Prazosin Displays Anticancer Activity against Human Prostate Cancers: Targeting DNA, Cell Cycle

AbstractQuinazoline-based α1,-adrenoceptor antagonists, in particular doxazosin, terazosin, are suggested to display antineoplastic activity against prostate cancers. However, there are few studies elucidating the effect of prazosin. In this study, prazosin displayed antiproliferative activity superior to that of other α1-blockers, including doxazosin, terazosin, tamsulosin, phentolamine. Prazosin induced G2 checkpoint arrest, subsequent apoptosis in prostate cancer PC-3, DU-145, LNCaP cells. In p53-null PC-3 cells, prazosin induced an increase in DNA str, breaks, ATM/ATR checkpoint pathways, leading to the activation of downstream signaling cascades, including Cdc25c phosphorylation at Ser216, nuclear export of Cdc25c, cyclin-dependent kinase (Cdk) 1 phosphorylation at Tyr15. The data, together with sustained elevated cyclin A levels (other than cyclin B1 levels), suggested that Cdki activity was inactivated by prazosin. Moreover, prazosin triggered mitochondria-mediated, caspaseexecuted apoptotic pathways in PC-3 cells. The oral administration of prazosin significantly reduced tumor mass in PC-3-derived cancer xenografts in nude mice. In summary, we suggest that prazosin is a potential antitumor agent that induces cell apoptosis through the induction of DNA damage stress, leading to Cdki inactivation, G2 checkpoint arrest. Subsequently, mitochondriamediated caspase cascades are triggered to induce apoptosis in PC-3 cells