Jérôme Tamburini

Key Points Genetic- or compound CB-839–induced GAC inhibition reduces OXPHOS and has antileukemic activity in AML. GAC inhibition synergizes with BCL-2 inhibition by compound ABT-199.

The PI3K/AKT and mTOR signaling pathways are activated in acute myeloid leukemia, including in the more immature leukemic populations. Constitutive PI3K activation is detectable in 50% of acute myeloid leukemia samples whereas mTORC1 is activated in all cases of this disease. In leukemic cells, the PI3K activity relates to the expression of the p110delta isoform of class IA PI3K. Constitutive PI3K activation is the result of autocrine IGF-1/IGF-1R signaling in 70% of acute myeloid leukemia samples but specific inhibition of this pathway does not induce apoptosis. Specific inhibition of PI3K/AKT or mTORC1 alone in vitro has anti-leukemic effects which are essentially exerted via the suppression of proliferation. However, as mTORC1 activation is independent of PI3K/AKT in acute myeloid leukemia, dual PI3K and mTOR inhibitors may induce apoptosis in blast cells. Moreover, mTORC1 inhibition using sirolimus overactivates PI3K/AKT via the upregulation of IRS2 expression and by favoring IGF-1/IGF-1R autocrine signaling. Recent data also indicate that mTORC1 does not control protein translation in acute myeloid leukemia. These results open the way for the design of direct inhibitors of protein synthesis as novel acute myeloid leukemia therapies and also for the development of second generation mTOR inhibitors (the TORKinhibs).

Cancer cells require nutrients and energy to adapt to increased biosynthetic activity, and protein synthesis inhibition downstream of mammalian target of rapamycin complex 1 (mTORC1) has shown promise as a possible therapy for acute myeloid leukemia (AML). Glutamine contributes to leucine import into cells, which controls the amino acid/Rag/mTORC1 signaling pathway. We show in our current study that glutamine removal inhibits mTORC1 and induces apoptosis in AML cells. The knockdown of the SLC1A5 high-affinity transporter for glutamine induces apoptosis and inhibits tumor formation in a mouse AML xenotransplantation model. l-asparaginase (l-ase) is an anticancer agent also harboring glutaminase activity. We show that l-ases from both Escherichia coli and Erwinia chrysanthemi profoundly inhibit mTORC1 and protein synthesis and that this inhibition correlates with their glutaminase activity levels and produces a strong apoptotic response in primary AML cells. We further show that l-ases upregulate glutamine synthase (GS) expression in leukemic cells and that a GS knockdown enhances l-ase-induced apoptosis in some AML cells. Finally, we observe a strong autophagic process upon l-ase treatment. These results suggest that l-ase anticancer activity and glutamine uptake inhibition are promising new therapeutic strategies for AML.

More than 90% of drugs with preclinical activity fail in human trials, largely due to insufficient efficacy. We hypothesized that adequately powered trials of patient-derived xenografts (PDX) in mice could efficiently define therapeutic activity across heterogeneous tumors. To address this hypothesis, we established a large, publicly available repository of well-characterized leukemia and lymphoma PDXs that undergo orthotopic engraftment, called the Public Repository of Xenografts (PRoXe). PRoXe includes all de-identified information relevant to the primary specimens and the PDXs derived from them. Using this repository, we demonstrate that large studies of acute leukemia PDXs that mimic human randomized clinical trials can characterize drug efficacy and generate transcriptional, functional, and proteomic biomarkers in both treatment-naive and relapsed/refractory disease.

<h3>Objective</h3> Real-life studies on patients with primary CNS lymphoma (PCNSL) are scarce. Our objective was to analyze, in a nationwide population-based study, the current medical practice in the management of PCNSL. <h3>Methods</h3> The French oculo-cerebral lymphoma network (LOC) database prospectively records all newly diagnosed PCNSL cases from 32 French centers. Data of patients diagnosed between 2011 and 2016 were retrospectively analyzed. <h3>Results</h3> We identified 1,002 immunocompetent patients (43% aged &gt;70 years, median Karnofsky Performance Status [KPS] 60). First-line treatment was high-dose methotrexate-based chemotherapy in 92% of cases, with an increasing use of rituximab over time (66%). Patients &lt;60 years of age received consolidation treatment in 77% of cases, consisting of whole-brain radiotherapy (WBRT) (54%) or high-dose chemotherapy with autologous stem cell transplantation (HCT-ASCT) (23%). Among patients &gt;60 years of age, WBRT and HCT-ASCT consolidation were administered in only 9% and 2%, respectively. The complete response rate to initial chemotherapy was 50%. Median progression-free survival was 10.5 months. For relapse, second-line chemotherapy, HCT-ASCT, WBRT, and palliative care were offered to 55%, 17%, 10%, and 18% of patients, respectively. The median, 2-year, and 5-year overall survival was 25.3 months, 51%, and 38%, respectively (&lt;60 years: not reached [NR], 70%, and 61%; &gt;60 years: 15.4 months, 44%, and 28%). Age, KPS, sex, and response to induction CT were independent prognostic factors in multivariate analysis. <h3>Conclusions</h3> Our study confirms the increasing proportion of elderly within the PCNSL population and shows comparable outcome in this population-based study with those reported by clinical trials, reflecting a notable application of recent PCNSL advances in treatment.

APR-246 is a promising new therapeutic agent that targets p53 mutated proteins in myelodysplastic syndromes and in acute myeloid leukemia (AML). APR-246 reactivates the transcriptional activity of p53 mutants by facilitating their binding to DNA target sites. Recent studies in solid cancers have found that APR-246 can also induce p53-independent cell death. In this study, we demonstrate that AML cell death occurring early after APR-246 exposure is suppressed by iron chelators, lipophilic antioxidants and inhibitors of lipid peroxidation, and correlates with the accumulation of markers of lipid peroxidation, thus fulfilling the definition of ferroptosis, a recently described cell death process. The capacity of AML cells to detoxify lipid peroxides by increasing their cystine uptake to maintain major antioxidant molecule glutathione biosynthesis after exposure to APR-246 may be a key determinant of sensitivity to this compound. The association of APR-246 with induction of ferroptosis (either by pharmacological compounds, or genetic inactivation of SLC7A11 or GPX4) had a synergistic effect on the promotion of cell death, both in vivo and ex vivo.

Abstract Although transcription factor CCAAT-enhancer binding protein α (C/EBPα) is critical for normal and leukemic differentiation, its role in cell and metabolic homeostasis is largely unknown in cancer. Here, multiomics analyses uncovered a coordinated activation of C/EBPα and Fms-like tyrosine kinase 3 (FLT3) that increased lipid anabolism in vivo and in patients with FLT3-mutant acute myeloid leukemia (AML). Mechanistically, C/EBPα regulated the fatty acid synthase (FASN)–stearoyl-CoA desaturase (SCD) axis to promote fatty acid (FA) biosynthesis and desaturation. We further demonstrated that FLT3 or C/EBPα inactivation decreased monounsaturated FA incorporation to membrane phospholipids through SCD downregulation. Consequently, SCD inhibition enhanced susceptibility to lipid redox stress that was exploited by combining FLT3 and glutathione peroxidase 4 inhibition to trigger lipid oxidative stress, enhancing ferroptotic death of FLT3-mutant AML cells. Altogether, our study reveals a C/EBPα function in lipid homeostasis and adaptation to redox stress, and a previously unreported vulnerability of FLT3-mutant AML to ferroptosis with promising therapeutic application. Significance: FLT3 mutations are found in 30% of AML cases and are actionable by tyrosine kinase inhibitors. Here, we discovered that C/EBPα regulates FA biosynthesis and protection from lipid redox stress downstream mutant-FLT3 signaling, which confers a vulnerability to ferroptosis upon FLT3 inhibition with therapeutic potential in AML. This article is highlighted in the In This Issue feature, p. 1501

The phosphatidylinositol 3-kinase (PI3K)/Akt and mTORC1 pathways are frequently activated, representing potential therapeutic targets in acute myeloid leukemia (AML). In 19 AML samples with constitutive PI3K/Akt activation, the rapamycin derivative inhibitor everolimus (RAD001) increased Akt phosphorylation. This mTOR C1-mediated Akt up-regulation was explained by an insulin-like growth factor-1 (IGF-1)/IGF-1 receptor autocrine loop: (1) blast cells expressed functional IGF-1 receptors, and IGF-1-induced Akt activation was increased by RAD001, (2) a neutralizing anti-IGF-1R α-IR3 monoclonal antibody reversed the RAD001-induced Akt phosphorylation, and (3) autocrine production of IGF-1 was detected in purified blast cells by quantitative reverse transcription-polymerase chain reaction and immunofluorescence. This RAD001-induced PI3K/Akt up-regulation was due to an up-regulated expression of the IRS2 adaptor. Finally, we observed that concomitant inhibition of mTORC1 and PI3K/Akt by RAD001 and IC87114 induced additive antiproliferative effects. Our results suggest that dual inhibition of the mTORC1 complex and the IGF-1/IGF-1R/PI3K/Akt pathway in AML may enhance the efficacy of mTOR inhibitors in treatment of this disease.

Abstract Finding an effective treatment for acute myeloid leukemia (AML) remains a challenge, and all cellular processes that are deregulated in AML cells should be considered in the design of targeted therapies. We show in our current study that the LKB1/AMPK/TSC tumor suppressor axis is functional in AML and can be activated by the biguanide molecule metformin, resulting in a specific inhibition of mammalian target of rapamycin (mTOR) catalytic activity. This induces a multisite dephosphorylation of the key translation regulator, 4E-BP1, which markedly inhibits the initiation step of mRNA translation. Consequently, metformin reduces the recruitment of mRNA molecules encoding oncogenic proteins to the polysomes, resulting in a strong antileukemic activity against primary AML cells while sparing normal hematopoiesis ex vivo and significantly reducing the growth of AML cells in nude mice. The induction of the LKB1/AMPK tumor-suppressor pathway thus represents a promising new strategy for AML therapy.

Tyrosine kinase inhibitors have revolutionized the treatment of chronic myeloid leukemia and are increasingly used for other indications. Fluid retention, however, including pleural effusions, are a significant side effect of imatinib, the first-line treatment for chronic myeloid leukemia. We investigated pleural and pulmonary complications in patients treated with dasatinib, a novel multitargeted tyrosine kinase inhibitor, as part of clinical trial protocols. Of 40 patients who received dasatinib (70 mg twice daily) for imatinib resistance or intolerance, 9 (22.5%) developed dyspnea, cough, and chest pain. Of these nine patients, six had pleural effusions (all were exudates) and seven had lung parenchyma changes with either ground-glass or alveolar opacities and septal thickening (four patients had both pleural effusions and lung parenchyma changes). Lymphocytic accumulations were detected in pleural and bronchoalveolar lavage fluids in all patients except for one who presented with neutrophilic alveolitis. Pleural biopsies revealed lymphocytic infiltration in one patient and myeloid infiltration in another. After dasatinib interruption, lung manifestations resolved in all cases and did not recur in three of four patients when dasatinib was reintroduced at a lower dose (40 mg twice daily). Thus, lung physicians should be aware that lung manifestations, presumably related to an immune-mediated mechanism rather than fluid retention, may occur with dasatinib treatment.

Abstract The deregulation of translation markedly contributes to the malignant phenotype in cancers, and the assembly of the translation initiating complex eIF4F is the limiting step of this process. The mammalian Target of Rapamycin Complex 1 (mTORC1) is thought to positively regulate eIF4F assembly and subsequent oncogenic protein synthesis through 4E-BP1 phosphorylation. We showed here that the translation inhibitor 4EGI-1 decreased the clonogenic growth of leukemic progenitors and induced apoptosis of blast cells, with limited toxicity against normal hematopoiesis, which emphasize the importance of translation deregulation in acute myeloid leukemia (AML) biology. However, the mTORC1 inhibitor RAD001 (a rapamycin derivate) did not induce AML blast cell apoptosis. We herein demonstrated that mTORC1 disruption using raptor siRNA or RAD001 failed to inhibit 4E-BP1 phosphorylation in AML. Moreover, RAD001 failed to inhibit eIF4F assembly, to decrease the proportion of polysome-bound c-Myc mRNA, and to reduce the translation-dependent accumulation of oncogenic proteins. We identified the Pim-2 serine/threonine kinase as mainly responsible for 4E-BP1 phosphorylation on the S65 residue and subsequent translation control in AML. Our results strongly implicate an mTORC1-independent deregulation of oncogenic proteins synthesis in human myeloid leukemogenesis. Direct inhibition of the translation initiating complex thus represents an attractive option for the development of new therapies in AML.

