Abstract: Objective The aim of this study was to detect the expression of miR-383-5p in bladder cancer tissues and bladder cancer 5637 cells,BIU-87 cells,TCCSUP cells and HT-1376 cells,and to explore the effects of miR-383-5p on the proliferation,invasion,migration and apoptosis of bladder cancer cells by targeting CIP2A. Methods The expression of miR-383-5p was detected by qRT-PCR in human bladder cancer tissues and their corresponding adjacent tissues,5637 cells,BIU-87 cells,TCCSUP cells,HT-1376 cells,human bladder transitional epithelial cells.BIU-87 cells with low miR-383-5p expression were selected for subsequent experiments.BIU-87 cells were divided into the blank group(normal culture),miR-383-5p NC group(negative control,transfected with miR-383-5p negative control),miR-383-5p mimic group(transfected with miR-383-5p mimic),and miR-383-5p mimic+pc-CIP2A group(co-transfected with miR-383-5p mimic and CIP2A overexpression plasmid pc-CIP2A).CCK-8 kit was used to detect the viability of BIU-87 cells in each group;Flow cytometry was used to detect apoptosis of BIU-87 cells;Transwell assay was used to measure cell invasion ability of BIU-87 cells;Scratch assay was used to measure cell migration ability of BIU-87 cells;Western blot was used to determine the expression of proteins related to apoptosis,invasion(MMP-2, MMP-9),and CIP2A/PP2A in BIU-87 cells;The dual luciferase assay was used to verify the targeting relationship between miR-383-5p and CIP2A in BIU-87 cells. Results The expression of miR-383-5p was low in bladder cancer tissues and bladder cancer cells. Compared with the blank group,BIU-87 cells in the miR-383-5p mimic group showed a significant increase the level of miR-383-5p(0.91±0.10 vs. 1.67±0.24,P＜0.01)and a significant decrease in the expression of CIP2A protein(1.32±0.17 vs. 0.45±0.03,P＜0.001),the cell viability,invasion, migration abilities,the expression of proteins related to invasion(MMP-2,MMP-9),and the expression of Bcl-2 protein[(100.00±4.36)% vs.(32.15±2.65)%,(150.20±12.95)vs.(82.35±7.01),(77.91±3.63)% vs.(46.12±2.54)%,1.02±0.11 vs. 0.22±0.04,1.03±0.18 vs. 0. 21±0.04,1.01±0.14 vs. 0.27±0.05,P＜0.001]; The apoptosis rate,the expression of caspase-3 and Bax proteins related to apoptosis,and PP2A expression were significantly increased[(14.02±2.29)% vs.(38.21±3.20)%],0.81±0.11 vs. 1.78±0.24,0.83±0.12 vs. 1.72±0.24,0.27±0.02 vs. 0.95±0.16,P＜0.001].Compared with the miR-383-5p mimic group,BIU-87 cells in the miR-383-5p mimic+pc-CIP2A group significantly increased the cell viability,invasion,migration abilities,the expression of proteins related to invasion,and the expression of Bcl-2 protein[(32.15±2.65)% vs. (50.18±3.77)%,(82.35±7.01)% vs.(116.30±13.70),(46.12±2.54)% vs.(58.43±3.15)%,0.22±0.04 vs. 0.60±0.08,0.21±0.04 vs. 0.5 8±0.06,0.27±0.05 vs. 0.64±0.08,P＜0.05];The apoptosis rate,the expression of caspase-3,Bax,and PP2A was significantly reduced in the miR-383-5p mimic+pc-CIP2A group[(38.21±3.20)%(23.15±2.74)%,1.78±0.24 vs. 1.25±0.21,1.72±0.24 vs. 1.23±0.18,0.95±0.16 vs. 0.60±0.13,P＜0.05].The results of dual luciferase experiments showed a corresponding targeting relationship between miR-383-5p and CIP2A. Conclusion Increasing the expression of miR-383-5p can inhibit the proliferation,invasion and migration of bladder cancer BIU-87 cells,and enhance the ability of apoptosis,which may be achieved by targeted regulation of CIP2A.

Key words: miR-383-5p, CIP2A, Bladder cancer, Proliferation, Invasion