3-bromopyruvate enhances cisplatin sensitivity of hepatocellular carcinoma cells in vitro

ZHAO Surong; ZHANG Yuanyuan; WU Chengzhu; LI Hongmei; JIANG Chenchen; JIANG Zhiwen; LIU Hao

doi:10.12122/j.issn.1673-4254.2014.01.006

Abstract：Objective To investigate the effect of 3-bromopyruvate (3-BP) in sensitizing hepatocellular carcinoma cells to cisplatin-induced apoptosis and its possible mechanism. Methods The growth inhibition of HepG2 and SMMC7721 cells following exposures to different concentrations of 3-BP and cisplatin was measured by MTT assay. The apoptosis of cells treated with 100μmol/L 3-BP with or without 8μmol/L cisplatin was assessed using flow cytometry with PI staining, and the activity of caspase-3 and intracellular ATP level were detected using commercial detection kits; the expression of XIAP and PARP was analyzed using Western blotting. Results 3-BP produced obvious inhibitory effects on HepG2 and SMMC7721 cells at the concentrations of 50-400 μmol/L with IC50 values of 238.9 ± 13.9 μmol/L and 278.7 ± 11.7 μmol/L for a 48-h treatment, respectively. Cisplatin also inhibited the growth of HepG2 and SMMC7721 cells at the concentrations of 2-32μmol/L, with IC50 values of 16.4±0.9μmol/L and 20.9±1.8μmol/L after a 48-h treatment, respectively. Treatment with 100μmol/L 3-BP combined with 8 μmol/L cisplatin for 48 h resulted in a growth inhibition rate of (60.6 ± 2.2)% in HepG2 cells and (56.8 ± 2.3)% in SMMC7721 cells, which were significantly higher than those in cells treated with 3-BP or cisplatin alone. The combined treatment for 48 h induced an apoptotic rate of (51.1±4.3)%in HepG2 cells and (46.5±3.9)%in SMMC7721 cells, which were also markedly higher than those in cells with 3-BP or cisplatin treatment alone. Conclusion 3-BP can sensitize HepG2 and SMMC7721 cells to cisplatin-induced apoptosis possibly by causing intracellular ATP deficiency, down-regulating XIAP, and increasing caspase-3 activity.