Effects of DACT2 on epithelial mesenchymal transition of glioma cells and its potential mechanism / 西安交通大学学报(医学版)

ABSTRACT

Objective: To investigate the effects and potential mechanism of tumor suppressor dishevelled-binding antagonist of beta-catenin 2 (DACT2) on epithelial-mesenchymal transition of glioma cells. Methods: The expressions of DACT2 in glioma cells U87, U251, A172 and SHG44 were detected by RT-PCR after 5-Aza treatment. The methylation status of DACT2 promoter was detected by methylation specific PCR (MSP). Western blot was used to detect the expression of DACT2 protein. U87 cells overexpressing DACT2 were constructed and verified by Western blot. Transwell assay was used to detect cell migratory and invasive ability. The protein levels of E-cadherin, Vimentin, MMP2 and Wnt/β-cadherin pathway proteins, i.e., active-β-cadherin, p-β-cadherin and total β-cadherin, in cells were detected by Western blot. Results: DACT2 expression was observed in all these cells after 5-Aza treatment; untreated U87 and U251 cells did not express DACT2 while A172 and SHG44 cells showed weak expression. The DACT2 promoter was completely methylated in U87 and U251 cells, and partially methylated in A172 and SHG44 cells. The level of DACT2 in U87 and U251 cells was lower than that in A172 and SHG44 cells (P<0.05). After transfection of pcDNA3.1-DACT2, the expression of DACT2 in U87 cells increased significantly (P<0.05), U87 cells overexpressing DACT2 were successfully constructed. Overexpression of DACT2 could significantly inhibit epithelial-mesenchymal transition, invasion and migration of U87 cells and block Wnt/β-catenin pathway activation (P<0.05). Conclusion: The DACT2 promoter in glioma cells is highly methylated, and the exogenous overexpression of DACT2 can promote the epithelial mesenchymal transition, invasion and migration of U87 cells. The underling mechanism may be related to the regulation of Wnt/β-catenin pathway by DACT2.