NCI-60 Human Tumor Cell Line Research Articles

EMT-Derived Alterations in Glutamine Metabolism Sensitize Mesenchymal Breast Cells to mTOR Inhibition.

Epithelial-to-mesenchymal transition (EMT) is a fundamental developmental process with strong implications in cancer progression. Understanding the metabolic alterations associated with EMT may open new avenues of treatment and prevention. Here we used 13C carbon analogs of glucose and glutamine to examine differences in their utilization within central carbon and lipid metabolism following EMT in breast epithelial cell lines. We found that there are inherent differences in metabolic profiles before and after EMT. We observed EMT-dependent re-routing of the TCA-cycle, characterized by increased mitochondrial IDH2-mediated reductive carboxylation of glutamine to lipid biosynthesis with a concomitant lowering of glycolytic rates and glutamine-dependent glutathione (GSH) generation. Using weighted correlation network analysis, we identified cancer drugs whose efficacy against the NCI-60 Human Tumor Cell Line panel is significantly associated with GSH abundance and confirmed these in vitro. We report that EMT-linked alterations in GSH synthesis modulate the sensitivity of breast epithelial cells to mTOR inhibitors. IMPLICATIONS: EMT in breast cells causes an increased demand for glutamine for fatty acid biosynthesis, altering its contribution to glutathione biosynthesis, which sensitizes the cells to mTOR inhibitors.

Design, Synthesis, and Biological Evaluation of Novel 1,3-Oxazole Sulfonamides as Tubulin Polymerization Inhibitors.

A series of novel 1,3-oxazole sulfonamides were constructed and screened for their potential to inhibit cancer cell growth. These compounds were evaluated against the full NCI-60 human tumor cell lines, with the majority exhibiting promising overall growth inhibitory properties. They displayed high specificity within the panel of leukemia cell lines versus all other lines tested. When examined in the dose-response assay, GI50 values fell within the low micromolar to nanomolar ranges. 1,3-Oxazole sulfonamide 16 displayed the best average growth inhibition, whereas the 2-chloro-5-methylphenyl and 1-naphthyl substituents on the sulfonamide nitrogen proved to be the most potent leukemia inhibitors with mean GI50 values of 48.8 and 44.7 nM, respectively. In vitro tubulin polymerization experiments revealed that this class of compounds effectively binds to tubulin and induces the depolymerization of microtubules within cells.

Total Synthesis of Stelletins through an Unconventional Annulation Strategy.

Marine ecosystems present the largest source of biodiversity on the planet and an immense reservoir of novel chemical entities. Sessile marine organisms such as sponges produce a wide range of complex secondary metabolites, many of these with potent biological activity engineered for chemical defense. That such compounds exert dynamic effects outside of their native context is perhaps not surprising, and the realm of marine natural products has attracted considerable attention as a largely untapped repository of potential candidates for drug development. Only a handful of the more than 15 000 marine natural products that have been isolated to date have advanced to the clinic, and more are to be expected. The rich chemical information encoded in the intricate three-dimensional structures of many marine natural products facilitates highly discriminating interactions with cell signaling pathways, and especially within cancer cells such nuanced effects offer an exciting opportunity for the development of targeted therapies that lack the side effects and general toxicity of conventional chemotherapeutics. The isomalabaricanes are a rare class of marine triterpenoids that have been hailed as promising cytotoxic lead compounds for the treatment of cancer, and they have attracted a flurry of excitement from researchers because of their potent cytotoxicity in certain human cancer cell lines along with a range of other antineoplastic effects. Most notably, their inhibitory activity is highly cell-selective, characterized by large deviations from their mean GI50 concentrations across 3 orders of magnitude in the NCI-60 Human Tumor Cell Lines screen, suggesting mechanistic specificity rather than general and unbridled toxicity. Despite these auspicious preliminary reports, the isomalabaricane scaffold remains largely unexplored as a potential anticancer lead because of lack of material. This Account describes our recent efforts to develop a general, modular synthesis of the isomalabaricanes, as exemplified by the successful total syntheses of rhabdastrellic acid A, stelletin E, and stelletin A. The unorthodox trans-syn-trans configuration of their perhydrobenz[e]indene core severely circumscribes the synthetic methods available for its construction and required several generations of strategy to assemble. Ultimately, a series of unconventional transformations were identified that were capable of building this highly strained motif, and the syntheses of rhabdastrellic acid A and stelletin E were completed in racemic fashion. Subsequently, a second-generation approach to these natural products was developed, rendering the synthesis enantioselective as well as providing access to stelletin A. These synthetic efforts were greatly assisted by computational techniques such as 13C NMR prediction, which enabled structural assignments of hydrocarbon diastereomers, as well as relaxed surface scan conformational analysis, which informed a campaign for directed hydrogenation of an alkene. High-throughput experimentation methods were brought to bear during optimization of a late-stage Suzuki coupling on stelletin A. Finally, preliminary structure-activity relationship studies in glioblastoma and nonsmall cell lung cancer cell lines were conducted on stelletin A, revealing that the singular trans-syn-trans perhydrobenz[e]indene core is essential for the cytotoxic activity of the isomalabaricane triterpenoids.

