Abstract: Objective To explore the effects and regulation mechanism of microRNA-489 (miR-489) on the stem cell phenotype and epithelial-mesenchymal transition of colon cancer cells in vitro. Methods The miR-489 expression of colon cancer cell lines (HT29, SW480 and SW620, HCT116) and normal intestinal epithelial cells HIEC were detected by RT-qPCR, the miR-489 expression in colon cancer cells was raised by gene transfection technology, the colon cancer stem cell markers CD133, CD44, EpCAM, ALDH1 and epithelial marker E-cadherin, mesenchymal cells markers Vimentin and N-cadherin were detected by Western blot. The expression of TWIST1 mRNA and protein were detected by RT-qPCR and Western blot. Results The miR-489 relative expression in four kinds of colon cancer cells (HT29, SW480 and SW620, HCT116) were significantly lower than that of normal HIEC intestinal epithelial cells, the difference was statistically significant (P<0.05). Up-regulation of miR-489 expression in HT29 and HCT116 cells leaded to lower expression of colon cancer stem cell marker CD133, CD44, EpCAM ALDH1 and mesenchymal cells markers Vimentin, N-cadherin, higher expression of epithelial markers E-cadherin (P<0.05). Also, up-regulation of miR-489 expression in HT29 and HCT116 cells leaded to lower expression of TWIST1 mRNA and protein (P<0.05). Conclusion MiR-489 is down-regulated in colon cancer cells and up-regulation of miR-489 expression inhibits stem cell phenotype and epithelial-mesenchymal transition through targeting TWIST1 in colon cancer.

Key words: microRNA-489, TWIST1, colon cancer, Cancer stem cells, Epithelial-mesenchymal transition