Anthony J. Di Pasqua

AbstractMesoporous silica nanoparticles (MSNs) have been widely explored as drug delivery vehicles in cell and animal studies. To move this nanoparticle platform into the clinic, however, further work needs to be done to predict and assess potential adverse reactions and side-effects to optimize for their efficacious and safe use in patients. Toxicity may be dependent on a number of characteristics, including the size, shape, surface chemistry, and charge of MSNs. Thus, altering various physical and chemical properties of MSNs, while controlling for others, should reveal important parameters necessary for biocompatibility. In this work, reports on biocompatibility of MSNs in recent years have been reviewed and the effects of size, shape, surface chemistry, and porosity highlighted. Advances in triggered release of the drug from MSN delivery systems are also discussed. This article brings together current research on MSN biocompatibility and emphasizes the need for standardized characterization of MSNs, predictive cell studies, and harmonization of animal studies by investigators in the field, to move these sophisticated nanodevices from bench to bedside.Keywords: biocompatibilitymesoporous silicananoparticles Additional informationFundingThe authors thank the University of North Texas System of College of Pharmacy for their support.

We here measure the toxicity of MCM-41, a mesoporous silica nanomaterial, two of its functionalized analogs, AP-T, which has grafted aminopropyl groups and MP-T, which has grafted mercaptopropyl groups, and spherical silica nanoparticles (SiO(2)), toward human neuroblastoma (SK-N-SH) cells. Since the particles studied are not soluble in aqueous media, the metric used to report the cytotoxicity of these materials is a new quantity, Q(50), which is the number of particles required to inhibit normal cell growth by 50%. Determining the number of particles per gram of material applied to the cells required both the calculated and experimentally determined surface areas of these nanomaterials. This study shows that Q(50) increases in the order, MCM-41<MP-T<AP-T approximately SiO(2), showing that on a per particle basis, MCM-41 is the most cytotoxic material studied. For the three mesoporous silica materials in this study, cytotoxicity appears related to the adsorptive surface area of the particle, although the nature of the functional group cannot be ruled out. Silica nanospheres have the lowest surface area of the particles studied but since they exhibit a Q(50) value similar to that of AP-T, shape may also be important in the cytotoxicity of these materials.

Isothiocyanates are versatile cancer-preventive compounds. Evidence from animal studies indicates that the anticarcinogenic activities of ITCs involve all the major stages of tumor growth: initiation, promotion and progression. Epidemiological studies have also shown that dietary intake of ITCs is associated with reduced risk of certain human cancers. A number of mechanisms have been proposed for the chemopreventive activities of ITCs. To identify the molecular targets of ITCs is a first step to understand the molecular mechanisms of ITCs. Studies in recent years have shown that the covalent binding to certain protein targets by ITCs seems to play an important role in ITC-induced apoptosis and cell growth inhibition and other cellular effects. The knowledge gained from these studies may be used to guide future design and screen of better and more efficacious compounds. In this review, we intend to cover all potential protein targets of ITCs so far studied and summarize what are known about their binding sites and the potential biological consequences. In the end, we also offer discussions to shed light onto the relationship between protein binding and reactive oxygen species generation by ITCs.

Isothiocyanates (ITCs) derived from cruciferous vegetables induce apoptosis in cancer cells. We demonstrate that certain naturally occurring ITCs selectively deplete mutant p53 but not the wild-type and do so via a transcription-independent mechanism. Direct p53 binding followed by conformational changes appears to be a mechanism by which mutant p53 is depleted. Structure−activity relationship studies (SARs) using naturally occurring and synthetic ITCs show that depletion is influenced by the ITC side-chain moiety. Furthermore, we show that cells with p53 mutations are more sensitive to cytotoxicity induced by phenethyl isothiocyanate (PEITC) than those with the wild-type protein. 2,2-Diphenylethyl ITC, a synthetic ITC, is one of the most potent depletors of mutant p53 studies and induces apoptosis to the greatest extent in mutant p53 breast cancer cells. Collectively, this study shows that mutant p53 depletion may be an important novel target for cancer chemoprevention and therapy by natural and synthetic ITCs.

Nitric oxide (NO) and cisplatin releasing wrinkle-structured amine-modified mesoporous silica (AMS) nanoparticles have been developed for the treatment of non-small cell lung cancer (NSCLC). The AMS and NO- and cisplatin-loaded AMS materials were characterized using TEM, BET surface area, FTIR and ICP-MS, and tested in cell culture. The results show that for NSCLC cell lines (i.e., H596 and A549), the toxicity of NO- and cisplatin-loaded silica nanoparticles (NO-Si-DETA-cisplatin-AMS) is significantly higher than that of silica nanoparticles loaded with only cisplatin (Si-DETA-cisplatin-AMS). In contrast, the toxicity of NO-Si-DETA-cisplatin-AMS toward normal lung cell lines is not significantly different from that of Si-DETA-cisplatin-AMS (normal lung fibroblast cells WI-38) or is even lower than that of Si-DETA-cisplatin-AMS (normal lung epithelial cells BEAS-2B). The NO-induced sensitization of tumor cell death demonstrates that NO is a promising enhancer of platinum-based lung cancer therapy.

