conducted outcome analyses. Molecular analyses were performed in some tumors by real-time polymerase chain reaction.CD3+ tumor-infiltrating T cells were detected within tumor-cell islets (intratumoral T cells) in 102 of the 186 tumors (54.8 percent); they were undetectable in 72 tumors (38.7 percent); the remaining 12 tumors (6.5 percent) could not be evaluated. There were significant differences in the distributions of progression-free survival and overall survival according to the presence or absence of intratumoral T cells (P<0.001 for both comparisons). The five-year overall survival rate was 38.0 percent among patients whose tumors contained T cells and 4.5 percent among patients whose tumors contained no T cells in islets. Significant differences in the distributions of progression-free survival and overall survival according to the presence or absence of intratumoral T cells (P<0.001 for both comparisons) were also seen among 74 patients with a complete clinical response after debulking and platinum-based chemotherapy: the five-year overall survival rate was 73.9 percent among patients whose tumors contained T cells and 11.9 percent among patients whose tumors contained no T cells in islets. The presence of intratumoral T cells independently correlated with delayed recurrence or delayed death in multivariate analysis and was associated with increased expression of interferon-gamma, interleukin-2, and lymphocyte-attracting chemokines within the tumor. The absence of intratumoral T cells was associated with increased levels of vascular endothelial growth factor.The presence of intratumoral T cells correlates with improved clinical outcome in advanced ovarian carcinoma.

Immune-checkpoint inhibitors (ICIs), including anti-cytotoxic T lymphocyte antigen 4 (CTLA-4), anti-programmed cell death 1 (PD-1) and anti-programmed cell death 1 ligand 1 (PD-L1) antibodies, are arguably the most important development in cancer therapy over the past decade. The indications for these agents continue to expand across malignancies and disease settings, thus reshaping many of the previous standard-of-care approaches and bringing new hope to patients. One of the costs of these advances is the emergence of a new spectrum of immune-related adverse events (irAEs), which are often distinctly different from the classical chemotherapy-related toxicities. Owing to the growing use of ICIs in oncology, clinicians will increasingly be confronted with common but also rare irAEs; hence, awareness needs to be raised regarding the clinical presentation, diagnosis and management of these toxicities. In this Review, we provide an overview of the various types of irAEs that have emerged to date. We discuss the epidemiology of these events and their kinetics, risk factors, subtypes and pathophysiology, as well as new insights regarding screening and surveillance strategies. We also highlight the most important aspects of the management of irAEs.

This Opinion article outlines nine major recommendations for improving our understanding of ovarian cancer and the outcomes of women with this group of diseases. There have been major advances in our understanding of the cellular and molecular biology of the human malignancies that are collectively referred to as ovarian cancer. At a recent Helene Harris Memorial Trust meeting, an international group of researchers considered actions that should be taken to improve the outcome for women with ovarian cancer. Nine major recommendations are outlined in this Opinion article.

MicroRNAs (miRNAs) are endogenous noncoding RNAs, which negatively regulate gene expression. To determine genomewide miRNA DNA copy number abnormalities in cancer, 283 known human miRNA genes were analyzed by high-resolution array-based comparative genomic hybridization in 227 human ovarian cancer, breast cancer, and melanoma specimens. A high proportion of genomic loci containing miRNA genes exhibited DNA copy number alterations in ovarian cancer (37.1%), breast cancer (72.8%), and melanoma (85.9%), where copy number alterations observed in &gt;15% tumors were considered significant for each miRNA gene. We identified 41 miRNA genes with gene copy number changes that were shared among the three cancer types (26 with gains and 15 with losses) as well as miRNA genes with copy number changes that were unique to each tumor type. Importantly, we show that miRNA copy changes correlate with miRNA expression. Finally, we identified high frequency copy number abnormalities of Dicer1 , Argonaute2 , and other miRNA-associated genes in breast and ovarian cancer as well as melanoma. These findings support the notion that copy number alterations of miRNAs and their regulatory genes are highly prevalent in cancer and may account partly for the frequent miRNA gene deregulation reported in several tumor types.

This Opinion article outlines a set of research priorities, based on discussions held at the 2015 Helene Harris Memorial Trust Ovarian Cancer Action meeting, that the authors believe will reduce incidence and improve outcomes for women with high-grade serous ovarian cancer. High-grade serous ovarian cancer (HGSOC) accounts for 70–80% of ovarian cancer deaths, and overall survival has not changed significantly for several decades. In this Opinion article, we outline a set of research priorities that we believe will reduce incidence and improve outcomes for women with this disease. This 'roadmap' for HGSOC was determined after extensive discussions at an Ovarian Cancer Action meeting in January 2015.

Tumors use numerous mechanisms to escape detection and killing by the immune system. George Coukos and colleagues now report that cancer cells can also co-opt tumor-associated endothelial cells to prevent immune eradication. The researchers show that factors secreted by cancer cells induce increased expression of Fas ligand on the tumor endothelium, resulting in killing of CD8+ effector T cells and thereby facilitating immune escape and tumor growth. We describe a new mechanism regulating the tumor endothelial barrier and T cell infiltration into tumors. We detected selective expression of the death mediator Fas ligand (FasL, also called CD95L) in the vasculature of human and mouse solid tumors but not in normal vasculature. In these tumors, FasL expression was associated with scarce CD8+ infiltration and a predominance of FoxP3+ T regulatory (Treg) cells. Tumor-derived vascular endothelial growth factor A (VEGF-A), interleukin 10 (IL-10) and prostaglandin E2 (PGE2) cooperatively induced FasL expression in endothelial cells, which acquired the ability to kill effector CD8+ T cells but not Treg cells because of higher levels of c-FLIP expression in Treg cells. In mice, genetic or pharmacologic suppression of FasL produced a substantial increase in the influx of tumor-rejecting CD8+ over FoxP3+ T cells. Pharmacologic inhibition of VEGF and PGE2 produced a marked increase in the influx of tumor-rejecting CD8+ over FoxP3+ T cells that was dependent on attenuation of FasL expression and led to CD8-dependent tumor growth suppression. Thus, tumor paracrine mechanisms establish a tumor endothelial death barrier, which has a critical role in establishing immune tolerance and determining the fate of tumors.

Th17 cells play an active role in autoimmune diseases. However, the nature of Th17 cells is poorly understood in cancer patients. We studied Th17 cells, the associated mechanisms, and clinical significance in 201 ovarian cancer patients. Tumor-infiltrating Th17 cells exhibit a polyfunctional effector T-cell phenotype, are positively associated with effector cells, and are negatively associated with tumor-infiltrating regulatory T cells. Tumor-associated macrophages promote Th17 cells through interleukin-1beta (IL-1beta), whereas tumor-infiltrating regulatory T cells inhibit Th17 cells through an adenosinergic pathway. Furthermore, through synergistic action between IL-17 and interferon-gamma, Th17 cells stimulate CXCL9 and CXCL10 production to recruit effector T cells to the tumor microenvironment. The levels of CXCL9 and CXCL10 are associated with tumor-infiltrating effector T cells. The levels of tumor-infiltrating Th17 cells and the levels of ascites IL-17 are reduced in more advanced diseases and positively predict patient outcome. Altogether, Th17 cells may contribute to protective human tumor immunity through inducing Th1-type chemokines and recruiting effector cells to the tumor microenvironment. Inhibition of Th17 cells represents a novel immune evasion mechanism. This study thus provides scientific and clinical rationale for developing novel immune-boosting strategies based on promoting the Th17 cell population in cancer patients.

Cells succumbing to stress via regulated cell death (RCD) can initiate an adaptive immune response associated with immunological memory, provided they display sufficient antigenicity and adjuvanticity. Moreover, multiple intracellular and microenvironmental features determine the propensity of RCD to drive adaptive immunity. Here, we provide an updated operational definition of immunogenic cell death (ICD), discuss the key factors that dictate the ability of dying cells to drive an adaptive immune response, summarize experimental assays that are currently available for the assessment of ICD in vitro and in vivo, and formulate guidelines for their interpretation.

T-regulatory cells (Tregs) are found infiltrating tumors in a vast array of tumor types, and tumor-infiltrating Tregs are often associated with a poor clinical outcome. Tregs are potent immunosuppressive cells of the immune system that promote progression of cancer through their ability to limit antitumor immunity and promote angiogenesis. Here, we discuss the ways in which Tregs suppress the antitumor immune response and elaborate on our recent discovery that Tregs make significant direct contributions to tumor angiogenesis. Further, we highlight several current therapies aimed at eliminating Tregs in cancer patients. Given the multifaceted role of Tregs in cancer, a greater understanding of their functions will ultimately strengthen future therapies.

The involvement of complement-activation products in promoting tumor growth has not yet been recognized. Here we show that the generation of complement C5a in a tumor microenvironment enhanced tumor growth by suppressing the antitumor CD8(+) T cell-mediated response. This suppression was associated with the recruitment of myeloid-derived suppressor cells into tumors and augmentation of their T cell-directed suppressive abilities. Amplification of the suppressive capacity of myeloid-derived suppressor cells by C5a occurred through regulation of the production of reactive oxygen and nitrogen species. Pharmacological blockade of the C5a receptor considerably impaired tumor growth to a degree similar to the effect produced by the anticancer drug paclitaxel. Thus, our study demonstrates a therapeutic function for complement inhibition in the treatment of cancer.

Tumor progression is facilitated by regulatory T cells (Treg) and restricted by effector T cells. In this study, we document parallel regulation of CD8(+) T cells and Foxp3(+) Tregs by programmed death-1 (PD-1, PDCD1). In addition, we identify an additional role of CTL antigen-4 (CTLA-4) inhibitory receptor in further promoting dysfunction of CD8(+) T effector cells in tumor models (CT26 colon carcinoma and ID8-VEGF ovarian carcinoma). Two thirds of CD8(+) tumor-infiltrating lymphocytes (TIL) expressed PD-1, whereas one third to half of CD8(+) TIL coexpressed PD-1 and CTLA-4. Double-positive (PD-1(+)CTLA-4(+)) CD8(+) TIL had characteristics of more severe dysfunction than single-positive (PD-1(+) or CTLA-4(+)) TIL, including an inability to proliferate and secrete effector cytokines. Blockade of both PD-1 and CTLA-4 resulted in reversal of CD8(+) TIL dysfunction and led to tumor rejection in two thirds of mice. Double blockade was associated with increased proliferation of antigen-specific effector CD8(+) and CD4(+) T cells, antigen-specific cytokine release, inhibition of suppressive functions of Tregs, and upregulation of key signaling molecules critical for T-cell function. When used in combination with GVAX vaccination (consisting of granulocyte macrophage colony-stimulating factor-expressing irradiated tumor cells), inhibitory pathway blockade induced rejection of CT26 tumors in 100% of mice and ID8-VEGF tumors in 75% of mice. Our study indicates that PD-1 signaling in tumors is required for both suppressing effector T cells and maintaining tumor Tregs, and that PD-1/PD-L1 pathway (CD274) blockade augments tumor inhibition by increasing effector T-cell activity, thereby attenuating Treg suppression.

The discovery of long non-coding RNA (lncRNA) has dramatically altered our understanding of cancer. Here, we describe a comprehensive analysis of lncRNA alterations at transcriptional, genomic, and epigenetic levels in 5,037 human tumor specimens across 13 cancer types from The Cancer Genome Atlas. Our results suggest that the expression and dysregulation of lncRNAs are highly cancer type specific compared with protein-coding genes. Using the integrative data generated by this analysis, we present a clinically guided small interfering RNA screening strategy and a co-expression analysis approach to identify cancer driver lncRNAs and predict their functions. This provides a resource for investigating lncRNAs in cancer and lays the groundwork for the development of new diagnostics and treatments.

The presence of T cells within the epithelial component of tumors, as histologic evidence of anti-tumor immunity, has been associated with a survival advantage in multiple studies across diverse patient cohorts. We performed a meta-analysis of studies evaluating the prognostic value of tumor-infiltrating lymphocytes (TIL) on survival among women with ovarian cancer and to investigate factors associated with variations in this effect, including patient characteristics, surgical outcomes, tumor histology, and study protocols.Published studies that evaluated the association between TIL and patient survival were identified. Descriptive statistics, outcome data, and study quality were extracted from studies that met inclusion criteria. Hazard ratios and 95% confidence intervals were pooled across studies using the random-effects model. Publication bias was investigated using a funnel plot and heterogeneity was assessed with subgroup analysis and I(2) statistics.Ten suitable studies comprising 1815 patients with ovarian cancer were analyzed. Our results demonstrate that a lack of intraepithelial TILs is significantly associated with a worse survival among patients (pooled HR: 2.24, 95% CI; 1.71-2.91). Variations in the prognostic value of TIL status based on debulking status, scoring method, and geographic regions were identified.Intraepithelial TILs are a robust predictor of outcome in ovarian cancer and define a specific class of patients, whose distinct tumor biology should be taken into account in devising appropriate therapeutic strategies.

This Opinion article discusses progress and challenges in using patient-derived xenograft (PDX) models in cancer precision medicine. It is primarily co-authored by members of the EurOPDX Consortium and as such highlights the merits of shared PDX resources. Patient-derived xenografts (PDXs) have emerged as an important platform to elucidate new treatments and biomarkers in oncology. PDX models are used to address clinically relevant questions, including the contribution of tumour heterogeneity to therapeutic responsiveness, the patterns of cancer evolutionary dynamics during tumour progression and under drug pressure, and the mechanisms of resistance to treatment. The ability of PDX models to predict clinical outcomes is being improved through mouse humanization strategies and the implementation of co-clinical trials, within which patients and PDXs reciprocally inform therapeutic decisions. This Opinion article discusses aspects of PDX modelling that are relevant to these questions and highlights the merits of shared PDX resources to advance cancer medicine from the perspective of EurOPDX, an international initiative devoted to PDX-based research.

Generating an anti-tumor immune response is a multi-step process that is executed by effector T cells that can recognize and kill tumor targets. However, tumors employ multiple strategies to attenuate the effectiveness of T-cell-mediated attack. They achieve this by interfering with nearly every step required for effective immunity, from deregulation of antigen-presenting cells to establishment of a physical barrier at the vasculature that prevents homing of effector tumor-rejecting cells and the suppression of effector lymphocytes through the recruitment and activation of immunosuppressive cells such as myeloid-derived suppressor cells, tolerogenic monocytes, and T regulatory cells. Here, we review the ways in which tumors exert immune suppression and highlight the new therapies that seek to reverse this phenomenon and promote anti-tumor immunity. Understanding anti-tumor immunity, and how it becomes disabled by tumors, will ultimately lead to improved immune therapies and prolonged survival of patients.

MicroRNAs (miRNAs) are an abundant class of small noncoding RNAs that function as negative gene regulators. miRNA deregulation is involved in the initiation and progression of human cancer; however, the underlying mechanism and its contributions to genome-wide transcriptional changes in cancer are still largely unknown. We studied miRNA deregulation in human epithelial ovarian cancer by integrative genomic approach, including miRNA microarray (n = 106), array-based comparative genomic hybridization (n = 109), cDNA microarray (n = 76), and tissue array (n = 504). miRNA expression is markedly down-regulated in malignant transformation and tumor progression. Genomic copy number loss and epigenetic silencing, respectively, may account for the down-regulation of approximately 15% and at least approximately 36% of miRNAs in advanced ovarian tumors and miRNA down-regulation contributes to a genome-wide transcriptional deregulation. Last, eight miRNAs located in the chromosome 14 miRNA cluster (Dlk1-Gtl2 domain) were identified as potential tumor suppressor genes. Therefore, our results suggest that miRNAs may offer new biomarkers and therapeutic targets in epithelial ovarian cancer.

