MicroRNA-140 regulates the proliferation of pancreatic cancer cell through targeting high mobility group protein B1

Abstract

Objective The present study was aimed to investigate the role of microRNA (miRNA, miR)-140/high mobility group protein B1 (HMGB1) in regulating the proliferation of pancreatic cancer cells. Methods In the present study, we chose miR-140 and HMGB1 as the research object. First we transfected the pancreatic cancer cells with miR-140 mimics or miR-140 inhibitor to achieve miR-140 overexpression or miR-140 silencing, and detected the expression of miR-140 and the expression level of HMGB1 proteins in response to miR-140 overexpression or miR-140 silencing; secondly luciferase reporter gene plasmid with or without a six base pairs mutation in the 3’untranslated regions (3’UTR) of HMGB1 (mut-HMGB1/wt-HMGB1) were conducted and co-transfected with miR-140 mimics or miR-140 inhibitor, then the changes of the luciferase activity were detected; then pcDNA3.1/HMGB1 plasmid was constructed and co-transfected with miR-140 mimics or miR-140 inhibitor, HMGB1 and RAGE protein expression level changes were determined in response to miR-140 overexpression or miR-140 silencing; lastly the cell proliferation was determined in response to mimics NC/miR-140 mimics and pcDNA3.1/HMGB1 co-transfection. Results Overexpression of miR-140 inhibited the expression of HMGB1 protein (0.406 3±0.018 9, t=11.250, P=0.000), miR-140 silencing promoted HMGB1 protein expression (1.975 8±0.069 3, t=9.121, P=0.001); miR-140 could regulate the expression of HMGB1 by direct targeting; HMGB1 overexpression was achieved by pcDNA3.1/HMGB1 transfection (5.458 9±0.463 7, t=16.140, P=0.000), and HMGB1 overexpression could attenuate the inhibitory effect of miR-140 on HMGB1 and RAGE; miR-140 could inhibit the growth and proliferation of pancreatic cancer cells (P=0.042), HMGB1 could promote the growth and proliferation of pancreatic cancer cells (P=0.008); HMGB1 could restore the inhibitory effect of miR-140 on growth and proliferation of pancreatic cancer cells (compared to miR-140 mimics + pcDNA3.1 group, t=3.850, P=0.020). Conclusion miR-140 regulates the proliferation of pancreatic cancer cell through targeting HMGB. Key words: MicroRNA-140; High mobility group protein B1; PANC-1; Proliferation; Pancreatic cancer