Lipid nanoparticles (LNPs) can be used as delivery vehicles for nucleic acid biotherapeutics. In fact, LNPs are currently being used in the Pfizer/BioNTech and Moderna COVID-19 vaccines. Cationic LNPs composed of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)/cholesterol (chol) LNPs have been classified as one of the most efficient gene delivery systems and are being tested in numerous clinical trials. The objective of this study was to examine the effect of the molar ratio of DOTAP/chol, PEGylation, and lipid to mRNA ratio on mRNA transfection, and explore the applications of DOTAP/chol LNPs in pDNA and oligonucleotide transfection. Here we showed that PEGylation significantly decreased mRNA transfection efficiency of DOTAP/chol LNPs. Among non-PEGylated LNP formulations, 1:3 molar ratio of DOTAP/chol in DOTAP/chol LNPs showed the highest mRNA transfection efficiency. Furthermore, the optimal ratio of DOTAP/chol LNPs to mRNA was tested to be 62.5 µM lipid to 1 μg mRNA. More importantly, these mRNA-loaded nanoparticles were stable for 60 days at 4 °C storage without showing reduction in transfection efficacy. We further found that DOTAP/chol LNPs were able to transfect pDNA and oligonucleotides, demonstrating the ability of these LNPs to transport the cargo into the cell nucleus. The influence of various factors in the formulation of DOTAP/chol cationic LNPs is thus described and will help improve drug delivery of nucleic acid–based vaccines and therapies.

Mesoporous silica nanoparticles (MSNs) were explored as a carrier material for the stable isotope (165)Ho and, after neutron capture, its subsequent therapeutic radionuclide, (166)Ho (half-life, 26.8 h), for use in radionuclide therapy of ovarian cancer metastasis.(165)Ho-MSNs were prepared using (165)Ho-acetylacetonate and MCM-41 silica particles, and stability was determined after irradiation in a nuclear reactor (reactor power, 1 MW; thermal neutron flux of approximately 5.5 × 10(12) neutrons/cm(2)s). SPECT/CT and tissue biodistribution studies were performed after intraperitoneal administration of (166)Ho-MSNs to SKOV-3 ovarian tumor-bearing mice. Radiotherapeutic efficacy was studied by using PET/CT with (18)F-FDG to determine tumor volume and by monitoring survival.The holmium-MSNs were able to withstand long irradiation times in a nuclear reactor and did not release (166)Ho after significant dilution. SPECT/CT images and tissue distribution results revealed that (166)Ho-MSNs accumulated predominantly in tumors (32.8% ± 8.1% injected dose/g after 24 h; 81% ± 7.5% injected dose/g after 1 wk) after intraperitoneal administration. PET/CT images showed reduced (18)F-FDG uptake in tumors, which correlated with a marked increase in survival after treatment with approximately 4 MBq of (166)Ho-MSNs.The retention of holmium in nanoparticles during irradiation and in vivo after intraperitoneal administration as well as their efficacy in extending survival in tumor-bearing mice underscores their potential as a radiotherapeutic agent for ovarian cancer metastasis.

Lung cancer is the leading cause of cancer-related death in the United States and approximately 85% of all lung cancers are classified as nonsmall cell (NSCLC). We here use an innovative approach that may ultimately allow for the clinician to target tumors and aggressively reduce tumor burden in patients with NSCLC. In this study, a platinum (Pt)-based chemotherapeutic (cisplatin, carboplatin, or oxaliplatin) and holmium-165 (Ho), which can be neutron-activated to produce the holmium-166 radionuclide, have been incorporated together in a garnet magnetic nanoparticle (HoIG-Pt) for selective delivery to tumors using an external magnet. The synthesized magnetic HoIG nanoparticles were characterized using PXRD, TEM, ICP-MS, and neutron-activation. Platinum(II) drugs were incorporated onto HoIG, and these were characterized using FTIR, EDX, ICP-MS, and zeta potential measurements, and in vitro and in vivo studies were performed using a HoIG-platinum system. Results indicate that neutron-activated 166HoIG-cisplatin is more toxic toward NSCLC A549 cells than is blank 166HoIG and free cisplatin, and that when an external magnetic field is applied in vivo, higher tumor to liver ratios of Ho are observed than when no magnet is applied, suggesting that magnetic targeting is achieved using this system. Furthermore, an efficacy study demonstrated the inhibition of tumor growth by chemoradiotherapeutic magnetic nanoparticles, compared to no treatment controls.

Tetracycline (TC) is a well-known broad spectrum antibiotic, which is effective against many Gram positive and Gram negative bacteria.Controlled release nanoparticle formulations of TC have been reported, and could be beneficial for application in the treatment of periodontitis and dental bone infections.Furthermore, TC-controlled transcriptional regulation systems (Tet-on and Tet-off) are useful for controlling transgene expression in vitro and in vivo for biomedical research purposes; controlled TC release systems could be useful here, as well.Mesoporous silica nanomaterials (MSNs) are widely studied for drug delivery applications; Mobile crystalline material 41 (MCM-41), a type of MSN, has a mesoporous structure with pores forming channels in a hexagonal fashion.We prepared 41 ˘4 and 406 ˘55 nm MCM-41 mesoporous silica nanoparticles with loaded TC for controlled drug release; TC content in the TC-MCM-41 nanoparticles was 18.7% and 17.7% w/w, respectively.Release of TC from TC-MCM-41 nanoparticles was then measured in phosphate-buffered saline (PBS), pH 7.2, at 37 ˝C over a period of 5 h.Most antibiotic was released from both over this observation period; however, the majority of TC was released over the first hour.Efficacy of the TC-MCM-41 nanoparticles was then shown to be superior to free TC against Escherichia coli (E.coli) in culture over a 24 h period, while blank nanoparticles had no effect.