Aldehyde dehydrogenase isoform 1 (ALDH1) has been proved useful for the identification of cancer stem cells. However, our knowledge of the expression and activity of ALDH1 in common epithelial cancers and their corresponding normal tissues is still largely absent. Therefore, we characterized ALDH1 expression in 24 types of normal tissues and a large collection of epithelial tumor specimens (six cancer types, n = 792) by immunohistochemical staining. Using the ALDEFUOR assay, ALDH1 activity was also examined in 16 primary tumor specimens and 43 established epithelial cancer cell lines. In addition, an ovarian cancer transgenic mouse model and 7 murine ovarian cancer cell lines were analyzed. We found that the expression levels and patterns of ALDH1 in epithelial cancers are remarkably distinct, and they correlate with their corresponding normal tissues. ALDH1 protein expression levels are positively correlated with ALDH1 enzymatic activity measured by ALDEFLUOR assay. Long-term in vitro culture doesn't significantly affect ALDH1 activity in epithelial tumor cells. Consistent with research on other cancers, we found that high ALDH1 expression is significantly associated with poor clinical outcomes in serous ovarian cancer patients (n = 439, p = 0.0036). Finally, ALDH(br) tumor cells exhibit cancer stem cell properties and are resistant to chemotherapy. As a novel cancer stem cell marker, ALDH1 can be used for tumors whose corresponding normal tissues express ALDH1 in relatively restricted or limited levels such as breast, lung, ovarian or colon cancer.

ABSTRACT Approximately one‐half of patients with newly diagnosed cancer and many patients with persistent or recurrent tumors receive radiotherapy (RT), with the explicit goal of eliminating tumors through direct killing. The current RT dose and schedule regimens have been empirically developed. Although early clinical studies revealed that RT could provoke important responses not only at the site of treatment but also on remote, nonirradiated tumor deposits—the so‐called “abscopal effect”— the underlying mechanisms were poorly understood and were not therapeutically exploited. Recent work has elucidated the immune mechanisms underlying these effects and has paved the way for developing combinations of RT with immune therapy. In the wake of recent therapeutic breakthroughs in the field of immunotherapy, rational combinations of immunotherapy with RT could profoundly change the standard of care for many tumor types in the next decade. Thus, a deep understanding of the immunologic effects of RT is urgently needed to design the next generation of therapeutic combinations. Here, the authors review the immune mechanisms of tumor radiation and summarize the preclinical and clinical evidence on immunotherapy‐RT combinations. Furthermore, a framework is provided for the practicing clinician and the clinician investigator to guide the development of novel combinations to more rapidly advance this important field. CA Cancer J Clin 2017;67:65–85. © 2016 American Cancer Society .

Abstract Summary: Cancer immunotherapy has great promise, but is limited by diverse mechanisms used by tumors to prevent sustained antitumor immune responses. Tumors disrupt antigen presentation, T/NK–cell activation, and T/NK–cell homing through soluble and cell-surface mediators, the vasculature, and immunosuppressive cells such as myeloid-derived suppressor cells and regulatory T cells. However, many molecular mechanisms preventing the efficacy of antitumor immunity have been identified and can be disrupted by combination immunotherapy. Here, we examine immunosuppressive mechanisms exploited by tumors and provide insights into the therapies under development to overcome them, focusing on lymphocyte traffic. Cancer Discov; 4(5); 522–6. ©2014 AACR.

MicroRNAs (miRNA) are approximately 22-nucleotide noncoding RNAs that negatively regulate protein-coding gene expression in a sequence-specific manner via translational inhibition or mRNA degradation. Our recent studies showed that miRNAs exhibit genomic alterations at a high frequency and their expression is remarkably deregulated in ovarian cancer, strongly suggesting that miRNAs are involved in the initiation and progression of this disease. In the present study, we performed miRNA microarray to identify the miRNAs associated with chemotherapy response in ovarian cancer and found that let-7i expression was significantly reduced in chemotherapy-resistant patients (n = 69, P = 0.003). This result was further validated by stem-loop real-time reverse transcription-PCR (n = 62, P = 0.015). Both loss-of-function (by synthetic let-7i inhibitor) and gain-of-function (by retroviral overexpression of let-7i) studies showed that reduced let-7i expression significantly increased the resistance of ovarian and breast cancer cells to the chemotherapy drug, cis-platinum. Finally, using miRNA microarray, we found that decreased let-7i expression was significantly associated with the shorter progression-free survival of patients with late-stage ovarian cancer (n = 72, P = 0.042). This finding was further validated in the same sample set by stem-loop real-time reverse transcription-PCR (n = 62, P = 0.001) and in an independent sample set by in situ hybridization (n = 53, P = 0.049). Taken together, our results strongly suggest that let-7i might be used as a therapeutic target to modulate platinum-based chemotherapy and as a biomarker to predict chemotherapy response and survival in patients with ovarian cancer.

AbstractTumor growth results in hypoxia. Understanding the mechanisms of gene expression reprogramming under hypoxia may provide important clues to cancer pathogenesis. We studied miRNA genes that are regulated by hypoxia in ovarian cancer cell lines by TaqMan miRNA assay containing 157 mature miRNAs. MiR-210 was the most prominent miRNA consistently stimulated under hypoxic conditions. We provide evidence for the involvement of the HIF signaling pathway in miR-210 regulation. Biocomputational analysis and in vitro assays demonstrated that e2f transcription factor 3 (e2f3), a key protein in cell cycle, is regulated by miR-210. E2F3 was further confirmed to be downregulated at the protein level upon induction of miR-210. Importantly, we found remarkably high frequency of miR-210 gene copy deletions in ovarian cancer patients (64%, n=114) and that gene copy number correlates with miR-210 expression levels. Taken together, our results indicate that miR-210 plays a crucial role in tumor onset as a key regulator of the hypoxia response and provide evidence for a link between hypoxia and the regulation of cell cycle.

Cancers often arise as the end stage of inflammation in adults, but not in children. As such there is a complex interplay between host immune cells during neoplastic development, with both an ability to promote cancer and limit or eliminate it, most often complicit with the host. In humans, defining inflammation and the presence of inflammatory cells within or surrounding the tumor is a critical aspect of modern pathology. Groups defining staging for neoplasms are strongly encouraged to assess and incorporate measures of the presence of apoptosis, autophagy, and necrosis and also the nature and quality of the immune infiltrate. Both environmental and genetic factors enhance the risk of cigarette smoking, Helicobacter pylori, hepatitis B/C, human papilloma virus, solar irradiation, asbestos, pancreatitis, or other causes of chronic inflammation. Identifying suitable genetic polymorphisms in cytokines, cytokine receptors, and Toll-like receptors among other immune response genes is also seen as high value as genomic sequencing becomes less expensive. Animal models that incorporate and assess not only the genetic anlagen but also the inflammatory cells and the presence of microbial pathogens and damage-associated molecular pattern molecules are necessary. Identifying micro-RNAs involved in regulating the response to damage or injury are seen as highly promising. Although no therapeutic strategies to prevent or treat cancers based on insights into inflammatory pathways are currently approved for the common epithelial malignancies, there remains substantial interest in agents targeting COX2 or PPARgamma, ethyl pyruvate and steroids, and several novel agents on the horizon.

Many approaches to identify therapeutically relevant neoantigens couple tumor sequencing with bioinformatic algorithms and inferred rules of tumor epitope immunogenicity. However, there are no reference data to compare these approaches, and the parameters governing tumor epitope immunogenicity remain unclear. Here, we assembled a global consortium wherein each participant predicted immunogenic epitopes from shared tumor sequencing data. 608 epitopes were subsequently assessed for T cell binding in patient-matched samples. By integrating peptide features associated with presentation and recognition, we developed a model of tumor epitope immunogenicity that filtered out 98% of non-immunogenic peptides with a precision above 0.70. Pipelines prioritizing model features had superior performance, and pipeline alterations leveraging them improved prediction performance. These findings were validated in an independent cohort of 310 epitopes prioritized from tumor sequencing data and assessed for T cell binding. This data resource enables identification of parameters underlying effective anti-tumor immunity and is available to the research community.

microRNAs (miRNAs) are an abundant class of small non-coding RNAs that function as gene regulators. Although deregulation of miRNA expression is involved in the initiation and progression of tumorigenesis, the underlying mechanisms of miRNA deregulation in human cancer are still largely unknown. Increasing evidence indicates that transcriptional deregulations, epigenetic alterations, mutations, DNA copy number abnormalities and defects in the miRNA biogenesis machinery might contribute to miRNA deregulation in human cancer. A clearer understanding of the mechanisms involved in miRNA deregulation in human cancer will contribute greatly to the development of new miRNA-based strategies in cancer diagnosis and treatment.

Abstract B7-H4 is a recently identified B7 family member. We previously showed that ovarian tumor and associated macrophages expressed B7-H4; tumor B7-H4+ macrophages and CD4+CD25+FOXP3+ regulatory T cells (Treg cells) suppressed tumor-associated antigen–specific T-cell immunity. To determine the pathologic relationship between B7-H4, macrophages, and Treg cells in the tumor environment, in addition to Treg cell numbers, we quantified B7-H4 expression in the tumor and tumor-associated macrophages in 103 patients with ovarian carcinoma. We observed that the intensity of B7-H4 expression in macrophages was significantly correlated with Treg cell numbers in the tumor. Further, both Treg cells and macrophage B7-H4, but not tumor B7-H4, were negatively associated with patient outcome. Tumor Treg cells enabled macrophages to spontaneously produce interleukin (IL)-10 and IL-6. Tumor macrophages stimulated B7-H4 expression in an autocrine manner through IL-10 and IL-6. Our previous work showed that tumor-associated macrophages spontaneously produced chemokine CCL22 to mediate Treg cell trafficking into tumor, and Treg cells induced B7-H4 on antigen-presenting cells (APC) including macrophages. Altogether, our data support the concept that there is a mechanistic interaction between Treg cells and macrophage, and that Treg cells may convey the suppressive activity to APCs through B7-H4 induction in human ovarian cancer. [Cancer Res 2007;67(18):8901–05]

T-lymphocytes play a critical role in cancer immunity as evidenced by their presence in resected tumor samples derived from long-surviving patients, and impressive clinical responses to various immunotherapies that reinvigorate them. Indeed, tumors can upregulate a wide array of defense mechanisms, both direct and indirect, to suppress the ability of Tcells to reach the tumor bed and mount curative responses upon infiltration. In addition, patient and tumor genetics, previous antigenic experience, and the microbiome, are all important factors in shaping the T-cell repertoire and sensitivity to immunotherapy. Here, we review the mechanisms that regulate T-cell homing, infiltration, and activity within the solid tumor bed. Finally, we summarize different immunotherapies and combinatorial treatment strategies that enable the immune system to overcome barriers for enhanced tumor control and improved patient outcome.

Intraepithelial tumor-infiltrating T cells have been correlated with improved outcomes in ovarian carcinoma, however, it is not known whether there is an association with disease stage, histological subtype, or BRCA mutation/expression. Two case series of ovarian carcinomas were included in the study; a retrospective series of 500 patients, and 40 prospectively collected cases fully characterized for BRCA1 mutation status and expression. Intraepithelial immune cells were assessed as present or absent by immunohistochemical staining of tissue microarrays. In the retrospective case series, the presence of intraepithelial CD8+ T-cells correlated with improved disease-specific survival (P=0.027), whereas intraepithelial CD3+ T cells did not (P=0.49). For serous ovarian carcinomas, the presence of intraepithelial CD3+ and CD8+ T-cells correlated with improved disease-specific survival (P=0.0016 and P≤0.0001, respectively). The presence of intraepithelial CD8+ T cells was not associated with improved survival in endometrioid or clear cell carcinomas. On multivariate analysis, disease stage and CD8+ T cells were found to be independently predictive of improved disease-specific survival, whereas grade, age at surgery, and type of adjuvant treatment were not. In the prospective patient cohort, intraepithelial CD8+ T-cells correlated with the presence of mutation or loss of expression of BRCA1 through promoter methylation (P=0.019). Intraepithelial CD8+ tumor-infiltrating T-cells correlate with improved clinical outcomes for all stages of ovarian cancer; this association is restricted to the serous ovarian cancer subtype, and is an independent prognostic factor on multivariate analysis. The presence of intraepithelial CD8+ T cells also significantly correlates with loss of BRCA1.

Abstract Human T cells engineered to express a chimeric antigen receptor (CAR) specific for folate receptor-α (FRα) have shown robust antitumor activity against epithelial cancers in vitro but not in the clinic because of their inability to persist and home to tumor in vivo. In this study, CARs were constructed containing a FRα-specific scFv (MOv19) coupled to the T-cell receptor CD3ζ chain signaling module alone (MOv19-ζ) or in combination with the CD137 (4-1BB) costimulatory motif in tandem (MOv19-BBζ). Primary human T cells transduced to express conventional MOv19-ζ or costimulated MOv19-BBζ CARs secreted various proinflammatory cytokines, and exerted cytotoxic function when cocultured with FRα+ tumor cells in vitro. However, only transfer of human T cells expressing the costimulated MOv19-BBζ CAR mediated tumor regression in immunodeficient mice bearing large, established FRα+ human cancer. MOv19-BBζ CAR T-cell infusion mediated tumor regression in models of metastatic intraperitoneal, subcutaneous, and lung-involved human ovarian cancer. Importantly, tumor response was associated with the selective survival and tumor localization of human T cells in vivo and was only observed in mice receiving costimulated MOv19-BBζ CAR T cells. T-cell persistence and antitumor activity were primarily antigen-driven; however, antigen-independent CD137 signaling by CAR improved T-cell persistence but not antitumor activity in vivo. Our results show that anti-FRα CAR outfitted with CD137 costimulatory signaling in tandem overcome issues of T-cell persistence and tumor localization that limit the conventional FRα T-cell targeting strategy to provide potent antitumor activity in vivo. Cancer Res; 71(13); 4617–27. ©2011 AACR.

Upregulation of CD137 (4-1BB) on recently activated CD8(+) T cells has been used to identify rare viral or tumor antigen-specific T cells from peripheral blood. Here, we evaluated the immunobiology of CD137 in human cancer and the utility of a CD137-positive separation methodology for the identification and enrichment of fresh tumor-reactive tumor-infiltrating lymphocytes (TIL) or tumor-associated lymphocytes (TAL) from ascites for use in adoptive immunotherapy.TILs from resected ovarian cancer or melanoma were measured for surface CD137 expression directly or after overnight incubation in the presence of tumor cells and homeostatic cytokines. CD137(pos) TILs were sorted and evaluated for antitumor activity in vitro and in vivo.Fresh ovarian TILs and TALs naturally expressed higher levels of CD137 than circulating T cells. An HLA-dependent increase in CD137 expression was observed following incubation of fresh enzyme-digested tumor or ascites in IL-7 and IL-15 cytokines, but not IL-2. Enriched CD137(pos) TILs, but not PD-1(pos) or PD-1(neg) CD137(neg) cells, possessed autologous tumor reactivity in vitro and in vivo. In melanoma studies, all MART-1-specific CD8(+) TILs upregulated CD137 expression after incubation with HLA-matched, MART-expressing cancer cells and antigen-specific effector function was restricted to the CD137(pos) subset in vitro. CD137(pos) TILs also mediated superior antitumor effects in vivo, compared with CD137(neg) TILs.Our findings reveal a role for the TNFR-family member CD137 in the immunobiology of human cancer where it is preferentially expressed on tumor-reactive subset of TILs, thus rationalizing its agonistic engagement in vivo and its use in TIL selection for adoptive immunotherapy trials.

T cells play a critical role in tumor immune surveillance as evidenced by extensive mouse-tumor model studies as well as encouraging patient responses to adoptive T cell therapies and dendritic cell vaccines. It is well established that the interplay of tumor cells with their local cellular environment can trigger events that are immunoinhibitory to T cells. More recently it is emerging that the tumor vasculature itself constitutes an important barrier to T cells. Endothelial cells lining the vessels can suppress T cell activity, target them for destruction, and block them from gaining entry into the tumor in the first place through the deregulation of adhesion molecules. Here we review approaches to break this tumor endothelial barrier and enhance T cell activity.

