The inhibitory action of EGCG on the proliferation in the triple-negative breast cancer cell MDA-MB-231 and its mechanism

Aim To study the effects of EGCG[(-)-epigallocatechin-3-gallate] on the proliferation and apoptosis in the triple-negative breast cancer cell MDA-MB-231 and the possible mechanism.Methods MDA-MB-231cells were treated with different concentrations of EGCG(10,20,40,80,160 mg·L-1) and then the proliferation of MDA-MB-231 cells was detected by CCK-8 assay.The morphological change of apoptosis of MDA-MB-231 cells was observed under fluorescence microscope through Hoechst-33258 staining.The mitochondrial membrane potential was measured by JC-1assay.The caspase-3 activity was measured by caspase-3 activity assay kit.Western blot assay was used to analyse the change of protein expression of GRP78(glucose regulatd protein 78) and activated caspase-3.Results EGCG significantly inhibited the proliferation of MDA-MB-231 cells in a time and concentration dependent manner.The IC50 of EGCG stimulating the cells 12,24,48 h was 69.1,40.4,29.4 mg·L-1 respectively.After treatment with different concentrations of EGCG for 24h,MDA-MB-231 cells showed the signs of the typical apoptosis morphology changes such as shrinkage,chromatin aggregation and nucleus marginalization and so on.Moreover,with increase of the concentration of EGCG,the apoptotic rate gradually increased,the mitochondrial membrane potential decreased,and the activated caspase-3 increased.Protein expression of GRP78 was inhibited and that of activated caspase-3 was increased.Conclusion EGCG can inhibit the proliferation and induce the apoptosis of MDA-MB-231 cells significantly,which might be related to the ERS(endoplasmic reticulum stress) pathway inducing caspase-3 activated.