We here describe a method for the simple synthesis of gold nanoparticles (~ 10 nm in diameter) conjugated with antibody to E. coli O157:H7. Gold nanoparticles with pendant carboxylic acid and alcohol functional groups were synthesized and characterized using transmission electron microscopy (TEM) and infrared spectroscopy. These nanoparticles were then reacted with anti-E. coli O157:H7, using EDC coupling chemistry, and the product was characterized with X-ray photoelectron spectroscopy. Furthermore, binding of the antibody-gold conjugates to E. coli O157:H7 was demonstrated using transmission electron microscopy.

We show that naturally occurring isothiocyanates (ITCs) sensitize human non-small cell lung cancer cells to cisplatin. Moreover, the structure of the ITC side chain moiety is important for sensitization. In NCI-H596 cells, 20 microM benzyl isothiocyanate (BITC) and phenethyl isothiocyanate (PEITC) enhance the efficacy of various concentrations of cisplatin, but sulforaphane (SFN) does not. Reducing the concentration of BITC and PEITC to 10 microM still allows for the sensitization of cells to cisplatin. Neither cellular platinum accumulation nor DNA platination account for this increased cytotoxicity. BITC and PEITC deplete beta-tubulin, but SFN does not; this correlates with and may be important for sensitization.

Carboplatin, a platinum anticancer drug used to treat many types of human cancer, contains a bidentate dicarboxylate chelate leaving ligand, a structural feature that makes it much less chemically reactive than the first-generation platinum anticancer drug cisplatin, which contains two monodentate chloride leaving ligands. In water, carboplatin exists in a monomer–dimer equilibrium with an association constant of K (M−1) ≈ 391, a property that accounts for the long-term stability of its ready-to-use infusion solution. When administered in the clinic, carboplatin is believed to exert its biological effects by interacting with genomic DNA and proteins. The slower substitution kinetics of carboplatin, compared to cisplatin, has prompted investigators to focus on mechanisms by which the compound can be activated in vivo. Carbonate, which is in equilibrium with hydrogen carbonate, carbonic acid, and dissolved carbon dioxide, is ubiquitous in biological systems, and is found in high concentrations in the blood, the interstitial fluid, and the cytosol. Activation of carboplatin by carbonate, CO32− (k1 = 2.04 ± 0.81 × 10−6 in 24 mM carbonate buffer, pH 7.5 at 37 °C), for example, leads to the formation of platinum species that are more cytotoxic than the parent drug. This short review focuses on the reason for the unusual stability of carboplatin in its aqueous ready-to-use infusion solution, describes the reactions of the drug with biologically common nucleophiles and summarizes the activation chemistry that make the drug more reactive toward substances present in the biological system.

Carboplatin, [Pt(NH3)2(CBDCA-O,O')], 1, where CBDCA is cyclobutane-1,1-dicarboxylate, is in wide clinical use for the treatment of ovarian, lung, and other types of cancer. Because carboplatin is relatively unreactive toward nucleophiles, an important question concerning the drug is the mechanism by which it is activated in vivo. Using [1H,15N] heteronuclear single quantum coherance spectroscopy (HSQC) NMR and 15N-labeled carboplatin, we show that carboplatin reacts with carbonate ion in carbonate buffer to produce ring-opened products, the nature of which depends on the pH of the medium. The assignment of HSQC NMR resonances was facilitated by studying the reaction of carboplatin in strong acid, which also produces a ring-opened product. The HSQC NMR spectra and UV-visible difference spectra show that reaction of carboplatin with carbonate at pH > 8.6 produces mainly cis-[Pt(NH3)2(CO3(-2))(CBDCA-O)]-2, 5, which contains the mono-dentate CBDCA ligand and mono-dentate carbonate. At pH 6.7, the primary product is the corresponding bicarbonato complex, which may be in equilibrium with its decarboxylated hydroxo analogue. The UV-visible absorption data indicate that the pKb for the protonation of 5 is approximately 8.6. Thus, the reaction of carboplatin with carbonate produces a mixture of ring-opened species that are anions at physiological pH. HSQC NMR studies on 15N-labeled carboplatin in RPMI culture media containing 10% fetal bovine serum with and without added carbonate suggest that carbonate is the attacking nucleophile in culture media. However, because the rate of reaction of carbonate with carboplatin at physiological pH is small, NMR peaks for ring-opened carboplatin were not detected with HSQC NMR. The rate of disappearance of carboplatin in culture medium containing 9 x 10(8) Jurkat cells is essentially the same as that in carbonate buffer, indicating that the ring-opening reaction is not affected by the presence of cells. This work shows that carbonate at concentrations found in culture media, blood, and the cytosol readily displaces one arm of the CBDCA ligand of carboplatin to give a ring-opened product, which at physiological pH is a mixture of anions. These ring-opened species may be important in the uptake, antitumor properties, and toxicity of carboplatin.

Radiation therapy is used as a primary treatment for inoperable tumors and in patients that cannot or will not undergo surgery. Radioactive holmium-166 (166Ho) is a viable candidate for use against skin cancer. Nonradioactive holmium-165 (165Ho) iron garnet nanoparticles have been incorporated into a bandage, which, after neutron-activation to 166Ho, can be applied to a tumor lesion. The 165Ho iron garnet nanoparticles (165HoIG) were synthesized and introduced into polyacrylonitrile (PAN) polymer solutions. The polymer solutions were then electrospun to produce flexible nonwoven bandages, which are stable to neutron-activation. The fiber mats were characterized using scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis and inductively coupled plasma mass spectrometry. The bandages are stable after neutron-activation at a thermal neutron-flux of approximately 3.5 × 1012 neutrons/cm2·s for at least 4 h and 100 °C. Different amounts of radioactivity can be produced by changing the amount of the 165HoIG nanoparticles inside the bandage and the duration of neutron-activation, which is important for different stages of skin cancer. Furthermore, the radioactive bandage can be easily manipulated to irradiate only the tumor site by cutting the bandage into specific shapes and sizes that cover the tumor prior to neutron-activation. Thus, exposure of healthy cells to high energy β-particles can be avoided. Moreover, there is no leakage of radioactive material after neutron activation, which is critical for safe handling by healthcare professionals treating skin cancer patients.

