Abstract: This study investigated the effect of tannic acid and cisplatin on IRE1-XBP1 pathway of endoplasmic reticulum stress in hepatocellular carcinoma HepG2 cells.HepG2 cells were cultured with 180 μM TA and/or 0.9 μg/mL CDDP for 24 h or 48 h.Then apoptosis rate was detected by flow cytometry and levels of IRE1α and XBP1 were analyzed by real-time fluorescence quantitative technology (q-RT-PCR) or western blot.MTT assay showed that TA or CDDP can inhibit HepG2 cells growth with dose dependence manner and TA combined with CDDP can significantly increase the growth inhibition rate of HepG2 cells.Flow cytometry results showed that tannic acid and cisplatin can significantly inhibit the proliferation of HepG2 cells and induce cell apoptosis.Q-RT-PCR and western blot results showed that tannic acid and cisplatin can significantly increase expression level of IRE1α and XBP-1.The results indicated that tannic acid can combine with cisplatin to increase the levels of IRE1-XBP1 pathway of endoplasmic reticulum stress in hepatocellular HepG2 cells,suggesting that the IRE1-XBP1 pathway may be one of the molecular mechanisms of synergistic anti-hepatocellular carcinoma effect of tannic acid and cisplatin on HepG2 cells.

Key words: tannic acid, cis-dichlorodiamine platinum, hepatocellular carcinoma, endoplasmic reticulum stress, inositol requiring enzymel 1, X box binding protein-1