The Apoptotic Mechanism of Hepatocellular Carcinoma Cell Line (HepG2) Induced by Arsenic Trioxide

Objective To explore the apoptotic mechanism of human hepatic carcinoma cell line HepG2 induced by arsenic trioxide (As2O3). Methods The human hepatoma cell line HepG2 was treated with 0, 2.5, 5 and 10 μmol/L arsenic trioxide for 24 h. Cytotoxicity was tested by MTT assay (additional 25 and 50 μmol/L arsenic trioxide treatment groups), cellular apoptosis were detected by flow cytometry, reactive oxygen species (ROS) level were quantified by DCFH-DA fluorescent probe staining and glutathione content were measured by DTNB method with commercial kits. Western blot assay was used to detect the protein expression of γ-glutamylcysteine synthetase (γ-GCS, GCLC and GCLM subunits) and nuclear factor erythroid 2-related factor 2 (Nrf2). Results With the increase of arsenic trioxide concentration, cellular survival, glutathione content and γ-GCS (GCLC and GCLM subunits) protein expression level decreased (P<0.05); while cellular apoptotic rate, reactive oxygen species level and Nrf2 protein expression increased (P<0.05). Conclusion Arsenic trioxide induces the apoptosis of human hepatoma cell line HepG2 through ROS induction, γ-GCS expression inhibition and cellular glutathione content depletion.