Over the last decade, the development and application of nanotechnology in cancer detection, diagnosis, and therapy have been widely reported. Engineering of vehicles for the simultaneous delivery of chemo- and radiotherapeutics increases the effectiveness of the therapy and reduces the dosage of each individual drug required to produce an observable therapeutic response. We here developed a novel chemoradiotherapeutic 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid coated/uncoated platinum drug loaded, holmium-containing, wrinkled mesoporous silica nanoparticle. The materials were characterized with TEM, FTIR, 1H NMR, energy dispersive x-ray, inductively coupled plasma-mass spectrometry, and zeta potential measurements. In vitro platinum drug release from both lipid coated and uncoated chemoradiotherapeutic wrinkled mesoporous silica are reported. Various kinetic models were used to analyze the release kinetics. The radioactivity of the chemoradiotherapeutic nanocarriers was measured after neutron-activation.

Carboplatin and oxaliplatin are commonly used platinum anticancer agents that are sold as ready-to-use aqueous infusion solutions with shelf lives of 2 and 3 years, respectively. The observed rate constants for the hydrolysis of these drugs, however, are too large to account for their long shelf lives. We here use electrospray-trap mass spectrometry to show that carboplatin and oxaliplatin are self-associated at concentrations in their ready-to-use infusion solutions (∼27 mM and 13 mM, respectively) and, as expected, when the drug concentration is reduced to more physiologically relevant concentrations (100 μM and 5 μM, respectively) the association equilibrium is shifted in favor of the monomeric forms of these drugs. Using 1H NMR we measure the intensity of the NH resonance of the two symmetry-equivalent NH3 molecules of carboplatin, relative to the intensity of the γ-methylene CH resonance, as a function of total drug concentration. Then, by fitting the data to models of different molecularity, we show that the association complex is a dimer with a monomer–dimer association constant of K (M−1) = 391 ± 127. The work presented here shows that carboplatin and oxaliplatin mainly exist as association complexes in concentrated aqueous solution, a property that accounts for the long term stability of their ready-to-use infusion solutions, and that these association complexes may exist, to some extent, in the blood after injection.

Naturally occurring phenethyl isothiocyanate (PEITC) was previously shown to sensitize human non-small cell lung cancer (NSCLC) cells to the platinum anticancer drug cisplatin (CDDP). Here, CDDP and PEITC were encapsulated in approximately 130 nm liposomes composed of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and l-α-phosphatidylglycerol (EPG). The liposomal formulation enhanced the toxicity of this doublet (1:2 molar ratio of CDDP/PEITC) toward NCI-H596 NSCLC cells; the percent survival of cells was 30.2 ± 6.2% after treatment with the nanoparticle formulation, compared to 50.9 ± 3.5% when administered together free. Thus, such a treatment modality could prove useful in the clinic for the treatment of NSCLC.

Objective: We review here the pharmacology, pharmacokinetics, efficacy, safety, dosage and administration, potential drug-drug interactions and place in therapy of brigatinib for abnormal anaplastic lymphoma kinase (ALK) specific non–small-cell lung cancer (NSCLC). Data Sources: A literature search using PubMed was conducted using the terms brigatinib and ALK positive NSCLC from January 2013 to November 2018. Study Selection and Data Extraction: All English-language articles evaluating brigatinib were analyzed for this review. Data Synthesis: Brigatinib was granted approval for the treatment of patients with metastatic ALK+ NSCLC who have progressed on or are intolerant to crizotinib. It is administered at a dose of 90 mg orally once daily for the first 7 days then, if tolerated, increased to a dose of 180 mg orally once daily. Common adverse effects include nausea, fatigue, diarrhea, increased creatine phosphokinase levels, headache, dyspnea, and hypertension. Serious treatment-emergent adverse effects were pulmonary related. Relevance to Patient Care and Clinical Practice: This article discusses the clinical trials that led to the accelerated approval of brigatinib for its ability to overcome crizotinib-resistant mutations and for its increased central nervous system penetration properties. Conclusion: Brigatinib was granted accelerated approval for the treatment of patients with metastatic ALK+ NSCLC who have progressed on or are intolerant to crizotinib. In a subset of NSCLC patients, brigatinib increases survival for approximately 1 year; however, side effects were detected.

Individualized drug delivery improves drug efficacy and safety for patients. To implement individualized drug delivery, patient-specific tailored dosages produced on a small scale are needed. However, current pharmaceutical manufacturing is not suitable for personalized dosage forms. Although convenient to deliver various drugs, current gelatin capsules using animal collagen protein have many limitations, such as releasing drugs too fast and incompatibility with some diets. In contrast, 3D printed capsules have great potential to advance individualized treatments. In this paper, we 3D printed and tested non-animal-based capsule shells for the delivery of acetaminophen. Capsule shells were composed of poly(vinyl) alcohol (PVA) and PVA blends with 5-25% hydroxypropyl methylcellulose (HPMC). Dissolution of acetaminophen when delivered in -hese capsule shells was tested using a USP dissolution test apparatus 2 (paddle type) at gastric pH. The novel shells were compared to each other and to commercially available hard gelatin capsules. Dissolution results show that acetaminophen when delivered in 3D printed capsules was slower than when delivered by gelatin capsules. Increasing the percentage of HPMC in the blend further delayed its release and dissolution. This delay could potentially increase the efficacy and reduce the side effects of acetaminophen. These shells also offer a non-animal-based alternative to gelatin capsules. Furthermore, 3D printing of capsule shells with specific polymer blends may be useful for patient-specific therapy in compounding pharmacies across the country.

