RIP1 and RIP3 contribute to shikonin-induced glycolysis suppression in glioma cells via increase of intracellular hydrogen peroxide

Abstract

RIP1 and RIP3 are necroptosis initiators, but their roles in regulation of glycolysis remain elusive. In this study, we found shikonin activated RIP1 and RIP3 in glioma cells in vitro and in vivo, which was accompanied with glycolysis suppression. Further investigation revealed that shikonin-induced decreases of glucose-6-phosphate and pyruvate and downregulation of HK II and PKM2 were significantly prevented when RIP1 or RIP3 was pharmacologically inhibited or genetically knocked down with SiRNA. Moreover, shikonin also triggered accumulation of intracellular H₂O₂ and depletion of GSH and cysteine. Mitigation of intracellular H₂O₂ via supplement of GSH reversed shikonin-induced glycolysis suppression. The role of intracellular H₂O₂ in regulation of glycolysis suppression was further confirmed in the cells treated with exogenous H₂O₂. Notably, inhibition of RIP1 or RIP3 prevented intracellular H₂O₂ accumulation, which was correlated with preventing shikonin-induced downregulation of x-CT and depletion of GSH and cysteine. In addition, supplement of pyruvate effectively inhibited shikonin- or exogenous H₂O₂-induced accumulation of intracellular H₂O₂ and glioma cell death. Taken together, we demonstrated in this study that RIP1 and RIP3 contributed to shikonin-induced glycolysis suppression via increasing intracellular H₂O₂.

Keywords: Glioma; Glycolysis; Hydrogen peroxide; RIP1; RIP3.