Aberrant androgen receptor (AR) signaling functions are implicated in prostate cancer (PCa) pathogenesis. Here, we studied interactions between miR-185 and the bromodomain containing 8 isoform 2 (BRD8 ISO2) to investigate indirect mechanisms of miR-185 with respect to AR function through BRD8 ISO2 in PCa.
Putative miRNA response element (MRE) of miR-185 in 3'-untranslated region (3'-UTR) of BRD8 ISO2 mRNA was predicted by software and confirmed using dual-luciferase assays and Ago2 immunoprecipitation. BRD8 and AR expression were determined by qRT-PCR and Western blot in PCa cells and tissues. MMTV-Fluc reporter plasmids and dual-luciferase assays were used to evaluate AR activity.
MRE prediction, dual-luciferase assays and Ago2 immunoprecipitation confirmed that miR-185 is capable of binding the 3'-UTR of BRD8 ISO2 mRNA. QRT-PCR and Western blot indicated that BRD8 ISO2 expression is decreased by miR-185 mimic transfection while increased by miR-185 inhibitor transfection. MMTV-Fluc reporter assays revealed that miR-185 can attenuate AR function by suppressing BRD8 ISO2. Additionally, Pearson's correlation analyses confirmed that BRD8 ISO2 mRNA expression is inversely correlated with miR-185 expression in clinical specimens.
In addition to suppression of AR expression, miR-185 can attenuate AR function indirectly by suppressing BRD8 ISO2. MiR-185 and BRD8 ISO2 may be possible therapeutic targets for PCa treatment.
Molecular and cellular endocrinology. 2016 Feb 29 [Epub ahead of print]
Chen-Yi Jiang, Yuan Ruan, Xiao-Hai Wang, Wei Zhao, Qi Jiang, Yi-Feng Jing, Bang-Min Han, Shu-Jie Xia, Fu-Jun Zhao
Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China., Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; Department of Urology, Shanghai General Hospital Affiliated to Nanjing Medical University, Shanghai 200080, China., Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China., Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China., Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China., Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China., Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; Institute of Urology, Shanghai Jiao Tong University, Shanghai 200080, China., Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; Department of Urology, Shanghai General Hospital Affiliated to Nanjing Medical University, Shanghai 200080, China; Institute of Urology, Shanghai Jiao Tong University, Shanghai 200080, China. Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China; Institute of Urology, Shanghai Jiao Tong University, Shanghai 200080, China.