Abstract: Objective To study the effect of miR-5195-3p on runt-related transcription factor 3 (RUNX3) and colorectal cancer cell apoptosis. Methods The mRNA expression of miR-5195-3p and protein expression of RUNX3 were detected by RT-qPCR and Western blot, respectively. The SW480 cells were randomly divided into 5 groups: control group, miR-5195-3p mimic group, mimic control group, miR-5195-3p inhibitor group and inhibitor control group. The expression level of RUNX3 was measured by western blot. Cell apoptosis was detected by flow cytometry. Results The expression of miR-5195-3p was significantly increased, while the protein expression of RUNX3 was dramatically decreased in colorectal cancer tissue compared with non-tumor normal tissue (P<0.05). Overexpression of miR-5195-3p significantly down-regulated RUNX3 expression and decreased cell apoptosis, while inhibition of miR-5195-3p significantly up-regulated RUNX3 expression and increased cell apoptosis in SW480 cells (P<0.05). Additionally, co-transfection with RUNX3 overexpression vector obviously elevated cell apoptosis compared with miR-5195-3p mimic group (P<0.05). Conclusions miR-5195-3p may act as a oncogene in colorectal cancer, and its function was related to the target regulation of RUNX3.

Key words: colorectal cancer, RUNX3, miR-5195-3p, SW480, cell apoptosis