Abstract PS18-46: Inhibition of breast cancer stem cells in 2- and 3-dimensional culture by novel salinomycin analogs

Abstract Breast cancer remains one of the leading cancers among women and an estimated 90% of breast cancer deaths are due to metastasis. Cancer stem cells (CSCs) are a sub-population of cancer cells which are responsible for its initiation, progression and metastasis. CSCs are resistant to conventional chemo- and radio-therapies and therefore therapeutic strategies targeting CSCs hold great potential for novel advances in cancer treatment. Salinomycin (SAL) is a naturally occurring polyether ionophore antibiotic which was shown to effectively target breast CSCs. A library of 17 novel SAL analogs was synthesized and screened to identify compounds with improved selectivity against breast cancer stem cells. SAL analogs were either single modified esters or amides in the C1 position or double-modified C20-oxo derivatives. Eight single- and two double-modified analogs were more potent (IC50 range of 1.13 ± 0.19 to 3.93 ± 0.39 µM) towards the breast cancer cell line MDA-MB-231 compared to parent SAL (IC50 of 4.90 ± 1.60 µM). These analogs induced DNA fragmentation suggestive of apoptotic cell death. Compounds 2 (butyl ester analog of SAL) and 17 (double-modified C20-oxosalinomycin with benzhydroxamic acid) have been chosen for follow-up screening due to their improved activity and selectivity versus parent SAL. This included clonogenic assays to assess the ability of the compounds to affect cell renewal, and wound healing assays to assess cell migratory properties. In both assays, compound 17 showed superior properties over SAL. Furthermore, analog 17 showed improved targeting of breast CSCs in both cell monolayer and organoid culture as assessed in assays measuring the CD44+/CD24- stem cell sub-population. Analogs and parent compound were further studied examining (ADP-ribose) polymerase (PARP) cleavage and Bcl-2 levels by immunoblotting. All three compounds induced loss of 116 kDa PARP expression within 48h, with the highest effect induced by analog 17. In addition, treatment with compound 17 caused a decrease in Bcl-2 expression as early as 24 h. Select analogs were next screened against the NCI-60 Human Tumor Cell Line Panel. The described above double-modified analog was found to be more potent than SAL towards all 6 breast cancer cell lines in the panel as well as other tumor types. The present findings highlight the therapeutic potential of SAL analogs towards breast stem cells and support further research and clinical development of these compounds. Funding: The present study was funded by grants (to AM and TCC) from the Arkansas Breast Cancer Research Program. Testing was performed by the Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, http://dtp.cancer.gov. Citation Format: Alicja Joanna Urbaniak, Megan R. Reed, Michał Antoszczak, Michał Sulik, Adam Huczyński, Robert L. Eoff, Melanie C. MacNicol, Timothy C. Chambers, Angus M. MacNicol. Inhibition of breast cancer stem cells in 2- and 3-dimensional culture by novel salinomycin analogs [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS18-46.

