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.