Abstract: Objective  To study the effects of miR-200b on proliferation and migration of sw620 colon cancer cells, and its regulation effect on E-cadherin expression. Methods  The expressions of miR-200b in sw620 cells at 24 h and 72 h after pEGP-miR-200b transfection were detected by real-time PCR (RT-PCR). The change of the expression level of E-cadherin after miR-200b transfection was detected using the methods of RT-PCR and Western blot. The proliferation and migration abilities were measured by MTT and scratch test after miR-200b transfection. Results  The expressions of miR-200b in sw620 cells at 24 h and 72 h after pEGP-miR-200b transfection raised significantly compared to the control group (t=11.579, P＜0.01; t=11.579, P＜0.01). MiR-200b transfection inhibited the proliferation abilities of sw620 cells. It is the most significant of the inhibitory effect on the third day and the inhibition rate was 55.34%. MiR-200b transfection  markedly inhibited the migration abilities of sw620 cells. The two groups had significant difference in the migration distance of 24, 48, 72 h (t=11.579, P＜0.01; t=10.419, P＜0.01; t=6.955, P＜0.01). The mRNA and protein expressions of E-cadherin gene increased significantly by transfecting miR-200b gene in sw620 cells (t=10.432, P＜0.01; t=8.325, P＜0.01). Conclusion  Up-regulated expression of miR-200b could inhibite the proliferation and migration abilities of sw620 colon cancer cells. The involved molecular mechanism is probably related to the change of E-cadherin expression.

Key words: MicroRNAs, Colonic neoplasms, Cell proliferation, Cell migration assays