Abstract:

Objective To investigate the effects of epigallocatechin-3-gallate (EGCG) combined with radiotherapy on the apoptosis in TE-1 cells of esophageal squamous cell carcinoma (ESCC) and explore related molecular mechanisms. Methods ESCC TE-1 cells served as subjects and were assigned to the control group, EGCG group, radiotherapy group, and EGCG+radiotherapy group. The effects of different concentrations of EGCG, different doses of radiation, and the combination of EGCG and radiation on the growth of ESCC TE-1 cells were detected by MTT assay. The apoptosis in different treatment groups were measured by flow cytometry. The expression of apoptosis-related proteins including cleaved caspase-3 and anti-apoptosis-related protein Bcl-2 after treatment were detected by Western blotting. Results Both EGCG and radiotherapy inhibited the proliferation of ESCC TE-1 cells. The inhibitory effect of EGCG combined with radiotherapy was significantly higher as compared with the EGCG group or the radiotherapy group in a concentration-dose dependent manner (P<0.01). Results of flow cytometry showed that EGCG combined with radiotherapy significantly increased the apoptosis of TE-1 cells induced by X ray (P<0.01), up-regulated the expression of cleaved caspase-3 (P<0.05), and down-regulated the expression of Bcl-2 (P<0.05) as compared with the radiotherapy group. Conclusion EGCG combined with radiotherapy can increase the apoptosis of ESCC TE-1 cells, which may be associated with cleaved caspase-3 and Bcl-2.

Key words: EGCG, radiotherapy, esophageal squamous cell carcinoma, apoptosis