Biological Evaluation of 3-Aminoisoquinolin-1(2H)-one Derivatives as Potential Anticancer Agents Authors Lyudmyla Potikha

Anticancer activity of a series of 3-(hetaryl/aryl)amino substituted isoquinolin-1(2H)-ones has been studied within the international scientific program “NCI-60 Human Tumor Cell Lines Screen”. Screening was performed in vitro on 60 cell lines of lungs, kidneys, CNS, ovaries, prostate, and breast cancer, epithelial cancer, leukemia, and melanoma. The most effective compounds were those with thiazolyl or pyrazolyl substituent at 3-amino group and had no substituents at C(4) of the isoquinoline cycle. We identified a new lead compound, 3-(1,3-thiazol-2-ylamino)isoquinolin-1(2H)-one 12, which effectively prevents tumor cell growth (average lg GI50 = -5.18, lg TGI = -4.1, lg LC50 > -4.0) with good selectivity.

Synthesis, Characterization, and Biological Activity of Anthraquinone-Substituted Imidazolium Salts for the Treatment of Bladder Cancer

BACKGROUND: Bladder cancer is one of the most common types of cancer diagnosed each year, and more than half of patients have non-muscle invasive bladder cancer (NMIBC). The standard of care for patients with high-grade NMIBC is Bacillus Calmette-Guerin (BCG). Unfortunately, multiple BCG shortages have limited access to this treatment. Available alternatives using intravesical administration of chemotherapy have some efficacy, but lack prospective validation and long-term outcomes. Development of novel intravesical therapies may provide more active alternatives to BCG for patients with high-grade NMIBC. OBJECTIVE: To develop an optimal imidazolium salt for the intravesical treatment of NMIBC and determine preliminary in vitro activity of anthraquinone-substituted imidazolium salts. METHODS: The development of the anthraquinone-substituted imidazolium salts was undertaken in an attempt to increase the potency of this class of compounds by incorporating the quinone functional group observed in the chemotherapeutics doxorubicin, valrubicin, and mitomycin. All compounds were characterized by 1H and 13C NMR spectroscopy and infrared spectroscopy. Furthermore, these imidazolium salts were tested for in vitro cytotoxicity by the Developmental Therapeutics Program (DTP) on the NCI-60 human tumor cell line screening. Additional in vitro testing was performed against diverse bladder cancer cell lines (RT112, TCCSUP, J82, and UMUC13) using CellTiter-Glo® assays and colony-forming assays. RESULTS: The NCI-60 cell line screening indicated that compound 7 had the highest activity and was concluded to be the optimal compound for further study. Using CellTiter-Glo® assays on bladder cancer cell lines, 50% growth inhibitory concentration (IC50) values were determined to range from 32–50μM after an exposure of 1 h, for compound 7. Further evaluation of the compound by colony-forming assays showed the complete inhibition of growth at 10 days post a 100μM dose of compound 7 for 1 h. CONCLUSIONS: The most active lipophilic anthraquinone imidazolium salt, compound 7, could be a viable treatment for non-muscle invasive bladder cancer as it exhibits a cell-killing effect at a 1 h time period and completely inhibits cancer regrowth in colony-forming assays.

Synthesis, characterization, in vitro SAR study, and preliminary in vivo toxicity evaluation of naphthylmethyl substituted bis-imidazolium salts

A series of novel bis-imidazolium salts was synthesized, characterized, and evaluated in vitro against a panel of non-small cell lung cancer (NSCLC) cells. Two imidazolium cores were connected with alkyl chains of varying lengths to develop a structure activity relationship (SAR). Increasing the length of the connecting alkyl chain was shown to correlate to an increase in the anti-proliferative activity. The National Cancer Institute’s NCI-60 human tumor cell line screen confirmed this trend. The compound containing a decyl linker chain, 10, was chosen for further in vivo toxicity studies with C578BL/6 mice. The compound was well tolerated by the mice and all of the animals survived and gained weight over the course of the study.

Anticancer evaluation of di- and trifunctional substituted 1,3-thiazoles

Anticancer activity of a series of polyfunctional substituted 1,3-thiazoles has been studied within the international scientific program “NCI-60 Human Tumor Cell Lines Screen”. Screening was performed in vitro on 60 cell lines of lungs, kidneys, CNS, ovaries, prostate, and breast cancer, epithelial cancer, leukemia, and melanoma. The most effective compounds were those with a piperazine substituent at C2 of the 1,3-thiazole cycle: 1-(4-((4-methylphenyl)-sulfonyl)-2-phenyl-1,3-thiazol-5-yl)piperazine (average lg GI50 = -5.87, lg TGI = -5.54, lg LC50 = -5.21), 1-(2-(3,5-dimethyl-1H-pyrazol-1-yl)-4-((4-methylpheyl)sulfonyl)-1,3-thiazol-5-yl)piperazine (average lg GI50 = -5.66, lg TGI = -5.26, lg LC50 = -4.83), and 1-(2,4-bis((4-methylphenyl)sulfonyl)-1,3-thiazol-5-yl)piperazine (average lg GI50 = -5.67, lg TGI = -5.21, lg LC5050 = -4.67).

