Growth inhibition and apoptosis of human colon cancer cells induced by vitamin E succinate / 第二军医大学学报

ABSTRACT

Objective: To investigate the growth inhibition and apoptosis induction effect of vitamin E succinate (VES) on human colon cancer cells and to analyze the modulation of apoptosis-mediator Fas expression in this process. Methods: Human colon 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-dimethylthiazo-2-yl)-3,5-diphenylformazan (MTT) assay was employed to detect the inhibitory effect of VES on the growth of colon cancer cells. Flow cytometry was then used to analyze the cell cycle of the colon cancer cells after being treated with VES and the apoptotic rate was calculated at the same time. To find out whether the Fas protein expression was modulated in this process, Western blotting assay and flow cytometry were used to detect the Fas protein level in whole cell lystates and on cell surface. Results: VES exhibited a significant inhibitory effect on the growth of human colon cancer cells in a doseand time-dependent manner. After being treated with VES at 5 mg/L, 10 mg/L and 20 mg/L for 48 h, the apoptotic rate of LS174T cells rose from 0.90% to 15.9%, 46.7% and 64.5%, respectively. Fas neutralizing antibody can significantly block VES-induced apoptosis. After the administration of VES, total Fas protein in whole-cell extracts increased in a dose-dependent manner. The flow cytometry showed that the mean fluorescence intensity rose from 5.43 to 9.88, 13.21 and 18.0 after being treated with VES. Conclusion: VES can induce significant growth inhibition and apoptosis in human colon cancer cells. The modulation of Fas expression is one of the mechanisms involved in this process and may be related to the upregulation of Fas molecule on the cancer cell surface.