[Hypoxia-inducible factor-1α is involved in arsenite-induced epithelial-mesenchymal transition and malignant transformation of human liver epithelial cells via regulating Snail].

Objective: To investigate the role of hypoxia-inducible factor-1α (HIF-1α) in arsenite-induced epithelial-mesenchymal transition (EMT) and malignant transformation of human liver epithelial cells (L-02 cells). Methods: After the L-02 cells were chronic treated with 2.0 μmol/L NaAsO(2) for 0 (reference), 10, 20, or 30 passages, con siRNA or HIF-1α siRNA was transfected into arsenite-transformed L-02 (T-L-02) cells by lipofectamine(TM)2000 and were set as T-L-02+con siRNA group and T-L-02+HIF-1α siRNA group as well as L-02 group and T-L-02 group, EMT index and levels of HIF-1α were detected by western blots. The reporter assays were performed to determine if HIF-1α directly regulate Snail transcriptional activity, and soft agar colony formation and Transwell assay were used to detect the malignancy, invasion, and migration ability of cells. Results: When L-02 cells were treated for 10 generations with 2 μmol/L NaAsO(2), relative expressions of E-cadherin were gradually increased compared to control cells, while the levels of N-cadherin, Snail, and HIF-1α were gradually increased in the L-02 cells compared to control cells, showing the longer the treatment time was, the more obvious the change was (P<0.05) . Down regulating the level of HIF-1α by siNRA caused E-cadherin levels to rise compared to T-L-02 group, while the levels of N-cadherin and Snail fall back compared to T-L-02 group (P<0.05) . Double luciferase reporter gene assays showed that HIF-1α directly targeted Snail to regulate its expression. Soft agar colony formation and Transwell assays showed that the numbers of formed colonies, invasion cells, and metastasis cells of cells in T-L-02 group were all lower than those in L-02 group (P<0.05) . Conclusion: HIF-1α is involved in arsenite-induced EMT and malignant transformation of human liver epithelial cells via regulating Snail.