Novel Salinomycin Analogs Show Improved Selectivity Towards Breast Cancer Stem Cells

Breast cancer tumor metastasis is the leading cause of mortality among women. Cancer stem cells (CSCs) are the tumor‐initiating cells which drive initiation, progression, metastasis, and tumor reoccurrence. Their resistance to conventional chemo‐ and radiotherapies and their ability to survive such treatment enables tumor reestablishment. Thus, therapeutic strategies targeting CSCs hold great potential for novel advances in cancer treatment. Salinomycin (SAL) is a naturally occurring polyether ionophore antibiotic with anti‐cancer activity towards various types of tumor cells, but its toxicity towards normal cells limits broad application. A library of 21 novel SAL analogs was screened to identify compounds with improved selectivity especially against breast cancer stem cells. SAL analogs were either single modified with ester or amide in the C1 position or double‐modified C20‐oxo derivatives. Eight single‐ and two double‐modified derivatives were more potent (IC50 range of 1.13 ± 0.19 to 3.93 ± 0.39 μM) towards the breast cancer cell line MDA‐MB‐231 compared to SAL (IC50 of 5.81 ± 1.50). These derivatives induced DNA fragmentation suggestive of apoptotic cell death. Further, most of these derivatives had improved selectivity toward MDA‐MB‐231 cells compared to SAL when also tested against normal breast epithelial MCF10A cells. In addition, a butyl ester derivative of SAL, chosen based on increased potency and selectivity versus SAL, significantly reduced the colony‐forming efficiency of MDA‐MB‐231 cells in association with selective loss of the CD44+/CD24−/low stem‐cell‐like subpopulation. Select derivatives were next screened against the NCI‐60 Human Tumor Cell Line Panel. A double‐modified analog of C20‐oxo‐SAL with hydroxamic acid was found to be more potent than SAL towards all 6 breast cancer cell lines in the panel as well as other tumor types especially leukemia. Studies are underway to test the analogs in three dimensional culture using breast cancer organoids derived from both cell lines and patients. The present findings highlight the therapeutic potential of SAL analogs towards breast cancer and breast cancer stem cells and support further research and clinical development of these compounds.Support or Funding InformationThe present study was funded by grants (to AMM and TCC) from the Arkansas Breast Cancer Research Program. Testing was performed by the Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, http://dtp.cancer.gov.

Extra-cellular vesicles carry proteome of cancer hallmarks.

Through lateral transfer, extra-cellular vesicles (EVs) transport their DNA, miRNA, mRNA and proteins such as enzymes mediating drug resistance, transporters as well as growth factors to neighboring cells. By virtue of this horizontal transfer, EVs potentially regulate cell growth, migration, angiogenesis and metastasis and increase tissue permeability in cancer. Furthermore, EVs regulate immune factors and allow the tumor cells to evade immune recognition and cell death. To explore if the proteomes of exosomes support functional transfer of cancer hallmarks, in this meta-analysis, we compared EVs and whole cell proteomes from the NCI-60 human tumor cell line panel. We observed a subgroup of proteins in each cancer hallmark signature as highly abundant and consistently expressed in EVs from all cell lines. Among these were oncoproteins frequently targeted in cancer therapies whose presence on EVs could potentially render therapies less effective by serving as decoys.

