Effects of the dual 5 α-reductase inhibitor dutasteride on apoptosis in primary cultures of prostate cancer epithelial cells and cell lines

BACKGROUND. The profound reduction in serum dihydrotestosterone (DHT) observed with the dual 5 a-reductase inhibitor (5ARI) dutasteride makes it an attractive agent for prostate cancer therapy. The objective of the current study was to determine whether dutasteride would induce apoptosis in a range of prostate epithelial cell lines and primary cultures. METHODS. Both human prostate androgen-sensitive cell lines (PwR-1E, PNT-2, LNCaP, and PC3[AR2]) and an androgen-independent cell line (PC-3) were grown to confluence. Primary epithelia] cells extracted from fresh prostate cancer radical prostatectomy specimens also were grown to confluence under optimal conditions. Total cellular protein was extracted to confirm cytokeratin 18 and antihuman alpha-methylacyl-CoA racemase (AMACR) expression of the primary cells. Apoptosis was assessed by propidium iodide DNA staining and flow cytometry after 24 hours of culture in from 0 mu M to 10 mu M of dutasteride. RESULTS. Dutasteride induced a dose-dependent increase in apoptosis in the androgen-sensitive prostate cell lines PwR-1E, PNT-2, and LNCaP and in the androgen receptor-expressing PC3(AR2) cell line. However, there was no significant apoptosis noted in the parental PC-3 cells. Of 16 primary epithelial cultures that were treated, 7 Cultures were induced to undergo apoptosis, and 9 cultures were unresponsive. All primary cultures were positive for cytokeratin 18 expression, confirming their epithelial phenotype. Responder epithelial cells were positive for AMACR expression. CONCLUSIONS. The results of the current study confirmed that dutasteride differentially induced apoptosis in a subset of prostate cell lines and primary prostate epithelial cells. Understanding the cellular phenotype may indicate susceptible cells.