The Research Of Anti-tumor Effects About Cysteinyl Leukotriene And Receptors In Human Breast Cancer

Objective:Cysteinyl leukotrienes(CysLTs),namely LTB4?LTC4?LTD4 and LTE4,are inflammatory lipid mediators derived from the lipoxygenase pathway of the arachidonic acid metabolism.They are potent biological mediators in the pathophysiology of inflammatory diseases.Cysteinyl leukotrienes and their corresponding receptors CysLT1R and CysLT2R are closely related with asthma and other allergic diseases,brain trauma,brain tumors,colon and breast cancer.Especially in the tumor tissue,the two receptors expression are corresponding with proliferation,migration,survival and prognosis of colon and breast cancer.The paper to study the role of Cysteinyl leukotriene receptor ?(CysLT2R)in the biological behaviors of human breast carcinoma cell line MCF-7 facilitated by proinflammatory leukotriene C4(LTC4).They are expected to become new targets for prevention and treatment of tumor metastasis.Methods:We first screened by Western Blotting CysLT2R expression-positive breast cancer cell lines as a model.First preliminary evaluation by MTT assay,the LTC4 survival of MCF-7 cell line,we used flow cytometry and wound-healing assay and Boyden chamber assay of LTC4 on cell cycle and the role of breast cancer cell migration.Study the role of CysLT2R in the biological behaviors of cell growth,migration and cell cycle in human breast carcinoma cell line MCF-7 facilitated by proinflammatory leukotriene C4(LTC4).Results:CysLT2R expression positive cell lines,MCF-7 were chosen as cell models considering the western blotting result.MTT assays were used to evaluate the effect of LTC4 on the survival of MCF-7.At the conentrations of O.1nM,1nM,10nM,20nM,50nM and100nM,the inhibition rates on MCF-7 cell line of LTC4 were(6.5±0.03)%,(11±0.02)%,(16.6±0.04)%,(35.2±0.04)%,(37.8±0.04)%,(38.5±0.02)%.To explain the mechanism of inhibition,we tested the cell cycle treated with LTC4 using flow cytometry.Results showed the G0/G1 phase arrest of MCF-7 and the restrict point cound not be surpassed.The effect of LTC4 on the cell movement(migration)was tested preliminarily by wound-healing assay and Boyden chamber assay.Comparing with control group,LTC4 could effectively enlong the wound-healing time and decreased the migration cell count.The effect displayed obvious dose-effect relationship.To study the role of CysLT2R in the biological behaviors of human breast carcinoma cell line MCF-7 facilitated by proinflammatory leukotriene C4(LTC4).Four small interfering RNA(shRNA)targeting CysLT2R were transfected into the human breast carcinoma cell line MCF-7 cells.Western Blotting was used to detect the down regulation of protein.The changes of cell cycle and apoptosis in the presence of LTC4 were detected by using flow cytometry(FCM).The proliferation of cells in the presence of LTC4 was analyzed by MTT assay.The invasion assays were performed on breast cancer cells in the presence of LTC4.There were no significant changes in cell cycle among MCF-7 cells(transfected with CysLT2R-shRNA).The low-expression of Cysteinyl leukotriene receptor ? have no significantly effect on the proliferation of MCF-7 cell.The LTC4 induced cell invasion was obviously increased by the silencing of CysLT2R(P<0.01).Conclusions:According to experiments of MTT and Western Blotting,flow cytometry,Transwell experiments,wound-healing assay and Boyden chamber assay,transfection and other technologies,the conclusions were:LTC4 can inhibit the proliferation and migration of breast cancer MCF-7 cells,and induction of MCF-7 cells arrest in G0/G1 phase,with a concentration of 50nM.There were no significant changes in cell cycle and apoptosis among MCF-7 cells(transfected with CysLT2R-shRNA).The low-expression of Cysteinyl leukotriene receptor ? have no significantly effect on the proliferation of MCF-7 cell.The LTC4 induced cell invasion was obviously increased by the silencing of CysLT2R.Our results show that a potential role for Cysteinyl leukotriene receptor ? in the process of the breast cancer cells invasion.