Growth inhibition and apoptosis of human colon cancer cells induced by vitamin Esuccinate

Objective :To investigate the growthinhibition and apoptosis induction effect of vitamin E succinate(VES) onhuman colon cancer cells and to analyze the modulation of apoptosis-mediator Fas expressionin this process.Methods :Humancolon cancer cell line LS174T was treated with VES for 12 h,24 h and 48 h at the concentrations of 5 mg/L,10 mg/L and 20mg/L.1-(4,5-di methylthiazo-2-yl)-3,5-diphenylformazan(MTT) assay was employed to detect the inhibitory effect of VES onthe growth of colon cancer cells.Flowcytometry was then used to analyze the cell cycle of the colon cancer cells after being trea-ted with VES and the apoptotic rate was calculated at the same ti me.To find out whether the Fas protein expression was modu-lated in this process,Western blotting assay and flowcytometry were used to detect the Fas proteinlevel in whole cell lystatesand on cell surface.Results :VES exhibited a significant inhibitory effect on the growth of human colon cancer cells in a dose-and ti me-dependent manner.After being treated with VES at 5 mg/L,10 mg/L and 20 mg/L for 48 h,the apoptotic rate ofLS174Tcells rose from0.90 %to 15.9 %,46.7 %and 64.5 %,respectively.Fas neutralizing antibody can significantly blockVES-induced apoptosis.After the administration of VES,total Fas proteinin whole-cell extracts increased in a dose-dependentmanner.The flowcytometry showed that the mean fluorescence intensity rose from5.43 to 9.88,13.21 and 18.0 after beingtreated with VES.Conclusion :VES can induce significant growth inhibition and apoptosis in human colon cancer cells.Themodulation of Fas expressionis one of the mechanisms involved in this process and may be related to the upregulation of Fasmolecule on the cancer cell surface.