The tumor microenvironment mediates induction of the immunosuppressive programmed cell death-1 (PD-1) pathway, and targeted interventions against this pathway can help restore antitumor immunity. To gain insight into these responses, we studied the interaction between PD-1 expressed on T cells and its ligands (PD-1:PD-L1, PD-1:PD-L2, and PD-L1:B7.1), expressed on other cells in the tumor microenvironment, using a syngeneic orthotopic mouse model of epithelial ovarian cancer (ID8). Exhaustion of tumor-infiltrating lymphocytes (TIL) correlated with expression of PD-1 ligands by tumor cells and tumor-derived myeloid cells, including tumor-associated macrophages (TAM), dendritic cells, and myeloid-derived suppressor cells (MDSC). When combined with GVAX or FVAX vaccination (consisting of irradiated ID8 cells expressing granulocyte macrophage colony-stimulating factor or FLT3 ligand) and costimulation by agonistic α-4-1BB or TLR 9 ligand, antibody-mediated blockade of PD-1 or PD-L1 triggered rejection of ID8 tumors in 75% of tumor-bearing mice. This therapeutic effect was associated with increased proliferation and function of tumor antigen-specific effector CD8(+) T cells, inhibition of suppressive regulatory T cells (Treg) and MDSC, upregulation of effector T-cell signaling molecules, and generation of T memory precursor cells. Overall, PD-1/PD-L1 blockade enhanced the amplitude of tumor immunity by reprogramming suppressive and stimulatory signals that yielded more powerful cancer control.

Abstract Single-cell RNA sequencing (scRNA-seq) has revealed an unprecedented degree of immune cell diversity. However, consistent definition of cell subtypes and cell states across studies and diseases remains a major challenge. Here we generate reference T cell atlases for cancer and viral infection by multi-study integration, and develop ProjecTILs, an algorithm for reference atlas projection. In contrast to other methods, ProjecTILs allows not only accurate embedding of new scRNA-seq data into a reference without altering its structure, but also characterizing previously unknown cell states that “deviate” from the reference. ProjecTILs accurately predicts the effects of cell perturbations and identifies gene programs that are altered in different conditions and tissues. A meta-analysis of tumor-infiltrating T cells from several cohorts reveals a strong conservation of T cell subtypes between human and mouse, providing a consistent basis to describe T cell heterogeneity across studies, diseases, and species.

Recent clinical trials revealed the impressive efficacy of immunological checkpoint blockade in different types of metastatic cancers. Such data underscore that immunotherapy is one of the most promising strategies for cancer treatment. In addition, preclinical studies provide evidence that some cytotoxic drugs have the ability to stimulate the immune system, resulting in anti-tumor immune responses that contribute to clinical efficacy of these agents. These observations raise the hypothesis that the next step for cancer treatment is the combination of cytotoxic agents and immunotherapies. The present review aims to summarize the immune-mediated effects of chemotherapeutic agents and their clinical relevance, the biological and clinical features of immune checkpoint blockers and finally, the preclinical and clinical rationale for novel therapeutic strategies combining anticancer agents and immune checkpoint blockers.

With its vast amount of uncharacterized and characterized T cell epitopes available for activating CD4⁺ T helper and CD8⁺ cytotoxic lymphocytes simultaneously, whole tumor antigen represents an attractive alternative source of antigens as compared to tumor-derived peptides and full-length recombinant tumor proteins for dendritic cell (DC)-based immunotherapy. Unlike defined tumor-derived peptides and proteins, whole tumor lysate therapy is applicable to all patients regardless of their HLA type. DCs are essentially the master regulators of immune response, and are the most potent antigen-presenting cell population for priming and activating naïve T cells to target tumors. Because of these unique properties, numerous DC-based immunotherapies have been initiated in the clinics. In this review, we describe the different types of whole tumor antigens that we could use to pulse DCs ex vivo and in vivo. We also discuss the different routes of delivering whole tumor antigens to DCs in vivo and activating them with toll-like receptor agonists.

The precise identification of Human Leukocyte Antigen class I (HLA-I) binding motifs plays a central role in our ability to understand and predict (neo-)antigen presentation in infectious diseases and cancer. Here, by exploiting co-occurrence of HLA-I alleles across ten newly generated as well as forty public HLA peptidomics datasets comprising more than 115,000 unique peptides, we show that we can rapidly and accurately identify many HLA-I binding motifs and map them to their corresponding alleles without any a priori knowledge of HLA-I binding specificity. Our approach recapitulates and refines known motifs for 43 of the most frequent alleles, uncovers new motifs for 9 alleles that up to now had less than five known ligands and provides a scalable framework to incorporate additional HLA peptidomics studies in the future. The refined motifs improve neo-antigen and cancer testis antigen predictions, indicating that unbiased HLA peptidomics data are ideal for in silico predictions of neo-antigens from tumor exome sequencing data. The new motifs further reveal distant modulation of the binding specificity at P2 for some HLA-I alleles by residues in the HLA-I binding site but outside of the B-pocket and we unravel the underlying mechanisms by protein structure analysis, mutagenesis and in vitro binding assays.

Abstract Purpose: Whole tumor lysates are promising antigen sources for dendritic cell (DC) therapy as they contain many relevant immunogenic epitopes to help prevent tumor escape. Two common methods of tumor lysate preparations are freeze-thaw processing and UVB irradiation to induce necrosis and apoptosis, respectively. Hypochlorous acid (HOCl) oxidation is a new method for inducing primary necrosis and enhancing the immunogenicity of tumor cells. Experimental Design: We compared the ability of DCs to engulf three different tumor lysate preparations, produce T-helper 1 (TH1)-priming cytokines and chemokines, stimulate mixed leukocyte reactions (MLR), and finally elicit T-cell responses capable of controlling tumor growth in vivo. Results: We showed that DCs engulfed HOCl-oxidized lysate most efficiently stimulated robust MLRs, and elicited strong tumor-specific IFN-γ secretions in autologous T cells. These DCs produced the highest levels of TH1-priming cytokines and chemokines, including interleukin (IL)-12. Mice vaccinated with HOCl-oxidized ID8-ova lysate–pulsed DCs developed T-cell responses that effectively controlled tumor growth. Safety, immunogenicity of autologous DCs pulsed with HOCl-oxidized autologous tumor lysate (OCDC vaccine), clinical efficacy, and progression-free survival (PFS) were evaluated in a pilot study of five subjects with recurrent ovarian cancer. OCDC vaccination produced few grade 1 toxicities and elicited potent T-cell responses against known ovarian tumor antigens. Circulating regulatory T cells and serum IL-10 were also reduced. Two subjects experienced durable PFS of 24 months or more after OCDC. Conclusions: This is the first study showing the potential efficacy of a DC vaccine pulsed with HOCl-oxidized tumor lysate, a novel approach in preparing DC vaccine that is potentially applicable to many cancers. Clin Cancer Res; 19(17); 4801–15. ©2013 AACR.

Group 2 innate lymphoid cells (ILC2s) are involved in human diseases, such as allergy, atopic dermatitis and nasal polyposis, but their function in human cancer remains unclear. Here we show that, in acute promyelocytic leukaemia (APL), ILC2s are increased and hyper-activated through the interaction of CRTH2 and NKp30 with elevated tumour-derived PGD2 and B7H6, respectively. ILC2s, in turn, activate monocytic myeloid-derived suppressor cells (M-MDSCs) via IL-13 secretion. Upon treating APL with all-trans retinoic acid and achieving complete remission, the levels of PGD2, NKp30, ILC2s, IL-13 and M-MDSCs are restored. Similarly, disruption of this tumour immunosuppressive axis by specifically blocking PGD2, IL-13 and NKp30 partially restores ILC2 and M-MDSC levels and results in increased survival. Thus, using APL as a model, we uncover a tolerogenic pathway that may represent a relevant immunosuppressive, therapeutic targetable, mechanism operating in various human tumour types, as supported by our observations in prostate cancer.Group 2 innate lymphoid cells (ILC2s) modulate inflammatory and allergic responses, but their function in cancer immunity is still unclear. Here the authors show that, in acute promyelocytic leukaemia, tumour-activated ILC2s secrete IL-13 to induce myeloid-derived suppressor cells and support tumour growth.

Cancer vaccine development has been vigorously pursued for 40 years. Immunity to tumor antigens can be elicited by most vaccines tested, but their clinical efficacy remains modest. We argue that a concerted international effort is necessary to understand the human antitumor immune response and achieve clinically effective cancer vaccines.

Immune checkpoint inhibitors are reshaping the prognosis of many cancer and are progressively becoming the standard of care in the treatment of many tumour types. Immunotherapy is bringing new hope to patients, but also a whole new spectrum of toxicities for healthcare practitioners to manage. Oncologists and specialists involved in the pluridisciplinary management of patients with cancer are increasingly confronted with the therapeutic challenge of treating patients with severe and refractory immune-related adverse events. In this Personal View, we summarise the therapeutic strategies that have been used to manage such toxicities resulting from immune checkpoint inhibitor treatment. On the basis of current knowledge about their pathogenesis, we discuss the use of new biological and non-biological immunosuppressive drugs to treat severe and steroid refractory immune-related adverse events. Depending on the immune infiltrate type that is predominant, we propose a treatment algorithm for personalised management that goes beyond typical corticosteroid use. We propose a so-called shut-off strategy that aims at inhibiting key inflammatory components involved in the pathophysiological processes of immune-related adverse events, and limits potential adverse effects of drug immunosuppression on tumour response. This approach develops on current guidelines and challenges the step-by-step increase approach to drug immunosuppression.

<h2>Abstract</h2> Adoptive cell therapy (ACT) using autologous tumor-infiltrating lymphocytes (TIL) has been tested in advanced melanoma patients at various centers. We conducted a systematic review and meta-analysis to assess its efficacy on previously treated advanced metastatic cutaneous melanoma. The PubMed electronic database was searched from inception to 17 December 2018 to identify studies administering TIL-ACT and recombinant interleukin-2 (IL-2) following non-myeloablative chemotherapy in previously treated metastatic melanoma patients. Objective response rate (ORR) was the primary end point. Secondary end points were complete response rate (CRR), overall survival (OS), duration of response (DOR) and toxicity. Pooled estimates were derived from fixed or random effect models, depending on the amount of heterogeneity detected. Analysis was carried out separately for high dose (HD) and low dose (LD) IL-2. Sensitivity analyses were carried out. Among 1211 records screened, 13 studies (published 1988 − 2016) were eligible for meta-analysis. Among 410 heavily pretreated patients (some with brain metastasis), 332 received HD-IL-2 and 78 LD-IL-2. The pooled overall ORR estimate was 41% [95% confidence interval (CI) 35% to 48%], and the overall CRR was 12% (95% CI 7% to 16%). For the HD-IL-2 group, the ORR was 43% (95% CI 36% to 50%), while for the LD-IL-2 it was 35% (95% CI 25% to 45%). Corresponding pooled estimates for CRR were 14% (95% CI 7% to 20%) and 7% (95% CI 1% to 12%). The majority of HD-IL-2 complete responders (27/28) remained in remission during the extent of follow-up after CR (median 40 months). Sensitivity analyses yielded similar results. Higher number of infused cells was associated with a favorable response. The ORR for HD-IL-2 compared favorably with the nivolumab/ipilimumab combination following anti-PD-1 failure. TIL-ACT therapy, especially when combined with HD-IL-2, achieves durable clinical benefit and warrants further investigation. We discuss the current position of TIL-ACT in the therapy of advanced melanoma, particularly in the era of immune checkpoint blockade therapy, and review future opportunities for improvement of this approach.

One key barrier to improving efficacy of personalized cancer immunotherapies that are dependent on the tumor antigenic landscape remains patient stratification. Although patients with CD3+CD8+ T cell-inflamed tumors typically show better response to immune checkpoint inhibitors, it is still unknown whether the immunopeptidome repertoire presented in highly inflamed and noninflamed tumors is substantially different. We surveyed 61 tumor regions and adjacent nonmalignant lung tissues from 8 patients with lung cancer and performed deep antigen discovery combining immunopeptidomics, genomics, bulk and spatial transcriptomics, and explored the heterogeneous expression and presentation of tumor (neo)antigens. In the present study, we associated diverse immune cell populations with the immunopeptidome and found a relatively higher frequency of predicted neoantigens located within HLA-I presentation hotspots in CD3+CD8+ T cell-excluded tumors. We associated such neoantigens with immune recognition, supporting their involvement in immune editing. This could have implications for the choice of combination therapies tailored to the patient's mutanome and immune microenvironment.

Abstract The success of cancer immunotherapy depends in part on the strength of antigen recognition by T cells. Here, we characterize the T cell receptor (TCR) functional (antigen sensitivity) and structural (monomeric pMHC-TCR off-rates) avidities of 371 CD8 T cell clones specific for neoantigens, tumor-associated antigens (TAAs) or viral antigens isolated from tumors or blood of patients and healthy donors. T cells from tumors exhibit stronger functional and structural avidity than their blood counterparts. Relative to TAA, neoantigen-specific T cells are of higher structural avidity and, consistently, are preferentially detected in tumors. Effective tumor infiltration in mice models is associated with high structural avidity and CXCR3 expression. Based on TCR biophysicochemical properties, we derive and apply an in silico model predicting TCR structural avidity and validate the enrichment in high avidity T cells in patients’ tumors. These observations indicate a direct relationship between neoantigen recognition, T cell functionality and tumor infiltration. These results delineate a rational approach to identify potent T cells for personalized cancer immunotherapy.

Adoptive cell therapy (ACT) using ex vivo-expanded tumor-infiltrating lymphocytes (TILs) can eliminate or shrink metastatic melanoma, but its long-term efficacy remains limited to a fraction of patients. Using longitudinal samples from 13 patients with metastatic melanoma treated with TIL-ACT in a phase 1 clinical study, we interrogated cellular states within the tumor microenvironment (TME) and their interactions. We performed bulk and single-cell RNA sequencing, whole-exome sequencing, and spatial proteomic analyses in pre- and post-ACT tumor tissues, finding that ACT responders exhibited higher basal tumor cell-intrinsic immunogenicity and mutational burden. Compared with nonresponders, CD8+ TILs exhibited increased cytotoxicity, exhaustion, and costimulation, whereas myeloid cells had increased type I interferon signaling in responders. Cell-cell interaction prediction analyses corroborated by spatial neighborhood analyses revealed that responders had rich baseline intratumoral and stromal tumor-reactive T cell networks with activated myeloid populations. Successful TIL-ACT therapy further reprogrammed the myeloid compartment and increased TIL-myeloid networks. Our systematic target discovery study identifies potential T-myeloid cell network-based biomarkers that could improve patient selection and guide the design of ACT clinical trials.

Overexpression of HER-2/neu (c-erbB2) is associated with increased risk of recurrent disease in ductal carcinoma in situ (DCIS) and a poorer prognosis in node-positive breast cancer. We therefore examined the early immunotherapeutic targeting of HER-2/neu in DCIS. Before surgical resection, HER-2/neu(pos) DCIS patients (n = 13) received 4 weekly vaccinations of dendritic cells pulsed with HER-2/neu HLA class I and II peptides. The vaccine dendritic cells were activated in vitro with IFN-gamma and bacterial lipopolysaccharide to become highly polarized DC1-type dendritic cells that secrete high levels of interleukin-12p70 (IL-12p70). Intranodal delivery of dendritic cells supplied both antigenic stimulation and a synchronized preconditioned burst of IL-12p70 production directly to the anatomic site of T-cell sensitization. Before vaccination, many subjects possessed HER-2/neu-HLA-A2 tetramer-staining CD8(pos) T cells that expressed low levels of CD28 and high levels of the inhibitory B7 ligand CTLA-4, but this ratio inverted after vaccination. The vaccinated subjects also showed high rates of peptide-specific sensitization for both IFN-gamma-secreting CD4(pos) (85%) and CD8(pos) (80%) T cells, with recognition of antigenically relevant breast cancer lines, accumulation of T and B lymphocytes in the breast, and induction of complement-dependent, tumor-lytic antibodies. Seven of 11 evaluable patients also showed markedly decreased HER-2/neu expression in surgical tumor specimens, often with measurable decreases in residual DCIS, suggesting an active process of "immunoediting" for HER-2/neu-expressing tumor cells following vaccination. DC1 vaccination strategies may therefore have potential for both the prevention and the treatment of early breast cancer.

