Abstract: Objective The aims of this study were to investigate the expression of microRNA-30a(miR-30a)in human bladder cancer cell lines and their effects on the proliferation,apoptosis and migration of human bladder cancer cells.Methods The expression levels of miR-30a in bladder cancer cell lines(5637 and T24)and bladder epithelial immortalized cells(SV-HUC-1)were detected by real-time quantitative PCR(qRT-PCR).The expression of miR-30a was up-regulated or down-regulated by T24 cells transfected with miR-30a mimic or 5637 cells transfected with miR-30a inhibitors and controls using NC mimic or NC inhibitor.The effects of miR-30a expression on the proliferation,apoptosis and invasion of bladder cancer cells were investigated by flow cytometry,MTT and Transwell assays.Results The expression level of miR-30a in two bladder cancer T24 and 5637 cell lines was significantly lower than that in normal bladder SV-HUC-1 cell line(P＜0.05),and the expression level of miR-30a was lower in the high degree of malignancy in bladder cancer T24 cells than that in malignant degree of relatively low 5637 cells.After 72h transfection,the values of optical density(OD)in the miR-30a mimic group(0.83±0.09)was significantly lower than that in NC mimic group(1.21±0.12)in T24 cells(P＜0.01).The OD values of miR-30a inhibitor group(1.28±0.14)was significantly lower than that in the NC inhibitor group(1.09±0.14)in 5637 cells(P＜0.01).The apoptotic rate of miR-30a mimic group in T24 cells(21.27±2.42)% was significantly higher than that in the NC mimic group(10.61±1.29)%(P＜0.01).The apoptotic rate of the miR-30a inhibitor group in 5637 cells(6.78±2.57)% was significantly lower than that in the NC mimic group(13.42±1.40)%(P＜0.01).The number of transmembrane cells in miR-30a mimic group in T24 cells(183.57±16.61)was significantly lower than that in NC mimic group(465.80±9.20)(P＜0.01).The number of transmembrane cells in the miR-30a inhibitor group in 5637 cells(581.25±11.02)was significantly lower than that in NC mimic group(397.13±7.57)(P＜0.01).Conclusion Up-regulation of miR-30a can inhibit the proliferation of bladder cancer cells,promote cell apoptosis and reduce the ability of migration and invasion in bladder cancer cells.The low expression of miR-30a in bladder cancer cells may be related to the development and metastasis in bladder cancer.

Key words: Bladder cancer cell, miRNA-30a, Proliferation, Apoptosis, Invasion