Knockdown of REGγ inhibits proliferation by inducing apoptosis and cell cycle arrest in prostate cancer

Prostate cancer (PCa) is the most common malignant tumor and the second leading cause of cancer related death among men in western countries. REGγ, a proteasome activator, is reported to play important roles in various human cancers. However, the expression patterns and potential roles of REGγ in prostate cancer have never been reported. In this study, we found for the first time that REGγ is overexpressed in prostate cancer tissues and cell lines at both protein and mRNA levels. In addition, we demonstrated that knockdown of REGγ significantly inhibited cell proliferation and induced apoptosis and cell cycle arrest in PCa cell lines PC-3 and DU145. Moreover, we observed that the expressions of P21 were increased while the levels of cycinD1 and bcl-2 were decreased after knockdown of REGγ in PCa cells. And the stabilization of P21 was enhanced after REGγ knockdown in PC-3 cells. In summary, our findings suggest that REGγ may play important roles in prostate cancer and may serve as a novel therapeutic target in the treatment of PCa patients.