[Inhibitory effect and mechanism of (-)-epigallocatechin-3-gallate on HT29 and HCT-8 colorectal cancer cell lines and expression of HES1 and JAG1].

Objective: To study the inhibitory effect of (-)-epigallocatechin-3-gallate (EGCG) on cancer cells line HCT-8 and HT29 and its influence on the expression of HES1 and JAG1.

Methods: Colorectal cancer cells line HCT-8 and HT29 were cultured in vitro and treated with different concentrations of EGCG(10 mg/L, 20 mg/L, 35 mg/L). The inhibition of proliferation was tested by MTT analysis. Influence of EGCG on the cell apoptosis and cell cycle of HCT-8 and HT29 were detected with flow cytometry, and gene expression of HCT-8 and HT29 after EGCG treatment with real-time polymerase chain reaction.

Results: EGCG affected the proliferation and apoptosis of HCT-8 and HT29. The inhibition rates of the three different concentrations of EGCG were(28.894±5.076)%, (34.903±1.794)%, and (39.028±0.105)% on HCT-8, and (14.682±4.244)%, (22.429±3.847)%, and (29.840±5.076)% on HT29. EGCG caused G(2)/M phase arrest and M phase transition in HCT-8 cell line, and S phase arrest and G2 phase transition in HT29 cell line. EGCG down-regulated HES1 gene expression in both cell lines, however, the differences were not statistically significant(both P>0.05). EGCG upregulated JAG1 gene expression in both cell lines, however only the difference in HCT-8 was statistically significant(0.201±0.018 vs. 0.440±0.077, P=0.029).

Conclusions: EGCG can significantly inhibit the proliferation of HT29 cells and HCT-8 cells by changing cell cycle and inducing cell apoptosis. The mechanism may be related to the upregulation of JAG1 gene expression.