Synthesis and Anticancer Activity of Tertiary Amides of Salinomycin and Their C20‐oxo Analogues

The polyether ionophore salinomycin (SAL) has captured much interest because of its potent activity against cancer cells and cancer stem cells. Our previous studies have indicated that C1/C20 double-modification of SAL is a useful strategy to generate diverse agents with promising biological activity profiles. Thus, herein we describe the synthesis of a new class of SAL analogues that combine key modifications at the C1 and C20 positions. The activity of the obtained SAL derivatives was evaluated using primary acute lymphoblastic leukemia, human breast adenocarcinoma and normal mammary epithelial cells. One single- [N,N-dipropyl amide of salinomycin (5 a)] and two novel double-modified analogues [N,N-dipropyl amide of C20-oxosalinomycin (5 b) and piperazine amide of C20-oxosalinomycin (13 b)] were found to be more potent toward the MDA-MB-231 cell line than SAL or its C20-oxo analogue 2. When select analogues were tested against the NCI-60 human tumor cell line panel, 4 a [N,N-diethyl amide of salinomycin] showed particular activity toward the ovarian cancer cell line SK-OV-3. Additionally, both SAL and 2 were found to be potent ex vivo against human ER/PR+ , Her2- invasive mammary carcinoma, with 2 showing minimal toxicity toward normal epithelial cells. The present findings highlight the therapeutic potential of SAL derivatives for select targeting of different cancer types.

Triazolothiadizepinylquinolines as potential MetAP-2 and NMT inhibitors: Microwave-assisted synthesis, pharmacological evaluation and molecular docking studies

The enzymes MetAP-2 and NMT play a crucial role in the process of myristoylation of oncoproteins which is deregulated in many types of cancers. Execution of both these enzymes is considered as strategy for the intervention of various cancers and relative fungal infections, and hence the discovery of novel MetAP-2 and NMT inhibitors necessitate their high relevancy. In this investigation, we have synthesized a series of novel seven-membered triazolothiadiazepinyl quinolines 10(a–m) distinctively under microwave irradiation technique and identified as selective MetAP-2 and NMT inhibitors. Amongst the functionalized derivatives when evaluated for the in vitro antifungal assay, compounds 10b, 10c, 10e and 10f were considered promising due to notable inhibitory effects (MIC = 0.2 mg/mL) on Aspergillus fumigatus. Screening of the anticancer activity against NCI-60 Human tumor cell lines portrayed that conjugates 10b, 10c, 10e and 10f were found to be moderately effective against the Renal Cancer cell line UO-31. The data acquired from biological studies was further validated by molecular docking studies and pharmacokinetic evaluation.

Synthesis and biological evaluation of 7-methoxy-1-(3,4,5-trimethoxyphenyl)-4,5-dihydro-2H-benzo[e]indazoles as new colchicine site inhibitors.

The colchicine site inhibitors (CSIs) displayed both antimitotic and vascular disrupting activities, therefore are promising potential antitumor agents. In this study, a series 1-phenyl-4,5-dihydro-2H-benzo[e]indazoles were found as new CSIs of which the bioactive configuration was locked. Among them, compounds C1 and C2 displayed the best activity, with tubulin polymerization IC50 of 3.4 and 1.5 μM, and growth IC50 of low nanomolar concentrations against human colon cancer cell lines. In addition, compound C1 showed excellent broad-spectrum antitumor activity in the NCI-60 Human Tumor Cell Lines Screen, encouraging further study of this antitumor compound.

Structural and Biological Investigations for a Series of N-5 Substituted Pyrrolo[3,2-d]pyrimidines as Potential Anti-Cancer Therapeutics.

Pyrrolo[3,2-d]pyrimidines have been studied for many years as potential lead compounds for the development of antiproliferative agents. Much of the focus has been on modifications to the pyrimidine ring, with enzymatic recognition often modulated by C2 and C4 substituents. In contrast, this work focuses on the N5 of the pyrrole ring by means of a series of novel N5-substituted pyrrolo[3,2-d]pyrimidines. The compounds were screened against the NCI-60 Human Tumor Cell Line panel, and the results were analyzed using the COMPARE algorithm to elucidate potential mechanisms of action. COMPARE analysis returned strong correlation to known DNA alkylators and groove binders, corroborating the hypothesis that these pyrrolo[3,2-d]pyrimidines act as DNA or RNA alkylators. In addition, N5 substitution reduced the EC50 against CCRF-CEM leukemia cells by up to 7-fold, indicating that this position is of interest in the development of antiproliferative lead compounds based on the pyrrolo[3,2-d]pyrimidine scaffold.