Defects in cell signaling pathways play a central role in cancer cell growth, survival, invasion and metastasis. An important goal of proteomics is to characterize and develop "circuit maps" of these signaling pathways in normal and diseased cells. We have used reverse-phase protein array technology coupled with laser capture microdissection and phospho-specific antibodies to examine the activation status of several key molecular "gates" involved in cell survival and proliferation signaling in human ovarian tumor tissue. The levels of activated extracellular-regulated kinase (ERK1/2) varied considerably in tumors of the same histotype, but no significant differences between histotypes were observed. Advanced stage tumors had slightly higher levels of phosphorylated ERK1/2 compared to early stage tumors. The activation status of Akt and glycogen synthase kinase 3beta, key proteins and indicators of the state of the phosphatidylinositol 3-kinase/Akt pro-survival pathway also showed more variation within each histotype than between the histotypes studied. Our results demonstrate the utility of reverse phase protein microarrays for the multiplexed analysis of signal transduction from discreet cell populations of cells procured directly from human ovarian tumor specimens and suggest that patterns in signal pathway activation in ovarian tumors may be patient-specific rather than type or stage specific.

Although cancer vaccines with defined antigens are commonly used, the use of whole tumor cell preparations in tumor immunotherapy is a very promising approach and can obviate some important limitations in vaccine development. Whole tumor cells are a good source of TAAs and can induce simultaneous CTLs and CD4(+) T helper cell activation. We review current approaches to prepare whole tumor cell vaccines, including traditional methods of freeze-thaw lysates, tumor cells treated with ultraviolet irradiation, and RNA electroporation, along with more recent methods to increase tumor cell immunogenicity with HOCl oxidation or infection with replication-incompetent herpes simplex virus.

Abstract There is no proof that hematopoietic cells contribute significantly to vasculogenesis in postnatal life. Here we report a novel leukocyte subset within ovarian carcinoma that coexpresses endothelial and dendritic cell markers. Fluorescence-activated cell sorter (FACS) analysis identified a high frequency of VE-cadherin+ CD45+ leukocytes (39% of host cells) in 10 of 10 solid tumors evaluated. This population represented less than 1% of nontumor cells in ascites and peripheral blood. At the protein level, more than 86% of these cells expressed the endothelial markers P1H12, CD34, and CD31 and leukocyte markers CD11c and major histocompatibility complex (MHC) class II. At the mRNA level, we detected TEM1, TEM7, and Thy-1, specific markers of angiogenic endothelium. Finally, this population has the capacity to generate functional blood vessels in vivo. Because of its mixed phenotype, we named this population vascular leukocytes (VLCs). Our data provide an important link between hematopoietic endothelial precursors and vascular development in postnatal life and a possible novel therapeutic target.

This study aimed to identify novel ovarian cancer biomarkers and potential therapeutic targets through molecular analysis of tumor vascular cells.Immunohistochemistry-guided laser-capture microdissection and genome-wide transcriptional profiling were used to identify genes that were differentially expressed between vascular cells from human epithelial ovarian cancer and healthy ovaries. Tumor vascular markers (TVMs) were validated through quantitative real-time polymerase chain reaction (qRT-PCR) of immunopurified tumor endothelial cells, in situ hybridization, immunohistochemistry, and Western blot analysis. TVM expression in tumors and noncancerous tissues was assessed by qRT-PCR and was profiled using gene expression data.We identified a tumor vascular cell profile of ovarian cancer that was distinct from the vascular profile of normal ovary and other tumors. We validated 12 novel ovarian TVMs. These were expressed by immunopurified tumor endothelial cells and localized to tumor vasculature. Select TVMs were found to be specifically expressed in ovarian cancer and were absent in all normal tissues tested, including female reproductive tissues with physiologic angiogenesis. Many ovarian TVMs were expressed by a variety of other solid tumors. Finally, overexpression of any one of three ovarian TVMs by vascular cells was associated with decreased disease-free interval (all P < .005).We have identified for the first time the molecular profile of ovarian tumor vasculature. We demonstrate that TVMs may serve as potential biomarkers and molecular targets for ovarian cancer and a variety of other solid tumors.

Metastasis is a complex multistep process, which requires the concerted action of many genes and is the primary cause of cancer death. Both pathways that regulate metastasis enhancement and those that regulate its suppression contribute to the tumour dissemination process. To identify new metastasis suppressors, we set up a forward genetic screen in a mouse model. We transduced a genome-wide RNA interference (RNAi) library into the non-metastatic 168FARN breast cancer cell line and orthotopically transplanted the cells into mouse mammary fat pads. We then selected cells that could metastasize to the lung and identified an RNAi for the KLF17 gene. Conversely, we demonstrate that ectopic expression of KLF17 in a highly metastatic 4T1 breast cancer cell line inhibits the ability of cells to metastasize from the mammary fat pad to the lung. We also show that suppression of KLF17 expression promotes breast cancer cell invasion and epithelial-mesenchymal transition (EMT), and that KLF17 protein functions by directly binding to the promoter region of Id1 (which encodes a key metastasis regulator in breast cancer) to inhibit its transcription. Finally, we demonstrate that KLF17 expression is significantly downregulated in primary human breast cancer samples and that the combined expression pattern of KLF17 and Id1 can serve as a potential biomarker for lymph node metastasis in breast cancer.

Cancer regression by gene-modified T cells bearing a chimeric antigen receptor (CAR) exodomain of mouse origin can be limited by the induction of transgene immunogenicity resulting in poor persistence and function in vivo. The development of functionally-active CAR of human origin can address this issue. Here, we constructed and evaluated fully human anti-mesothelin CARs comprised of a human mesothelin-specific single-chain antibody variable fragment (P4 scFv) coupled to T cell signaling domains. Primary human T cells expressing P4 CAR specifically produced proinflammatory cytokines, degranulated and exerted potent cytolytic functions when cultured with mesothelin-expressing tumors in vitro. P4 CAR T cells also mediated bystander killing of mesothelin-negative cancer cells during coculture. CAR reactivity was not abrogated by soluble tumor-secreted or recombinant mesothelin protein even at supraphysiological levels. Importantly, adoptive transfer of P4 CAR-expressing T cells mediated the regression of large, established tumor in the presence of soluble mesothelin in a xenogenic model of human ovarian cancer. Thus, primary human T cells expressing fully human anti-mesothelin CAR efficiently kill mesothelin-expressing tumors in vitro and in vivo and have the potential to overcome the issue of transgene immunogenicity that may limit CAR T cell trials that utilize scFvs of mouse origin.

MicroRNAs (miRNAs) are approximately 22 nucleotide long, noncoding, endogenous RNA molecules which exert their functions by base pairing with messenger RNAs (mRNAs), thereby regulate protein-coding gene expression. In eukaryotic cells, miRNAs play important roles in regulating biological processes such as proliferation, differentiation, apoptosis, and stem cell self-renewal. The human genome may contain as many as 1,000 miRNAs, and more than 700 of them have been identified. miRNAs are predicted to target up to one third of mRNAs. Each miRNA can target hundreds of transcripts directly or indirectly, while more than one miRNA can converge on a single transcript target. Therefore, the potential regulatory circuitry afforded by miRNA is enormous. Recently, mounting evidence implicates miRNAs as a new class of modulator for human tumor initiation and progression. Therefore, it has been proposed that manipulating miRNA activity and miRNA biogenesis may be a novel avenue for developing efficient therapies against cancer.

The increase in incidence of oral discomfort among women in a menopause is probably due to hormone modifications. This study evaluated the efficacy of hormone replacement therapy in 27 postmenopausal patients, aged 48 to 58 years, with oral discomfort and no local irritants and in 47 postmenopausal women with no oral discomfort. Patients were treated with conjugated estrogens for 21 days and medroxyprogesterone acetate from day 12 through day 21. Hormone-replacement therapy had no effect on oral cytology in the 40 symptom-free postmenopausal women compared with a group of 47 postmenopausal women who had no oral symptoms and were not treated. Hormone-replacement therapy relieved symptoms and improved oral cytohormonal features in 15 of 27 patients with symptoms. Nuclear estrogen receptors were found by immunohistochemical assay in 8 of 10 randomly selected patients with symptoms who responded to hormone-replacement therapy, but not in 2 patients who did not benefit from hormone-replacement therapy. Estrogen receptors were also found in 6 of 10 fertile women with no oral disease. Our results suggest that oral discomfort may be related to steroid hormone withdrawal only in some postmenopausal women and that replacement therapy may improve the clinical picture and cytologic features in this group of patients. Immunohistochemical identification of estrogen receptors may help to identify patients for whom hormone-replacement therapy may be beneficial.

A relatively rare aldehyde dehydrogenase 1 (ALDH1)-positive "stem cell-like" subpopulation of tumor cells has the unique ability to initiate and perpetuate tumor growth; moreover, it is highly resistant to chemotherapy and significantly associated with poor clinical outcomes. The development of more effective therapies for cancer requires targeting of this cell population. Using cDNA microarray analysis, we identified that the expression of the Caenorhabditis elegans lin-28 homologue (LIN28) was positively correlated with the percentage of ALDH1+ tumor cells; this was further validated in an independent set of tissue arrays (n=197). Both loss-of-function and gain-of-function studies showed that LIN28 plays a critical role in the maintenance of ALDH1+ tumor cells. In addition, we found that there is a double-negative feedback loop between LIN28 and let-7 in tumor cells, and that let-7 negatively regulates ALDH1+ tumor cells. Finally, we report that a LIN28/let-7 loop modulates self-renewal and differentiation of mammary gland epithelial progenitor cells. Our data provide evidence that cancer stem cells may arise through a "reprogramming-like" mechanism. A rebalancing of the LIN28/let-7 regulatory loop could be a novel therapeutic strategy to target ALDH1+ cancer stem cells.

LIN28 (a homologue of the Caenorhabditis elegans lin-28 gene) is an evolutionarily conserved RNA-binding protein and a master regulator controlling the pluripotency of embryonic stem cells. Together with OCT4, SOX2, and NANOG, LIN28 can reprogram somatic cells, producing induced pluripotent stem cells. Expression of LIN28 is highly restricted to embryonic stem cells and developing tissues. In human tumors, LIN28 is up-regulated and functions as an oncogene promoting malignant transformation and tumor progression. However, the mechanisms of transcriptional and post-transcriptional regulation of LIN28 are still largely unknown. To examine microRNAs (miRNAs) that repress LIN28 expression, a combined in silico prediction and miRNA library screening approach was used in the present study. Four miRNAs directly regulating LIN28 (let-7, mir-125, mir-9, and mir-30) were initially identified by this approach and further validated by quantitative RT-PCR, Western blot analysis, and a LIN28 3'-UTR reporter assay. We found that expression levels of these four miRNAs were clustered together and inversely correlated with LIN28 expression during embryonic stem cell differentiation. In addition, the expression of these miRNAs was remarkably lower in LIN28-positive tumor cells compared with LIN28-negative tumor cells. Importantly, we demonstrated that these miRNAs were able to regulate the expression and activity of let-7, mediated by LIN28. Taken together, our studies demonstrate that miRNAs let-7, mir-125, mir-9, and mir-30 directly repress LIN28 expression in embryonic stem and cancer cells. Global down-regulation of these miRNAs may be one of the mechanisms of LIN28 reactivation in human cancers.

Scientific discoveries that provide strong evidence of antitumor effects in preclinical models often encounter significant delays before being tested in patients with cancer. While some of these delays have a scientific basis, others do not. We need to do better. Innovative strategies need to move into early stage clinical trials as quickly as it is safe, and if successful, these therapies should efficiently obtain regulatory approval and widespread clinical application. In late 2009 and 2010 the Society for Immunotherapy of Cancer (SITC), convened an "Immunotherapy Summit" with representatives from immunotherapy organizations representing Europe, Japan, China and North America to discuss collaborations to improve development and delivery of cancer immunotherapy. One of the concepts raised by SITC and defined as critical by all parties was the need to identify hurdles that impede effective translation of cancer immunotherapy. With consensus on these hurdles, international working groups could be developed to make recommendations vetted by the participating organizations. These recommendations could then be considered by regulatory bodies, governmental and private funding agencies, pharmaceutical companies and academic institutions to facilitate changes necessary to accelerate clinical translation of novel immune-based cancer therapies. The critical hurdles identified by representatives of the collaborating organizations, now organized as the World Immunotherapy Council, are presented and discussed in this report. Some of the identified hurdles impede all investigators; others hinder investigators only in certain regions or institutions or are more relevant to specific types of immunotherapy or first-in-humans studies. Each of these hurdles can significantly delay clinical translation of promising advances in immunotherapy yet if overcome, have the potential to improve outcomes of patients with cancer.

Novel strategies for the therapy of recurrent ovarian cancer are warranted. We report a study of a combinatorial approach encompassing dendritic cell (DC)-based autologous whole tumor vaccination and anti-angiogenesis therapy, followed by the adoptive transfer of autologous vaccine-primed CD3/CD28-co-stimulated lymphocytes. Recurrent ovarian cancer patients for whom tumor lysate was available from prior cytoreductive surgery underwent conditioning with intravenous bevacizumab and oral metronomic cyclophosphamide, sequentially followed by (1) bevacizumab plus vaccination with DCs pulsed with autologous tumor cell lysate supernatants, (2) lymphodepletion and (3) transfer of 5 × 109 autologous vaccine-primed T-cells in combination with the vaccine. Feasibility, safety as well as immunological and clinical efficacy were evaluated. Six subjects received this vaccination. Therapy was feasible, well tolerated, and elicited antitumor immune responses in four subjects, who also experienced clinical benefits. Of these, three patients with residual measurable disease received outpatient lymphodepletion and adoptive T-cell transfer, which was well tolerated and resulted in a durable reduction of circulating regulatory T cells and increased CD8+ lymphocyte counts. The vaccine-induced restoration of antitumor immunity was achieved in two subjects, who also demonstrated clinical benefits, including one complete response. Our findings indicate that combinatorial cellular immunotherapy for the treatment of recurrent ovarian cancer is well tolerated and warrants further investigation. Several modifications of this approach can be envisioned to optimize immunological and clinical outcomes.

Humans and other mammals are colonized by microbial agents across the kingdom which can represent a unique microbiome pattern.Dysbiosis of the microbiome has been associated with pathology including cancer.We have identified a microbiome signature unique to ovarian cancers, one of the most lethal malignancies of the female reproductive system, primarily because of its asymptomatic nature during the early stages in development.We screened ovarian cancer samples along with matched, and non-matched control samples using our pan-pathogen array (PathoChip), combined with capture-next generation sequencing.The results show a distinct group of viral, bacterial, fungal and parasitic signatures of high significance in ovarian cases.Further analysis shows specific viral integration sites within the host genome of tumor samples, which may contribute to the carcinogenic process.The ovarian cancer microbiome signature provides insights for the development of targeted therapeutics against ovarian cancers.

A gold electrode decorated with gold nanoparticles, CdSe quantum dots and anti-CA-125 antibody (MPA|AuNP@SiO₂|QD|mAb immunosensor) sensitively specifically detects the CA-125 oncomarker.

In the past decade, we have witnessed important gains in the treatment of ovarian cancer; however, additional advances are required to reduce mortality. With compelling evidence that ovarian cancers are immunogenic tumors, immunotherapy should be further pursued and optimized. The dramatic advances in laboratory and clinical procedures in cellular immunotherapy, along with the development of powerful immunomodulatory antibodies, create new opportunities in ovarian cancer therapeutics. Herein, we review current progress and future prospects in vaccine and adoptive T-cell therapy development as well as immunomodulatory therapy tools available for immediate clinical testing.

