MKL-1/miR-142-5p/DNMT1/maspin Signaling Pathway Regulates Cell Migration And Proliferation Of Breast Cancer

Objective:Breast cancer is the second leading cause of death among women with cancer.The occurrence and progression are related to a variety of signaling pathways and transcription factors.It has been reported that the methylation of tumor suppressor genes and abnormal expression of some micro RNA(miRNA)are involved in the occurrence and development of tumors.Among which DNMT1,as a methyltransferase,is expressed at elevated levels in several tumors including breast cancer.The miR-142-5p as a member of miRNA is abnormally expressed in various tumors.What role does DNMT1 play in the occurrence and development of breast tumors? How does miR-142-5p interact with DNMT1 to affect the proliferation and migration of breast cancer cells? This study will explore the signaling pathways and transcription factors related to breast cancer migration and proliferation,clarify the mechanism of breast cancer development,and provide new directions for finding new biomarkers and therapeutic targets.This article focuses on the regulation of the MKL-1/miR-142/DNMT1/maspin signaling pathway on the migration and proliferation of breast cancer cells.Methods:The expression plasmids of MKL-1 pcDNA3.1-MKL-1 and the luciferase reporter plasmids pGL-3-mi R-142-5p-WT-LUC,pGL-3-miR-142-5p-MUT-LUC,pmirGLO-DNMT1-WT-3'UTR-LUC and pmirGLO-DNMT1-MUT-3'UTR-LUC were constructed by molecular biology techniques.DNMT1 was knocked down in breast cancer cells,and the effects of DNMT1 on breast cancer cell migration ability were verified by scratch and Transwell experiments.Transfection of miR-142-5p mimics and inhibitors in breast cancer cells,and the effects of miR-142-5p on breast cancer cell migration ability were verified by scratch and Transwell experiments.The effects of mir-142-5p on proliferation and cell cycle of breast cancer cell were verified by cck-8,EdU,and flow cytometry.The luciferase reporter gene activity assay was used to verify the binding of miR-142-5p to the 3'UTR of DNMT1 and the binding of MKL-1 and miR-142-5p promoters.The effect of miR-142-5p on tumorigenesis and progression in vivo was verified by tumorigenesis in mice.Real-time PCR was used to analyze the expression levels of miR-142-5p,DNMT1,and maspin.The protein expression levels of MKL-1,DNMT1,and maspin were analyzed by Western Blot technology.Result:According to the above experimental protocol,the following results were obtained: knockdown of DNMT1 can inhibit the migration of breast cancer cells,and overexpression of miR-142-5p can also inhibit the migration,proliferation and cell cycle of breast cancer cells.Luciferase activity assay showed that mi R-142-5p can target the 3'UTR region of DNMT1 to inhibit the translation of DNMT1 and affect the migration of breast cancer cells.MKL-1 promotes its transcriptional activity by acting on the binding site on the miR-142-5p promoter to inhibit the migration and proliferation of breast cancer cells.DNMT1 can act on the tumor suppressor gene maspin to inhibit its expression and promote the occurrence of breast cancer.MKL-1/miR-142/DNMT1/maspin signaling pathway affects the occurrence and development of breast cancer by regulating the migration and proliferation of breast cancer cells.Conclusion:The above results proved that the activation of the MKL-1/miR-142-5p pathway inhibits the expression of DNMT1,while miR-142-5p interferes with the expression of DNMT1 by binding to the 3'UTR region of DNMT1,and up-regulates the target gene maspin downstream of DNMT1,MKL-1/miR-142-5p promotes DNMT1-mediated maspin to regulate breast cancer cell migration and proliferation.These findings clarified the molecular pathogenesis of breast cancer and had positive implications for the discovery of new molecular markers and therapeutic targets.This research provided new research ideas for the development of anti-breast tumor metastatic drugs.