Carboplatin, [Pt(NH3)2(CBDCA-O,O‘)], 1, where CBDCA is cyclobutane-1,1-dicarboxylate, is used against ovarian, lung, and other types of cancer. We recently showed (Di Pasqua et al. (2006) Chem. Res. Toxicol. 19, 139−149) that carboplatin reacts with carbonate under conditions that simulate therapy to produce carbonato carboplatin, cis-[Pt(NH3)2(O-CBDCA)(CO3)]2-, 2. We use 13C and 1H NMR and UV−visible absorption spectroscopy to show that solutions containing carboplatin that have been aged in carbonate buffer under various conditions contain 1, 2, and other compounds. We then show that aging carboplatin in carbonate produces compounds that are more toxic to human neuroblastoma (SK-N-SH), proximal renal tubule (HK-2) and Namalwa-luc Burkitt's lymphoma (BL) cells than carboplatin alone. Moreover, increasing the aging time increases the cytotoxicity of the platinum solutions as measured by the increase in cell death. Although HK-2 cells experience a large loss in survival upon exposure to carbonato forms of the drug, they have the highest values of IC50 of the three cell lines studied, so that HK-2 cells remain the most resistant to the toxic effects of the carbonato forms in the culture medium. This is consistent with the well-known low renal toxicity observed for carboplatin in therapy. The uptake rates for normal Jurkat cells (NJ) and cisplatin-resistant Jurkat cells (RJ), measured by inductively coupled plasma mass spectrometry (ICP-MS), are 16.6 ± 4.2 and 12.3 ± 4.8 amol of Pt h-1 cell-1, respectively, when exposed to carboplatin alone. However, when these cells are exposed to carboplatin that has been aged in carbonate media, normal Jurkat cells strongly bind/take up Pt at a rate of 14.5 ± 4.1 amol of Pt h-1 cell-1, while resistant cells strongly bind/take up 5.1 ± 3.3 amol of Pt h-1 cell-1. Collectively, these studies show that carboplatin carbonato species may play a major role in the cytotoxicity and uptake of carboplatin by cells.

MCM-41, a mesoporous silica nanomaterial with a high surface area for adsorption of small molecules, is a potential new type of delivery vehicle for therapeutic and diagnostic agents. In this report, we show that MCM-41 adsorbs the front-line anticancer drug carboplatin, [Pt(CBDCA-O,O')(NH3)2] (CBDCA=cyclobutane-1,1-dicarboxylate; 1), which is used to treat ovarian, lung, and other types of cancer. UV/Visible difference absorption spectroscopy shows that MCM-41 adsorbs 1.8+/-0.2% of its own weight of carboplatin after a 24 h exposure to 26.9 mM drug in H2O. The pseudo-first-order rate constant for adsorption of carboplatin by MCM-41, measured using [1H,15N] heteronuclear single quantum coherence (HSQC) NMR, and 15N-labeled carboplatin is k(1)=2.92+/-2.17 x 10(-6) s(-1) at ca. 25 degrees.

The second-generation PtII anticancer drug carboplatin is here shown to react with carbonate, which is present in blood, interstitial fluid, cytosol, and culture medium, to produce platinum−carbonato and −hydroxo complexes. Using [1H−15N] HSQC NMR and 15N-labeled carboplatin, we observe that cis-[Pt(CBDCA-O)(OH)(NH3)2]−, cis-[Pt(OH)2(NH3)2], cis-[Pt(CO3)(OH)(NH3)2]−, and what may be cis-[Pt(CO3)(NH3)2] are produced when 1 is allowed to react in 23.8 mM carbonate buffer. When 15N-labeled carboplatin is allowed to react in 0.5 M carbonate buffer, these platinum species, as well as other hydroxo and carbonato species, some of which may be dinuclear complexes, are produced. Furthermore, we show that the carbonato species cis-[Pt(CO3)(OH)(NH3)2]− is also produced when cisplatin is allowed to react in carbonate buffer. The study outlines the conditions under which carboplatin and cisplatin form carbonato and aqua/hydroxo species in carbonate media.

Mesoporous silica MCM-41 nanoparticles containing the stable isotope holmium-165 (165Ho) were prepared by exposing the approximately 400 nm particles to an aqueous solution of 165Ho acetylacetonate for 24 h at room temperature; the obtained solid was subsequently irradiated in a PULSTAR nuclear reactor (reactor power = 1 MW; thermal neutron flux of approximately 5.5 or 7.7 × 1012 n/cm2s) to produce holmium-166-containing mesoporous silica (166Ho-MCM-41) nanoparticles (20.8 ± 1.9% w/w 166Ho). The 166Ho-MCM-41 nanoparticles were administered intravenously (i.v.) to orthotopic non-small cell lung cancer A549-luciferase tumor-bearing mice. After 24 h, 4.5 ± 3.9% initial dose per gram (ID/g) of tissue was detected in tumors and after 1 week, this value increased to 58.8 ± 34.7% ID/g. These results demonstrate that mesoporous silica MCM-41 nanoparticles can deliver significant amounts of a therapeutic radionuclide to tumors after i.v. injection.

