(A) combination treatment of glycolytic inhibitor and reactive oxygen stress enhancer in Sorafenib-resistant and high metastatic potential hepatocellular carcinoma cells

Abstract

BACKGROUND & AIM: Acquisition of anoikis resistance (AR) is a prerequisite for the metastasis in hepatocellular carcinoma (HCC). However, little is known about how energy metabolism and antioxidant system are changed in HCC AR cells. We aimed to evaluate the anti-tumor effect of a combination treatment of 3-bromopyruvate (3-BP), an inhibitor for glycolysis, and buthionine sulfoximine (BSO), an inhibitor for glutathione synthesis in HCC AR cells. METHODS: We compared glycolysis, reactive oxygen species (ROS) production, and chemoresistance among Huh-BAT, HepG2 human HCC cells, and corresponding AR cells. Expression of hexokinase II, gamma-glutamylcystine synthetase (rGCS), and epithelial–mesenchymal transition markers in AR cells was assessed. Anti-tumor effect of a combination treatment of 3-BP and BSO were evaluated in AR cells and HCC xenograft mouse model. RESULTS: AR cells showed a significantly higher chemoresistance, glycolysis, and lower ROS production than attached cells. Expression of hexokinase II, rGCS, and Snail was higher in HCC AR cells than attached cells. A combination treatment of 3-BP and BSO effectively suppressed proliferation of HCC AR cells through apoptosis induction by blocking glycolysis and enhancing ROS levels. In a xenograft mouse model, tumors induced from HCC AR cells more rapidly grew than HCC attached cells. Growth rates of tumors derived from HCC AR cells were significantly suppressed in the group treated with 3-BP and BSO as compared to the group treated with 3-BP or sorafenib alone. CONCLUSIONS: These results demonstrate that a combination treatment of 3-BP and BSO has a synergistic anti-tumor effect in HCC AR model. This strategy might be an effective adjuvant therapy to patients with sorafenib-resistant HCC.