MicroRNA-29b promotes cellular senescence of colorectal tumors by targeting tribbles pseudokinase 2

Objective To investigate the mechanism of microRNA (miRNA, miR)-29b regulation of tribbles pseudokinase 2 (TRIB2) in colorectal tumors. Methods The online database was used to analyze the miRNAs that bind to the 3’Untranslated Region (UTR) of TRIB2, and the highest scored miR-29b was selected for study. The eukaryotic cell transfection technique was used to interfere with the expression of miR-29b in colorectal tumor cells; Western blotting and real-time quantitative polymerase chain reaction (Real-time PCR) was used to detect the difference in protein and mRNA expression of TRIB2; the position of miR-29b binding on TRIB2-3’untranslated regions (3’UTR) was confirmed by luciferase reporter gene assay; β-galactosidase staining was used to detect effects of miR-29b on colorectal cancer cell senescence. All data were quantified as Mean±SD. Two-tailed Student’s t-test was used to evaluate the differences between two groups. All statistical analyses were performed using SPSS 24.0 (SPSS Inc.). Results In SW48 and SW480 cell lines overexpressing miR-29b, the mRNA levels of TRIB2 decreased to (63.468±4.154)% and (43.145±7.523)% (t=5.351, P 0.05). In the cancer cells overexpressing of miR-29b, the proportion of senescent cells increased from 41.473% to 62.085% (χ2=19.731, P<0.01), and overexpression of TRIB2 reduced the proportion to 46.866% (χ2=12.031, P<0.01). Conclusion miR-29b can inhibits TRIB2 expression and promote the senescence of colorectal tumors, and it can be used as a potential therapeutic target for colorectal cancer. Key words: MicroRNA-29b; Tribbles pseudokinase 2; Colorectal cancer; Cell senescence