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-β1, 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-β1 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-β1 and IL-8.