MiR-200a promotes epithelial-mesenchymal transition of endometrial cancer cells by negatively regulating FOXA2 expression.

Endometrial cancer is the most common gynecological cancer. Epithelial-mesenchymal transition (EMT) plays a critical role in tumor invasion and metastasis, which limits the success of treatment. Here, we investigated the roles of forkhead box A2 (FOXA2) and microRNA-200a (miR-200a) in regulating the EMT of endometrial cancer cells RL95-2. Empty vector or FOXA2 was stably transfected into RL95-2 cells. MTT assay measured cell proliferation, apoptosis assay measured apoptosis, Transwell invasion assay measured cell invasion, and Western blot measured the protein expression of FOXA2, E-cadherin, and vimentin. ChIP assay determined the binding of FOXA2 to E-cadherin promoter. For miR-200a analysis, the cells with stable FOXA2 expression were transfected with miR-negative control or miR-200a. Forced expression of FOXA2 decreased the proliferation and invasion, and increased the apoptosis of RL95-2 cells. FOXA2 also affected the EMT-associated proteins: FOXA2 increased the protein expression of E-cadherin and decreased the expression of vimentin. Moreover, FOXA2 positively regulated the promoter of E-cadherin in RL95-2 cells. Luciferase reporter assay identified FOXA2 as a target of miR-200a, which negatively regulated FOXA2. Western blot results showed that overexpression of miR-200a decreased the expression of E-cadherin but increased the expression of vimentin in the endometrial cancer cells by downregulating FOXA2 expression. FOXA2 may act as a tumor suppressor and inhibit EMT of endometrial cancer cells. FOXA2 expression is controlled by miR-200a, which promotes EMT of the endometrial cancer cells.