High-throughput cell-based screening of 4910 known drugs and drug-like small molecules identifies disulfiram as an inhibitor of prostate cancer cell growth.
OBJECTIVE
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.


METHODS
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 well-known molecules can be readily translated to in vivo preclinical studies and clinical trials.
Iljin
Kristiina
K
Medical Biotechnology, VTT Technical Research Centre of Finland, Turku, Finland.
Ketola
Kirsi
K
Vainio
Paula
P
Halonen
Pasi
P
Kohonen
Pekka
P
Fey
Vidal
V
Grafström
Roland C
RC
Perälä
Merja
M
Kallioniemi
Olli
O
D000818:Animals; D000970:Antineoplastic Agents / Q000302:isolation & purification / Q000494:pharmacology; D002277:Carcinoma / Q000473:pathology*; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D004221:Disulfiram / Q000302:isolation & purification / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor / Q000379:methods; D057166:High-Throughput Screening Assays / Q000379:methods; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008954:Models, Biological; D011471:Prostatic Neoplasms / Q000473:pathology*; D054852:Small Molecule Libraries / Q000032:analysis; D023041:Xenograft Model Antitumor Assays
D000970:Antineoplastic Agents; D054852:Small Molecule Libraries; D004221:Disulfiram