2009•Zhonghua zhongliu fangzhi zazhiRequires access
Effect of IFN-γ on TRAIL-induced apoptosis of human thyroid cancer cells
Hai Zhang
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Abstract
OBJECTIVE:To determine the effect of IFN-γ on TRAIL-induced apoptosis of human thyroid cancer cells. METHODS: Flow cytometry (FCM) and Western blot analysis were respectively employed for apoptotic analysis and GAPDH protein expression. Protein carbonyl assay and confocal microscopy were respectively used for evaluation of oxidative damage and immunohistochemical expression of GAPDH in nuclei. GAPDH gene expression was downregulated by using small interfering RNA (siRNA) technique. RESULTS: GAPDH was observed in the nuclear fraction in TRAIL-sensitive FRO and KTC2 cells, but not ARO, KTC1, and KTC3 cells. Carbonyls were detected in FRO and KTC2 cells, but not in the other cell lines. IFN-γ increased the expression level of GAPDH in nuclear fraction of TRAIL-resistance ARO cells. The apoptosis rate of the IFN-γ or TRAIL single drug group was less than 5%, but that of the IFN-γ/TRAIL group was 28.5%. The difference of apoptosis rates between the siGAPDH group and siRNA control group(11%) was statistical significant(t=4.909,P=0.08). CONCLUSION: IFN-γ enhancing TRAIL-induced apoptosis of human thyroid cancer cells may be through the upregulation of nucleic expression of GAPDH.