Inhibition Effect Of Metapristone On Metastasis Of Breast Cancer Cells Through Regulating Cyr61 And Underlying Mechanisms

Objective:Breast cancer patients after primary tumor treatment are in the risk of tumor metastasis and death.It is urgent to develop effective anti-metastatic therapeutic drugs for breast cancer,and the understanding for biomarkers and mechanisms of anti-metastatic drugs is also crucial.This study aims to investigate the effect of Cyr61,a potential biomarker for a novel cancer metastasis chemopreventive agent from pharmacoproteomic study,on the inhibition of metapristone towards the triple negative breast cancer and its mechanism.Methods:The cell proliferation and toxicity were determined using MTT colorimetric assay.After the human breast cancer cell MDA-MB-231 and human pulmonary microvascular endothelial cell HPMEC treated with the metapristone for 0-48 h,high-efficiency compound concentration and time point were selected.A biomarker cysteine-rich 61(Cyr61)was choosed from pharmacoproteomic study(iTRAQ).ELISA and cell morphology assays were carried out to determine the effect of metapristone on co-culture model.The effect of metapristone induction on Cyr61 activity to interfering cell adhesion and migration was examined by the transfection of siRNA-Cyr61 and pcDNA3.1-Cyr61 into MDA-MB-231.The mechanisms of metapristone inhitited breast cancer cells metastasis were determined by using wound-healing migration and adhesion assays combined with RT-PCR,Western Blot,CO-IP and IF assays.Experimental lung metastasis model,combined with the results of HE and IHC assays,were used to evaluate the anti-metastatic activity of metapristone in vivo.Results:Our results showed that metapristone significantly inhibited MDA-MB-231 cells proliferation,but had weak toxicity toward HPMECs within the concentration of IC50.Pharmacoproteomic study showed that the expression of Cyr61 was significantly down-regulated by metapristone,being inhibited by up to 60.35%.Co-culture system enhanced the expression of Cyr61,and Cyr61 mainly secreted by breast cancer.The migration and adhesion abilities of MDA-MB-231 cells were enhanced or decreased by overexpression or silencing Cyr61,and inhibited by metapristone in a dose-dependent manner.Metapristone significantly inhibited the expression of Cyr61 and its novel receptor protein integrin ?v?1 levels.In addition,it was showed that the high dose of metapristone resulted in remarkable reduction of lung metastasis in vivo.Conclusion:Metapristone is highly effective in suppressing cancer adhesion,migration and metastasis in vitro and in vivo.We for the first time,the metapristone-mediated metastasis chemoprevention of a highly metastatic MDA-MB-231 cancer cell line is through potential marker Cyr61 and its novel receptor integrin ?v?1 signaling pathway.