Whereas preclinical investigations and clinical studies have established that CD8+ T cells can profoundly affect cancer progression, the underlying mechanisms are still elusive. Challenging the prevalent view that the beneficial effect of CD8+ T cells in cancer is solely attributable to their cytotoxic activity, several reports have indicated that the ability of CD8+ T cells to promote tumor regression is dependent on their cytokine secretion profile and their ability to self-renew. Evidence has also shown that the tumor microenvironment can disarm CD8+ T cell immunity, leading to the emergence of dysfunctional CD8+ T cells. The existence of different types of CD8+ T cells in cancer calls for a more precise definition of the CD8+ T cell immune phenotypes in cancer and the abandonment of the generic terms “pro-tumor” and “antitumor.” Based on recent studies investigating the functions of CD8+ T cells in cancer, we here propose some guidelines to precisely define the functional states of CD8+ T cells in cancer.

The antigenic landscape of tumors is distinct from healthy cells and has been the rationale behind a variety of vaccination trials. Typically the target tumor-associated antigens have been of self origin and have rarely induced effective anti-tumor responses. Recent data show that activation of the immune system by immune checkpoint blocking therapies leads to tumor rejection and that recognition of mutated antigens, known as ‘neo-antigens’ plays a key role. Discovery of neo-antigens relies mainly on prediction-based interrogation of the ‘mutanome’ using genomic information as input, followed by T-cell screening. Recent breakthroughs in mass spectrometry (MS) based immunopeptidomics have allowed the discovery of very large pools of naturally presented peptides, among them neo-epitopes. This review highlights the current progress related to neo-antigens discovery with emphasis on prediction algorithms and MS as well as the synergy of the two methodologies and how they can be exploited to develop effective personalized immunotherapy.

Complement activation plays a critical role in controlling inflammatory responses. To assess the role of complement during ovarian cancer progression, we crossed two strains of mice with genetic complement deficiencies with transgenic mice that develop epithelial ovarian cancer (TgMISIIR-TAg). TgMISIIR-TAg mice fully or partially deficient for complement factor 3 (C3) (Tg+C3KO and Tg+C3HET, respectively) or fully deficient for complement factor C5a receptor (C5aR) (Tg+C5aRKO) develop either no ovarian tumors or tumors that were small and poorly vascularized compared to wild-type littermates (Tg+C3WT, Tg+C5aRWT). The percentage of tumor infiltrating immune cells in Tg+C3HET tumors compared to Tg+C3WT controls was either similar (macrophages, B cells, myeloid-derived suppressor cells), elevated (effector T cells), or decreased (regulatory T cells). Regardless of these ratios, cytokine production by immune cells taken from Tg+C3HET tumors was reduced on stimulation compared to Tg+C3WT controls. Interestingly, CD31+ endothelial cell (EC) function in angiogenesis was significantly impaired in both C3KO and C5aRKO mice. Further, using the C5aR antagonist PMX53, tube formation of ECs was shown to be C5a-dependent, possibly through interactions with the VEGF165 but not VEGF121 isoform. Finally, the mouse VEGF164 transcript was underexpressed in C3KO livers compare to C3WT livers. Thus, we conclude that complement inhibition blocks tumor outgrowth by altering EC function and VEGF165 expression.

In spite of increased rates of complete response to initial chemotherapy, most patients with advanced ovarian cancer relapse and succumb to progressive disease.Genetically reprogrammed, patient-derived chimeric antigen receptor (CAR)-T lymphocytes with the ability to recognize predefined surface antigens with high specificity in a non-MHC restricted manner have shown increasing anti-tumor efficacy in preclinical and clinical studies. Folate receptor-α (FRα) is an ovarian cancer-specific tumor target; however, it is expressed at low levels in certain organs with risk for toxicity.Here we propose a phase I study testing the feasibility, safety and preliminary activity of FRα-redirected CAR-T cells bearing the CD137 (4-1BB) costimulatory domain, administered after lymphodepletion for the treatment of recurrent ovarian cancer. A novel trial design is proposed that maximizes safety features.This design involves an initial accelerated dose escalation phase of FR-α CAR-T cells followed by a standard 3 + 3 escalation phase. A split-dose approach is proposed to mitigate acute adverse events. Furthermore, infusion of bulk untransduced autologous peripheral blood lymphocytes (PBL) is proposed two days after CAR-T cell infusion at the lower dose levels of CAR-T cells, to suppress excessive expansion of CAR-T cells in vivo and mitigate toxicity.

Magnetic nanoparticles (MNPs) have been widely used as drug delivery nanosystems and contrast agent for imaging and detection. To engineer multifunctional nanomedicines for simultaneous imaging and therapy of cancer cells, in the current study, we synthesized tamoxifen (TMX) loaded folic acid (FA) armed MNPs to target the folate receptor (FR) positive cancer cells. To this end, Fe3O4 nanoparticles (NPs) were synthesized through thermal decomposition of Fe(acac)3. Polyethylene glycol (PEG) was treated with excess bromoacetyl chloride (BrAc) and then with 3-aminopropyltriethoxysilane (APS) to synthesize bromoacetyl-terminal polyethylene glycol silane (APS-PEG-BrAc). The latter complex was treated with protected ethylene diamine to form a bifunctional PEG compound containing triethoxysilane at one end and amino group at the other end (APS-PEG-NH2). The Fe3O4-APS-PEG-NH2 NPs were prepared through self-assembly of APS-PEG-NH2 on MNPs, while the amino groups at the end of Fe3O4-APS-PEG-NH2 were conjugated with folic acid (FA), then loaded with TMX (Fe3O4-APS-PEG-FA-TMX). The average size of "Fe3O4-APS-PEG-FA-TMX" NPs was approximately 40 nm. The engineered MNPs were further characterized and examined in the human breast cancer MCF-7 cells that express FR. The TMX loaded MNPs (with loading efficiency of 49.1%) showed sustained liberation of TMX molecules (with 90% release in 72 h). Fluorescence microcopy and flow cytometry analyses revealed substantial interaction of Fe3O4-APS-PEG-FA-TMX NPs with the FR-positive MCF-7 cells. Cytotoxicity analysis resulted in significant growth inhibition in MCF-7 cells treated with Fe3O4-APS-PEG-FA-TMX NPs. Based on these findings, the TMX-loaded FA-armed PEGylated MNPs as a novel multifunctional nanomedicine/theranostic for concurrent targeting, imaging and therapy of the FR-positive cancer cells.

Phage display technology (PDT), a combinatorial screening approach, provides a molecular diversity tool for creating libraries of peptides/proteins and discovery of new recombinant therapeutics. Expression of proteins such as monoclonal antibodies (mAbs) on the surface of filamentous phage can permit the selection of high affinity and specificity therapeutic mAbs against virtually any target antigen. Using a number of diverse selection platforms (e.g. solid phase, solution phase, whole cell and in vivo biopannings), phage antibody libraries (PALs) from the start point provides great potential for the isolation of functional mAb fragments with diagnostic and/or therapeutic purposes. Given the pivotal role of PDT in the discovery of novel therapeutic/diagnostic mAbs, in the current review, we provide an overview on PALs and discuss their impact in the advancement of engineered mAbs.

Introduction: Brain tumors are inherently difficult to treat in large part due to the cellular blood–brain barriers (BBBs) that limit the delivery of therapeutics to the tumor tissue from the systemic circulation. Virtually no large molecules, including antibody-based proteins, can penetrate the BBB. With antibodies fast becoming attractive ligands for highly specific molecular targeting to tumor antigens, a variety of methods are being investigated to enhance the access of these agents to intracranial tumors for imaging or therapeutic applications. Areas covered: This review describes the characteristics of the BBB and the vasculature in brain tumors, described as the blood–brain tumor barrier (BBTB). Antibodies targeted to molecular markers of central nervous system (CNS) tumors will be highlighted, and current strategies for enhancing the delivery of antibodies across these cellular barriers into the brain parenchyma to the tumor will be discussed. Noninvasive imaging approaches to assess BBB/BBTB permeability and/or antibody targeting will be presented as a means of guiding the optimal delivery of targeted agents to brain tumors. Expert opinion: Preclinical and clinical studies highlight the potential of several approaches in increasing brain tumor delivery across the BBB divide. However, each carries its own risks and challenges. There is tremendous potential in using neuroimaging strategies to assist in understanding and defining the challenges to translating and optimizing molecularly targeted antibody delivery to CNS tumors to improve clinical outcomes.

Abstract Aberrant blood vessels enable tumor growth, provide a barrier to immune infiltration, and serve as a source of protumorigenic signals. Targeting tumor blood vessels for destruction, or tumor vascular disruption therapy, can therefore provide significant therapeutic benefit. Here, we describe the ability of chimeric antigen receptor (CAR)–bearing T cells to recognize human prostate–specific membrane antigen (hPSMA) on endothelial targets in vitro as well as in vivo. CAR T cells were generated using the anti-PSMA scFv, J591, and the intracellular signaling domains: CD3ζ, CD28, and/or CD137/4-1BB. We found that all anti-hPSMA CAR T cells recognized and eliminated PSMA+ endothelial targets in vitro, regardless of the signaling domain. T cells bearing the third-generation anti-hPSMA CAR, P28BBζ, were able to recognize and kill primary human endothelial cells isolated from gynecologic cancers. In addition, the P28BBζ CAR T cells mediated regression of hPSMA-expressing vascular neoplasms in mice. Finally, in murine models of ovarian cancers populated by murine vessels expressing hPSMA, the P28BBζ CAR T cells were able to ablate PSMA+ vessels, cause secondary depletion of tumor cells, and reduce tumor burden. Taken together, these results provide a strong rationale for the use of CAR T cells as agents of tumor vascular disruption, specifically those targeting PSMA. Cancer Immunol Res; 3(1); 68–84. ©2014 AACR.

Limited clinical benefit has been demonstrated for chimeric antigen receptor (CAR) therapy of solid tumors, but coengineering strategies to generate so-called fourth-generation (4G) CAR-T cells are advancing toward overcoming barriers in the tumor microenvironment (TME) for improved responses. In large part due to technical challenges, there are relatively few preclinical CAR therapy studies in immunocompetent, syngeneic tumor-bearing mice. Here, we describe optimized methods for the efficient retroviral transduction and expansion of murine T lymphocytes of a predominantly central memory T cell (TCM cell) phenotype. We present a bicistronic retroviral vector encoding both a tumor vasculature–targeted CAR and murine interleukin-15 (mIL-15), conferring enhanced effector functions, engraftment, tumor control, and TME reprogramming, including NK cell activation and reduced presence of M2 macrophages. The 4G-CAR-T cells coexpressing mIL-15 were further characterized by up-regulation of the antiapoptotic marker Bcl-2 and lower cell-surface expression of the inhibitory receptor PD-1. Overall, this work introduces robust tools for the development and evaluation of 4G-CAR-T cells in immunocompetent mice, an important step toward the acceleration of effective therapies reaching the clinic.

To date, no immunotherapy approaches have managed to fully overcome T-cell exhaustion, which remains a mandatory fate for chronically activated effector cells and a major therapeutic challenge. Understanding how to reprogram CD8+ tumor-infiltrating lymphocytes away from exhausted effector states remains an elusive goal. Our work provides evidence that orthogonal gene engineering of T cells to secrete an interleukin (IL)-2 variant binding the IL-2Rβγ receptor and the alarmin IL-33 reprogrammed adoptively transferred T cells to acquire a novel, synthetic effector state, which deviated from canonical exhaustion and displayed superior effector functions. These cells successfully overcame homeostatic barriers in the host and led-in the absence of lymphodepletion or exogenous cytokine support-to high levels of engraftment and tumor regression. Our work unlocks a new opportunity of rationally engineering synthetic CD8+ T-cell states endowed with the ability to avoid exhaustion and control advanced solid tumors.

Abstract Expansion of antigen-experienced CD8 + T cells is critical for the success of tumour-infiltrating lymphocyte (TIL)-adoptive cell therapy (ACT) in patients with cancer 1 . Interleukin-2 (IL-2) acts as a key regulator of CD8 + cytotoxic T lymphocyte functions by promoting expansion and cytotoxic capability 2,3 . Therefore, it is essential to comprehend mechanistic barriers to IL-2 sensing in the tumour microenvironment to implement strategies to reinvigorate IL-2 responsiveness and T cell antitumour responses. Here we report that prostaglandin E2 (PGE 2 ), a known negative regulator of immune response in the tumour microenvironment 4,5 , is present at high concentrations in tumour tissue from patients and leads to impaired IL-2 sensing in human CD8 + TILs via the PGE 2 receptors EP2 and EP4. Mechanistically, PGE 2 inhibits IL-2 sensing in TILs by downregulating the IL-2Rγ c chain, resulting in defective assembly of IL-2Rβ–IL2Rγ c membrane dimers. This results in impaired IL-2–mTOR adaptation and PGC1α transcriptional repression, causing oxidative stress and ferroptotic cell death in tumour-reactive TILs. Inhibition of PGE 2 signalling to EP2 and EP4 during TIL expansion for ACT resulted in increased IL-2 sensing, leading to enhanced proliferation of tumour-reactive TILs and enhanced tumour control once the cells were transferred in vivo. Our study reveals fundamental features that underlie impairment of human TILs mediated by PGE 2 in the tumour microenvironment. These findings have therapeutic implications for cancer immunotherapy and cell therapy, and enable the development of targeted strategies to enhance IL-2 sensing and amplify the IL-2 response in TILs, thereby promoting the expansion of effector T cells with enhanced therapeutic potential.

Vascular endothelial growth factor (VEGF) performs multifaceted functions in the tumor microenvironment promoting angiogenesis, suppressing anti-tumor immune response, and possibly exerting autocrine functions on tumor cells. However, appropriate syngeneic animal models for in vivo studies are lacking. Using retroviral transfection and fluorescence-activated cell sorting, we generated a C57BL6 murine ovarian carcinoma cell line that stably overexpresses the murine VEGF164 isoform and the enhanced green fluorescent protein. VEGF164 overexpression dramatically accelerated tumor growth and ascites formation, significantly enhanced tumor angiogenesis, and substantially promoted the survival of tumor cells in vivo. In vitro, VEGF164 overexpression significantly enhanced cell survival after growth factor withdrawal and conferred resistance to apoptosis induced by cis-platin through an autocrine mechanism. VEGF/green fluorescent protein-expressing tumors were not recognized by the adaptive immune system. After vaccination, a specific anti-tumor T-cell response was detected, but tumor growth was not inhibited. This engineered murine carcinoma model should prove useful in the investigation of the role of VEGF in modulating the tumor microenvironment and affecting the complex interactions among angiogenesis mechanisms, anti-tumor immune mechanisms, and tumor cell behavior at the natural state or during therapy in ovarian carcinoma.