The phosphatidylinositol 3-kinase (PI3K)/Akt and mammalian target of rapamycin complex 1 (mTORC1) signaling pathways are frequently activated in acute myelogenous leukemia (AML). mTORC1 inhibition with RAD001 induces PI3K/Akt activation and both pathways are activated independently, providing a rationale for dual inhibition of both pathways. PI-103 is a new potent PI3K/Akt and mTOR inhibitor. In human leukemic cell lines and in primary blast cells from AML patients, PI-103 inhibited constitutive and growth factor-induced PI3K/Akt and mTORC1 activation. PI-103 was essentially cytostatic for cell lines and induced cell cycle arrest in the G1 phase. In blast cells, PI-103 inhibited leukemic proliferation, the clonogenicity of leukemic progenitors and induced mitochondrial apoptosis, especially in the compartment containing leukemic stem cells. In contrast, apoptosis was not induced with RAD001 and IC87114 association, which specifically inhibits mTORC1 and p110δ activity, respectively. PI-103 had additive proapoptotic effects with etoposide in blast cells and in immature leukemic cells. Interestingly, PI-103 did not induce apoptosis in normal CD34+ cells and had moderate effects on their clonogenic and proliferative properties. Here, we demonstrate that multitargeted therapy against PI3K/Akt and mTOR with PI-103 may be of therapeutic value in AML.

The growth and survival of acute myeloid leukemia (AML) cells are enhanced by the deregulation of signaling pathways such as phosphoinositide 3-kinase (PI3K)/Akt and mammalian target of rapamycin (mTOR). Major efforts have thus been made to develop molecules targeting these activated pathways. The mTOR serine/threonine kinase belongs to two separate complexes: mTORC1 and mTORC2. The mTORC1 pathway is rapamycin sensitive and controls protein translation through the phosphorylation of 4E-BP1 in most models. In AML, however, the translation process is deregulated and rapamycin resistant. Furthermore, the activity of PI3K/Akt and mTOR is closely related, as mTORC2 activates the oncogenic kinase Akt. We therefore tested, in this study, the antileukemic activity of the dual PI3K/mTOR ATP-competitive inhibitor NVP-BEZ235 compound (Novartis).The activity of NVP-BEZ235 was tested in primary AML samples (n = 21) and human leukemic cell lines. The different signaling pathways were analyzed by Western blotting. The cap-dependent mRNA translation was studied by 7-methyl-GTP pull-down experiments, polysomal analysis, and [(3)H]leucine incorporation assays. The antileukemic activity of NVP-BEZ235 was tested by analyzing its effects on leukemic progenitor clonogenicity, blast cell proliferation, and survival.The NVP-BEZ235 compound was found to inhibit PI3K and mTORC1 signaling and also mTORC2 activity. Furthermore, NVP-BEZ235 fully inhibits the rapamycin-resistant phosphorylation of 4E-BP1, resulting in a marked inhibition of protein translation in AML cells. Hence, NVP-BEZ235 reduces the proliferation rate and induces an important apoptotic response in AML cells without affecting normal CD34(+) survival.Our results clearly show the antileukemic efficiency of the NVP-BEZ235 compound, which therefore represents a promising option for future AML therapies.

The serine/threonine kinase mammalian target of rapamycin (mTOR) is crucial for cell growth and proliferation, and is constitutively activated in primary acute myeloid leukemia (AML) cells, therefore representing a major target for drug development in this disease. We show here that the specific mTOR kinase inhibitor AZD8055 blocked mTORC1 and mTORC2 signaling in AML. Particularly, AZD8055 fully inhibited multisite eIF4E-binding protein 1 phosphorylation, subsequently blocking protein translation, which was in contrast to the effects of rapamycin. In addition, the mTORC1-dependent PI3K/Akt feedback activation was fully abrogated in AZD8055-treated AML cells. Significantly, AZD8055 decreased AML blast cell proliferation and cell cycle progression, reduced the clonogenic growth of leukemic progenitors and induced caspase-dependent apoptosis in leukemic cells but not in normal immature CD34+ cells. Interestingly, AZD8055 strongly induced autophagy, which may be either protective or cell death inducing, depending on concentration. Finally, AZD8055 markedly increased the survival of AML transplanted mice through a significant reduction of tumor growth, without apparent toxicity. Our current results strongly suggest that AZD8055 should be tested in AML patients in clinical trials.

Abstract The phosphoinositide 3-kinase (PI3K/Akt) pathway is activated in acute myelogenous leukemia (AML) and is promising for targeted inhibition. Ninety-two patients with primary AML were analyzed for PI3K/Akt constitutive activation. Fifty percent of the patients presented with constitutive PI3K activation (PI3K +). No difference was observed between PI3K + and PI3K − groups concerning age, sex, white blood cell count, lactate dehydrogenase (LDH) level, bone marrow blast cells, French-American-British (FAB) classification, cytogenetics, RAS or nucleophosmin (NPM) mutations. Slightly more FLT3-ITD was detected in the PI3K − group (P = .048). The complete remission rate was similar between the 2 groups. With a median follow-up of 26 months, we observed for PI3K + and PI3K − patients, respectively, 56% and 33% overall survival (P = .001) and 72% and 41% relapse-free survival (P = .001). Constitutive PI3K/Akt activity is a favorable prognosis factor in AML, even after adjustment for FLT3-ITD, and may confer a particular sensitivity to chemotherapy. A better understanding of the downstream effectors of the PI3K/Akt pathway is needed before targeting in AML.

Alterations in the PI3K/Akt pathway are found in a wide range of cancers and the development of PI3K inhibitors represents a promising approach to cancer therapy. Constitutive PI3K activation, reflecting an intrinsic oncogenic deregulation of primary blast cells, is detected in 50% of patients with acute myeloid leukemia. However, the mechanisms leading to this activation are currently unknown. As we previously reported IGF-1 autocriny in acute myeloid leukemia cells, we investigated whether IGF-1 signaling was involved in the constitutive activation of PI3K.We analyzed the IGF-1/IGF-1R signaling pathway and PI3K activity in 40 acute myeloid leukemia bone marrow samples. Specific inhibition of IGF-1/IGF-1R signaling was investigated using neutralizing anti-IGF-1R, anti-IGF-1 antibodies or IGF-1 short interfering RNA. The anti-leukemic activity of the neutralizing anti-IGF-1R was tested by analyzing its effects on leukemic progenitor clonogenicity, blast cell proliferation and survival.In all samples tested, we found that functional IGF-1R was constantly expressed in leukemic cells. In the acute myeloid leukemia samples with PI3K activation, we found that the IGF-1R was constitutively phosphorylated, although no IGF-1R activating mutation was detected. Specific inhibition of IGF-1R signaling with neutralizing anti-IGF-1R strongly inhibited the constitutive phosphorylation of both IGF-1R and Akt in 70% of the PI3K activated samples. Moreover, both incubation with anti-IGF-1 antibody and IGF-1 short interfering RNA inhibited Akt phosphorylation in leukemic cells. Finally, neutralizing anti-IGF-1R treatment decreased the clonogenicity of leukemic progenitors and the proliferation of PI3K activated acute myeloid leukemia cells.Our current data indicate a critical role for IGF-1 autocriny in constitutive PI3K/Akt activation in primary acute myeloid leukemia cells and provide a strong rationale for targeting IGF-1R as a potential new therapy for this disease.

Key Points Bortezomib induces the degradation of FLT3-ITD through an autophagy-dependent mechanism that contributes to cell death. This finding provides a mechanism-based rationale for the study of proteasome inhibitors in FLT3-ITD–mutant acute myeloid leukemia.

Zebrafish were proposed as an alternative to mammalian models to assess the efficacy and toxicity of anti-leukemic drugs.Due to the limited number of transgenic zebrafish leukemia models, we explored human leukemic cell xenograft in zebrafish embryos.Human leukemic cell lines and blast cells sorted from patients with acute myelogenous leukemia were injected 48 hours post-fertilization and remained in the circulation of zebrafish embryos for several days without affecting their development.Imatinib and oxaphorines did not demonstrate any toxicity on normal zebrafish embryos and decreased the leukemic burden in animals xenografted with sensitive leukemic cell lines.Two other molecules, all-trans retinoic acid and the translation inhibitor 4EGI-1, demonstrated teratogenic effects at concentrations shown to be efficient in vitro, which precluded investigation of their anti-leukemic activity in such models.Altogether, xenografted leukemic cells in zebrafish embryos are a pharmacologically relevant model for screening nonteratogenic drugs.

Abstract Autophagy has been associated with oncogenesis with one of its emerging key functions being its contribution to the metabolism of tumors. Therefore, deciphering the mechanisms of how autophagy supports tumor cell metabolism is essential. Here, we demonstrate that the inhibition of autophagy induces an accumulation of lipid droplets (LD) due to a decrease in fatty acid β-oxidation, that leads to a reduction of oxidative phosphorylation (OxPHOS) in acute myeloid leukemia (AML), but not in normal cells. Thus, the autophagic process participates in lipid catabolism that supports OxPHOS in AML cells. Interestingly, the inhibition of OxPHOS leads to LD accumulation with the concomitant inhibition of autophagy. Mechanistically, we show that the disruption of mitochondria–endoplasmic reticulum (ER) contact sites (MERCs) phenocopies OxPHOS inhibition. Altogether, our data establish that mitochondria, through the regulation of MERCs, controls autophagy that, in turn finely tunes lipid degradation to fuel OxPHOS supporting proliferation and growth in leukemia.

AMPK is a master regulator of cellular metabolism that exerts either oncogenic or tumor suppressor activity depending on context. Here, we report that the specific AMPK agonist GSK621 selectively kills acute myeloid leukemia (AML) cells but spares normal hematopoietic progenitors. This differential sensitivity results from a unique synthetic lethal interaction involving concurrent activation of AMPK and mTORC1. Strikingly, the lethality of GSK621 in primary AML cells and AML cell lines is abrogated by chemical or genetic ablation of mTORC1 signaling. The same synthetic lethality between AMPK and mTORC1 activation is established in CD34-positive hematopoietic progenitors by constitutive activation of AKT or enhanced in AML cells by deletion of TSC2. Finally, cytotoxicity in AML cells from GSK621 involves the eIF2α/ATF4 signaling pathway that specifically results from mTORC1 activation. AMPK activation may represent a therapeutic opportunity in mTORC1-overactivated cancers.

Abstract Tanasi et al present a prospective strategy for identifying patients with Philadelphia-like acute lymphoblastic leukemia, demonstrating the efficacy of early introduction of tyrosine kinase inhibitors in improving outcomes.

Abstract Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive leukemia for which we developed a nationwide network to collect data from new cases diagnosed in France. In a retrospective, observational study of 86 patients (2000-2013), we described clinical and biological data focusing on morphologies and immunophenotype. We found expression of markers associated with plasmacytoid dendritic cell origin (HLA-DRhigh, CD303+, CD304+, and cTCL1+) plus CD4 and CD56 and frequent expression of isolated markers from the myeloid, B-, and T-lymphoid lineages, whereas specific markers (myeloperoxidase, CD14, cCD3, CD19, and cCD22) were not expressed. Fifty-one percent of cytogenetic abnormalities impact chromosomes 13, 12, 9, and 15. Myelemia was associated with an adverse prognosis. We categorized chemotherapeutic regimens into 5 groups: acute myeloid leukemia (AML)–like, acute lymphoid leukemia (ALL)–like, lymphoma (cyclophosphamide, doxorubicin, vincristine, and prednisone [CHOP])–like, high-dose methotrexate with asparaginase (Aspa-MTX) chemotherapies, and not otherwise specified (NOS) treatments. Thirty patients received allogeneic hematopoietic cell transplantation (allo-HCT), and 4 patients received autologous hematopoietic cell transplantation. There was no difference in survival between patients receiving AML-like, ALL-like, or Aspa-MTX regimens; survival was longer in patients who received AML-like, ALL-like, or Aspa-MTX regimens than in those who received CHOP-like regimens or NOS. Eleven patients are in persistent complete remission after allo-HCT with a median survival of 49 months vs 8 for other patients. Our series confirms a high response rate with a lower toxicity profile with the Aspa-MTX regimen, offering the best chance of access to hematopoietic cell transplantation and a possible cure.

Mitochondrial metabolism recently emerged as a critical dependency in acute myeloid leukemia (AML). The shape of mitochondria is tightly regulated by dynamin GTPase proteins, which drive opposing fusion and fission forces to consistently adapt bioenergetics to the cellular context. Here, we showed that targeting mitochondrial fusion was a new vulnerability of AML cells, when assayed in patient-derived xenograft (PDX) models. Genetic depletion of mitofusin 2 (MFN2) or optic atrophy 1 (OPA1) or pharmacological inhibition of OPA1 (MYLS22) blocked mitochondrial fusion and had significant anti-leukemic activity, while having limited impact on normal hematopoietic cells ex vivo and in vivo. Mechanistically, inhibition of mitochondrial fusion disrupted mitochondrial respiration and reactive oxygen species production, leading to cell cycle arrest at the G0/G1 transition. These results nominate the inhibition of mitochondrial fusion as a promising therapeutic approach for AML.

