Sodium nitrite induces epithelial-mesenchymal transition of SMMC-7721 cells

This study is to find out the induction by sodium nitrite of epithelial-mesenchymal transition (EMT) in human hepatocellular carcinoma cells, SMMC-7721. After treatment of SMMC-7721 with 0.25 - 25 mmol.L-1 sodium nitrite for 48 h, the assays used include enzyme-linked immunosorbent assay (ELISA) for evaluation of TGF-beta1, IL-6 and IL-8 level in the conditioned medium, phase-contrast microscopy for morphology observation, and scratch wound healing as well as transwell migration assays for measurement of migration and metastatic potential. Additionally, the hallmarks of EMT, p-AKT and its downstream signaling molecules were examined by Western blotting. The results showed that TGF-beta1 secreted by SMMC-7721 elevated significantly in a dose-dependent fashion, whereas the increased IL-8 and IL-6 did not show dose-dependent response. The EMT was induced by exposure of SMMC-7721 with 0.25 mmol.L-1 of sodium nitrite, which was characterized by increased level of Vimentin, decreased E-cadherin and elevated activity of migration and metastatic potential. The results suggest that sodium nitrite could induce SMMC-7721 EMT by increased secretion of TGF-beta1 and IL-8.