Squamous cell carcinoma (SCC) is the second most common form of skin cancer in the United States. The efficacy of a pharmaceutically elegant radiotherapeutic bandage, previously described by us for application against SCC of the skin, was tested for the first time in vivo using a subcutaneous SCC mouse model and a therapeutically relevant radiation dose. Female athymic nude mice were injected with human Colo-16 SCC cells subcutaneously and after eight days (average tumor volume: 35 ± 8.6 mm3) received no treatment, or were exposed to non-radioactive or radioactive (92.5 ± 18.5 MBq) bandages for approximately 1 h (n = 10 per group). After treatment, tumors were measured over fifteen days, tumor volume ratios (TVRs) compared and histopathology performed. Fifteen days after treatment, the TVR of the radioactive bandage treatment group was 3.3 ± 4.5, while TVRs of the non-radioactive bandage treatment and no treatment control groups were 33.2 ± 14.7 and 26.9 ± 12.6, respectively. At the time of necropsy, there was mild focal epidermal hyperplasia surrounding a small area of epidermal ulceration in the radioactive bandage group. No other examined tissue (i.e., muscle, liver, kidney, lung, spleen and heart) showed significant lesions. Our radiotherapeutic bandage exhibits promising efficacy against SCC of the skin in a mouse model. It can be individually tailored for easy application on tumor lesions of all shapes and sizes, and could complement or possibly replace surgery in the clinic.

Nanoparticles containing stable holmium (165Ho) are prepared by nanotemplate engineering and subsequently irradiated in a neutron flux to yield 166Ho, a beta-emitting radiotherapeutic isotope. After intraperitoneal injection to mice bearing SKOV-3 ovarian tumors, significant tumor accumulation of the 166Ho-nanoparticles is observed by SPECT imaging indicating the potential of these neutron activatable nanoparticles for internal radiation therapy of ovarian cancer metastases.

A penta-ethyl ester prodrug of the radionuclide decorporation agent diethylenetriaminepentaacetic acid (DTPA), which exists as an oily liquid, was encapsulated in alginate beads by the ionotropic gelation method. An optimal formulation was found by varying initial concentrations of DTPA penta-ethyl ester, alginate polymer, Tween 80 surfactant and calcium chloride. All prepared alginate beads were ~1.6mm in diameter, and the optimal formulation had loading and encapsulation efficiencies of 91.0±1.1 and 72.6±2.2%, respectively, and only 3.2±0.8% water absorption after storage at room temperature in ~80% relative humidity. Moreover, Fourier transform infrared spectroscopy showed that DTPA penta-ethyl ester did not react with excipients during formation of the DTPA penta-ethyl ester-containing alginate beads. Release of prodrug from alginate beads was via anomalous transport, and its stability enhanced by encapsulation. Collectively, these data suggest that this solid dosage form may be suitable for oral administration after radionuclide contamination.

Diethylenetriaminepentaacetic acid (DTPA) is a chelating agent that is used to facilitate the elimination of radionuclides such as americium from contaminated individuals. Its primary site of action is in the blood, where it competes with various biological ligands, including transferrin and albumin, for the binding of radioactive metals. To evaluate the chelation potential of DTPA under these conditions, the competitive binding of 241Am between DTPA and plasma proteins was studied in rat, beagle, and human plasma in vitro. Following incubation of DTPA and 241Am in plasma, the 241Am-bound ligands were fractionated by ultrafiltration and ion-exchange chromatography, and each fraction was assayed for 241Am content by gamma scintillation counting. Dose response curves of DTPA for 241Am binding were established, and these models were used to calculate the 90% maximal effective concentration, or EC90, of DTPA in each plasma system. The EC90 were determined to be 31.4, 15.9, and 10.0 μM in rat, beagle, and human plasma, respectively. These values correspond to plasma concentrations of DTPA that maximize 241Am chelation while minimizing excess DTPA. Based on the pharmacokinetic profile of DTPA in humans, after a standard 30 μmol kg−1 intravenous bolus injection, the plasma concentration of DTPA remains above EC90 for approximately 5.6 h. Likewise, the effective duration of DTPA in rat and beagle were determined to be 0.67 and 1.7 h, respectively. These results suggest that species differences must be considered when translating DTPA efficacy data from animals to humans and offer further insights into improving the current DTPA treatment regimen.

Over the last few decades, holmium (Ho) has been investigated for its application in laser surgery, magnetic resonance imaging, and internal and topical radionuclide therapy. Ho has a 100% natural abundance of holmium-165, which is a stable nuclide that can undergo a process called neutron-activation to generate radioactive holmium-166 (166Ho). 166Ho emits β–particles and γ photons, with a half-life of 26.8 h; β–particles can damage a cancer cell’s DNA, while γ photons allow for 166Ho to be imaged in vivo and easily quantitated prior to, or during, dosing. This article gives a thorough account of the work being done around the world on 166Ho for use as an internal or topical radionuclide therapy against cancer. Our research group and others have generated compelling data that support the use of 166Ho as a radiotherapeutic in the clinic, especially since pharmaceutical formulations can be made while non-radioactive (Ho) and then made radioactive (166Ho) just prior to use.

Despite their well-known function in maintaining normal cell physiology, how inorganic elements are relevant to cellular pluripotency and differentiation in human pluripotent stem cells (hPSCs) has yet to be systematically explored. Using total reflection X-ray fluorescence (TXRF) spectrometry and inductively coupled plasma mass spectrometry (ICP-MS), we analyzed the inorganic components of human cells with isogenic backgrounds in distinct states of cellular pluripotency. The elemental profiles revealed that the potassium content of human cells significantly differs when their cellular pluripotency changes. Pharmacological treatment that alters cell membrane permeability to potassium affected the maintenance and establishment of cellular pluripotency via multiple mechanisms in bona fide hPSCs and reprogrammed cells. Collectively, we report that potassium is a pluripotency-associated inorganic element in human cells and provide novel insights into the manipulation of cellular pluripotency in hPSCs by regulating intracellular potassium.