The link between cancer and metabolism has been suggested for a long time but further evidence of this hypothesis came from the recent molecular characterization of the LKB1/AMPK signaling pathway as a tumor suppressor axis. Besides the discovery of somatic mutations in the LKB1 gene in certain type of cancers, a critical emerging point was that the LKB1/AMPK axis remains generally functional and could be stimulated by pharmacological molecules such as metformin in cancer cells. Notably, most of experimental evidence of the anti-tumor activity of AMPK agonists comes from the study of solid tumors such as breast or prostate cancers and only few data are available in hematological malignancies, although recent works emphasized the potential therapeutic value of AMPK agonists in this setting. Further basic research work should be conducted to elucidate the molecular targets of LKB1/AMPK responsible for its anti-tumor activity in parallel of conducting clinical trials using metformin, AICAR or new AMPK activating agents to explore the potential of the LKB1/AMPK signaling pathway as a new target for anticancer drug development.

Fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) is frequently detected in acute myeloid leukemia (AML) patients and is associated with a dismal long-term prognosis. FLT3 tyrosine kinase inhibitors provide short-term disease control, but relapse invariably occurs within months. Pim protein kinases are oncogenic FLT3-ITD targets expressed in AML cells. We show that increased Pim kinase expression is found in relapse samples from AML patients treated with FLT3 inhibitors. Ectopic Pim-2 expression induces resistance to FLT3 inhibition in both FLT3-ITD-induced myeloproliferative neoplasm and AML models in mice. Strikingly, we found that Pim kinases govern FLT3-ITD signaling and that their pharmacological or genetic inhibition restores cell sensitivity to FLT3 inhibitors. Finally, dual inhibition of FLT3 and Pim kinases eradicates FLT3-ITD(+) cells including primary AML cells. Concomitant Pim and FLT3 inhibition represents a promising new avenue for AML therapy.

The authors identify mutations in β subunits of G proteins that promote transformation and therapy resistance. Activating mutations in genes encoding G protein α (Gα) subunits occur in 4–5% of all human cancers1, but oncogenic alterations in Gβ subunits have not been defined. Here we demonstrate that recurrent mutations in the Gβ proteins GNB1 and GNB2 confer cytokine-independent growth and activate canonical G protein signaling. Multiple mutations in GNB1 affect the protein interface that binds Gα subunits as well as downstream effectors and disrupt Gα interactions with the Gβγ dimer. Different mutations in Gβ proteins clustered partly on the basis of lineage; for example, all 11 GNB1 K57 mutations were in myeloid neoplasms, and seven of eight GNB1 I80 mutations were in B cell neoplasms. Expression of patient-derived GNB1 variants in Cdkn2a-deficient mouse bone marrow followed by transplantation resulted in either myeloid or B cell malignancies. In vivo treatment with the dual PI3K-mTOR inhibitor BEZ235 suppressed GNB1-induced signaling and markedly increased survival. In several human tumors, mutations in the gene encoding GNB1 co-occurred with oncogenic kinase alterations, including the BCR-ABL fusion protein, the V617F substitution in JAK2 and the V600K substitution in BRAF. Coexpression of patient-derived GNB1 variants with these mutant kinases resulted in inhibitor resistance in each context. Thus, GNB1 and GNB2 alterations confer transformed and resistance phenotypes across a range of human tumors and may be targetable with inhibitors of G protein signaling.

(Cancer Cell 29, 574–586; April 11, 2016) In the originally published version of this article, coauthor Andrew M. Intlekofer was listed incorrectly as Andrew M. Intlekoffer and coauthor Nicole R. LeBoeuf was listed incorrectly as Nicole LaBoeuf. These errors have now been corrected here and in the article online. The authors apologize for the errors and any inconvenience that may have resulted. The Public Repository of Xenografts Enables Discovery and Randomized Phase II-like Trials in MiceTownsend et al.Cancer CellApril 11, 2016In BriefTownsend et al. create a large, publicly available repository of leukemia and lymphoma patient-derived xenografts with well-characterized molecular and clinical information, and illustrate the utility of this repository by performing a preclinical in vivo study that mimics randomized human clinical trials. Full-Text PDF Open Archive

In this retrospective multicentre study, we investigated the outcomes of elderly primary central nervous system lymphoma (PCNSL) patients (⩾65 years) who underwent high-dose chemotherapy followed by autologous stem cell transplantation (HDT-ASCT) at 11 centres between 2003 and 2016. End points included remission, progression-free survival (PFS), overall survival (OS) and treatment-related mortality. We identified 52 patients (median age 68.5 years, median Karnofsky Performance Status before HDT-ASCT 80%) who all underwent thiotepa-based HDT-ASCT. Fifteen patients (28.8%) received HDT-ASCT as first-line treatment and 37 (71.2%) received it as second or subsequent line. Remission status before HDT-ASCT was: CR 34.6%, PR 51.9%, stable disease 3.8% and progressive disease 9.6%. Following completion of HDT-ASCT, 36 patients (69.2%) achieved CR (21.2% first-line setting and 48.1% second or subsequent line setting) and 9 (17.3%) PR (5.8% first-line setting and 11.5% second or subsequent line setting). With a median follow-up of 22 months after HDT-ASCT, median PFS and OS were reached after 51.1 and 122.3 months, respectively. The 2-year PFS and OS rates were 62.0% and 70.8%, respectively. We observed two HDT-ASCT-associated deaths (3.8%). In selected elderly PCNSL patients, HDT-ASCT, using thiotepa-based conditioning regimes, is feasible and effective. Further prospective and comparative studies are warranted to further evaluate the role of HDT-ASCT in elderly PCNSL patients.

Key Points GO before transplant improves outcome of CBF-AML patients in first relapse.

An in vitro drug-screening platform on patient samples was developed and validated to design personalized treatment for relapsed/refractory acute myeloid leukemia (AML). Unbiased clustering and correlation showed that homoharringtonine (HHT), also known as omacetaxine mepesuccinate, exhibited preferential antileukemia effect against AML carrying internal tandem duplication of fms-like tyrosine kinase 3 (FLT3-ITD). It worked synergistically with FLT3 inhibitors to suppress leukemia growth in vitro and in xenograft mouse models. Mechanistically, the effect was mediated by protein synthesis inhibition and reduction of short-lived proteins, including total and phosphorylated forms of FLT3 and its downstream signaling proteins. A phase 2 clinical trial of sorafenib and HHT combination treatment in FLT3-ITD AML patients resulted in complete remission (true or with insufficient hematological recovery) in 20 of 24 patients (83.3%), reduction of ITD allelic burden, and median leukemia-free and overall survivals of 12 and 33 weeks. The regimen has successfully bridged five patients to allogeneic hematopoietic stem cell transplantation and was well tolerated in patients unfit for conventional chemotherapy, including elderly and heavily pretreated patients. This study validated the principle and clinical relevance of in vitro drug testing and identified an improved treatment for FLT3-ITD AML. The results provided the foundation for phase 2/3 clinical trials to ascertain the clinical efficacy of FLT3 inhibitors and HHT in combination.

The AMP-activated protein kinase (AMPK) is principally known as a major regulator of cellular energy status, but it has been recently shown to play a key structural role in cell-cell junctions. The aim of this study was to evaluate the impact of AMPK activation on the reassembly of tight junctions in intestinal epithelial Caco-2 cells. We generated Caco-2 cells invalidated for AMPK α1/α2 (AMPK dKO) by CRISPR/Cas9 technology and evaluated the effect of the direct AMPK activator 991 on the reassembly of tight junctions following a calcium switch assay. We analyzed the integrity of the epithelial barrier by measuring the trans-epithelial electrical resistance (TEER), the paracellular permeability, and quantification of zonula occludens 1 (ZO-1) deposit at plasma membrane by immunofluorescence. Here, we demonstrated that AMPK deletion induced a delay in tight junction reassembly and relocalization at the plasma membrane during calcium switch, leading to impairments in the establishment of TEER and paracellular permeability. We also showed that 991-induced AMPK activation accelerated the reassembly and reorganization of tight junctions, improved the development of TEER and paracellular permeability after calcium switch. Thus, our results show that AMPK activation ensures a better recovery of epithelial barrier function following injury.

Abstract Relapses driven by chemoresistant leukemic cell populations are the main cause of mortality for patients with acute myeloid leukemia (AML). Here, we show that the ectonucleotidase CD39 (ENTPD1) is upregulated in cytarabine-resistant leukemic cells from both AML cell lines and patient samples in vivo and in vitro. CD39 cell-surface expression and activity is increased in patients with AML upon chemotherapy compared with diagnosis, and enrichment in CD39-expressing blasts is a marker of adverse prognosis in the clinics. High CD39 activity promotes cytarabine resistance by enhancing mitochondrial activity and biogenesis through activation of a cAMP-mediated adaptive mitochondrial stress response. Finally, genetic and pharmacologic inhibition of CD39 ecto-ATPase activity blocks the mitochondrial reprogramming triggered by cytarabine treatment and markedly enhances its cytotoxicity in AML cells in vitro and in vivo. Together, these results reveal CD39 as a new residual disease marker and a promising therapeutic target to improve chemotherapy response in AML. Significance: Extracellular ATP and CD39–P2RY13–cAMP–OxPHOS axis are key regulators of cytarabine resistance, offering a new promising therapeutic strategy in AML. This article is highlighted in the In This Issue feature, p. 1426

Abstract Objectives Venetoclax combined with hypomethylating agents is a new therapeutic strategy frequently used for treating AML patients who are not eligible for conventional chemotherapy. However, high response rates are heterogeneous due to different mechanisms mediating resistance to venetoclax such as up‐regulation of MCL‐1 expression. We thus tested the anti‐leukemic activity of S63845, a specific MCL‐1 inhibitor. Methods Apoptosis induces by S63845 with or without venetoclax was evaluated in primary AML samples and in AML cell lines co‐cultured or not with bone marrow (BM) mesenchymal stromal cells. Sensitivity of leukemic cells to S63845 was correlated to the expression level of BCL‐2, MCL‐1, and BCL‐XL determined by Western Blot and mass spectrometry‐based proteomics. Results We observed that even if MCL‐1 expression is weak compared to BCL‐2, S63845 induces apoptosis of AML cells and strongly synergizes with venetoclax. Furthermore, AML cells resistant to venetoclax are highly sensitive to S63845. Interestingly, the synergistic effect of S63845 toward venetoclax‐mediated apoptosis of AML cells is still observed in a context of interaction with the BM microenvironment that intrinsically mediates resistance to BCL2 inhibition. Conclusion These results are therefore of great relevance for clinicians as they provide the rational for combining BCL‐2 and MCL‐1 inhibition in AML.

Abstract Drug tolerant/resistant leukemic stem cell (LSC) subpopulations may explain frequent relapses in acute myeloid leukemia (AML), suggesting that these relapse-initiating cells (RICs) persistent after chemotherapy represent bona fide targets to prevent drug resistance and relapse. We uncover that calcitonin receptor-like receptor (CALCRL) is expressed in RICs, and that the overexpression of CALCRL and/or of its ligand adrenomedullin (ADM), and not CGRP, correlates to adverse outcome in AML. CALCRL knockdown impairs leukemic growth, decreases LSC frequency, and sensitizes to cytarabine in patient-derived xenograft models. Mechanistically, the ADM-CALCRL axis drives cell cycle, DNA repair, and mitochondrial OxPHOS function of AML blasts dependent on E2F1 and BCL2. Finally, CALCRL depletion reduces LSC frequency of RICs post-chemotherapy in vivo. In summary, our data highlight a critical role of ADM-CALCRL in post-chemotherapy persistence of these cells, and disclose a promising therapeutic target to prevent relapse in AML.

CRISPR-Cas9-based genetic screens have successfully identified cell type-dependent liabilities in cancer, including acute myeloid leukemia (AML), a devastating hematologic malignancy with poor overall survival. Because most of these screens have been performed in vitro using established cell lines, evaluating the physiologic relevance of these targets is critical. We have established a CRISPR screening approach using orthotopic xenograft models to validate and prioritize AML-enriched dependencies in vivo, including in CRISPR-competent AML patient-derived xenograft (PDX) models tractable for genome editing. Our integrated pipeline has revealed several targets with translational value, including SLC5A3 as a metabolic vulnerability for AML addicted to exogenous myo-inositol and MARCH5 as a critical guardian to prevent apoptosis in AML. MARCH5 repression enhanced the efficacy of BCL2 inhibitors such as venetoclax, further highlighting the clinical potential of targeting MARCH5 in AML. Our study provides a valuable strategy for discovery and prioritization of new candidate AML therapeutic targets. SIGNIFICANCE: There is an unmet need to improve the clinical outcome of AML. We developed an integrated in vivo screening approach to prioritize and validate AML dependencies with high translational potential. We identified SLC5A3 as a metabolic vulnerability and MARCH5 as a critical apoptosis regulator in AML, both of which represent novel therapeutic opportunities.This article is highlighted in the In This Issue feature, p. 275.

AMP-activated protein kinase (AMPK) regulates the balance between cellular anabolism and catabolism dependent on energy resources to maintain proliferation and survival. Small-compound AMPK activators show anti-cancer activity in preclinical models. Using the direct AMPK activator GSK621, we show that the unfolded protein response (UPR) is activated by AMPK in acute myeloid leukemia (AML) cells. Mechanistically, the UPR effector protein kinase RNA-like ER kinase (PERK) represses oxidative phosphorylation, tricarboxylic acid (TCA) cycle, and pyrimidine biosynthesis and primes the mitochondrial membrane to apoptotic signals in an AMPK-dependent manner. Accordingly, in vitro and in vivo studies reveal synergy between the direct AMPK activator GSK621 and the Bcl-2 inhibitor venetoclax. Thus, selective AMPK-activating compounds kill AML cells by rewiring mitochondrial metabolism that primes mitochondria to apoptosis by BH3 mimetics, holding therapeutic promise in AML.