CD44, a cell-surface receptor for hyaluronan, has been implicated in endothelial cell functions, but its role in the formation of blood vessels in vivo has not been established. In CD44-null mice, vascularization of Matrigel implants and tumor and wound angiogenesis were inhibited. Leukocyte accumulation during tumor growth and wound healing in wild-type and CD44-null mice were comparable, and reconstitution of CD44-null mice with wild-type bone marrow did not restore the wild-type phenotype, suggesting that impairments in angiogenesis in CD44-deficient mice are due to the loss of endothelial CD44. Although the cell proliferation, survival, and wound-induced migration of CD44-null endothelial cells were intact, these cells were impaired in their in vitro ability to form tubes. Nascent vessels in Matrigel implants from CD44-null mice demonstrated irregular luminal surfaces characterized by retracted cells and thinned endothelia. Further, an anti-CD44 antibody that disrupted in vitro tube formation induced hemorrhage around Matrigel implants, suggesting that antagonism of endothelial CD44 undermined the integrity of the endothelium of nascent vessels. These data establish a role for CD44 during in vivo angiogenesis and suggest that CD44 may contribute to the organization and/or stability of developing endothelial tubular networks. CD44, a cell-surface receptor for hyaluronan, has been implicated in endothelial cell functions, but its role in the formation of blood vessels in vivo has not been established. In CD44-null mice, vascularization of Matrigel implants and tumor and wound angiogenesis were inhibited. Leukocyte accumulation during tumor growth and wound healing in wild-type and CD44-null mice were comparable, and reconstitution of CD44-null mice with wild-type bone marrow did not restore the wild-type phenotype, suggesting that impairments in angiogenesis in CD44-deficient mice are due to the loss of endothelial CD44. Although the cell proliferation, survival, and wound-induced migration of CD44-null endothelial cells were intact, these cells were impaired in their in vitro ability to form tubes. Nascent vessels in Matrigel implants from CD44-null mice demonstrated irregular luminal surfaces characterized by retracted cells and thinned endothelia. Further, an anti-CD44 antibody that disrupted in vitro tube formation induced hemorrhage around Matrigel implants, suggesting that antagonism of endothelial CD44 undermined the integrity of the endothelium of nascent vessels. These data establish a role for CD44 during in vivo angiogenesis and suggest that CD44 may contribute to the organization and/or stability of developing endothelial tubular networks. Hyaluronan (HA), an important glycosaminoglycan constituent of the extracellular matrix, is composed of repeating disaccharide units of d-glucuronic acid and N-acetyl-d-glucosamine.1Laurent TC Fraser JR Hyaluronan.FASEB J. 1992; 6: 2397-2404Crossref PubMed Scopus (2066) Google Scholar This widely distributed molecule regulates cellular events such as cell proliferation and locomotion that are required for a variety of biological processes, including morphogenesis, tumorigenesis, inflammation, and host responses to injury (reviewed in Ref. 2Savani RC DeLisser Hyaluronan and its receptors in lung health and disease.in: Garg HG Roughley PJ Hales CA Proteoglycans in Lung Disease. Marcel Dekker, Inc., New York2002: 73-106Google Scholar). HA has also been implicated in the formation of vessels, but its effects on in vivo angiogenesis and endothelial cell (EC) function are complex and depend on HA concentration and molecular size.3Rooney P Kumar S Ponting J Wang M The role of hyaluronan in tumour neovascularization.Int J Cancer. 1995; 60: 632-636Crossref PubMed Scopus (258) Google Scholar High molecular weight HA (at concentrations of >100 μg/ml) inhibits EC proliferation and disrupts confluent endothelial monolayers.4West DC Kumar S The effect of hyaluronate and its oligosaccharides on endothelial cell proliferation and monolayer integrity.Exp Cell Res. 1989; 183: 179-196Crossref PubMed Scopus (308) Google Scholar These findings are consistent with the fact that avascular regions in chick embryo limb buds are rich in native high molecular weight HA and that expression of this form of HA in normally vascular areas results in decreased vascularity.5Feinberg RN Beebe DC Hyaluronate in vasculogenesis.Science. 1983; 220: 1177-1179Crossref PubMed Scopus (299) Google Scholar In contrast, low molecular weight HA stimulates EC proliferation,4West DC Kumar S The effect of hyaluronate and its oligosaccharides on endothelial cell proliferation and monolayer integrity.Exp Cell Res. 1989; 183: 179-196Crossref PubMed Scopus (308) Google Scholar, 6Slevin M Kumar S Gaffney J Angiogenic oligosaccharides of hyaluronan induce multiple signaling pathways affecting vascular endothelial cell mitogenic and wound healing responses.J Biol Chem. 2002; 277: 41046-41059Crossref PubMed Scopus (278) Google Scholar wound-induced migration,6Slevin M Kumar S Gaffney J Angiogenic oligosaccharides of hyaluronan induce multiple signaling pathways affecting vascular endothelial cell mitogenic and wound healing responses.J Biol Chem. 2002; 277: 41046-41059Crossref PubMed Scopus (278) Google Scholar in vitro endothelial tube formation,7Rahmanian M Pertoft H Kanda S Christofferson R Claesson-Welsh L Heldin P Hyaluronan oligosaccharides induce tube formation of a brain endothelial cell line in vitro.Exp Cell Res. 1997; 237: 223-230Crossref PubMed Scopus (65) Google Scholar and neovascularization in chick chorioallantoic membranes8West DC Hampson IN Arnold F Kumar S Angiogenesis induced by degradation products of hyaluronic acid.Science. 1985; 228: 1324-1326Crossref PubMed Scopus (972) Google Scholar and cutaneous wounds.9Sattar A Rooney P Kumar S Pye D West DC Scott I Ledger P Application of angiogenic oligosaccharides of hyaluronan increases blood vessel numbers in rat skin.J Invest Dermatol. 1994; 103: 576-579Abstract Full Text PDF PubMed Scopus (155) Google Scholar, 10Lees VC Fan TP West DC Angiogenesis in a delayed revascularization model is accelerated by angiogenic oligosaccharides of hyaluronan.Lab Invest. 1995; 73: 259-266PubMed Google Scholar HA mediates its biological effects through binding interactions with specific cell-associated receptors.11Sherman L Sleeman J Herrlich P Ponta H Hyaluronate receptors: key players in growth, differentiation, migration and tumor progression.Curr Opin Cell Biol. 1994; 6: 726-733Crossref PubMed Scopus (381) Google Scholar A number of HA-binding proteins (so-called hyaladherins) have been identified, with CD44 and Receptor for HA-Mediated Motility (RHAMM) being the two best characterized cell-surface receptors for HA.2Savani RC DeLisser Hyaluronan and its receptors in lung health and disease.in: Garg HG Roughley PJ Hales CA Proteoglycans in Lung Disease. Marcel Dekker, Inc., New York2002: 73-106Google Scholar Although several other binding interactions for CD44 and RHAMM have been reported,12Naor D Sionov RV Ish-Shalom D CD44: structure, function, and association with the malignant process.Adv Cancer Res. 1997; 71: 241-319Crossref PubMed Google Scholar, 13Yang B Hall CL Yang BL Savani RC Turley EA Identification of a novel heparin binding domain in RHAMM and evidence that it modifies HA mediated locomotion of ras-transformed cells.J Cell Biochem. 1994; 56: 455-468Crossref PubMed Scopus (35) Google Scholar currently their interactions with HA appear to be the ones most likely to directly activate intracellular signals required to stimulate processes relevant to angiogenesis.14Turley EA Noble PW Bourguignon LY Signaling properties of hyaluronan receptors.J Biol Chem. 2002; 277: 4589-4592Crossref PubMed Scopus (872) Google Scholar With respect to EC functions, previous studies have implicated CD44 in EC proliferation, migration, and adhesion to HA; RHAMM in EC motility; and both receptors in EC tube formation.15Trochon V Mabilat C Bertrand P Legrand Y Smadja-Joffe F Soria C Delpech B Lu H Evidence of involvement of CD44 in endothelial cell proliferation, migration and angiogenesis in vitro.Int J Cancer. 1996; 66: 664-668Crossref PubMed Scopus (198) Google Scholar, 16Savani RC Cao G Pooler PM Zaman A Zhou Z DeLisser HM Differential involvement of the hyaluronan (HA) receptors CD44 and receptor for HA-mediated motility in endothelial cell function and angiogenesis.J Biol Chem. 2001; 276: 36770-36778Crossref PubMed Scopus (284) Google Scholar, 17Singleton PA Bourguignon LY CD44v10 interaction with Rho-kinase (ROK) activates inositol 1,4,5-triphosphate (IP3) receptor-mediated Ca2+ signaling during hyaluronan (HA)-induced endothelial cell migration.Cell Motil Cytoskeleton. 2002; 53: 293-316Crossref PubMed Scopus (71) Google Scholar, 18Rahmanian M Heldin P Testicular hyaluronidase induces tubular structures of endothelial cells grown in three-dimensional collagen gel through a CD44-mediated mechanism.Int J Cancer. 2002; 97: 601-607Crossref PubMed Scopus (26) Google Scholar, 19Abecassis I Olofsson B Schmid M Zalcman G Karniguian A RhoA induces MMP-9 expression at CD44 lamellipodial focal complexes and promotes HMEC-1 cell invasion.Exp Cell Res. 2003; 291: 363-376Crossref PubMed Scopus (87) Google Scholar, 20Forster-Horvath C Meszaros L Raso E Dome B Ladanyi A Morini M Albini A Timar J Expression of CD44v3 protein in human endothelial cells in vitro and in tumoral microvessels in vivo.Microvasc Res. 2004; 68: 110-118Crossref PubMed Scopus (33) Google Scholar, 21Pall T Gad A Kasak L Drews M Stromblad S Kogerman P Recombinant CD44-HABD is a novel and potent direct angiogenesis inhibitor enforcing endothelial cell-specific growth inhibition independently of hyaluronic acid binding.Oncogene. 2004; 23: 7874-7881Crossref PubMed Scopus (10) Google Scholar, 22Murphy JF Lennon F Steele C Kelleher D Fitzgerald D Long AC Engagement of CD44 modulates cyclooxygenase induction, VEGF generation, and proliferation in human vascular endothelial cells.FASEB J. 2005; 19: 446-448Crossref PubMed Scopus (59) Google Scholar Although there is evidence for the activity of RHAMM during in vivo angiogenesis,16Savani RC Cao G Pooler PM Zaman A Zhou Z DeLisser HM Differential involvement of the hyaluronan (HA) receptors CD44 and receptor for HA-mediated motility in endothelial cell function and angiogenesis.J Biol Chem. 2001; 276: 36770-36778Crossref PubMed Scopus (284) Google Scholar the involvement of CD44 in the formation of blood vessels has not been established.16Savani RC Cao G Pooler PM Zaman A Zhou Z DeLisser HM Differential involvement of the hyaluronan (HA) receptors CD44 and receptor for HA-mediated motility in endothelial cell function and angiogenesis.J Biol Chem. 2001; 276: 36770-36778Crossref PubMed Scopus (284) Google Scholar We therefore investigated in vivo angiogenesis in CD44-null mice and found that vascularization of subcutaneous Matrigel (Collaborative Biomedical Products, Bedford, MA) plugs, as well as tumor and wound angiogenesis, was inhibited in CD44-null animals. Leukocyte recruitment during tumor growth and wound healing in wild-type and CD44-null mice were similar, and reconstitution of CD44-deficient mice with wild-type bone marrow did not restore the wild-type phenotype, suggesting that impairments in angiogenesis in CD44-null mice result from the absence of endothelial and not leukocyte CD44. ECs were isolated from wild-type and CD44-null mice. Although the cell proliferation, survival, and wound-induced migration of the CD44-null ECs were intact, these cells were impaired in their in vitro ability to form tubes on Matrigel as compared to wild-type EC controls. Electron microscopic analysis of Matrigel implants in the CD44-null mice revealed nascent vessels with irregular luminal surfaces characterized by retracted cells and thinned endothelia. Treatment of wild-type mice with an anti-CD44 antibody that disrupted in vitro tube formation induced vessel hemorrhage around subcutaneous Matrigel implants, suggesting that antagonism of endothelial CD44 undermined the integrity of the endothelium of nascent vessels. These data establish for the first time the involvement CD44 in the in vivo formation of blood vessels and suggest that CD44 may be involved in morphological events required for the organization and/or stability of endothelial tubular networks during in vivo angiogenesis. All reagents and chemicals were obtained from Sigma-Aldrich (St. Louis, MO) unless otherwise specified. The following antibodies against murine surface receptors were used: IM7.8.1,22Murphy JF Lennon F Steele C Kelleher D Fitzgerald D Long AC Engagement of CD44 modulates cyclooxygenase induction, VEGF generation, and proliferation in human vascular endothelial cells.FASEB J. 2005; 19: 446-448Crossref PubMed Scopus (59) Google Scholar a rat anti-CD44 antibody from American Type Culture Collection (Rockville, MD); 390, rat anti-PECAM-1 antibody,23Zhou Z Christofidou-Solomidou M Garlanda C DeLisser HM Antibody against murine PECAM-1 inhibits tumor angiogenesis in mice.Angiogenesis. 1999; 3: 181-188Crossref PubMed Scopus (69) Google Scholar and F4/80 antibody against murine macrophages (Serotec, Raleigh, NC); anti-ICAM-2 antibody (Southern Biotech, Birmingham, AL); anti-murine CD11b antibody (Chemicon, Temecula, CA) and anti-CD8 and anti-CD45 antibodies (BD Pharmingen, San Jose, CA). Cell-surface antibody binding was determined by fluorescence-activated cell sorting (FACS) analysis using previously described procedures.16Savani RC Cao G Pooler PM Zaman A Zhou Z DeLisser HM Differential involvement of the hyaluronan (HA) receptors CD44 and receptor for HA-mediated motility in endothelial cell function and angiogenesis.J Biol Chem. 2001; 276: 36770-36778Crossref PubMed Scopus (284) Google Scholar The H5V murine EC line,23Zhou Z Christofidou-Solomidou M Garlanda C DeLisser HM Antibody against murine PECAM-1 inhibits tumor angiogenesis in mice.Angiogenesis. 1999; 3: 181-188Crossref PubMed Scopus (69) Google Scholar B16 murine melanoma line (obtained from the American Type Culture Collection) and ID8-VEGF (vascular endothelial growth factor) tumor line, developed in the laboratory of Dr. George Coukos,24Zhang L Yang N Garcia JR Mohamed A Benencia F Rubin SC Allman D Coukos G Generation of a syngeneic mouse model to study the effects of vascular endothelial growth factor in ovarian carcinoma.Am J Pathol. 2002; 161: 2295-2309Abstract Full Text Full Text PDF PubMed Scopus (117) Google Scholar were cultured in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum, penicillin/streptomycin, and 2 mmol/L l-glutamine, with insulin also added to the medium for the culturing of the ID8-VEGF cells. Lung ECs were isolated immunomagnetically from wild-type and CD44-null mice using published protocols25Bowden RA Ding ZM Donnachie EM Petersen TK Michael LH Ballantyne CM Burns AR Role of alpha4 integrin and VCAM-1 in CD18-independent neutrophil migration across mouse cardiac endothelium.Circ Res. 2002; 90: 562-569Crossref PubMed Scopus (96) Google Scholar and were cultured in EGM-2 MV medium from Cambrex Bioscience Inc. (Walkersville, MD). The Institutional Animal Care and Utilization Committees at both the Wistar Institute and the University of Pennsylvania School of Medicine approved all animal care procedures. CD44-null mice, on a C57BL/6 background, were the kind gift of Dr. Tak Mak (University of Toronto, Toronto, ON, Canada). Wild-type mice, also on a C57BL/6 background, were obtained from Taconic (Germantown, NY). Wild-type and CD44-null mice in the C57BL/6 background were injected subcutaneously with 0.5 ml of Matrigel containing 1 × 106 B16 melanoma cells to induce the growth of vessels into the gel. After 5 to 7 days, the animals were sacrificed, and the gels were harvested and processed for hemoglobin analysis as a measure of the vascularization the gels. For the antibody studies, four injections (200 μg) of antibody were administered via the tail vein, beginning 2 days after Matrigel implantation. 2 × 106 B16 melanoma or ID8-VEGF ovarian tumor cells in a total volume of 50 μl were injected into wild-type and CD44-null mice. After 14 days (B16 melanoma) or 9 weeks (ID8-VEGF ovarian tumor) the mice were sacrificed, and the tumors were harvested, measured, and processed for staining. Wounding was performed as previously described.26Livant DL Brabec RK Kurachi K Allen DL Wu Y Haaseth R Andrews P Ethier SP Markwart S The PHSRN sequence induces extracellular matrix invasion and accelerates wound healing in obese diabetic mice.J Clin Invest. 2000; 105: 1537-1545Crossref PubMed Scopus (86) Google Scholar Briefly, 1-cm2 wounds were made in the skin on the upper back of the mice with the wounds placed so as to not injure the underlying muscle. Digital images of the wounds were captured at the time of wounding and then on days 1, 3, 5, 7, and 10 after placement of the wounds. At these time points the wounds and surrounding tissue were harvested and processed for immunohistochemical staining for vessel density and leukocyte infiltration. Bone marrow chimeric mice were generated as previously described.27Mahooti S Graesser D Patil S Newman P Duncan G Mak T Madri JA PECAM-1 (CD31) expression modulates bleeding time in vivo.Am J Pathol. 2000; 157: 75-81Abstract Full Text Full Text PDF PubMed Scopus (94) Google Scholar Briefly, to generate recipient animals, 6-week-old wild-type or CD44-null mice were irradiated with 1000 rads from a Cs-137 irradiation source. Within 24 hours after irradiation, donor marrow was obtained from the femur and tibia of non-irradiated mice and 5 × 106 cells were injected via the tail vein into the irradiated recipient mice. Experiments were subsequently conducted 4 to 6 weeks after transplantation. FACS analysis of leukocytes using an anti-mouse CD44 antibody confirmed the phenotype of each chimeric mouse. Immunohistochemistry was performed using a commercially available kit according to the manufacturer's instructions (ABC Immunodetection kit, Vector Laboratories, Burlingame, CA). Briefly, 6-μm-thick sections were prepared by cryostat, transferred to glass slides, and fixed in ice-cold acetone and rinsed in phosphate-buffered saline (PBS). The sections were then permeabilized with 0.3% Triton X-100 in PBS for 10 minutes, treated with 0.5% H2O2 in PBS for 30 minutes, and then blocked with 0.5% bovine serum albumin for 30 minutes. The sections were incubated with primary antibody for 1 hour, washed, and then incubated with biotinylated secondary antibody for 1 hour. The reaction was developed with an avidin-biotin complex reaction, and the sections were lightly counterstained with hematoxylin. For quantitation of angiogenesis, frozen tissue sections were stained with monoclonal antibody 390 or ICAM-2 antibodies to identify murine blood vessels. To assess the tumor angiogenic response, serial sections were obtained from different levels within the tumor separated by ∼100 μm. A total of four to eight levels per tumor were analyzed. For the B16 tumors, the vessel density at the margins of the tumors was determined by counting the number of vessels per 40× field. For the ID8-VEGF tumors, computer-assisted image analysis was used to determine the vessel area of a defined optical field of 3.6 × 105 μm2 positioned at serial locations along the margins of the tumor. For each section eight to 12 optical fields were analyzed. To assess wound angiogenesis computer-assisted image analysis was used to determine the vessel density within 300 μm of the edge of the wound, expressed as the percentage of tissue at wound edge occupied by vessels. Staining for leukocytes and macrophages in wounded tissue was achieved with anti-CD11b and F4/80 antibodies, respectively, and the number of cells/40× field at the base of the wound was determined. FACS analysis of cells from minced and filtered tumors was used to determine the percentage of cells expressing CD8, CD11b, or CD45 leukocyte markers. Tissues were fixed in 10% formalin (for paraffin sections) or 1% paraformaldehyde and 2.5% glutaraldehyde in 0.1 mol/L cacodylate buffer (pH 7.4) (for electron microscopy). Paraffin blocks were sectioned for hematoxylin and eosin staining, while electron microscopy sections were obtained after fixation in 2% osmium tetroxide and embedding in epoxy resin. Sufficient sections for representative serial sampling were produced and reviewed. Endothelial cells were cultured for 24 hours in 96-well plates (4000 cells/well), and the number of viable cells was determined using the Cell Titer 96® Aqueous Non-Radioactive Cell Proliferation Assay (Promega Madison, WI). This assay is composed of solutions of a novel tetrazolium compound (designated MTS) and an electron coupling (phenazine methosulfate) agent. MTS is bioreduced by dehydrogenase enzymes in metabolically active cells into a soluble formazan product. The absorbance of the formazan at 490 nm can be measured directly from 96-well assay plates without further processing and is directly proportional to the number of living cells in culture. As per the manufacture, the linear range for this assay is between 1000 and 200,000/well. In our hands we found a similar linear range for human umbilical vein endothelial cells with this assay (data not shown). Cell doubling was determined for isolated murine ECs by culturing the cells in T-25 flasks (25,000 cells/flask initially) over 6 days with the number of cells determined by Coulter counter. Wild-type and CD44-null ECs were incubated with HA (Healon; Pharmacia and Upjohn, Kalamazoo, MI) for 30 minutes at 4°C, then washed two times with PBS. The cells were then lysed, and HA binding was determined by enzyme-linked immunosorbent assay according to the manufacturer's instructions (Echelon Bioscience, Inc., Salt Lake City, UT). HA binding was also assessed by FACS analysis in which wild-type and CD44-null cells were incubated with biotinylated HA for 60 minutes at 4°C, followed by incubation with fluorescein-conjugated streptavidin (Vector Laboratories). 96-well plates were coated with HA (as Healon) using previously described procedures,16Savani RC Cao G Pooler PM Zaman A Zhou Z DeLisser HM Differential involvement of the hyaluronan (HA) receptors CD44 and receptor for HA-mediated motility in endothelial cell function and angiogenesis.J Biol Chem. 2001; 276: 36770-36778Crossref PubMed Scopus (284) Google Scholar and 40,000 H5V cells in 200 μl of serum-free Dulbecco's modified Eagle's medium were added to the plates for 30 minutes. After gentle washing, the number of adherent cells was determined using a commercially available nonradioactive colorimetric assay according to the manufacturer's instructions (Titer 96 Aqueous Non-Radioactive Cell Proliferation Assay). EC wounding was performed as previously described.28Cao G O'Brien CD Zhou Z Sanders SM Greenbaum JN Makrigiannakis A DeLisser HM Involvement of human PECAM-1 in angiogenesis and in vitro endothelial cell migration.Am J Physiol. 2002; 282: C1181-C1190Crossref Scopus (173) Google Scholar 20,000 ECs were added to 24-well tissue culture plates and allowed to grow to confluence. Linear defects were then made in the monolayer. The wounded culture was washed with PBS and then incubated for 24 hours in medium (with 1% serum). Using computer-assisted image analysis, and the Image-Pro Plus program (Media Cybernetics, Silver Spring, MD), images were obtained immediately after wounding and 24 hours later, and then the distance migrated by cells at the wound edge was determined. For each condition three to five wounds were analyzed. In vitro tube formation was studied using previously described procedures.23Zhou Z Christofidou-Solomidou M Garlanda C DeLisser HM Antibody against murine PECAM-1 inhibits tumor angiogenesis in mice.Angiogenesis. 1999; 3: 181-188Crossref PubMed Scopus (69) Google Scholar Fifty microliters of Matrigel was added to each well of a 96-well plate and allowed to form a gel at 37°C for 30 minutes. Cells (20,000) in 200 μl of complete medium were subsequently added to each well, and the mixture was incubated for 6 hours at 37°C in 5% CO2. The wells were washed, and the gel and its cells were fixed with 3% paraformaldehyde. Total tube length per well was determined by computer-assisted image analysis using the Image-Pro Plus program. For the studies of apoptosis, confluent cells were exposed for 5 hours to serum-free medium or complete medium, with or without antibody. Apoptosis was then assessed using the APOPercentage Apoptosis Assay (Bicolor Ltd., Belfast, Ireland). Differences among groups were analyzed using one-way analysis of variance. Results are presented as means ± SE. When statistically significant differences were found (P < 0.05), individual comparisons were made using the Bonferroni/Dunn test. To investigate the involvement of CD44 in the formation of blood vessels, in vivo angiogenesis was studied in mice deficient in CD44.29Teder P Vandivier RW Jiang D Liang J Cohn L Pure E Henson PM Noble PW Resolution of lung inflammation by CD44.Science. 2002; 296: 155-158Crossref PubMed Scopus (571) Google Scholar Initial studies were performed with a model in which vessels develop around and within subcutaneously implanted Matrigel plugs containing B16 tumor cells as a source of angiogenic growth factors. After 5 to 7 days, a “blush” of vessel proliferation was seen surrounding plugs in the wild-type animals that was not evident in the CD44-null mice (Figure 1, A and B). Consistent with this, vascularization of the plugs, as assessed by hemoglobin concentration, was significantly reduced in CD44-deficient mice compared to wild-type animals (Figure 1C). To confirm and extend the findings of the Matrigel studies, the subcutaneous growth and associated tumor angiogenesis of the B16 melanoma line and an ovarian tumor line overexpressing VEGF (ID8-VEGF) were studied in CD44-deficient mice. The growth of both tumors in the CD44-null mice was significantly reduced (>70%) compared to that of tumors in wild-type animals (Figure 2, A, B, C, and E). The vessel densities of tumors of comparable sizes from wild-type and mutant mice were subsequently determined and found to be significantly reduced in the CD44-null mice (Figure 2, D and F). Further, histological analysis of B16 melanoma tumors from CD44-null animals revealed a paucity of the large sinusoidal vessels characteristic of the tumors harvested from wild-type mice (Figure 2G). These data suggest that the inhibition of tumor growth in the CD44-null mice resulted at least in part from a reduced angiogenic response. With the data above implicating CD44 in the pathological formation of blood vessels additional studies were performed to determine whether CD44 might also be involved in physiological angiogenesis. The closure of 1-cm2 skin wounds was therefore studied in wild-type and CD44-null mice. We observed that wound closure in the CD44-mutant animals was delayed during days 1 to 3 after wounding but by day 7 had recovered and was similar to that of wild-type animals (Figure 3A). The density of vessels at the edge of the wounds on day 3 was reduced by 20% in the CD44-null animals compared to wild-type mice (Figure 3B). Thus, the absence of CD44 results in an early delay in the closure of skin wounds that is associated with a modest but significant reduction in the neovascularization of the wounded tissue. HA receptors are expressed on leukocytes and have been implicated in leukocyte trafficking.30Katayama Y Hidalgo A Chang J Peired A Frenette PS CD44 is a physiological E-selectin ligand on neutrophils.J Exp Med. 2005; 201: 1183-1189Crossref PubMed Scopus (157) Google Scholar, 31Khan AI Kerfoot SM Heit B Liu L Andonegui G Ruffell B Johnson P Kubes P Role of CD44 and hyaluronan in neutrophil recruitment.J Immunol. 2004; 173: 7594-7601PubMed Google Scholar, 32Zaman A Cui Z Foley JP Zhao H Grimm PC Delisser HM Savani RC Expression and role of the hyaluronan receptor RHAMM in inflammation after bleomycin injury.Am J Respir Cell Mol Biol. 2005; 33: 447-454Crossref PubMed Scopus (87) Google Scholar Consequently, the absence of CD44 could lead to less leukocyte recruitment and thus a loss of a source of pro-angiogenic factors. We, however, found that leukocyte accumulation in wild-type and CD44-mutant mice in the B16 and ID8-VEGF tumors (Figure 2H; data not shown for ID8-VEGF tumors) and during wound healing were comparable (Figure 3C). This suggests that the diminished tumor and wound angiogenesis arising from the loss of CD44 was not the result of reduced leukocyte recruitment. The recruitment data presented above do not exclude functional consequences arising from the loss of CD44 expression on leukocytes or on circulating bone marrow-derived progenitor endothelial cells, both of which have been identified along with ECs as cellular participants during in vivo angiogenesis.33Schruefer R Lutze N Schymeinsky J Walzog B Human neutrophils promote angiogenesis by a paracrine feedforward mechanism involving endothelial interleukin-8.Am J Physiol. 2005; 288: H1186-H1192Google Scholar, 34Chavakis T Cines DB Rhee JS Liang OD Schubert U Hammes HP Higazi AA Nawroth PP Preissner KT Bdeir K Regulation of neovascularization by human neutrophil peptides (alpha-defensins): a link between inflammation and angiogenesis.FASEB J. 2004; 18: 1306-1308Crossref PubMed Scopus (126) Google Scholar, 35Asahara T Murohara T Sullivan A Silver M van der Zee R Li T Witzenbichler B Schatteman G Isner JM Isolation of putative progenitor endothelial cells for angiogenesis.Science. 1997; 275: 964-967Crossref PubMed Scopus (7692) Google Scholar, 36Crowther M Brown NJ Bishop ET Lewis CE Microenvironmental influence on macrophage regulation of angiogenesis in wounds and malignant tumors.J Leukoc Biol. 2001; 70: 478-490PubMed Google Schola

