Abstract: Objective To study the expression and function of miR-433 in the development of colorectal cancer. Methods RT-qPCR was used to detect the expression of miR-433 in clinical specimens and serum of patients with colorectal cancer, and compared with those from adjacent tissues or at different stages of tumore development and from normal persons. The colorectal cancer cell lines HT-29, HCT-116, SW480 and normal colon cell line NCM460 were cultured, and the expression of miR-433 was measured by real-time quantitative PCR. Subsequently, miR-433 mimic was transfected into SW480 cells,CCK-8 was used to detect cell proliferation, flow cytometry was used to detect cell cycle changes, scratch test and Transwell test were used to detect cell migration and invasion respectively. Results Compared with the adjacent tissues, the expression of miR-433 in colorectal cancer tissues was significantly decreased(P＜0.05). The serum level of miR-433 in patients with colon cancer was also significantly lower than that in normal persons(P＜0.05). In addition, from stage Ⅰ to stage Ⅳ of TNM, the expression of miR-433 in colorectal cancer tissues gradually and significantly decreased. Compared with normal human colon epithelial cell line NCM460, the expression of miR-433 was down-regulated in colorectal cancer cell lines HT-29, HCT-116 and SW480(P＜0.05). Compared with the control group, the proliferation of SW480 cells was significantly inhibited(P＜0.05) and the proportion of G2 and M phase cells increased after SW480 transfection. The invasion and migration of cells decreased significantly after up-regulation of miR-433(P＜0.05). Conclusions The expression of miR-433 is decreased in colorectal cancer. Up-regulation of its expression in SW480 cells inhibits cell proliferation, invasion and migration.

Key words: colorectal cancer, proliferation, miR-433