MicroRNA-320c inhibits tumorous behaviors of bladder cancer by targeting Cyclin-dependent kinase 6

Background: increasing evidence has suggested that dysregulation of micrornas (mirnas) could contribute to human disease including cancer. previous mirna microarray analysis illustrated that mir-320c is down-regulated in various cancers. however,the roles of mir-320c in human bladder cancer have not been well elucidated. therefore,this study was performed to investigate the biological functions and molecular mechanisms of mir-320c in human bladder cancer cell lines,discussing whether it could be a therapeutic biomarker of bladder cancer in the future. methods. two human bladder cancer cell lines and samples from thirteen patients with bladder cancer were analyzed for the expression of mir-320c by quantitative rt-pcr. over-expression of mir-320c was established by transfecting mimics into t24 and um-uc-3. cell proliferation and cell cycle were assessed by cell viability assay,flow cytometry and colony formation assay. cell motility ability was evaluated by transwell assay. the target gene of mir-320c was determined by luciferase assay,quantitative rt-pcr and western blot. the regulation of cell cycle and mobility by mir-320c was analyzed by western blot. results: we observed that mir-320c was down-regulated in human bladder cancer tissues and bladder cancer cell lines t24 and um-uc-3. over-expression of mir-320c could induce g1 phase arrest in um-uc-3 and t24 cells,and subsequently inhibited cell growth. we also indentified mir-320c could impair um-uc-3 and t24 cell motility. in addition,we identified cdk6,a cell cycle regulator,as a novel target of mir-320c. moreover,we demonstrated mir-320c could induce bladder cancer cell cycle arrest and mobility via regulating cdk6. we also observed that inhibition of mir-320c or restoration of cdk6 in mir-320c-over-expressed bladder cancer cells partly reversed the suppressive effects of mir-320c. conclusions: mir-320c could inhibit the proliferation,migration and invasion of bladder cancer cells via regulating cdk6. our study revealed that mir-320c could be a therapeutic biomarker of bladder cancer in the future. © 2014 wang et al.; licensee biomed central ltd.