The effect and underlying mechanisms of down-regulated CDX2 on migration and invasion of colon cancer cells

Objective: To observe the effect of down-regulated CDX2 gene on the migration and invasion abilities of colon cancer cells (SW480 and HT29) and investigate the role and mechanisms of CDX2 gene in occurrence and development of colon cancer metastasis. Methods: CDX2 gene in HT29 and SW480 cells was down-regulated using lentivirus RNA interference (RNAi) vector. The interference efficiency of CDX2 was detected by qRT-PCR and Western blotting. The effect of down-regulated CDX2 expression on colon cancer cells' migration and invasion was determined by Transwell and wound heal methods. Then the effects of down-regulated CDX2 on the expressions of epithelial-mesenchymal transition (EMT)-related genes (E-cadherin, ZEB-1, Vimentin, Twist and Snail) were detected by RT-PCR and Western blotting. Results: The constructed CDX2 siRNA expression vector could significantly inhibit the expression of CDX2 in HT29 and SW480 cells. Compared with those of the cells transfected with empty vector (LV-NT-shRNA) and non-transfected cells, the migration and invasion abilities of cells transfected with LV-CDX2-shRNA were markedly enhanced (P<0.05). E-cadherin expression was reduced while expressions of ZEB-1, Vimentin, Twist, and Snail were significantly increased (all P<0.05). Conclusion: Down-regulating the expression of CDX2 can induce the occurrence of EMT, thus enhancing the invasion and migration of colon cancer cells.