The protein kinase C (PKC) family plays a key regulatory role in a wide range of cellular functions as well as in various cancer-associated signal transduction pathways. Here, we investigated the genomic alteration and gene expression of most known PKC family members in human ovarian cancer. The DNA copy number of PKC family genes was screened by a high-resolution array-based comparative genomic hybridization in 89 human ovarian cancer specimens. Five PKC genes exhibited significant DNA copy number gains, including PKCiota (43.8%), PKCbeta1 (37.1%), PKCgamma (27.6%), PKCzeta (22.5%), and PKCtheta (21.3%). None of the PKC genes exhibited copy number loss. The mRNA expression level of PKC genes was analyzed by microarray retrieval approach. Two of the amplified PKC genes, PKCiota and PKCtheta, were significantly up-regulated in ovarian cancer compared with normal ovary. Increased PKCiota expression correlated with tumor stage or grade, and PKCiota overexpression was seen mostly in ovarian carcinoma but not in other solid tumors. The above results were further validated by real-time reverse transcription-PCR with 54 ovarian cancer specimens and 24 cell lines; overexpression of PKCiota protein was also confirmed by tissue array and Western blot. Interestingly, overexpressed PKCiota did not affect ovarian cancer cell proliferation or apoptosis in vitro. However, decreased PKCiota expression significantly reduced anchorage-independent growth of ovarian cancer cells, whereas overexpression of PKCiota contributed to murine ovarian surface epithelium transformation in cooperation with mutant Ras. We propose that PKCiota may serve as an oncogene and a biomarker of aggressive disease in human ovarian cancer.

The phosphatidylinositol 3'-kinase (PI3K) family plays a key regulatory role in various cancer-associated signal transduction pathways. Here, we investigated the genomic alterations and gene expression of most known PI3K family members in human epithelial ovarian cancer.The DNA copy number of PI3K family genes was screened by a high-resolution array comparative genomic hybridization in 89 human ovarian cancer specimens. The mRNA expression level of PI3K genes was analyzed by microarray retrieval approach, and further validated by real-time reverse transcription-PCR. The expression of p55gamma protein in ovarian cancer was analyzed on tissue arrays. Small interfering RNA was used to study the function of PIK3R3 in ovarian cancer.In ovarian cancer, 6 of 12 PI3K genes exhibited significant DNA copy number gains (>20%), including PIK3CA (23.6%), PIK3CB (27.0%), PIK3CG (25.8%), PIK3R2 (29.2%), PIK3R3 (21.3%), and PIK3C2B (40.4%). Among those, only PIK3R3 had significantly up-regulated mRNA expression level in ovarian cancer compared with normal ovary. Up-regulated PIK3R3 mRNA expression was also observed in liver, prostate, and breast cancers. The PIK3R3 mRNA expression level was significantly higher in ovarian cancer cell lines (n = 18) than in human ovarian surface epithelial cells (n = 6, P = 0.002). Overexpression of p55gamma protein in ovarian cancer was confirmed by tissue array analysis. In addition, we found that knockdown of PIK3R3 expression by small interfering RNA significantly increased the apoptosis in cultured ovarian cancer cell lines.We propose that PIK3R3 may serve as a potential therapeutic target in human ovarian cancer.