Abstract 1671: Characterization of a gene signature predictive of cancer patient survival prognosis and chemo-response

Abstract Precision oncology aims to match cancer patients with drugs based on their unique molecular profiles. The MATCH trial results indicate ~80% of cancer patients do not benefit from screening cancer patients for actionable genomic aberrations. We aim to identify potentially druggable gene signatures that are molecular drivers of poor survival outcome for these cancer patients. We analyze data from The Cancer Genome Atlas (TCGA) to identify patient groups with differential survival characteristics using gene expression data. We applied a univariate Cox regression model to identify genes associated with patient survival and identified a 67 gene signature of highly correlated genes significant for cell cycle related gene ontologies on over-representation analysis. Patients from the TCGA dataset whose tumors have a higher gene expression score are more likely to have worse survival prognosis compared to tumors with a lower gene expression score, demonstrated through Kaplan-Meier survival analysis and univariate and multivariate Cox proportional hazard models. This suggests we have identified a co-regulated gene expression network associated with cellular proliferation which predicts overall and recurrence-free survival in many of the cancers in the TCGA dataset. We further analyzed data from the NCI-60 Human Tumor Cell Lines Screen and found the cellular proliferation gene signature expression is correlated with response to cell cycle inhibitors. We then validated this finding using resistant cell lines and gene knockdown models in vitro. This gene signature may provide an important tool for selecting patients for chemotherapy administration. Citation Format: Paul Tran, Shuchun Li, Hai-Tao Liu, Lynn Tran, Sharad Purohit, Boying Dun, Jin-Xiong She. Characterization of a gene signature predictive of cancer patient survival prognosis and chemo-response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1671.

Predictive power of the Triticum root elongation test for the assessment of novel anti‑proliferative therapies.

The use of alternative techniques to reduce the number of animals used in anticancer research is an issue of current interest. The aim of this study was to validate the use of a simple and efficient alternative tool for the assessment of the potential of novel anti-proliferative agents. A set of 20 compounds with various mechanisms were tested in the Triticum aestivum root elongation assay, using aminophyl-line as negative control. Hierarchical cluster analyses were performed using the furthest neighbor method based on Euclidean distance measure, and the compounds were statistically analyzed in reference to their anti-proliferative pattern registered in the NCI60 human tumor cell line anticancer drug screen. A correlation between the Triticum test results and the NCI60 anti-proliferative profile was made for a number of human cells that we defined as the Triticum cell panel. Linear equations were computed that can be used to transform the inhibitory effect measured in any future Triticum assay in order to predict the effect on particular human cells. Of the tested anti-proliferative agents, methotrexate, colchicine, cantharidin, cisplatin and verapamil produced a growth inhibition over 50%. On the whole, the findings of this study suggest that the Triticum test can be used to detect several types of anti-proliferative mechanisms, particularly those targeting tubulin, rendering it a useful tool with which to identify novel mitotic spindle inhibitors.

Synthesis and Antiproliferative Activity of 9‐Formyl and 9‐Ethynyl Noscapines

AbstractAppending functional groups to the core skeleton of natural α‐noscapine, an FDA approved cough medicine, resulted in analogues with anticancer activity. In this study, we report the synthesis and antiproliferative activity of 9‐formyl and 9‐ethynylnoscapines. 9‐Formylnoscapine 5 was synthesized from 9‐bromonoscapine 2c via a three‐step reaction sequence involving palladium catalysed Heck reaction with ethyl acrylate leading to noscapinoid 7, dihydroxylation of 7 with OsO4 and oxidative cleavage of diol 8. Further, Seyferth‐Gilbert homologation of 9‐formylnoscapine using Bestmann‐Ohira reagent resulted in 9‐ethynylnoscapine 6 in excellent yield. Antiproliferative activity screening of new noscapinoids 5‐7 against NCI60 human tumor cell lines resulted in 9‐ethynylnoscapine 6 as a potent anticancer agent with the lowest mean percentage growth against the full 60‐cell line panel.

Arsenoplatin-1 Is a Dual Pharmacophore Anticancer Agent.