Abstract The FOXO transcription factors are involved in multiple signaling pathways and have tumor-suppressor functions. In acute myeloid leukemia (AML), deregulation of oncogenic kinases, including Akt, extra-signal–regulated kinase, or IκB kinase, is frequently observed, which may potentially inactivate FOXO activity. We therefore investigated the mechanism underlying the regulation of FOXO3a, the only FOXO protein constantly expressed in AML blast cells. We show that in both primary AML samples and in a MV4-11/FOXO3a-GFP cell line, FOXO3a is in a constant inactive state due to its cytoplasmic localization, and that neither PI3K/Akt nor extra-signal–regulated kinase–specific inhibition resulted in its nuclear translocation. In contrast, the anti-Nemo peptide that specifically inhibits IKK activity was found to induce FOXO3a nuclear localization in leukemic cells. Furthermore, an IKK-insensitive FOXO3a protein mutated at S644 translocated into the nucleus and activated the transcription of the Fas-L and p21Cip1 genes. This, in turn, inhibited leukemic cell proliferation and induced apoptosis. These results thus indicate that IKK activity maintains FOXO3a in the cytoplasm and establishes an important role of FOXO3a inactivation in the proliferation and survival of AML cells. The restoration of FOXO3a activity by interacting with its subcellular distribution may thus represent a new attractive therapeutic strategy for AML.

The mTORC1 signaling pathway is constitutively activated in almost all acute myelogenous leukemia (AML) patients. We conducted a phase Ib trial combining RAD001 (everolimus), an allosteric inhibitor of mTORC1, and conventional chemotherapy, in AML patients under 65 years of age at first relapse (clinical trial NCT 01074086). Increasing doses of RAD001 from 10-70 mg were administrated orally on days 1 and 7 (d1 and d7) of a 3+7 daunorubicin+cytarabine conventional induction chemotherapy regimen. Twenty-eight patients were enrolled in this trial. The treatment was well tolerated with <10% toxicity, mainly involving the gastrointestinal tract and lungs. In this phase Ib trial, the RAD001 maximum tolerated dose was not reached at 70 mg. Sixty-eight percent of patients achieved CR, of which 14 received a double induction. Eight subsequently were intensified with allogeneic-stem cell transplant. Strong plasma inhibition of P-p70S6K was observed after RAD001 administration, still detectable at d7 (d7)at the 70 mg dosage. CR rates in patients with RAD001 areas under or above the curve median were 53% versus 85%. A 70 mg dose of RAD001 at d1 and d7 of an induction chemotherapy regimen for AML has acceptable toxicity and may improve treatment.

The type I cryoglobulins (CGs) account for 10–15% of all cryoglobulins and are found in patients with hematological disorders. We here describe the largest series of seven cases of type I cryoglobulinemia associated with multiple myeloma (MM) and provide a detailed review of the literature associated with this disorder, with the aim of improving the future diagnosis and therapeutic management of this rare disease. Six of the cases in our series were men aged 28–69 years, and most of the subject patients had an immunoglobulin G (IgG) monoclonal component and stage I indolent MM that manifested as cryoglobulin-related symptoms. The patients were all karyotypically normal. Clinical manifestations in this group were: skin lesions (five cases, 71.4%), rheumatologic failure (four cases, 57.1%), neurological abnormalities (two cases, 28.6%), mixed cutaneous/rheumatologic/renal defects (one case, 14.3%) and one case in which the cryoglobulinemia was asymptomatic. Two patients experienced acute renal failure but underwent a full recovery following treatment for MM. We conclude from our analysis that treatment approaches for severe type I cryoglobulinemia should involve plasmapheresis at the onset to achieve a rapid control of the CG-related symptoms, and that specific MM treatments should be introduced also at an early stage to avoid cryoglobulinemia relapse. In this context, bortezomib and lenalidomide are potentially the most effective therapeutic agents.

We assessed the antileukemic activity of 2-deoxy-d-glucose (2-DG) through the modulation of expression of receptor tyrosine kinases (RTK) commonly mutated in acute myeloid leukemia (AML). We used human leukemic cell lines cells, both in vitro and in vivo, as well as leukemic samples from AML patients to demonstrate the role of 2-DG in tumor cell growth inhibition. 2-DG, through N-linked glycosylation inhibition, affected the cell-surface expression and cellular signaling of both FTL3-ITD and mutated c-KIT and induced apoptotic cell death. Leukemic cells harboring these mutated RTKs (MV4-11, MOLM-14, Kasumi-1, and TF-1 c-KIT D816V) were the most sensitive to 2-DG treatment in vitro as compared with nonmutated cells. 2-DG activity was also demonstrated in leukemic cells harboring FLT3-TKD mutations resistant to the tyrosine kinase inhibitor (TKI) quizartinib. Moreover, the antileukemic activity of 2-DG was particularly marked in c-KIT-mutated cell lines and cell samples from core binding factor-AML patients. In these cells, 2-DG inhibited the cell-surface expression of c-KIT, abrogated STAT3 and MAPK-ERK pathways, and strongly downregulated the expression of the receptor resulting in a strong in vivo effect in NOD/SCID mice xenografted with Kasumi-1 cells. Finally, we showed that 2-DG decreases Mcl-1 protein expression in AML cells and induces sensitization to both the BH3 mimetic inhibitor of Bcl-xL, Bcl-2 and Bcl-w, ABT-737, and cytarabine. In conclusion, 2-DG displays a significant antileukemic activity in AML with FLT3-ITD or KIT mutations, opening a new therapeutic window in a subset of AML with mutated RTKs.

Vitamin D (VD) is a known differentiating agent, but the role of VD receptor (VDR) is still incompletely described in acute myeloid leukemia (AML), whose treatment is based mostly on antimitotic chemotherapy. Here, we present an unexpected role of VDR in normal hematopoiesis and in leukemogenesis. Limited VDR expression is associated with impaired myeloid progenitor differentiation and is a new prognostic factor in AML. In mice, the lack of Vdr results in increased numbers of hematopoietic and leukemia stem cells and quiescent hematopoietic stem cells. In addition, malignant transformation of Vdr-/- cells results in myeloid differentiation block and increases self-renewal. Vdr promoter is methylated in AML as in CD34+ cells, and demethylating agents induce VDR expression. Association of VDR agonists with hypomethylating agents promotes leukemia stem cell exhaustion and decreases tumor burden in AML mouse models. Thus, Vdr functions as a regulator of stem cell homeostasis and leukemic propagation.

Despite recent advances in acute myeloid leukemia (AML) molecular characterization and targeted therapies, a majority of AML cases still lack therapeutically actionable targets. In 127 AML cases with unmet therapeutic needs, as defined by the exclusion of ELN favorable cases and of FLT3-ITD mutations, we identified 51 (40%) cases with alterations in RAS pathway genes (RAS+, mostly NF1, NRAS, KRAS, and PTPN11 genes). In 79 homogeneously treated AML patients from this cohort, RAS+ status were associated with higher white blood cell count, higher LDH, and reduced survival. In AML models of oncogenic addiction to RAS-MEK signaling, the MEK inhibitor trametinib demonstrated antileukemic activity in vitro and in vivo. However, the efficacy of trametinib was heterogeneous in ex vivo cultures of primary RAS+ AML patient specimens. From repurposing drug screens in RAS-activated AML cells, we identified pyrvinium pamoate, an anti-helminthic agent efficiently inhibiting the growth of RAS+ primary AML cells ex vivo, preferentially in trametinib-resistant PTPN11- or KRAS-mutated samples. Metabolic and genetic complementarity between trametinib and pyrvinium pamoate translated into anti-AML synergy in vitro. Moreover, this combination inhibited the propagation of RA+ AML cells in vivo in mice, indicating a potential for future clinical development of this strategy in AML.

Abstract STUDY QUESTION What biological processes are linked to the signaling of the energy sensor 5′-AMP-activated protein kinase (AMPK) in mouse and human granulosa cells (GCs)? SUMMARY ANSWER The lack of α1AMPK in GCs impacted cell cycle, adhesion, lipid metabolism and induced a hyperandrogenic response. WHAT IS KNOWN ALREADY AMPK is expressed in the ovarian follicle, and its activation by pharmacological medications, such as metformin, inhibits the production of steroids. Polycystic ovary syndrome (PCOS) is responsible for infertility in approximately 5–20% of women of childbearing age and possible treatments include reducing body weight, improving lifestyle and the administration of a combination of drugs to improve insulin resistance, such as metformin. STUDY DESIGN, SIZE, DURATION AMPK signaling was evaluated by analyzing differential gene expression in immortalized human granulosa cells (KGNs) with and without silencing α1AMPK using CRISPR/Cas9. In vivo studies included the use of a α1AMPK knock-out mouse model to evaluate the role of α1AMPK in folliculogenesis and fertility. Expression of α1AMPK was evaluated in primary human granulosa-luteal cells retrieved from women undergoing IVF with and without a lean PCOS phenotype (i.e. BMI: 18–25 kg/m2). PARTICIPANTS/MATERIALS, SETTING, METHODS α1AMPK was disrupted in KGN cells and a transgenic mouse model. Cell viability, proliferation and metabolism were evaluated. Androgen production was evaluated by analyzing protein levels of relevant enzymes in the steroid pathway by western blots, and steroid levels obtained from in vitro and in vivo models by mass spectrometry. Differential gene expression in human GC was obtained by RNA sequencing. Analysis of in vivo murine folliculogenesis was performed by histology and immunochemistry, including evaluation of the anti-Müllerian hormone (AMH) marker. The α1AMPK gene expression was evaluated by quantitative RT-PCR in primary GCs obtained from women with the lean PCOS phenotype (n = 8) and without PCOS (n = 9). MAIN RESULTS AND THE ROLE OF CHANCE Silencing of α1AMPK in KGN increased cell proliferation (P &amp;lt; 0.05 versus control, n = 4), promoted the use of fatty acids over glucose, and induced a hyperandrogenic response resulting from upregulation of two of the enzymes involved in steroid production, namely 3β-hydroxysteroid dehydrogenase (3βHSD) and P450 side-chain cleavage enzyme (P450scc) (P &amp;lt; 0.05, n = 3). Female mice deficient in α1AMPK had a 30% decrease in their ovulation rate (P &amp;lt; 0.05, n = 7) and litter size, a hyperandrogenic response (P &amp;lt; 0.05, n = 7) with higher levels of 3βHSD and p450scc levels in the ovaries, and an increase in the population of antral follicles (P &amp;lt; 0.01, n = 10) compared to controls. Primary GCs from lean women with PCOS had lower α1AMPK mRNA expression levels than the control group (P &amp;lt; 0.05, n = 8–9) LARGE SCALE DATA The FastQ files and metadata were submitted to the European Nucleotide Archive (ENA) at EMBL-EBI under accession number PRJEB46048. LIMITATIONS, REASONS FOR CAUTION The human KGN is a not fully differentiated, transformed cell line. As such, to confirm the role of AMPK in GC and the PCOS phenotype, this model was compared to two others: an α1AMPK transgenic mouse model and primary differentiated granulosa-lutein cells from non-obese women undergoing IVF (with and without PCOS). A clear limitation is the small number of patients with PCOS utilized in this study and that the collection of human GCs was performed after hormonal stimulation. WIDER IMPLICATIONS OF THE FINDINGS Our results reveal that AMPK is directly involved in steroid production in human GCs. In addition, AMPK signaling was associated with other processes frequently reported as dysfunctional in PCOS models, such as cell adhesion, lipid metabolism and inflammation. Silencing of α1AMPK in KGN promoted folliculogenesis, with increases in AMH. Evaluating the expression of the α1AMPK subunit could be considered as a marker of interest in infertility cases related to hormonal imbalances and metabolic disorders, including PCOS. STUDY FUNDING/COMPETING INTEREST(S) This study was financially supported by the Institut National de la Recherche Agronomique (INRA) and the national programme « FERTiNERGY » funded by the French National Research Agency (ANR). The authors report no intellectual or financial conflicts of interest related to this work. R.K. is identified as personnel of the International Agency for Research on Cancer/World Health Organization. R.K. alone is responsible for the views expressed in this article and she does not necessarily represent the decisions, policy or views of the International Agency for Research on Cancer/World Health Organization. TRIAL REGISTRATION NUMBER N/A.

