Abstract: AIM: To investigate the effect of endoplasmic reticulum stress pathway on the apoptosis of tongue squamous cancer Tca8113 cells induced by antitumor component-I from Agkistrodon acutus venom (AAVC-I). METHODS: The in vitro experiments were performed on subculture tongue squamous cancer Tca8113 cells in their growth period. A normal control group, a DL-dithiothreitol (DTT) positive control group and different AAVC-I concentrations were set according to the experiment objective. MTT assay was used to detect the proliferation inhibition of Tca8113 cells after been treated with different concentrations of DTT and AAVC-I for 24 h. The results were used to choose appropriate concentrations of DTT and AAVC-I in DTT positive control group and AAVC-I treated group, respectively. HE staining and Annexin V-FITC/PI double fluorescence staining were used to monitor the apoptosis of Tca8113 cells. Western blot was used to identify the expression levels of apoptosis-related proteins including endoplasmic reticulum stress glucose-regulatory protein 78 (GRP78), enhance-binding protein-homologousprotein (CHOP), cysteine-containing aspartate specific protease-12 (Caspase-12), cysteine-containing aspartate specific protease-9 (Caspase-9) and cysteine-containing aspartate specific protease-3 (Caspase-3).RESULTS:The proliferation inhibition of Tca8113 cells increased with an increased concentration of AAVC-I concentration (P<0.05), causing cell shrinkage, increased cell gaps, cytonuclear condensation, cell fragmentation, the appearance of apoptotic bodies, and increased rate of apoptosis (P<0.05). In addition, the expression level of GRP78 protein, CHOP protein, proteins of Caspase-12, Caspase-9 and Caspase-3 were increased (P<0.05).CONCLUSION: Endoplasmic reticulum stress CHOP/Caspase-12 pathway plays an important role in AAVC-I induced Tca8113 cells apoptosis.

Key words: endoplasmic reticulum stress, tongue squamous cancer Tca8113 cells, snake venom