Mechanism of Cucurbitacin B in Regulating Glycolysis and Inhibiting Proliferation of HuCCT1 Cells / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo explore the mechanism of cucurbitacin B （CuB） in inhibiting cell proliferation and glycolysis. MethodCell counting kit-8 （CCK-8） was applied to investigate the effect of different concentrations of CuB （0， 40， 80， 120， 160， 200， 400， and 800 nmol·L-1） on the proliferation of HuCCT1 cells. The effect of different concentrations of CuB （50， 100， and 200 nmol·L-1） on the colony formation ability of HuCCT1 cells was detected by plate cloning assay. The effect of different concentrations of CuB （50， 100， 200 nmol·L-1） on the HuCCT1 cell cycle was analyzed by flow cytometry. Visible spectrophotometry was employed to detect the activity of key glycolytic enzymes hexokinase （HK） and pyruvate kinase （PK）） and changes in glucose consumption， lactate production， and adenosine triphosphate （ATP） production in HuCCT1 cells after administration of different concentrations of CuB （50， 100， 200 nmol·L-1）. Western blotting was used to assay the effect of CuB on the expression of cell cycle-related proteins， proliferation-related proteins， key glycolytic proteins， and Akt/mammalian target of rapamycin （mTOR） pathway-related proteins. ResultAs compared with the blank group， CuB at dose of 160-800 nmol·L-1 after 24 h administration and CuB at dose of 80-800 nmol·L-1 after 48 h administration inhibited the proliferation of HuCCT1 cells in a time- and dose-dependent manner （P<0.05， P<0.01）， and the median inhibitory concentration was 200 nmol·L-1 48 h after administration. CuB can restrain the colony formation ability of HuCCT1 cells in a dose-dependent manner （P<0.01）， and block HuCCT1 cell cycle in G2 phase （P<0.05， P<0.01）. CuB （100 and 200 nmol·L-1） can suppress the activities of HK and PK and reduce cell glucose consumption and production of lactate and ATP （P<0.05， P<0.01）. Western blot results showed that CuB （100 and 200 nmol·L-1） can inhibit the protein levels of cycle-related protein Cyclin B1， proliferating cell nuclear antigen （PCNA）， HK1， HK2， PKM1， PKM2， phosphorylated Akt （p-Akt）， phosphorylated mTOR （p-mTOR）， and phosphorylated ribosomal protein S6 （p-RPS6） （P<0.05， P<0.01）. ConclusionCuB can inhibit aerobic glycolysis in HuCCT1 cells via the Akt/mTOR pathway， thereby affecting cell proliferation.