Cancer cells are frequently addicted to deregulated oncogenic protein translation. The small molecule 4EG-I selectively inhibits the cap-dependent translation of mRNAs. As multiple myeloma is an incurable disease that requires new therapeutic approaches, we investigated whether targeting the translation initiation pathway could be a target for myeloma therapy.Six myeloma cell lines and primary samples were included in this study. The 4EGI-1 effect was determined by AnnexinV staining and caspase activation. Modification of Bcl-2 protein expression was analysed, and the significance of modified proteins was analysed by knock-down experiments.We demonstrated that 4EGI-1 impaired the assembly of the eIF4F complex and decreased the expression of the eIF4E-regulated proteins in myeloma cells. Furthermore, we showed that 4EGI-1 induced strong apoptosis in five out of six myeloma cell lines. Apoptosis is associated with the activation of the intrinsic mitochondrial pathway. The 4EGI-1 triggered Noxa induction only in cells undergoing apoptosis through endoplasmic reticulum (ER) stress. Furthermore, Noxa silencing prevented myeloma cells from 4EGI-1-induced apoptosis. Finally, Noxa induction led to a disruption of Mcl-1/Bim complexes in parallel to the generation of 'Mcl-1-free Noxa'.Our results suggested that the use of inhibitors that directly target the translation initiation complex eIF4F could represent a potential novel approach for multiple myeloma therapy.

Splenectomy is part of the therapeutic arsenal for benign or malignant hematological disorders that constitute the main indication for elective splenectomy. With the development of minimally invasive approaches, and in particular, laparoscopy, as well as the advent of monoclonal antibody therapy, the indications and the outcomes of splenectomy for hematologic disease have changed in recent years. Nonetheless, splenectomy has its place in hemoglobinopathies and hemolytic diseases, improves thrombocytopenia in refractory immune thrombocytopenic purpura, can reverse sequelae linked to voluminous splenomegaly secondary to myelofibrosis, or can be used for diagnostic purposes or for splenomegaly in lymphoproliferative syndromes.

Acute myeloid leukemia (AML) is an aggressive hematopoietic malignancy that is cured in as few as 15%-40% of cases. Tremendous improvements in AML prognostication arose from a comprehensive analysis of leukemia cell genomes. Among normal karyotype AML cases, mutations in the FLT3 gene are the ones most commonly detected as having a deleterious prognostic impact. FLT3 is a transmembrane tyrosine kinase receptor, and alterations of the FLT3 gene such as internal tandem duplications (FLT3-ITD) deregulate FLT3 downstream signaling pathways in favor of increased cell proliferation and survival. FLT3 tyrosine kinase inhibitors (TKI) emerged as a new therapeutic option in FLT3-ITD AML, and clinical trials are ongoing with a variety of TKI either alone, combined with chemotherapy, or even as maintenance after allogenic stem cell transplantation. However, a wide range of molecular resistance mechanisms are activated upon TKI therapy, thus limiting their clinical impact. Massive research efforts are now ongoing to develop more efficient FLT3 TKI and/or new therapies targeting these resistance mechanisms to improve the prognosis of FLT3-ITD AML patients in the future.

Metabolic reprogramming is a common cancer cell phenotype as it sustains growth and proliferation. Targeting metabolic activities offers a wide range of therapeutic possibilities which are applicable to acute myeloid leukemia (AML). Indeed, in addition to the IDH1/2-mutated AML model which established the proof-of-concept for specifically targeting metabolic adaptations in AML, several recent reports have expanded the scope of such strategies in these diseases. This review highlights recent findings on metabolic deregulation in AML and summarizes their implications in leukemogenesis.

The mammalian Target Of Rapamycin Complex 1 (mTORC1) pathway is commonly activated in cancer cells including acute myeloid leukemia (AML) and has been designed as a major target for cancer therapy. However, the efficacy of rapalogs (mTORC1 inhibitors) is limited in AML, due to the feedback activation of PI3K or ERK signaling pathways upon mTORC1 inhibition, which pathways should be simultaneously targeted to enhance the anti-leukemic activity of rapalogs. Moreover, the mRNA translation process is mTORC1-independent in AML, although markedly contributing to oncogenesis in this disease, and this also strongly participates to rapalogs resistance. Translation inhibition could be achieved by directly targeting the translation initiating complex using the 4EGI-1 compound, anti-eIF4E antisense oligonucleotides or the antiviral drug ribavirin or by second generation mTOR inhibitors (TORkinhibs). These new approaches represent promising perspectives for AML therapy that should have clinical development in the future.

Nucleoside Analogues (NA) are considered as appropriate agents in the treatment of Waldenström's Macroglobulinemia (WM). There are sporadic reports on increased incidence of transformation to high grade non-Hodgkin lymphoma (transformation to NHL) and development of therapy related-myelodysplasia/acute leukemia (t-MDS/AML) among WM patients treated with NA. Several studies have been conducted in Europe and in the United States to retrospectively examine the incidence of such events in WM patients. The incidences of transformation to NHL and t-MDS/AML ranged from 4.7% to 8%, and from 1.4% to 8.9%, respectively, and demonstrated an increased incidence of these late events among WM patients treated with NA. The effect of these secondary malignancies needs to be better evaluated in prospective studies, especially in young patients. These NA treatment–associated risks should not by themselves be used to justify avoidance of NA therapy for WM patients but should be used in considering risk versus benefit for a particular patient given the expanding options of therapy for WM patients.

Summary Acute myeloid leukaemia ( AML ) is a heterogeneous malignancy. Intracellular signalling through the phosphatidylinositol 3‐kinase ( PI 3 K )‐ A kt‐mammalian target of rapamycin (m TOR ) pathway is important for regulation of cellular growth and metabolism, and inhibitors of this pathway is considered for AML treatment. Primary human AML cells, derived from 96 consecutive adult patients, were examined. The effects of two m TOR inhibitors (rapamycin, temsirolimus) and two PI 3 K inhibitors ( GDC ‐0941, 3‐methyladenine) were studied, and we investigated cytokine‐dependent proliferation, regulation of apoptosis and global gene expression profiles. Only a subset of patients demonstrated strong antiproliferative effects of PI 3 K ‐m TOR inhibitors. Unsupervised hierarchical clustering analysis identified two main clusters of patients; one subset showing weak or absent antiproliferative effects (59%) and another group showing a strong growth inhibition for all drugs and concentrations examined (41%). Global gene expression analyses showed that patients with AML cell resistance against PI 3 K ‐m TOR inhibitors showed increased m RNA expression of the CDC 25 B gene that encodes the cell cycle regulator Cell Division Cycle 25 B . The antileukaemic effect of PI 3 K ‐ A kt‐m TOR inhibition varies between patients, and resistance to these inhibitors is associated with the expression of the cell cycle regulator CDC 25 B , which is known to crosstalk with the PI 3 K ‐ A kt‐m TOR pathway and mediate rapamycin resistance in experimental models.

Limited data is available on the feasibility of high-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (AHSCT) in elderly patients over 70 years of age with non-Hodgkin's lymphoma (NHL).In the setting of the Société Française de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC) group, we retrospectively analyzed 81 consecutive patients with NHL over 70 years of age who received AHSCT.The median age at AHSCT was 72.3 years [70-80]. Patients' were diagnosed with diffuse large B-cell lymphoma (n=40), follicular lymphoma (n=16), mantle cell lymphoma (n=15), T-cell lymphoma (n=5), and other (n=5). Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI) was 0 in 73% of patients. Main conditionings were BEAM (Carmustine-Etoposide-Cytarabine-Melphalan, n=61) and melphalan alone (n=14). Median delays to reach 0.5×10⁹/L neutrophils and 20 × 10(9)/L platelets were of 12 [9-76] days and 12 [0-143] days, respectively. One hundred day and one year cumulative incidence of NRM was 5.4% and 8.5%, respectively. The main cause of death remains relapse.In conclusion, this study revealed that AHSCT seemed to be acceptable in patients over 70 years of age with NHL. Patient age is not a limiting factor if clinical condition is adequate.

Waldenstrom's macroglobulinemia is generally treated with alkylating agents, purine analogs and monoclonal antibodies, alone or in combination. We report the outcomes of 82 patients (median age 61 years) treated with the RFC combination. Twenty-five patients were treatment-naive. RFC was administered every 4 weeks, for a median of five cycles. At treatment discontinuation, the overall response rate was 85.4%. The responses improved after treatment discontinuation in 25 patients, with a median time to best response achievement of 10.8 months, raising the major response rate (PR, VGPR and CR) from 64.6% to 76.8%. With a median follow-up of 47 months, the median progression-free survival time had not been reached (67% PFS at 48 months) and was influenced by age and treatment status before RFC. Likewise, the median time to next therapy had not been reached. Two cases of myelodysplastic syndrome/AML and 3 cases of transformation to aggressive lymphoma occurred. Thirteen patients died. The 3-year overall survival rate was 90%. Long-lasting cytopenias occurred in 19 patients. The RFC combination thus gave a high response rate and durable responses, even in heavily treatment-experienced patients. The high incidence of long-lasting cytopenia might be reduced by giving fewer courses and thereby minimizing myelotoxicity. Am. J. Hematol. 91:782-786, 2016. © 2016 Wiley Periodicals, Inc.

Acute myeloid leukemia (AML) is an aggressive disease with a poor prognosis. Vacuolar protein sorting 34 (VPS34) is a member of the phosphatidylinositol-3-kinase lipid kinase family that controls the canonical autophagy pathway and vesicular trafficking. Using a recently developed specific inhibitor (VPS34-IN1), we found that VPS34 inhibition induces apoptosis in AML cells but not in normal CD34+ hematopoietic cells. Complete and acute inhibition of VPS34 was required for the antileukemic activity of VPS34-IN1. This inhibitor also has pleiotropic effects against various cellular functions related to class III PI3K in AML cells that may explain their survival impairment. VPS34-IN1 inhibits basal and L-asparaginase-induced autophagy in AML cells. A synergistic cell death activity of this drug was also demonstrated. VPS34-IN1 was additionally found to impair vesicular trafficking and mTORC1 signaling. From an unbiased approach based on phosphoproteomic analysis, we identified that VPS34-IN1 specifically inhibits STAT5 phosphorylation downstream of FLT3-ITD signaling in AML. The identification of the mechanisms controlling FLT3-ITD signaling by VPS34 represents an important insight into the oncogenesis of AML and could lead to new therapeutic strategies.

To the editor: The Pim (for provirus integration site for Moloney murine leukemia virus) family of serine/threonine kinases are strongly involved in oncogenic processes and efforts are ongoing to develop specific Pim kinase inhibitors as anti-cancer therapy.[1][1] Interestingly, recent reports from

l-asparaginase (L-ase) is a major drug used to treat acute lymphoblastic leukemia (ALL) [1]. L-ase kills leukemic cells by depleting circulating asparagine pools related to its asparaginase activit...

Fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) is one of the most common genetic lesions in acute myeloid leukemia patients (AML). Although FLT3 tyrosine kinase inhibitors initially exhibit clinical activity, resistance to treatment inevitably occurs within months. PIM kinases are thought to be major drivers of the resistance phenotype and their inhibition in relapsed samples restores cell sensitivity to FLT3 inhibitors. Thus, simultaneous PIM and FLT3 inhibition represents a promising strategy in AML therapy. For such reasons, we have developed SEL24-B489 - a potent, dual PIM and FLT3-ITD inhibitor. SEL24-B489 exhibited significantly broader on-target activity in AML cell lines and primary AML blasts than selective FLT3-ITD or PIM inhibitors. SEL24-B489 also demonstrated marked activity in cells bearing FLT3 tyrosine kinase domain (TKD) mutations that lead to FLT3 inhibitor resistance. Moreover, SEL24-B489 inhibited the growth of a broad panel of AML cell lines in xenograft models with a clear pharmacodynamic-pharmacokinetic relationship. Taken together, our data highlight the unique dual activity of the SEL24-B489 that abrogates the activity of signaling circuits involved in proliferation, inhibition of apoptosis and protein translation/metabolism. These results underscore the therapeutic potential of the dual PIM/FLT3-ITD inhibitor for the treatment of AML.

The oncogenic Pim2 kinase is overexpressed in several haematological malignancies, such as multiple myeloma and acute myeloid leukaemia (AML), and constitutes a strong therapeutic target candidate. Like other Pim kinases, Pim2 is constitutively active and is believed to be essentially regulated through its accumulation. We show that in leukaemic cells, the three Pim2 isoforms have dramatically short half-lives although the longer isoform is significantly more stable than the shorter isoforms. All isoforms present a cytoplasmic localization and their degradation was neither modified by broad-spectrum kinase or phosphatase inhibitors such as staurosporine or okadaic acid nor by specific inhibition of several intracellular signalling pathways including Erk, Akt and mTORC1. Pim2 degradation was inhibited by proteasome inhibitors but Pim2 ubiquitination was not detected even by blocking both proteasome activity and protein de-ubiquitinases (DUBs). Moreover, Pyr41, an ubiquitin-activating enzyme (E1) inhibitor, did not stabilize Pim2, strongly suggesting that Pim2 was degraded by the proteasome without ubiquitination. In agreement, we observed that purified 20S proteasome particles could degrade Pim2 molecule in vitro. Pim2 mRNA accumulation in UT7 cells was controlled by erythropoietin (Epo) through STAT5 transcription factors. In contrast, the translation of Pim2 mRNA was not regulated by mTORC1. Overall, our results suggest that Pim2 is only controlled by its mRNA accumulation level. Catalytically active Pim2 accumulated in proteasome inhibitor-treated myeloma cells. We show that Pim2 inhibitors and proteasome inhibitors, such as bortezomib, have additive effects to inhibit the growth of myeloma cells, suggesting that Pim2 could be an interesting target for the treatment of multiple myeloma.

