Effect of brazilin on apoptosis and autophagy of tongue cancer Tca8113 cells and its molecular mechanism

Abstract

To investigate the effects of brazilin on the proliferation, apoptosis and autophagy of human tongue squamous cell carcinoma Tca8113 cells in vitro and explore its molecular mechanism. The changes in the proliferation, morphology and apoptosis of Tca8113 cells in response to brazilin treatment were detected using MTT assay, Hoechst33342 staining, and Annexin V/PI double staining, respectively. The expressions of apoptosis-related protein Bax, Bcl-2, cleaved caspase-3 and autophagy-related proteins p-AMPK, p-mTOR, LC3B, and p62 in the treated cells were detected using Western blotting. The effect of treatment with both the AMPK pathway inhibitor and brazilin on the expressions of the pathway-related proteins p-AMPK, p-mTOR, and LC3B was assessed. MTT assay showed that brazilin significantly inhibited the proliferation of Tca8113 cells with an IC50 of 31.17 μmol/L at 24 h. Hoechst33342 staining showed that brazilin induced apoptotic morphological changes in Tca8113 cells in a concentration-dependent manner. Treatment with different concentrations of brazilin resulted in increased apoptosis in the cells. Brazilin obviously inhibited the expression of Bcl-2, p62 and p-mTOR and enhanced the expressions of Bax, cleaved caspase-3, LC3B and p-AMPK. The AMPK pathway inhibitor significantly inhibited the increase in p-AMPK and LC3B expressions and the decrease in p-mTOR expression induced by brazilin. Brazilin can inhibit the proliferation and promote apoptosis in Tca8113 cells and at the same time induces autophagy in the cells through the AMPK/mTOR pathway.