Abstract BACKGROUND: The aim of the study was to determine whether tumor‐infiltrating lymphocytes and/or tumor mitotic activity could identify subgroups of patients with advanced serous epithelial ovarian cancer who would maximally benefit from aggressive surgical cytoreduction. METHODS: Snap‐frozen specimens from 134 consecutive patients with stage III or IV serous or poorly differentiated ovarian adenocarcinoma undergoing primary debulking surgery from a single US institution were characterized based on CD3 + , CD8 + , FoxP3 + tumor‐infiltrating lymphocytes, and Ki67 expression. Kaplan‐Meier survival curves were estimated and compared using a log‐rank statistic. A multivariate Cox model was used to estimate adjusted hazard ratios. Interactions were modeled using recursive partitioning based on maximal prognostic differentiation. RESULTS: Brisk intraepithelial CD8 + cells ( P = .035) and low Ki67 expression ( P = .042) portended prolonged survival. The T‐cell infiltration was more likely to occur in tumors with high proliferation index. Patients whose tumors exhibited low Ki67 expression and high intraepithelial CD8 + frequency had a 5‐year survival rate of 73.3%. Patients with aggressive tumor behavior, that is, whose tumors exhibited low frequency of intraepithelial CD8 + T cells or high Ki67 expression were more likely to draw benefit from aggressive surgical cytoreduction. Survival was similar for patients with brisk CD8 + T cells who had optimal or suboptimal debulking. Likewise, survival was similar for patients with low Ki67 expression who had optimal or suboptimal debulking. CONCLUSIONS: For the first time, these novel interactions of T cells, tumor proliferation index, and surgical treatment reveal that biological prognosticators may be useful for surgical decision making in ovarian cancer. Cancer 2009. © 2009 American Cancer Society.

Cooperation between oncolytic herpes simplex virus (HSV) and host effector immune mechanisms has been previously described. In the present study, we investigated the mechanism underlying such cooperation in a murine syngeneic model of ovarian carcinoma. Therapeutic administration of HSV-1716, a replication-restricted mutant, resulted in significant reduction of tumor growth and a significant survival advantage. Intratumoral injection of HSV-1716 induced expression of IFN-gamma, MIG, and IP-10 in the tumor. This was accompanied by a significant increase in the number of tumor-associated NK and CD8+ T cells expressing CXCR3 and CD25. Ascites from HSV-1716-treated animals efficiently induced in vitro migration of NK and CD8+ T cells, which was dependent on the presence of MIG and IP-10. Murine monocytes and dendritic cells (DCs) were responsible for the production of MIG and IP-10 upon HSV-1716 infection. In monocytes, this was partially abrogated by neutralizing antibodies against IFN-alpha and -beta, thus indicating a role for type-1 IFNs in the reported effect. Human ovarian carcinomas showed high numbers of monocytes and DCs. Upon HSV-1716 infection, human monocyte-derived DCs produced large amounts of IFN-gamma and upregulated MIG and IP-10 expression. These results indicate that HSV-1716 induces an inflammatory response that may facilitate antitumor immune response upon oncolytic therapy.

In this review, we discuss the recent identification in vivo of a population of CD11c+ cells exhibiting simultaneous expression of both endothelial and dendritic cell markers, termed vascular leukocytes (VLCs). VLCs are highly represented in human ovarian carcinomas and, depending on the milieu, can assemble into functional blood vessels or act as antigen-presenting cells. The identification of dendritic cell precursors as bipotent cells has important implications for the physiopathology and therapy of tumours. VLCs emerge as a novel therapeutic target against tumour vascularisation.

Abstract The endothelins and their G protein-coupled receptors A and B have been implicated in numerous diseases and have recently emerged as pivotal players in a variety of malignancies. Tumors overexpress the endothelin 1 (ET-1) ligand and the endothelin-A-receptor (ETAR). Their interaction induces tumor growth and metastasis by promoting tumor cell survival and proliferation, angiogenesis, and tissue remodeling. On the basis of results from xenograft models, drug development efforts have focused on antagonizing the autocrine-paracrine effects mediated by ET-1/ETAR. In this review, we discuss a novel role of the endothelin-B-receptor (ETBR) in tumorigenesis and the effect of its blockade during cancer immune therapy. We highlight key characteristics of the B receptor such as its specific overexpression in the tumor compartment; and specifically, in the tumor endothelium, where its activation by ET-1 suppresses T-cell adhesion and homing to tumors. We also review our recent findings on the effects of ETBR-specific blockade in increasing T-cell homing to tumors and enhancing the efficacy of otherwise ineffective immunotherapy.

Whole tumor cell lysates can serve as excellent multivalent vaccines for priming tumor-specific CD8+ and CD4+ T cells. Whole cell vaccines can be prepared with hypochlorous acid oxidation, UVB-irradiation and repeat cycles of freeze and thaw. One major obstacle to successful immunotherapy is breaking self-tolerance to tumor antigens. Clinically approved adjuvants, including Montanide™ ISA-51 and 720, and keyhole-limpet proteins can be used to enhance tumor cell immunogenicity by stimulating both humoral and cellular anti-tumor responses. Other potential adjuvants, such as Toll-like receptor agonists (e.g., CpG, MPLA and PolyI:C), and cytokines (e.g., granulocyte-macrophage colony stimulating factor), have also been investigated.

Abstract Identification and characterization of underlying genetic aberrations could facilitate diagnosis and treatment of ovarian cancer. Copy number analysis using array Comparative Genomic Hybridization (aCGH) on 93 primary ovarian tumors identified PI3K/AKT pathway as the most frequently altered cancer related pathway. Furthermore, survival analyses to correlate gene copy number and mutation data with patient outcome showed that copy number gains of PIK3CA , PIK3CB, and PIK3R4 in these tumors were associated with decreased survival. To confirm these findings at the protein level, immunohistochemistry (IHC) for PIK3CA product p110α and p‐Akt was performed on tissue microarrays from 522 independent serous ovarian cancers. Overexpression of either of these two proteins was found to be associated with decreased survival. Multivariant analysis from these samples further showed that overexpression of p‐AKT and/or p110α is an independent prognostic factor for these tumors. siRNAs targeting altered PI3K/AKT pathway genes inhibited proliferation and induced apoptosis in ovarian cancer cell lines. In addition, the effect of the siRNAs in different cell lines seemed to correlate with the particular genetic alterations that the cell line carries. These results strongly support the utilization of PI3K pathway inhibitors in ovarian cancer. They also suggest identifying the specific component in the PI3K pathway that is genetically altered has the potential to help select the most effective therapy. Both mutation as well as copy number changes can be used as predictive markers for this purpose. © 2011 Wiley‐Liss, Inc.

<h3>Background</h3> A phase 2, randomized, placebo-controlled trial was conducted in women with recurrent epithelial ovarian carcinoma to evaluate the efficacy and safety of motolimod—a Toll-like receptor 8 (TLR8) agonist that stimulates robust innate immune responses—combined with pegylated liposomal doxorubicin (PLD), a chemotherapeutic that induces immunogenic cell death. <h3>Patients and methods</h3> Women with ovarian, fallopian tube, or primary peritoneal carcinoma were randomized 1 : 1 to receive PLD in combination with blinded motolimod or placebo. Randomization was stratified by platinum-free interval (≤6 versus >6–12 months) and Gynecologic Oncology Group (GOG) performance status (0 versus 1). Treatment cycles were repeated every 28 days until disease progression. <h3>Results</h3> The addition of motolimod to PLD did not significantly improve overall survival (OS; log rank one-sided <i>P</i>=0.923, HR=1.22) or progression-free survival (PFS; log rank one-sided <i>P</i>=0.943, HR=1.21). The combination was well tolerated, with no synergistic or unexpected serious toxicity. Most patients experienced adverse events of fatigue, anemia, nausea, decreased white blood cells, and constipation. In pre-specified subgroup analyses, motolimod-treated patients who experienced injection site reactions (ISR) had a lower risk of death compared with those who did not experience ISR. Additionally, pre-treatment <i>in vitro</i> responses of immune biomarkers to TLR8 stimulation predicted OS outcomes in patients receiving motolimod on study. Immune score (tumor infiltrating lymphocytes; TIL), TLR8 single-nucleotide polymorphisms, mutational status in BRCA and other DNA repair genes, and autoantibody biomarkers did not correlate with OS or PFS. <h3>Conclusions</h3> The addition of motolimod to PLD did not improve clinical outcomes compared with placebo. However, subset analyses identified statistically significant differences in the OS of motolimod-treated patients on the basis of ISR and <i>in vitro</i> immune responses. Collectively, these data may provide important clues for identifying patients for treatment with immunomodulatory agents in novel combinations and/or delivery approaches. <h3>Trial registration</h3> Clinicaltrials.gov, NCT 01666444.

Abstract: Emerging clinical evidence on the role of the antitumor activity of the immune system has generated great interest in immunotherapy in all cancer types. Recent clinical data clearly demonstrated that human tumor cells express antigenic peptides (epitopes) that can be recognized by autologous tumor-specific T cells and that enhancement of such immune reactivity can potentially lead to cancer control and cancer regression in patients with advanced disease. However, in most cases, it is unclear which tumor antigens (Ags) mediated cancer regression. Mounting evidence indicates that numerous endogenous mutated cancer proteins, a hallmark of tumor cells, can be processed into peptides and presented on the surface of tumor cells, leading to their immune recognition in vivo as “non-self” or foreign. Massively parallel sequencing has now overcome the challenge of rapidly identifying the comprehensive mutational spectrum of individual tumors (i.e., the “mutanome”) and current technologies, as well as computational tools, have emerged that allow the identification of private epitopes derived from their mutanome and called neoantigens (neoAgs). On this basis, both CD4+ and CD8+ neoantigen-specific T cells have been identified in multiple human cancers and shown to be associated with a favorable clinical outcome. Notably, emerging data also indicate that neoantigen recognition represents a major factor in the activity of clinical immunotherapies. In the post-genome era, the mutanome holds promise as a long-awaited ‘gold mine’ for the discovery of unique cancer cell targets, which are exclusively tumor-specific and unlikely to drive immune tolerance, hence offering the chance for highly promising clinical programs of cancer immunotherapy.

Adoptive transfer of T cells gene-engineered with T cell receptors (TCRs) has proven its feasibility and therapeutic potential in the treatment of malignant tumors. To ensure further clinical development of TCR gene therapy, it is necessary to accurately select TCRs that demonstrate antigen-selective responses that are restricted to tumor cells and, at the same time, include strategies that restore or enhance the entry, migration and local accumulation of T cells in tumor tissues. Here, we present the current standing of TCR-engineered T cell therapy, discuss and propose procedures to select TCRs as well as strategies to sensitize the tumor to T cell trafficking, and provide a rationale for combination therapies with TCR-engineered T cells.

T-cells play a critical role in tumor immunity. Indeed, the presence of tumor-infiltrating lymphocytes is a predictor of favorable patient prognosis for many indications and is a requirement for responsiveness to immune checkpoint blockade therapy targeting programmed cell death 1. For tumors lacking immune infiltrate, or for which antigen processing and/or presentation has been downregulated, a promising immunotherapeutic approach is chimeric antigen receptor (CAR) T-cell therapy. CARs are hybrid receptors that link the tumor antigen specificity and affinity of an antibody-derived single-chain variable fragment with signaling endodomains associated with T-cell activation. CAR therapy targeting CD19 has yielded extraordinary clinical responses against some hematological tumors. Solid tumors, however, remain an important challenge to CAR T-cells due to issues of homing, tumor vasculature and stromal barriers, and a range of obstacles in the tumor bed. Protumoral immune infiltrate including T regulatory cells and myeloid-derived suppressor cells have been well characterized for their ability to upregulate inhibitory receptors and molecules that hinder effector T-cells. A critical role for metabolic barriers in the tumor microenvironment (TME) is emerging. High glucose consumption and competition for key amino acids by tumor cells can leave T-cells with insufficient energy and biosynthetic precursors to support activities such as cytokine secretion and lead to a phenotypic state of anergy or exhaustion. CAR T-cell expansion protocols that promote a less differentiated phenotype, combined with optimal receptor design and coengineering strategies, along with immunomodulatory therapies that also promote endogenous immunity, offer great promise in surmounting immunometabolic barriers in the TME and curing solid tumors.

Tumor endothelial marker 1 (TEM1; also known as endosialin or CD248) is a protein found on tumor vasculature and in tumor stroma. Here, we tested whether TEM1 has potential as a therapeutic target for cancer immunotherapy by immunizing immunocompetent mice with Tem1 cDNA fused to the minimal domain of the C fragment of tetanus toxoid (referred to herein as Tem1-TT vaccine). Tem1-TT vaccination elicited CD8+ and/or CD4+ T cell responses against immunodominant TEM1 protein sequences. Prophylactic immunization of animals with Tem1-TT prevented or delayed tumor formation in several murine tumor models. Therapeutic vaccination of tumor-bearing mice reduced tumor vascularity, increased infiltration of CD3+ T cells into the tumor, and controlled progression of established tumors. Tem1-TT vaccination also elicited CD8+ cytotoxic T cell responses against murine tumor-specific antigens. Effective Tem1-TT vaccination did not affect angiogenesis-dependent physiological processes, including wound healing and reproduction. Based on these data and the widespread expression of TEM1 on the vasculature of different tumor types, we conclude that targeting TEM1 has therapeutic potential in cancer immunotherapy.

We have identified eight genes whose expression in human melanoma metastases and ovarian cancers is associated with a lack of Th1 immune signatures. They encode molecules with mechanical barrier function in the skin and other normal tissues and include filaggrin (FLG), tumor-associated calcium signal transducer 2 (TACSTD2), and six desmosomal proteins (DST, DSC3, DSP, PPL, PKP3, and JUP). This association has been validated in an independent series of 114 melanoma metastases. In these, DST expression alone is sufficient to identify melanomas without immune signatures, while FLG and the other six putative barrier molecules are overexpressed in a different subset of melanomas lacking immune signatures. Similar associations have been identified in a set of 186 ovarian cancers. RNA-seq data from 471 melanomas and 307 ovarian cancers in the TCGA database further support these findings and also reveal that overexpression of barrier molecules is strongly associated with early patient mortality for melanoma (p = 0.0002) and for ovarian cancer (p < 0.01). Interestingly, this association persists for FLG for melanoma (p = 0.012) and ovarian cancer (p = 0.006), whereas DST overexpression is negatively associated with CD8+ gene expression, but not with patient survival. Thus, overexpression of FLG or DST identifies two distinct patient populations with low immune cell infiltration in these cancers, but with different prognostic implications for each. These data raise the possibility that molecules with mechanical barrier function in skin and other tissues may be used by cancer cells to protect them from immune cell infiltration and immune-mediated destruction.

Ovarian cancer (OC) is the most important cause of gynecological cancer-related mortality, with the majority of women presenting with advanced disease. Although surgery and chemotherapy can improve survival, the 5-year survival rates remain ominously low at 45%. Novel therapies are urgently needed. The presence of T cells in the OC tumor microenvironment is correlated with improved progression-free and overall survival, while the presence of regulatory T cells and expression of T-cell inhibitory molecules is correlated with a poor prognosis. These data indicate that immunotherapy could hold promise in improving the treatment of OC. In this review, we will discuss the rational of immunotherapy, highlight current results with cancer vaccines, adoptive T-cell therapy and immunomodulatory agents and summarize the immune effects of selected chemotherapeutic and radiotherapeutic agents.

Vascular endothelial growth factor (VEGF) carries out multifaceted functions in tumor development, and it exists as at least five isoforms with distinct biologic activities and clinical implications. Several strategies have been developed to block VEGF for cancer therapy; however, the approach to target-specific VEGF isoform(s) has not been explored to date. In the present study, we show that DNA vector-based RNA interference (RNAi), in which RNAi sequences targeting murine VEGF isoforms are inserted downstream of an RNA polymerase III promoter, has potential applications in isoform-specific "knock-down" of VEGF. Large molecular weight VEGF isoforms were specifically reduced in vitro in the presence of isoform-specific RNAi constructs. Additionally, H1 promoter may be superior to U6 promoter when used for vector-based RNAi of VEGF isoforms. This strategy provides a novel tool to study the function of various VEGF isoforms and may contribute to VEGF isoform-specific treatment in cancer.