CHK1 Ser/Thr kinase, a well characterized regulator of DNA damage response, is also involved in normal cell cycle progression. In this study, we investigate how CHK1 participates to proliferation of acute myeloid leukemia cells expressing the mutated FLT3-ITD tyrosine kinase receptor. Pharmacological inhibition of CHK1 as well as its shRNA mediated down regulation reduced the proliferation rate of FLT-ITD expressing leukemic cell lines in a cytostatic manner. Flow cytometry analysis revealed no accumulation in a specific phase of the cell cycle upon CHK1 inhibition. Accordingly, lentiviral-mediated CHK1 overexpression increased the proliferation rate of FLT3-ITD expressing cells, as judged by cell viability and [3H] thymidine incorporation experiments. By contrast, expression of a ser280 mutant did not, suggesting that phosphorylation of this residue is an important determinant of CHK1 proliferative function. Clonogenic growth of primary leukemic cells from patients in semi-solid medium was reduced upon CHK1 inhibition, confirming the data obtained with leukemic established cell lines. Surprisingly, 3 out of 4 CHK1 inhibitory compounds tested in this study were also potent inhibitors of the FLT3-ITD tyrosine kinase receptor. Altogether, these data identify CHK1 as a regulator of FLT3-ITD-positive leukemic cells proliferation, and they open interesting perspectives in terms of new therapeutic strategies for these pathologies.

Since the development of tyrosine kinase inhibitors (TKIs) targeting BCR/ABL1 and significantly improved outcomes on long-term disease-free survival in Philadelphia chromosome–positive (Ph+) acute ...

The purine analogs (PAs) cladribine and pentostatin have transformed the prognosis of hairy cell leukemia (HCL). However, some patients still relapse after PAs, or fail to reach an optimal response, and new agents are needed to further improve treatment outcome. We retrospectively studied 41 HCL patients from 10 centers in France and Belgium, who received 49 treatment courses with the anti-CD20 monoclonal antibody rituximab. Most of the patients were treated at relapse (84 % of cases) and rituximab was combined to a PA in 41 % of cases. Overall, response rate is 90 % including 71 % complete hematologic responses (CHRs). Frontline treatment, combination therapy, and absolute neutrophil count were associated with response in multivariate analysis. Three-year relapse-free and overall survivals are 68 and 90 %, respectively. When combined to a PA, rituximab yields a 100 % response rate, even beyond frontline therapy. In contrast, response rate is only 82 % (59 % CHR) when rituximab is used alone. In this latter setting, relapse rate is 56 % and median time to relapse is 17.5 months. All eight patients who were treated two times with the antibody responded again to re-treatment. We confirm the high efficacy of the combination rituximab + PA. However, when rituximab is used as monotherapy, response rate is lower and the high relapse rate is a concern. Prospective clinical trials are needed to confirm the superiority of the combination rituximab + PA over PA alone, both as frontline therapy and at relapse.

We investigated cell cycle regulation in acute myeloid leukemia cells expressing the FLT3-ITD mutated tyrosine kinase receptor, an underexplored field in this disease. Upon FLT3 inhibition, CDC25A mRNA and protein were rapidly down-regulated, while levels of other cell cycle proteins remained unchanged. This regulation was dependent on STAT5, arguing for FLT3-ITD-dependent transcriptional regulation of CDC25A. CDC25 inhibitors triggered proliferation arrest and cell death of FLT3-ITD as well as FLT3-ITD/TKD AC-220 resistant cells, but not of FLT3-wt cells. Consistently, RNA interference-mediated knock-down of CDC25A reduced the proliferation of FLT3-ITD cell lines. Finally, the clonogenic capacity of primary FLT3-ITD AML cells was reduced by the CDC25 inhibitor IRC-083864, while FLT3-wt AML and normal CD34+ myeloid cells were unaffected. In good agreement, in a cohort of 100 samples from AML patients with intermediate-risk cytogenetics, high levels of CDC25A mRNA were predictive of higher clonogenic potential in FLT3-ITD+ samples, not in FLT3-wt ones.Importantly, pharmacological inhibition as well as RNA interference-mediated knock-down of CDC25A also induced monocytic differentiation of FLT3-ITD positive cells, as judged by cell surface markers expression, morphological modifications, and C/EBPα phosphorylation. CDC25 inhibition also re-induced monocytic differentiation in primary AML blasts carrying the FLT3-ITD mutation, but not in blasts expressing wild type FLT3. Altogether, these data identify CDC25A as an early cell cycle transducer of FLT3-ITD oncogenic signaling, and as a promising target to inhibit proliferation and re-induce differentiation of FLT3-ITD AML cells.

Primary central nervous system lymphoma (PCNSL) is a rare topographic variant of diffuse large B-cell lymphoma (DLBCL). While prognostic scales are useful in clinical trials, no dynamic prognostic marker is available in this disease. We report here the prognostic value of early metabolic response by 18F-FDG PET scanner (PET) in 25 newly diagnosed immunocompetent PCNSL patients. Induction treatment consisted of four cycles of Rituximab, Methotrexate and Temozolamide (RMT). Based on patient's general condition, consolidation by high-dose Etoposide and Aracytine was given to responding patients. Brain MRI and PET were performed at diagnosis, after two and four cycles of RMT, and after treatment completion. Two-year progression-free (PFS) and overall survival (OS) were 62% and 74%, respectively for the whole cohort. Best responses after RMT induction were 18 (72%) complete response (CR)/CR undetermined (CRu), 4 (16%) partial response, 1 (4%) progressive disease and 2 (8%) stable disease. Response evaluation was concordant between MRI and PET at the end of induction therapy. Nineteen patients (76%) had a negative PET2. Predictive positive and negative values of PET2 on end-of-treatment (ETR) CR were 66.67% and 94.74%, respectively. We observed a significant association between PET2 negativity and ETR (p = 0.001) and longer PFS (p = 0.02), while having no impact on OS (p = 0.32). Two years PFS was 72% and 33% for PET2- and PET2+ patients, respectively (p < 0.02). PET2 evaluation may help to early define a subgroup of CR PCNSL patients with a favorable outcome.

Aplastic anemia is a rare but potentially life-threatening disease that may affect older patients. Data regarding the treatment of aplastic anemia in this ageing population remains scarce. We conducted a retrospective nationwide multicenter study in France to examine current treatments for aplastic anemia patients over 60 years old. Our aims were to evaluate efficacy and tolerance, and to analyze predictive factors for response and survival. Over the course of a decade, 88 patients (median age 68.5 years) were identified in 19 centers, with a median follow up of 2.7 years; 21% had very severe and 36% severe aplastic anemia. We analyzed 184 treatment lines, mostly involving the standard combination of anti-thymocyte globulin and cyclosporine-A (33%), which was also the most frequent first-line treatment (50%). After first-line therapy, 32% of patients achieved a complete response, and 15% a partial response. Responses were significantly better in first line and in patients with good performance status, as well as in those that had followed an anti-thymocyte globulin and cyclosporine-A regimen (overall response rate of 70% after first-line treatment). All treatments were well tolerated by patients, including over the age of 70. Three-year survival was 74.7% (median 7.36 years). Age, Charlson comorbidity index and very severe aplastic anemia were independently associated with mortality. Age, per se, is not a limiting factor to aplastic anemia treatment with anti-thymocyte globulin and cyclosporine-A; this regimen should be used as a first-line treatment in elderly patients if they have a good performance status and low comorbidity index score.

IL-35 is an immunosuppressive cytokine of the IL-12 family consisting of two subunits, EBV-induced gene 3 (EBI3) and p35. It has been shown to play a pro-tumor role in murine tumor models, and in various types of human cancer such as colorectal, pancreatic, or liver carcinoma, its expression has been associated with a worse clinical outcome. Here, we show by analyzing gene expression data from public databases and by immunohistochemical studies that IL-35 is overexpressed by tumor cells in diffuse-large B-cell lymphoma (DLBCL) compared to another type of mature aggressive B-cell lymphoma, Burkitt lymphoma. However, while high IL-35 expression was significantly associated with a worse overall survival in DLBCL patients treated with chemotherapy only (cyclophosphamide, doxorubicin, vincristine, prednisone, CHOP), no significant correlation between IL-35 expression levels and the patient outcome was observed in DLBCL patients treated with CHOP combined to rituximab (R-CHOP), the current conventional treatment. In addition, we found that an anti-IL-35 antibody, clone 15k8D10, used to assess IL-35 expression by immunohistochemistry in various human tissues including tumor tissues does not recognize IL-35 heterodimer, nor its individual subunits EBI3 and p35, but cross-reacts with human IgG1, indicating that IL-35 expression in human cancers needs to be re-evaluated.

Not available.

Glioblastoma (GBM) is a deadly and the most common primary brain tumor in adults. Due to their regulation of a high number of mRNA transcripts, microRNAs (miRNAs) are key molecules in the control of biological processes and are thereby promising therapeutic targets for GBM patients. In this regard, we recently reported miRNAs as strong modulators of GBM aggressiveness. Here, using an integrative and comprehensive analysis of the TCGA database and the transcriptome of GBM biopsies, we identified three critical and clinically relevant miRNAs for GBM, miR-17-3p, miR-222, and miR-340. In addition, we showed that the combinatorial modulation of three of these miRNAs efficiently inhibited several biological processes in patient-derived GBM cells of all these three GBM subtypes (Mesenchymal, Proneural, Classical), induced cell death, and delayed tumor growth in a mouse tumor model. Finally, in a doxycycline-inducible model, we observed a significant inhibition of GBM stem cell viability and a significant delay of orthotopic tumor growth. Collectively, our results reveal, for the first time, the potential of miR-17-3p, miR-222 and miR-340 multi-targeting as a promising therapeutic strategy for GBM patients.

Abnormal activation of several signal transduction pathways such as phosphoinositide 3-kinase (PI3K) and MAP kinases has been reported in acute myeloid leukemia (AML). To test new targeted therapeutics, it is critical to develop sensitive analytical tools to detect abnormal activation of these pathways and to monitor their inhibition in response to treatment.We analyzed Akt and ERK phosphorylation in 32 samples from patients using western blot and a two-color flow cytometry protocol using CD34. To circumvent the CD34 negative AML found in our series, we developed a two-color protocol using CD45 to isolate the blast cell population. Finally, a four-color protocol was used to detect phosphorylation in an enriched population of AML stem cells.We compared western blot analysis and flow cytometry for the detection of PI3K/Akt and ERK activation and found a 100% correlation between the two techniques in a series of 32 AML samples. Using a flow cytometry protocol, we were able to analyze all the patients' samples, even those with low blast infiltration or CD34 negative blast cells. We were also able to detect the phosphorylated proteins in the most immature blast cell population with the CD34+ CD38-/low CD123+ phenotype. Interpretations andOur study shows that flow cytometry is a reliable method for detecting Akt and ERK phosphorylation in all patients' samples. Activation can also be detected in the most immature blast cells, which represent exquisite target cells for new therapeutics.

Objectives: Hematologic malignancies may result in multiple organ involvement including pulmonary and renal dysfunctions, and the less common acute circulatory failure. We herein addressed the outcome of patients with sepsis-like shock related to aggressive hematologic malignancies. Design: A 10-year (2007–2016) monocenter retrospective study. Settings: A medical ICU in a tertiary care center. Patients: Patients with circulatory shock requiring vasopressors and who subsequently received chemotherapy. Shock was presumably related to the underlying malignancy after ruling out an ongoing or new-onset infectious process. The extent and time course of organ failures was assessed by a modified Sequential Organ Failure Assessment score devoid of the platelet component. Interventions: None. Measurements and Main Results: Seventeen patients were included, including 13 with non-Hodgkin lymphoma, two with hyperleukocytic acute myeloid leukemia, and two with “Human Herpes virus 8”–associated multicentric Castleman’s disease. The following associated conditions prompted urgent administration of chemotherapy: tumor lysis syndrome ( n = 10), hemophagocytic lymphohistiocytosis ( n = 3), compressive bulky tumor ( n = 3), pulmonary involvement ( n = 3), and disseminated intravascular coagulation ( n = 1). Following the initiation of chemotherapy, a number of patients died rapidly from untractable multiple organ failure. In contrast, chemotherapy led to a fast and dramatic improvement in organ failures in early survivors, as shown by the decrease in the modified Sequential Organ Failure Assessment score. However, the overall outcome was poor since only four and three patients could be discharged alive from the ICU and the hospital, and three and two patients remained alive at 6 months and 1 year. Conclusions: Multiple organ dysfunction syndrome related to hematologic malignancies is associated with a dismal outcome. A chemotherapy trial may provide a fast prognostic assessment of the reversibility of organ failure.