Abstract The reaction of aged carboplatin (reaction of carboplatin in 24 m M NaHCO 3 for 45 h, 37°, pH 8.6) with pBR322 DNA at 0&lt; r &lt;2.8, where r =[drug]/[DNA‐bp], in 24 m M HEPES buffer, pH 7.4, for 24 h, followed by agarose gel electrophoresis showed DNA mobility changes consistent with unwinding closed circular DNA. However, identical experiments conducted in a two‐buffer system, 24 m M HEPES plus 24 m M carbonate, showed no DNA mobility changes, indicating that carbonate blocks formation of the 1,2 intrastrand cross‐link on DNA. Studies with aged carboplatin and with cisplatin carried out with ca. 4.0&lt; r &lt;10.0 in the two‐buffer system show that some DNA binding and unwinding occurs for both drugs. Since carbonate inhibits the binding of aged carboplatin and cisplatin to DNA, carbonate present in the body likely modulates the reactivity of these drugs with a variety of biological targets including DNA.

Using [(1)H,(15)N] heteronuclear single quantum coherance (HSQC) NMR and (15)N-labeled carboplatin, 1, we show that Jurkat cells affect the rate of disappearance of the HSQC NMR peak in culture medium for this Pt(2+) anticancer drug. The decay or disappearance rate constant for 1 in culture medium containing cells is k(1)=k(c)[CO(3)(2-)]+k(m)+k(u)N, where k(c) is the rate constant for reaction of 1 with carbonate in the medium, k(m) is the rate constant for reaction of 1 with all other components of the medium, and k(u) is the rate constant for reaction of 1 with cells having a number density N in the medium. Since Jurkat cells only take up a small amount of the platinum present in the medium (<1%), the observed disappearance of the HSQC NMR peak for 1 cannot be due to uptake of carboplatin by the cells.

It is currently estimated that one in every five Americans will develop skin cancer during their lifetime. Squamous cell carcinoma (SCC) is a common type of skin cancer that can develop due to the skin’s exposure to the sun. Herein, we prepared a topical gel containing 0.5% v/w phenethyl isothiocyanate (PEITC) for the treatment of SCC. PEITC is a naturally occurring isothiocyanate that has been shown to have efficacy against various types of cancer in preclinical studies. We first incorporated PEITC into a carbomer gel. A uniform formulation was prepared, and its viscosity was appropriate for topical application. We then demonstrated the release of PEITC from the gel into and through a Strat-M skin-like membrane. Finally, the effects of the PEITC-containing gel were tested against SCC and normal keratinocytes skin cells in culture, and these results were compared to those obtained for free 5-fluoruracil (5-FU), a commonly used skin-cancer drug. Our results show that a homogeneous PEITC-containing topical gel can be prepared and used to kill SCC cells. Thus, our formulation may be useful for treating SCC in the clinic.

The pain caused by lidocaine injections into the face prior to facial plastic surgeries intended to remove growths or tumorous lesions has been reported by many patients to be the worst part of these procedures. However, the lidocaine gels and creams currently on the market do not deliver an equal or better local anesthetic effect to replace these injections. To develop an alternative to the painful local anesthetic injection, we prepared ultraflexible liposomes using soy phosphatidylcholine, lidocaine, and different amounts of sodium cholate, a surfactant. The prepared ultraflexible liposomes (UFLs) were examined for particle size, zeta potential, cytotoxicity, and in vitro release. By using a carbomer as a gelling agent, the prepared UFL lidocaine gels were evaluated for their penetration ability in a Franz diffusion cell, using Strat-M membranes. The formulation achieving the highest amount of penetrated lidocaine was chosen for further pH, viscosity, and stability tests. The local anesthetic efficacy of the formulation was investigated by an in vivo tail-flick test in rats. Our findings suggested that this topical gel formulated with ultraflexible liposomal lidocaine has enhanced skin permeation ability, as well as an improved local analgesic effect from the lidocaine.

Lung cancer is the leading cause of cancer-related death in the United States, and non-small cell lung cancer (NSCLC) the most common type. Platinum (Pt) anticancer agents, such as cisplatin, remain a mainstay in the clinic; however, these agents are not tumor-specific and, thus, the patient experiences negative side-effects. We here prepare trans, cis, cis-bis(heptanoato)amine(cyclohexylamine)dichloridoplatinum(IV) and demonstrate that it is greater than 50-fold more toxic toward NSCLC cells than is cisplatin. Furthermore, it has a much improved therapeutic index. This Pt(IV) complex binds to DNA in a manner similar to that of cisplatin, and can be incorporated into mesoporous silica nanoparticles for fine-controlled release and the targeting of tumors.

