Prostate cancer is still considered a significant health care challenge worldwide due in part to the distinct transformation of androgen-dependent prostate cancer (ADPC) into treatment-refractory castration-resistant prostate cancer (CRPC). Consequently, there is an urgent need to explore novel molecular mechanisms underlying treatment resistance in ADPC. Although numerous studies have alluded to the role of miR-200a in several cancers, the biological significance of miR-200a in prostate cancer remains unknown. After performing microarray analysis and reanalysis of the publicly available Memorial Sloan Kettering Cancer Center dataset, miR-200a expression was found higher in ADPC tissues and its expression was positively associated with survival of CRPC patients. In vitro studies showed that miR-200a overexpression in CRPC cells markedly suppressed cellular proliferation and facilitated apoptosis. In vivo studies indicated that overexpression of miR-200a inhibited growth and metastasis of prostate cancer. The luciferase reporter assay demonstrated that BRD4 is a direct target gene of miR-200a and it could reverse miR-200a-mediated biological effects in prostate cancer cells. Most importantly, our findings indicated that miR-200a suppresses the progression of CRPC by inhibiting the activation of BRD4-mediated AR signaling. This finding provides the foundation for the development of more personalized therapeutic approaches for CRPC patients.
Keywords: BRD4; androgen receptor; miRNA; prostate cancer; signaling pathway.
© 2019 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.