Abstract Haematopoietic stem cell (HSC) transplantation (HSCT) is the only curative treatment for a broad range of haematological malignancies, but the standard of care relies on untargeted chemotherapies and limited possibilities to treat malignant cells after HSCT without affecting the transplanted healthy cells 1 . Antigen-specific cell-depleting therapies hold the promise of much more targeted elimination of diseased cells, as witnessed in the past decade by the revolution of clinical practice for B cell malignancies 2 . However, target selection is complex and limited to antigens expressed on subsets of haematopoietic cells, resulting in a fragmented therapy landscape with high development costs 2–5 . Here we demonstrate that an antibody–drug conjugate (ADC) targeting the pan-haematopoietic marker CD45 enables the antigen-specific depletion of the entire haematopoietic system, including HSCs. Pairing this ADC with the transplantation of human HSCs engineered to be shielded from the CD45-targeting ADC enables the selective eradication of leukaemic cells with preserved haematopoiesis. The combination of CD45-targeting ADCs and engineered HSCs creates an almost universal strategy to replace a diseased haematopoietic system, irrespective of disease aetiology or originating cell type. We propose that this approach could have broad implications beyond haematological malignancies.

Constitutive phosphoinositide 3-kinase activation in acute myeloid leukemia is not due to p110 δ mutations

Follicular lymphomas (FLs) are frequent B-cell derived malignancies, generally demonstrating an indolent evolution. Although circulating FL cells may be detected by high-resolution analysis, bloodstream involvement by FL cells is unusual. We observed in 10 patients a leukemic phase of FL at the onset of the disease. Six of them had concomitant lymph node involvement and all of them required treatment at diagnosis due to a high tumor burden, whereas four patients had pure FL-cell leukemia, which was associated with a more indolent clinical outcome. The detection of a leukemic phase should therefore be studied as a potential prognosis marker in further studies.

In our series, none of the 7 cases with NPM1 deletions showed at karyotypic examination a deletion that included the NPM1 gene locus at 5q35.However, it should be noted that the inaccuracy of the deleted region assignment by chromosome banding has been reported for 5q deletions in both MDS and AML. 11 Our findings suggest that NPM1 haploinsufficiency may have a role in myeloid malignancies associated with large 5q-deletions contributing to MDS development likely through genetic instability.This would be in line with the finding that NPM1 is haploinsufficient in the control of centrosome duplication in the mouse model, as well as with evidence that NPM1 hypomorphic mouse embryonic fibroblasts reveal high levels of tetraploidy and aneuploidy. 4Alternatively, NPM1 deletions may represent secondary events linked to the progression of the disease in MDS.Given the low number of cases and heterogeneity of treatments, we were unable to determine here the clinical significance of NPM1 deletion in MDS with 5q-.Hence a larger series of cases including homogeneously treated patients is needed to investigate the prognostic impact of these abnormalities.

Primary bone diffuse large B-cell lymphoma (PB-DLBCL) is a rare DLBCL location variant. We treated 76 PB-DLBCL patients by immuno-chemotherapy, resulting in an 84% sustained complete remission rate and a 78.9% survival over a 4.7-year median follow-up period. Ann Arbor stage IV and high age-adjusted international prognostic index were predictive of adverse outcome in univariate analysis. In multivariate analysis using a Cox model, only aa-IPI predicted long-term survival. While based on a limited number of cases, we suggested that radiotherapy may be useful as a consolidation modality in PB-DLBCL. We also suggested that positron emission tomography/CT scan should be interpreted with caution due to a persistent [18F]fluorodeoxyglucose [18FDG] uptake of bone lesions even after remission in some in PB-DLBCL patients. Our study based on a homogeneous cohort of PB-DLBCL patients confirmed the favorable outcome of this DLBCL variant and support the implementation of prospective clinical trials in this disease.

We analysed the evolution of different cytokines (IL-4, IL-6, tumour necrosis factor alpha and vascular endothelial growth factor; VEGF) involved in the development of Kaposi's sarcoma in two patients in whom HIV infection presented with disseminated Mycobacterium tuberculosis infection. They simultaneously developed tuberculosis-associated immune restoration disease and Kaposi's sarcoma shortly after the initiation of HAART. Analysis of VEGF and pro-inflammatory cytokines led us to hypothesize that Kaposi's sarcoma could be promoted by the tuberculosis immune response.

Effectiveness and tolerance of low to very low dose thalidomide in low-risk myelodysplastic syndromes J. Tamburini a,∗, C. Elie b, S. Park a, O. Beyne-Rauzy c, M. Gardembas d, C. Berthou e, B. Mahe f, L. Sanhes g, A. Stamatoullas h, N. Vey i, A. Aouba j, B. Slama k, B. Quesnel l, A. Vekhoff n, J.J. Sotto m, D. Vassilief a, C. Al-Nawakil a, P. Fenaux o, F. Dreyfus a, D. Bouscary a, for the “Groupe Francophone des Myelodysplasies, GFM” a Department of haematology Hopital Cochin, France b Department of biostatistiques universite Paris 5, France c Department of Hematology Odile; Hopital Purpan, Toulouse, France d Department of Hematology Martine; Centre Hospitalier d’Angers, France e Department of Hematology Christian; Hopital de Brest, France f Department of Hematology Centre hospitalier de Nantes, France g Department of Hematology Centre Hospitalier de Perpignan, France h Department of Hematology Aspasia; Centre Hospitalier de Rouen, France i Department of HematologyInstitut Paoli Calmette, Marseille, France j Hopital Cochin, Paris, internal medicine, France k Department of Hematology Centre Hospitalier d’Avignon, France l Department of Hematology Centre Hospitalier de Lille, France m Department of Hematology Centre Hospitalier de Grenoble, France n Department of Hematology Hopital Hotel Dieu, Paris, Hematology, France o Department of Hematology Hopital Avicenne, Bobigny, France

Tandem stem cell transplantation (SCT) is an option for high-risk relapsed/refractory Hodgkin Lymphoma (HL) patients. We evaluated the tolerance/efficacy of double autologous or autologous SCT (ASCT) followed by allogenic SCT (alloSCT) in 120 HL patients prospectively registered on a French nationwide database. Median age was 26 (14-56) years. Complete remission rate was 60%, including 33% after a single line, and another 27% after two or more salvage regimens. Partial response rate was 32%, and 8% suffered treatment failure. Overall, 115 (96%) patients underwent a first ASCT, and 73 (61%) had a tandem SCT, including alloSCT in 44 (60%) and ASCT in 29 (40%). The median follow-up was 43 months (4.8-73.7 months). The two-year progression-free survival rate for the whole population and for patients receiving tandem transplant was 56% (95% confidence interval [CI]: 46-65%) and 71% (95% CI: 49-84%), respectively. Among tandem transplants, we observed 20 deaths (17%), 10 of which were transplant-related (6 alloSCT and 4 ASCT). We suggest that tandem SCT is efficient in high-risk relapsed/refractory HL patients, although transplant-related mortality remains high. The benefit of tandem SCT should be balanced with the efficacy of Brentuximab vedotin-based post-transplant consolidative strategies in high-risk relapsed/refractory HL patients.

Primary cutaneous follicle center lymphoma (PCFCL) is the most common cutaneous B cell lymphoma. It is most often indolent and responds well to rituximab. We present a case of transient rituximab-induced edematous lesions located exclusively on tumor papules in a patient treated for PCFCL. Based on this observation and on a review of the literature, we discuss the mechanism of this edematous reaction which does not seem to be allergic. Indeed, this focal reaction observed solely during the first infusion of rituximab is more likely linked with local cytokine release induced by B cell lysis in the skin. This reaction is neither unusual nor severe and should not lead to an interruption of rituximab.

Protein kinase inhibitors have proved to be effective and well tolerated in special form of malignant diseases in which targeted kinases play a central role in the development and progression of the malignant clone. In addition, the development of acquired drug resistance, due to new mutations or clonal evolution, during treatment is common. Methods for measuring the activity and predicting the efficacy of such compounds are warranted for evaluating individual responses to treatment, particularly in a context of widespread preclinical and clinical studies of protein kinase inhibitors in patients with heterogeneous myeloid malignancies.

Thirteen patients who had refused a blood transfusion for religious reasons were treated by autologous stem cell transplantation (ASCT) without a blood product transfusion at our Institution between 2005 and 2012. The study protocol was approved by the Ethics Review Committee (ccp Ile-de-France, Paris, France). The patients included eight males and five females with multiple myeloma (MM, n = 8), Hodgkin lymphoma (HL, n = 3) and non-Hodgkin lymphoma (NHL, n = 2) (Table 1). The median age was 51 (range, 19·4–64·6) years at diagnosis and 51·8 (range, 21·6–65·2) years at ASCT. The conditioning regimens before transplantation were as follows: 140 mg/m² melphalan (n = 1); 200 mg/m² melphalan (n = 7) and BEAM (BCNU 300 mg/m² day 1, etoposide 200 mg/m² days 2–4, cytarabine 200 mg/m² days 2–4 and melphalan 140 mg/m² day 5) (n = 5). The mean number of CD34+ immature haematopoietic cells infused was 6·8 × 106 CD34+/kg (range, 2·5–11·28). The median delay between diagnosis and transplant was 9·3 (range, 4·9–46·3) months. Before and after the procedure, all patients received erythropoietin (EPO). After transplantation, 77% (10/13) of the patients received 4 μg/kg of the thrombopoietin receptor (TPO-R) agonist romiplostim (Nplate®; Amgen, Thousand Oaks, CA, USA) for a median of 1 (0–2) injections, along with a single injection of 6 mg pegylated granulocyte colony-stimulating factor (G-CSF) pegfilgrastim (Neulasta®; Amgen, Thousand Oaks, CA, USA) at day +2. In addition, 30% (4/13) of our patients were treated with romiplostim before transplantation (4 μg/kg 8 d before conditioning in three patients and 15 and 8 d before in one patient) (Table 1). The blood tests at the time of cell transplant were (mean values) haemoglobin 135 g/l (range, 101–153); platelets 377·5 (range, 153–860) ×109/l, and neutrophils 3·71 (range, 1–11·5) ×109/l. The mean duration of neutropenia (<0·5 × 109/l) and thrombocytopenia (<10 × 109/l) was 4·5 (range, 3–8) and 2·8 (range, 0–15) days, respectively. The mean haemoglobin level consistently remained over 110 g/l. Figure 1 illustrates the course of the neutrophil count, haemoglobin level and platelet count. No significant bleeding complications were observed. The median follow-up was 39·5 months (range, 10·5–157) post-diagnosis and 28 months (2–149) post-transplantation. Five patients relapsed, at a median of 28 (range, 20·5–51) months. Two MM patients and one HL patient died from disease progression. Among patients with religious objection to transfusion of blood products on religious grounds, Jehovah's Witnesses (JW) represent the largest community, estimated to be 6 million people worldwide (Ballen et al, 2004). Although JW patients generally refuse transfusions of red cells, white cells, plasma, and platelets, some of these individuals may eventually accept blood fractions that include haematopoietic stem cells (Ballen et al, 2004). Few reports have been published in this setting however (Sloan & Ballen, 2008) and the only two reported studies revealed a significant degree of transplant-related mortality (TRM) (8% and 4%, respectively), mostly due to thrombocytopenia-related haemorrhagic complications (Ballen et al, 2004; Brown et al, 2006), emphasizing the need for new strategies to enhance the haematological tolerance of ASCT without transfusion. Importantly, the mean number of CD34+ cells infused to our patients was 6·8 × 106/kg (minimum threshold 2·5 × 106/kg) and significantly, the two patients with a low CD34+ count (2·5 and 3·6 × 106/kg) experienced a delayed haematological recovery (Table 1). We thus clearly recommend collecting at least 5 × 106/kg CD34+ cells, which may be achieved in almost all patients by using the CXCR4 antagonist plerixafor (Mozobil®; Genzyme, Cambridge, MA, USA), which has recently been approved for stem cell mobilization in cancer patients (Mohty et al, 2011). It should also be noted from our current results that the time to haematopoietic recovery was significantly delayed when using BEAM compared with melphalan, probably due to more important microenvironment damages with the BEAM regimen. We also systematically used pegfilgrastim to accelerate neutrophil recovery, a compound which is now widely used after cell transplantation (Samaras et al, 2011). Interestingly, we used the recently discovered TPO-R agonist romiplostim for the first time in a post-transplant setting. Romiplostim has been approved for the treatment of refractory immune thrombocytopenia (ITP), demonstrating a favourable safety profile (Nurden et al, 2009; George, 2010; Kuter et al, 2010), which was also observed in our current study, although based on a limited number of patients. Of particular note, no rebound thrombocytopenia was observed after romiplostim discontinuation. The main problems observed in an earlier study (Ballen et al, 2004) was the occurrence of severe bleeding complications, occurring in 5/26 (19%) of the patients and the cause of two deaths (8%). These results were thereafter confirmed by a study of 48 patients, which reported a 4% bleeding-related TRM rate (Brown et al, 2006). Interestingly, no significant bleeding event occurred among our 13 patients. Several factors may have influenced this difference with previous reports, including, in comparison to study reported by Ballen et al (2004), a smaller number of patients in our cohort, a predominance of MM patients with conditioning regimens less toxic to the bone marrow microenvironment (8/13, 61% vs. 8/26, 31%) and a higher number of CD34+ cells infused (mean 6·8 × 106 vs. 3·8 × 106). However, the period of severe thrombocytopenia appeared to be reduced in our patient population (a mean of 2·6 (range, 0–15) versus 4 (range, 0–12) days reported previously (Ballen et al, 2004)), and we speculate that romiplostim may have contributed to this outcome, leading to a reduction of haemorrhagic complications. Hence, we significantly modified our protocol in four patients, who were treated with one injection of 4 μg/kg romiplostim 1 week before transplantation and at days +2 and +8 post-transplant. For these patients, of whom two were treated by BEAM, the mean period of severe thrombocytopenia was 1 (range, 0–4) day. The last patient received 4 μg/kg romiplostim before melphalan on days 15 and 8; the nadir platelet count was 34 × 109/l. Further studies may help to determine a more accurate dosage and schedule for romiplostim administration during ASCT, based on ongoing studies with TPO-R agonists as a supporting intervention after chemotherapy (Stasi et al, 2010). Overall, our current study confirms the feasibility of ASCT without transfusion and emphasizes the benefit of using haematopoiesis-stimulating agents in this setting. J.T. designed the research study, M.C.Q., F.H., B.D., S.P., F.D. and D.B. provided patient care, clinical information and analysed the data, C.A.N. and J.T. provided patient care, clinical information, analysed the data and wrote the paper. The author(s) indicated no potential conflicts of interest.

