GABP? Regulates VEGF-mediated Breast Cancer Angiogenesis And Its Mechanism

Background: Breast cancer is a malignant tumor that seriously endangers human life and health.It is the most common cancer in women and the leading cause of cancer death in women worldwide.Due to the lack of sufficient molecular targets,it cannot be completely cured clinically.Studies have shown that tumor angiogenesis is considered to be a key link necessary for tumor progression and metastasis,and an important factor affecting tumorigenesis and development.Vascular endothelial growth factor(VEGF),as an angiogenic factor,plays a vital role in the formation of new blood vessels.Interestingly,we found that VEGF is highly expressed in breast cancer.It can be seen that the analysis of key regulatory factors affecting VEGF expression is helpful for the prevention and treatment of breast cancer.The expression of VEGF is regulated by many factors,including cytokines,growth factors,hypoxia,differentiation,and carcinogenic transformation.GA-binding protein(GABP)is the only polyprotein complex with specificity,consisting of GABP? and GABP?.GABP? is involved in the physiological and pathological processes of many diseases.In previous work,we found 18-bp indel mutations in the VEGF promoter region,and bioinformatics predictions found GABP? binding sites in the 18-bp region,which attracted our attention.The purpose of this study is to reveal the molecular mechanisms by which GABP? regulates the expression of VEGF and thus affects the angiogenesis of breast cancer,as well as the proliferation,apoptosis and migration of breast cancer cells,and provides new ideas for the clinical prevention and treatment of breast cancer.Methods: Screening of breast cancer cells MDA-MB-231 with stable overexpression / interference with GABP? by lentivirus infection;detection of breast normal epithelial cells(MCF-10A)and stable overexpression / interference with GABP? breast cancer cells using RT-qPCR and Western Blot Expression of GABP?,VEGF and proliferation-and apoptosis-related genes in MDA-MB-231 cell line;Detect the expression of GABP? and VEGF in tissue samples of breast cancer patients by immunohistochemistry;through cell cloning,scratch test,Transwell,CCK8,flow cytometry and other experiments to detect the overexpression / interference of GABP? on the proliferation and apoptosis and the effects of death and migration of MDA-MB-231 cells.Tube formation and CAM experiments were used to detect the effect of overexpression / interference with GABP? on angiogenesis of breast cancer;by injecting stable overexpression / interference with GABP? breast cancer cell MDA-MB-231 cell line to establish a nude mouse tumorigenic model,measuring tumors of different days Size,and finally remove the tumor for H & E staining and immunohistochemistry to detect the expression of GABP?,CD31 and VEGF in the tumor tissue,and explore the influence of GABP? on angiogenesis and tumor growth of breast cancer;Through experiments such as ChIP,EMSA,and dual luciferase reporter system,it was determined that GABP? regulates VEGF by binding to the promoter region of VEGF.RESULTS: Detection of GABP? and VEGF expression in normal breast epithelial cells(MCF-10A)and breast cancer cells MDA-MB-231 and MCF-7.The results showed that compared with normal breast epithelial cells,VEGF expression in breast cancer cell lines Higher expression of GABP?;detection of the expression of GABP? and VEGF in breast tissue samples and adjacent tissues of breast cancer patients,and the results showed that relative to adjacent cancer tissues,VEGF was highly expressed in tissue samples of breast cancer patients and GABP? was low expression.Overexpression / interference GABP? can inhibit / promote the proliferation,migration and invasion of breast cancer cells,and can promote / inhibit the apoptosis of breast cancer cells.Overexpression / interference GABP? can inhibit / promote the expression of VEGF.Overexpression / interference of GABP? can inhibit / promote angiogenesis of breast cancer and thus affect tumor growth of breast cancer.GABP? affects angiogenesis of breast cancer by regulating VEGF,and further affects the occurrence and development of breast cancer.At the same time,it has been proved that GABP? regulates VEGF by binding to the 18-bp site between the VEGF promoter region-1529 to-1512.Realized.Conclusion: GABP? affects its transcriptional activity by binding to the VEGF promoter region,which in turn affects the expression level of VEGF,and ultimately regulates breast cancer angiogenesis and the development of breast cancer.