Preliminary Rearch On The Mechanism Of Mifepristione About Proliferation And Promote Apoptosis Of Breast Cancer Cell Lines

Background: The treatment of breast cancer in addition to conventional surgery, radiation therapy,chemotherapy, endocrine therapy is also more and more people’s attention. Endocrine treatment of breastcancer in the United States accounted for about55%, about48percent in Japan, while China accounted foronly4%, it is the endocrine treatment of breast cancer in China has good prospects for development. Withthe increasing incidence of breast cancer in recent years (new cases per year about1.3million), themortality rate also increased year by year, breast cancer has become one of the major diseases of a seriousthreat to women’s lives and safety. Now, Endocrine therapy drugs such as aromatase inhibitors, the efficacyof tamoxifen (TAM) has been confirmed, but different because of their own side effects, and hormonereceptor expression levels, greatly limiting their clinical application. Whether a drug can replace thesedrugs, and can reduce the side effects of these drugs is the starting point of our study.Mifepristone(MIF) as, a derivation of19-nortestosterone, has drastic chemical force toprogesteronereceptor(PR) and glucocorticoidreceptor(GR). Recent years had find MIF has anti-tumor,enhanced anti-cancer drug efficacy and other new uses. Progestin can stimulate proliferation of breastcancer cells in vitro,it is likely related to breast cancer metastasis,and the MIF for the progesterone receptorantagonist, it can be used for the treatment of breast cancer. And studies have shown that the antitumoreffect of MIF relate to antiprogestin formerly, but its role in cancer progesterone receptor-negative breasttumors showed that: anti-tumor effect of the MIF is not only the result of single antiprogestin, and it’smechanism of action is far more complicated,that is MIF can produce a marked effect through differentmechanisms under different conditions. Objctive:In this study, different concentrations of mifepristone, and observe its impact on breastcancer cell line MCF-7, T47D growth, apoptosis, and associated with BRCA1/BRCA2gene expression invitro environment. Explore m MIF on breast cancer cell growth, apoptosis and related genes may affect themechanism, to provide new ideas for the endocrine treatment of breast cancer research.Methods: The breast cancer cell line MCF-7,T47D was each cultured in DMEMhigh-sugar,RPMI1640culture medium, the biological characteristics of stability through the passage, takethe logarithmic phase cells inoculated into culture bottles or orifice. We design control (by adding MIFdrug solvent) and the drug treatment group (divided into three groups to join the MIF concentrations were10μM,25μM,50μM). The longest intervention was72hour. After the drug treatment,24h,48h,72h,observed the change of cellular morphology under on inverted microscope; MTS assay for measuringcell viability;measured apoptosis rate by flow cytometer; Real-Time PCR detection BRCA1/BRCA2geneexpression changes. ELISA method to detect cell changes in apoptosis-related factorsResults:(1) Cellular morphology results: The control group’s cell adherence were aequalis and ingood condition. The treatment group’s cell adherence fall off obviously and cell debris in the culturemedium increased significantly, and with the increase of the dose and time extension more obvious..(2)MTS activity of experimental results: The absorbance values of each drug dose group compared withblank control group was significantly lower, but with drug dose, the increase in processing time,theabsorbance value decreased more powerful, and difference is obvious.(3) flow cytometry results: Theapoptosis rate of each drug treated group were much higher than the control group，and had doses andtime dependent.(4)real-time PCR：2d after treatment in T47D cells by mifepristone (10μM,25μM,50μM), BRCA1and BRCA2gene expression relative to the control group increased with the dose increased.MCF-7cells results10μM,50μM of mifepristone treatment days after the BRCA1and BRCA2geneexpression increased with the dose for the control group increased, but25μM mifepristone treatment inMCF7cell gene expression was significantly lower than in the control group.(4) the ELISA method for thedetection of apoptosis related factors change results: different concentrations of MIF treatment breastcancer cells after24h, with the increase of MIF concentration, intracellular VEGF expression quantity decreased gradually, while the TGF-β in cell supernatant of expression with mifepristone concentrationschange and produce change. And in the drug concentration for25μM, two kinds of cells in TGF-βexpression level was significantly higher, and significantly higher than that in the control group and theother group of drugs.Conclusion:(1) Mifepristone can inhibit the growth of breast cancer cell(MCF7,T47D).(2) MIFinhibit the growth of breast cancer cell lines and its related to apoptosis promotion,and had the doses andtime dependent.(3) mifepristone inhibitied breast cancer cell growth relates to it’s demotion breast cancergene level.(4) mifepristone’s inhibition of breast cancer cell growth may play a role mainly through PR..(5)mifepristone to inhibit breast cancer cell proliferation may play a role by regulating the expression ofdifferent cytokines.