MiR-186 suppresses the growth and metastasis of bladder cancer by targeting NSBP1

BACKGROUND Increasing evidence has shown that microRNAs function as oncogenes or tumor suppressors in human malignancies, but the roles of miR-186 in human bladder cancer (BC) is still unclear. METHODS First, quantitative real-time PCR (qRT-PCR) was performed to detect miR-186 expression in bladder cancer tissues and cell lines. Then, Bioinformatics analysis, combined with luciferase reporter assay demonstrated the target gene of miR-186. Finally, the roles of miR-186 in regulation of tumor proliferation and invasion were further investigated. RESULTS Here, our study showed miR-186 was down-regulated in bladder cancer tissues and cell lines. Luciferase reporter assay showed that miR-186 targets NSBP1 3'-untranslated region (UTR) directly and suppresses NSBP1 (HMGN5) expression in human bladder cancer cells. NSBP1 siRNA- and miR-186-mediated NSBP1 knock-down experiments revealed that miR-186 suppresses cell proliferation and invasion through suppression of NSBP1 expression. Expression analysis of a set of epithelial-mesenchymal transition (EMT) markers showed that NSBP1 involves miR-186 suppressed EMT which reducing the expression of mesenchymal markers (vimentin and N-cadherin) and inducing the expression of epithelial marker (E-cadherin). CONCLUSIONS Our data first time identified miR-186 as the upstream regulator of NSBP1 and also suggest miR-186-suppressed NSBP1 as a novel therapeutic approach for bladder cancer.