| Purpose: At present,breast cancer has become one of the common cancers threatening the health of women worldwide,and its incidence rate and mortality will continue to increase in the next few years.Among them,triple negative breast cancer(TNBC)accounts for less than a quarter.Clinically,TNBC accounts for 15% of the incidence rate of breast cancer,which is characterized by the lack of expression of estrogen receptor(ER)and progesterone receptor(PR),and the lack of amplification or overexpression of human epidermal growth factor receptor-2(HER-2).As a heterogeneous disease,TNBC has a high risk of local and distant recurrence,with visceral and/or brain metastasis common,but the effect of radiotherapy and chemotherapy is not ideal.Therefore,in recent years,in order to seek a more effective treatment,there are more and more studies on the treatment of TNBC with traditional Chinese medicine,in order to find a new way to prevent,control and treat TNBC.Research shows that traditional Chinese medicine therapy can reduce the adverse reactions and drug resistance of traditional treatment to a certain extent.Therefore,more and more attention has been paid to the study of the effect of traditional Chinese medicine extracts on tumor.Green tea is one of people’s favorite beverages,which contains a variety of active substances.As the key active ingredient of tea health quality,catechin has attracted a lot of attention.At present,the anti-tumor effect of epigallocatechin gallate(EGCG),the core component of catechin,is basically affirmed by people,but its inhibitory effect on TNBC is less studied.Therefore,the purpose of this study is to explore the modern mechanism of EGCG activating bcl-2/bax signaling pathway and promoting TNBC apoptosis through cell experiments,so as to provide a theoretical basis for the clinical application of drugs.Material and method:Triple negative breast cancer(MDA-MB-231)cells grown in logarithmic phase were selected and inoculated into 96 well plates.Different concentrations of EGCG(0,10,20,40,60,80 umol/l)were used to intervene for 24 h,48h and 72 h respectively.After the intervention,the effect of green tea extract EGCG on cell activity was detected by CCK8 method,and the effective drug concentration and intervention time were screened.Then,MDA-MB-231 cells were inoculated into 6-well plates again,and the gradient concentration of EGCG was selected to intervene the cells for 48 h.The cells were collected and the protein was extracted with Ripa lysate.The expression of apoptosis related proteins Bcl-2,Bax and caspase-3 was detected by Western blot,and the effect of EGCG on MDA-MB-231 cell apoptosis was detected by flow cytometry.Results:1.EGCG can inhibit the proliferation of triple negative breast cancer MDA-MB-231 cells.The survival rate of breast cancer cells decreased significantly with the prolongation of time and the increase of concentration after EGCG at different concentrations acted on cells for24 h,48h and 72 h.After the same time treatment of breast cancer cells,the greater the drug concentration,the more obvious the effect on the proliferation rate of cells.Similarly,for cells treated with the same drug concentration,the longer the treatment time,the more obvious the effect on the proliferation rate of cells,and the difference was statistically significant(p<0.05).2.EGCG can activate the apoptosis related signal pathway of triple negative breast cancer cells,thereby promoting MDA-MB-231 cell apoptosis.Among them,the expression of Caspase3 and Bax protein increased with the increase of EGCG concentration,and the expression of Bcl-2 protein decreased with the increase of EGCG concentration(p<0.05).3.EGCG can induce apoptosis of MDA-MB-231 cells in triple negative breast cancer.With the increase of concentration,20umol/l EGCG can most significantly promote the early apoptosis of MDA-MB-231 cells(p<0.05);The proportion of late apoptosis increased with the increase of EGCG concentration(p<0.05);Compared with the group without drugs,EGCG could significantly promote the total apoptosis of MDA-MB-231 cells(p<0.05).Conclusion:1.EGCG can inhibit the proliferation of triple negative breast cancer MDA-MB-231 cells by promoting the apoptosis of triple negative breast cancer MDA-MB-231 cells,and its drug effect is dose-dependent.2.The apoptotic effect of EGCG on triple negative breast cancer MDA-MB-231 cells is closely related to its activation of Bcl-2/Bax signaling pathway and promotion of Caspase-3expression.The study on the apoptosis promoting effect of EGCG can be used as an important natural substance supplementary treatment for triple negative breast cancer,and provide an important experimental basis for the clinical application of EGCG. |
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