High-Throughput Cell-Based Screening of 4910 Known Drugs and Drug-like Small Molecules Identifies Disulfiram as an Inhibitor of Prostate Cancer Cell Growth

Abstract

Purpose: To identify novel therapeutic opportunities for patients with prostate cancer, we applied high-throughput screening to systematically explore most currently marketed drugs and drug-like molecules for their efficacy against a panel of prostate cancer cells. Experimental Design: We carried out a high-throughput cell-based screening with proliferation as a primary end-point using a library of 4,910 drug-like small molecule compounds in four prostate cancer (VCaP, LNCaP, DU 145, and PC-3) and two nonmalignant prostate epithelial cell lines (RWPE-1 and EP156T). The EC 50 values were determined for each cell type to identify cancer selective compounds. The in vivo effect of disulfiram (DSF) was studied in VCaP cell xenografts, and gene microarray and combinatorial studies with copper or zinc were done in vitro for mechanistic exploration. Results: Most of the effective compounds, including antineoplastic agents, were nonselective and found to inhibit both cancer and control cells in equal amounts. In contrast, histone deacetylase inhibitor trichostatin A, thiram, DSF, and monensin were identified as selective antineoplastic agents that inhibited VCaP and LNCaP cell proliferation at nanomolar concentrations. DSF reduced tumor growth in vivo, induced metallothionein expression, and reduced DNA replication by downregulating MCM mRNA expression. The effect of DSF was potentiated by copper in vitro. Conclusions: We identified three novel cancer-selective growth inhibitory compounds for human prostate cancer cells among marketed drugs. We then validated DSF as a potential prostate cancer therapeutic agent. These kinds of pharmacologically wellknown molecules can be readily translated to in vivo preclinical studies and clinical trials. (Clin Cancer Res 2009;15(19):6070-8)

Cancer Biology, Toxicology and Alternative Methods Development Go Hand‐in‐Hand

“…Clearly, such knowledge is also imperative for accurate understanding of the usefulness and limitations of commonly applied infinite cell line models to toxicity experiments [19]. Clinically oriented studies for understanding responsiveness of tumour cells to cell killing from exposure to cancer therapeutics provide useful information on the biological fates that cells also encounter from exposure to environmental agents [6,21,22]. Over-expression or knockout of oncogenes or tumour suppressor genes provides much needed information on driving forces underlying transformation, but useful to toxicology, also informs on genes critically regulating survival or killing mechanisms [23].…”

“…Inspirational to increasing the efficiency of toxicological evaluations, pre-clinical cancer drug development includes the application of a variety of methods and technologies to pinpoint the target specificity and the absence of unwanted side effects [23]. The HTS experiments are mainly carried out to discover new and more selective cancer-associated pathways or processes [16,21]. To study pathway activation or repression caused by the drug candidates, reverse-phase protein lysate arrays (RPPA) or gene expression profiling are commonly employed thereafter [29,30].…”

“…In stage 3, class-representative agents with high intrinsic potency for exerting toxic effects are typically subjected to even broader characterization taking into account the concentrations and time points defined in the stage 1 and 2 results. Additionally, if following stage 1 testing, only a low number of compounds has indicated toxicity, or if the toxicity mechanism remains unclear, one could conceptually see stages 2 and 3 being assayed simultaneously, or stage 2 could follow stage 3 to verify mechanisms inferred from genomics profiling [21,30]. Typically, the gene expression profiling analysis of stage 3 would serve to determine broad toxicology-relevant bioidentities of 'the selected few' group.…”

Development and characterisation of disulfiram-loaded PLGA nanoparticles for the treatment of non-small cell lung cancer

“…Therefore the discovery of a CSC-targeting drug would significantly improve chemotherapy outcomes for NSCLC patients. The antialcoholism drug disulfiram (DSF) has been shown to have an anticancer effect against prostate cancer, breast cancer, brain tumours, leukaemia, cervical adenocarcinoma and NSCLC [21][22][23][24][25][26][27][28][29][30][31][32][33][34]. Furthermore, DSF has been shown to be an irreversible aldehyde dehydrogenase (ALDH) inhibitor targeting CSCs [22,[35][36].…”

Regrowth Concentration Zero (RC0) as Complementary Endpoint Parameter to Evaluate Compound Candidates During Preclinical Drug Development for Cancer Treatment

“…MTT assay). In these assays, cell line(s) are tested against a broad range of drug concentrations typically for 48-72 h and the results are usually reported as a plot and the IC 50 and LC 100 (See Glossary) are calculated by interpolation (Brown, 1997;Iljin et al, 2009). For instance, in the NCI60 human tumor cell line anticancer drug screen program, the GI50 (50% growth inhibition) and LC50 (50% lethal concentration) are derived from concentrationresponse curves by linear interpolation while the TGI (total growth inhibition) is read as the x-axis intercept (Shoemaker, 2006).…”