Multiple myeloma (MM) is a clonal plasma cell disorder, which remains incurable. The t(4;14) translocation is present in 15% of patients with symptomatic disease and, despite recent therapeutic improvements such as bortezomib treatment, still indicates a poor prognosis.[1][1],[2][2] However, t(4;14

The British Journal of Haematology publishes original research papers in clinical, laboratory and experimental haematology. The Journal also features annotations, reviews, short reports, images in haematology and Letters to the Editor.

Abstract Identification of specific and therapeutically actionable vulnerabilities in acute myeloid leukaemia (AML) is needed to improve patients’ outcome. These features should be ideally present in many patients independently of mutational background. Here we identify de novo fatty acid (FA) desaturation, specifically stearoyl-CoA desaturase (SCD) inhibition, as a therapeutic vulnerability across multiple AML models in vitro and in vivo . We use the novel clinical grade SCD inhibitor SSI-4 to show that SCD inhibition induces AML cell death via pleiotropic effects, and sensitivity is based on their dependency on FA desaturation regardless of mutational profile. SSI-4 efficacy is enhanced by driving FA biosynthesis in vitro while stroma confers protective effects that extend to in vivo models. SCD inhibition increases DNA damage and its combination with standard DNA damage-inducing chemotherapy prolongs survival in aggressive murine AML models. Our work supports developing FA desaturase inhibitors in AML while stressing the importance of identifying predictive biomarkers of response and biologically validated combination therapies to realize their therapeutic potential. One Sentence Summary SCD inhibition is toxic to AML cells with high rates of fatty acid desaturation and in combination with chemotherapy prolongs survival in murine AML models.

AMP-activated protein kinase (AMPK) is a heterotrimeric complex containing α, β, and γ subunits involved in maintaining integrity and survival of murine red blood cells. Indeed, Ampk α1-/- , Ampk β1-/- and Ampk γ1-/- mice develop hemolytic anemia and the plasma membrane of their red blood cells shows elasticity defects. The membrane composition evolves continuously along erythropoiesis and during red blood cell maturation; defects due to the absence of Ampk could be initiated during erythropoiesis. We, therefore, studied the role of AMPK during human erythropoiesis. Our data show that AMPK activation had two distinct phases in primary erythroblasts. The phosphorylation of AMPK (Thr172) and its target acetyl CoA carboxylase (Ser79) was elevated in immature erythroblasts (glycophorin Alow), then decreased conjointly with erythroid differentiation. In erythroblasts, knockdown of the α1 catalytic subunit by short hairpin RNA led to a decrease in cell proliferation and alterations in the expression of membrane proteins (band 3 and glycophorin A) associated with an increase in phosphorylation of adducin (Ser726). AMPK activation in mature erythroblasts (glycophorin Ahigh), achieved through the use of direct activators (GSK621 and compound 991), induced cell cycle arrest in the S phase, the induction of autophagy and caspase-dependent apoptosis, whereas no such effects were observed in similarly treated immature erythroblasts. Thus, our work suggests that AMPK activation during the final stages of erythropoiesis is deleterious. As the use of direct AMPK activators is being considered as a treatment in several pathologies (diabetes, acute myeloid leukemia), this observation is pivotal. Our data highlighted the importance of the finely-tuned regulation of AMPK during human erythropoiesis.

AMP-activated protein kinase (AMPK) is a critical energy sensor, regulating signaling networks involved in pathology including metabolic diseases and cancer. This increasingly recognized role of AMPK has prompted tremendous research efforts to develop new pharmacological AMPK activators. To precisely study the role of AMPK, and the specificity and activity of AMPK activators in cellular models, genetic AMPK inactivating tools are required. We report here methods for genetic inactivation of AMPK α1/α2 catalytic subunits in human cell lines by the CRISPR/Cas9 technology, a recent breakthrough technique for genome editing.

We report the therapeutic potential of GSK621, an AMP-activated protein kinase (AMPK) agonist, in acute myeloid leukemia (AML). GSK621-induced cytotoxicity is restricted to AML cells compared to normal hematopoietic progenitors due to a unique synthetic lethal interaction of co-activation of AMPK and mammalian target of rapamycin complex 1 (mTORC1) that involves the stress response pathway. AMPK activation thus represents an attractive perspective for cancer therapy.

We would like to report a study on solitary plasmacytoma of the bone (SPB) treatment.SPB is a rare plasma cell dyscrasia characterized by a single bone tumor with no evidence of other lesions or mu...

Immune Thrombocytopenic Purpura (ITP) is an autoimmune disease that mainly results from a rapid splenic and hepatic clearance of autoantibody-loaded platelets from the circulation (Koehrer et al, 2010). Secondary causes of ITP must be excluded at diagnosis, including autoimmune conditions, chronic infection (e.g. Hepatitis C virus, human immunodeficiency virus) and lymphoproliferative disorders (LPD), particularly B-cell chronic lymphocytic leukaemia (B-CLL) (Cines et al, 2009). Treatment options for idiopathic ITP are well defined, including steroids, intravenous immunoglobulins (IVIG) in acute ITP, and the anti-CD20 monoclonal antibody rituximab, splenectomy and immune suppressive drugs in chronic ITP (George, 2010). Recently, a breakthrough in chronic ITP treatment has been achieved with the use of the thrombopoietin receptor (TPO-R) agonists, romiplostim (Nplate; Amgen, Thousand Oaks, CA, USA) and eltrombopag (Promacta; GlaxoSmithKline, Research Triangle Park, NC, USA), which produce rapid dose-dependent increases in the platelet count, even in patients with refractory ITP. Moreover, responses to these new agents are generally sustained during therapy and their long-term use appears to be associated with a good safety profile (Nurden et al, 2009). In B-CLL patients, the occurrence of an autoimmune disorder (AID) negatively impact on the prognosis (Zent et al, 2009). Although no therapeutic guidelines are available in this situation, recent reports emphasized the use of rituximab alone (D’Arena et al, 2010) or in combination with chemotherapy (Kaufman et al, 2009; Bowen et al, 2010) or TPO-R agonist (Koehrer et al, 2010; D’Arena & Cascavilla, 2011). However, other causes of thrombocytopenia, including disease progression, hypersplenism and therapy-related thrombocytopenia, must be ruled out in this situation and this generally requires a bone marrow examination (Zent et al, 2009). In addition to ITP in B-CLL, ITP has occasionally been reported in association with Hodgkin lymphomas or non-Hodgkin lymphomas (NHL) of T or B cell origin. However in those single-case reports, treatment was variable and mostly focused on the lymphoma. We thus report here four cases of life-threatening ITP, diagnosed simultaneously to a B-cell NHL, and primarily managed by using the TPO-R agonist, romiplostim. This retrospective study was approved by our local Review Board. There were four patients, two males and two females, with a median age of 76 (70–83) years (Table I). Three of them (Patients 1, 3 and 4) had no history of haematological malignancy. Patient 2 had been previously diagnosed with B-CLL, but with an initially normal platelet count. The median platelet count at presentation was 3 (3–17) × 109/l. The diagnosis of ITP was based on bone marrow smear in three patients and bone marrow biopsy in one, after the exclusion of other causes of peripheral thrombocytopenia. In all cases, the bone marrow examination showed increased megakaryopoiesis and also showed moderate infiltration (30%) by B-CLL in Patient 2 and refractory cytopenia with multilineage dysplasia (RCMD) in Patient 3. The diagnosis of ITP was thus confirmed in Patient 3 by the positivity of specific anti-platelets antibodies; this test was not performed for the other patients. All patients received 1 mg/kg per d intravenous methylprednisolone at the onset of ITP. Two patients received IVIG 0·5 g/kg per d for 2 d (Patients 1 and 3) while a third (Patient 2) was already receiving monthly IVIG treatment as supportive therapy for immune deficiency in the context of B-CLL. Patients 1, 2 and 3 were treated with romiplostim 5 μg/kg per w s.c. after failure of initial treatment; Patient 4 received romiplostim upfront for acute gastrointestinal bleeding. Patient 3 also received rituximab as a salvage therapy. The mean follow-up was 8·5 (1–18) months. The evolution of the patients’ platelet count upon treatment is detailed in Fig 1. In Patient 1, steroids and IVIG treatment failed and romiplostim was used as salvage therapy, which rapidly normalized the platelet count. This enabled a diagnosis of mantle cell lymphoma (MCL) through a laparoscopic abdominal lymph node biopsy, and treatment by rituximab plus CHOP (cyclophosphamide, adriamycin, vincristine and prednisone), then with RDHAP (rituximab, dexamethasone, cytarabine and cisplatin) and finally, high-dose chemotherapy by BEAM (BCNU, etoposide, cytarabine and melphalan) followed by autologous stem-cell transplantation. This patient is still in complete remission of both MCL and ITP. Patient 2 was diagnosed with DLBCL and was treated by three cycles of R-CHOP and then four cycles of cisplatin and navelbin, due to the concomitant diagnosis of lung epidermoid carcinoma. This patient relapsed from B-CLL, but not from DLBCL, and required further treatment by the anti-CD20 monoclonal antibody Ofatumumab. Patient 3, who had a concomitant diagnosis of RCMD, was diagnosed with marginal-zone lymphoma (MZL) and died from cerebral bleeding due to refractory thrombocytopenia. For Patient 4, romiplostim was initiated immediately after the diagnosis of ITP and resulted in a rapid normalization of the platelet count. An attempt to discontinue romiplostim led to a rapid relapse, which was rapidly corrected after the reintroduction of romiplostim (Fig 1). Evolution of the platelet count following treatment in the four study patients. MCL, Mantle Cell Lymphoma; DLBCL, Diffuse Large B-Cell Lymphoma; MZL, Marginal Zone Lymphoma. Lymphoma-associated ITP is an uncommon condition for which no consensual therapeutic approach is currently available. The TPO-R agonists’ romiplostim and eltrombopag are generally well tolerated and their immediate side effects are moderate. In particular, an increase in marrow reticulin was reported in a few patients, which generally resolved upon treatment discontinuation (Nurden et al, 2009). However in the case of our patients, treatment with romiplostim had multiple goals: (i) to overcome a life-threatening ITP refractory to conventional treatment, (ii) to obtain the histological diagnosis of the lymphoma through a safe and unmodified (e.g. by steroids and/or rituximab) tissue sample biopsy, (iii) to eventually postpone splenectomy and/or to limit the use of steroids in severely immunocompromised patients and (iv) to avoid excessive toxicity of the megakaryocyte lineage after the initiation of chemotherapy. Treatment of the underlying lymphoma was required for two patients, and appeared to be essential for the long-term control of ITP in those cases, as reported (Zent et al, 2009). However, both patients received rituximab, vincristine and cyclophosphamide, which are also used in chronic ITP and may explain the improved platelet count (George, 2010). Importantly, the cost/benefit balance should also be considered when using a TPO-R agonist. However, we considered only a time-limited use of those molecules and the cost may be even less than that of IVIG, although this assertion should be verified in future studies. Study design: Jerome Tamburini and Didier Bouscary; Data analysis: Chadi Al-Nawakil, Sophie Park, Nicolas Chapuis, Francois Dreyfus, Tali-Anne Szwebel, Laure Gibault, Thierry Molina, Olivier Hermine, Didier Bouscary and Jerome Tamburini; Manuscript writing: Chadi Al-Nawakil, Didier Bouscary and Jerome Tamburini; Patient enrolment: Sophie Park, Olivier Hermine, Didier Bouscary and Jerome Tamburini. All co-authors approved the final version of the manuscript.