Cationic liposomes composed of 3-[N-(N’,N’-dimethylaminoethane)-carbamoyl] cholesterol (DC-chol) and dioleoylphosphatidylethanolamine (DOPE) have previously been shown to have applications in gene delivery. Our study aims to explore the effects of inclusion of polyethylene glycol (PEG) and using different molar ratios of DC-chol/DOPE on size, zeta potential, cytotoxicity and DNA delivery of DC-chol/DOPE liposomes. Our results show that PEGylation reduces the cytotoxicity of DC-chol/DOPE liposomes, and, furthermore, PEGylated liposome-DNA lipoplexes are smaller in size and more uniform in size distribution than those that are not PEGylated. Additionally, toxicity against ovarian cancer SKOV-3 cells decreases with the amount of cationic DC-chol present in the formulation; however, decreased delivery of DNA to cellular nuclei is also observed. Transfection with the PEGylated liposomes was successfully demonstrated using plasmid DNA with a known functional outcome. These results offer further insight into physicochemical properties important for cationic liposomes as vehicles for DNA delivery and demonstrate the potential of PEGylated DC-chol/DOPE liposomes as systemic delivery carriers for DNA-mediated ovarian cancer therapy.

The number of non-melanoma skin cancer (NMSC) cases in the US will increase significantly over the next decade due to a rise in UV exposure. One of the treatment methods used to remove NMSC lesions is radiation therapy. The two types of radiation therapy used in the clinic are external beam therapy and brachytherapy. However, both require specialized on-site instrumentation and for patients to remain immobile. In this work, we studied an alternative radiation therapy - one that does not require expensive on-site equipment and would allow for enhanced patient mobility and, thus, comfort. We prepared sealed source, nylon-laminated holmium-166-containing radiotherapeutic bandages and used them in C3H/HeN mice with murine SCCVII tumor grafts. Overall, tumor sizes were smallest when treated with therapeutically relevant radiation doses via radiotherapeutic bandages (compared to controls), and no histological evidence of toxicity to tissues was observed. Thus, our optimized radiotherapeutic bandage offers a flexible approach to treating NMSC.

The penta-ethyl ester prodrug of diethylenetriaminepentaacetic acid (DTPA), which exists as an oily liquid, was incorporated into a solid dispersion for oral administration by the solvent evaporation method using blends of polyvinylpyrrolidone (PVP), Eudragit® RL PO and α-tocopherol. D-optimal mixture design was used to optimize the formulation. Formulations that had a high concentration of both Eudragit® RL PO and α-tocopherol exhibited low water absorption and enhanced stability of the DTPA prodrug. Physicochemical properties of the optimal formulation were evaluated using Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). In vitro release of the prodrug was evaluated using the USP Type II apparatus dissolution method. DSC studies indicated that the matrix had an amorphous structure, while FTIR spectrometry showed that DTPA penta-ethyl ester and excipients did not react with each other during formation of the solid dispersion. Dissolution testing showed that the optimized solid dispersion exhibited a prolonged release profile, which could potentially result in a sustained delivery of DTPA penta-ethyl to enhance bioavailability. In conclusion, DTPA penta-ethyl ester was successfully incorporated into a solid matrix with high drug loading and improved stability compared to prodrug alone.

Abstract p53 mutations occur in more than 50% of all human tumor. Mutant p53 is incapable of activating downstream target genes necessary for cell cycle arrest and apoptosis. Phenethyl isothiocyanate (PEITC), a cruciferous vegetable-derived compound, has been shown to possess anti-cancer property by causing cell growth arrest or apoptosis in tumor cell lines and animal models. Recently, we have found that PEITC can selectively reduce mutant p53, but not wild type protein levels in a variety of tumor cell lines. Here, we demonstrate that PEITC can increase sequence specific DNA binding of p53 in NSCLC H596 cells expressing mutant p53 and induce the expression of p53-dependent target proteins, such as p21 and Noxa. Similar effects were observed in human glioblastoma T98G cells which also express mutant p53. H596 cells incubated with sulforaphane (SFN), another widely studied ITC compound with much weaker cytotoxicity, showed no increased specific DNA binding of p53. In addition, PEITC induced p53-responsive p21 and Noxa promoter luciferase activity. Blocking mutant p53 protein expression with shRNA in T98G cells entirely prevented p21 protein induction triggered by PEITC. Immunoprecipitation studies with conformation-specific p53 antibodies (Pab1620 and Pab240) show that treatment with PEITC alters mutant p53 to wild type conformation in H596 cells. Currently, we are investigating the significance of function restoration to mutant p53 by phenethyl isothiocyanate in the regulation of apoptosis by PEITC or other conventional chemotherapeutic drugs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1629.

Non-small cell lung cancer (NSCLC) is one of the leading causes of cancer-related deaths in the United States. It is extremely difficult to treat, and its survival rate is low. Today, the most effective treatments are still those that implement the platinum anticancer drug cisplatin (CDDP) in combination with other drugs. We previously demonstrated that the naturally occurring compound phenethyl isothiocyanate (PEITC) could be used to sensitize NSCLC cells to CDDP. Furthermore, co-encapsulation of PEITC and CDDP in liposomes enhances their toxicity toward NSCLC cells. We have optimized a liposomal-PEITC-CDDP formulation and investigated its cytotoxicity. We determined that liposomal-PEITC-CDDP is much more toxic toward human NSCLC cell lines than it is toward human normal lung cell lines. In this chapter, we describe detailed methods for preparing liposomal-PEITC-CDDP and determining its cytotoxicity.

The effects of irradiation of pig kidney Dopa decarboxylase by visible light absorbed by the intrinsic chromophore, pyridoxal-P, and by the externally added dyes, pyridoxal-P or proflavin, have been studied. In all cases inactivation was observed, even though to different extens, which seemed to be essentially correlated to tryptophanyl residues photodestruction. Kinetics of inactivation and oxidation of these amino acid residues revealed the presence of two distinct groups of tryptophan residues with different photooxidation rate constants. A different role for these classes of residues in the structure and function of Dopa decarboxylase has been suggested.