Background: KMUP-1 has been suggested to be beneficial in the treatment of benign prostatic hyperplasia. This study is aimed to further investigate whether KMUP-1 and doxazosin prevent from prostate cancer cell growth via androgen-dependent and -independent pathway in vivo and in vitro.

Methods: KMUP-1 was measured the activity on proliferation, apoptosis and cell cycle distribution in prostate cancer cells (LNCaP, DU-145, PC-3) by MTT assay, flow cytometry, Western Blotting and enzyme-linked immunosorbent assay (ELISA). The inhibition activities on androgen receptor (AR) and AR-targeting molecular prostate-specific antigen (PSA) expression by KMUP-1 and doxazosin were measured by RT-PCR, Western Blotting, and ELISA. Furthermore, we confirmed the effects of KMUP-1 on growth of LNCaP xenografts in nude mice.

Results: KMUP-1 significantly inhibited LNCaP cell growth and induced apoptosis in time- and dose-dependent manner. KMUP-1 and doxazosin further inhibited the expression of AR and PSA. Treatment of LNCaP cells with KMUP-1 resulted in cell cycle arrest and apoptotic activities, increasing p21 and p27 and decreasing expressions of cyclin D1, cyclin E, cyclin dependent kinase (CDK) 4, CDK2 and CDK6. Moreover, KMUP-1 activated p53, cleaved poly (ADP-ribose) polymerase and caspase-3, but reduced the expression of Bcl-2. Regular administration of KMUP-1 suppressed the LNCaP xenograft tumor growth in nude mice.

Conclusion: These evidences indicate that KMUP-1 and doxazosin inhibit LNCaP cell growth and downregulate expression of AR and PSA. KMUP-1 might be used as a chemoprevention agent for preventing the development of prostate cancer without cardiovascular adverse effect of doxazosin.