Silencing Hexokinase II Gene Sensitizes Human Colon Cancer Cells to 5-fluorouracil

Background/Aims: Extensive trials have indicated that cancer cells with high glycolytic activity exhibit decreased sensitivity to anticancer agents. Moreover, recent research has proved that a specific inhibitor of hexokinase II, which is a key glycolytic enzyme, may enhance the activity of anticancer drugs. The purpose of this study is to further investigate the effect and mechanisms of hexokinase II on chemosensitivity of colon cancer cells to 5-fluorouracil. Methodology: The expression of hexokinase II gene was down regulated by RNA interference in colon cancer cell line LoVo, then the IC50 value of 5-fluorouracil to LoVo cells was carried out by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and the protein expression of hexokinase II and thymidylate synthas by Western blot analysis Meanwhile, cell apoptosis and mitochondrial membrane potential were assessed by flow cytometry. Caspase-3 activity was also determined by its substrate color reaction. Results: Down-regulation of the hexokinase II gene of LoVo cells resulted in decreased IC50 value of 5-fluorouracil and increased apoptosis rate, respectively. Furthermore, silencing hexokinase II of LoVo cells induced loss of mitochondrial membrane potential, activation of caspase-3, and inhibition of thymidylate synthase expression. Conclusions: Our findings suggest targeting hexokinase II has a potential role in the combination 5-fluorouracil treatments of colon cancer.