Arsenoplatins are adducts of two chemically important anticancer drugs, cisplatin and arsenic trioxide, that have a Pt(II) bond to an As(III) hydroxide center. Screens of the NCI-60 human tumor cell lines reveal that arsenoplatin-1 (AP-1), [Pt(μ-NHC(CH3)O)2ClAs(OH)2], the first representative of this novel class of anticancer agents, displays a superior activity profile relative to the parent drugs As2O3 or cisplatin in a majority of cancer cell lines tested. These activity profiles are important because the success of arsenic trioxide in blood cancers (such as APL) has not been seen in solid tumors due to the rapid clearance of arsenous acid from the body. To understand the biological chemistry of these compounds, we evaluated interactions of AP-1 with the two important classes of biomolecules-proteins and DNA. The first structural studies of AP-1 bound to model proteins reveal that platinum(II) binds the Nε of His in a manner that preserves the Pt-As bond. We find that AP-1 readily enters cells and binds to DNA with an intact Pt-As bond (Pt:As ratio of 1). At longer incubation times, however, the Pt:As ratio in DNA samples increases, suggesting that the Pt-As bond breaks and releases the As(OH)2 moiety. We conclude that arsenoplatin-1 has the potential to deliver both Pt and As species to a variety of hematological and solid cancers.

Implementation of the NCI-60 Human Tumor Cell Line Panel to Screen 2260 Cancer Drug Combinations to Generate >3 Million Data Points Used to Populate a Large Matrix of Anti-Neoplastic Agent Combinations (ALMANAC) Database

Animal and clinical studies demonstrate that cancer drug combinations (DCs) are more effective than single agents. However, it is difficult to predict which DCs will be more efficacious than individual drugs. Systematic DC high-throughput screening (HTS) of 100 approved drugs in the National Cancer Institute’s panel of 60 cancer cell lines (NCI-60) produced data to help select DCs for further consideration. We miniaturized growth inhibition assays into 384-well format, increased the fetal bovine serum amount to 10%, lengthened compound exposure to 72 h, and used a homogeneous detection reagent. We determined the growth inhibition 50% values of individual drugs across 60 cell lines, selected drug concentrations for 4 × 4 DC matrices (DCMs), created DCM master and replica daughter plate sets, implemented the HTS, quality control reviewed the data, and analyzed the results. A total of 2620 DCMs were screened in 60 cancer cell lines to generate 3.04 million data points for the NCI ALMANAC (A Large Matrix of Anti-Neoplastic Agent Combinations) database. We confirmed in vitro a synergistic drug interaction flagged in the DC HTS between the vinca-alkaloid microtubule assembly inhibitor vinorelbine (Navelbine) tartrate and the epidermal growth factor-receptor tyrosine kinase inhibitor gefitinib (Iressa) in the SK-MEL-5 melanoma cell line. Seventy-five percent of the DCs examined in the screen are not currently in the clinical trials database. Selected synergistic drug interactions flagged in the DC HTS described herein were subsequently confirmed by the NCI in vitro, evaluated mechanistically, and were shown to have greater than single-agent efficacy in mouse xenograft human cancer models. Enrollment is open for two clinical trials for DCs that were identified in the DC HTS. The NCI ALMANAC database therefore constitutes a valuable resource for selecting promising DCs for confirmation, mechanistic studies, and clinical translation.

Synthesis and antitumor activities of aquayamycin and analogues of derhodinosylurdamycin A.

Total syntheses of aquayamycin (3) and a number of analogues of angucycline antitumor antibiotic derhodinosylurdamycin A bearing various 2-deoxy sugar subunits (4-7) have been achieved. These molecules (3-7) were synthesized based on a convergent strategy for the synthesis of derhodinosylurdamycin A (2) previously reported from our group. In particular, our recently developed mild cationic gold-catalyzed glycosylation with S-but-3-ynyl thioglycoside donors was employed for the synthesis of analogues (6 and 7) bearing disaccharide subunits containing α-l-olivoside and α-l-olioside moiety, respectively. Aquayamycin (3), analogues (4-7), and our previously synthesized derhodinosylurdamycin A (2) were then submitted to the Development Therapeutics Program of the National Cancer Institute of National Institutes of Health for the NCI-60 Human Tumor Cell Lines Screening using standard protocols. It was found that derhodinosylurdamycin A (2), aquayamycin (3), and three other analogues (5-7) bearing sugar subunits did not show significant antiproliferative activity against those cancer cell lines. Interestingly, analogue (4) bearing no sugar subunit demonstrates good potential for growth inhibition and cytotoxic activity against a variety of human cancer cell lines.