Legumain Promote The Invasion And Migration Of Breast Cancer Through PI3K/AKT Pathway

Background: Breast cancer,as the primary tumor type that threatens women's life and health,has become one of the focuses of the medical field many years ago.With the early diagnosis,early treatment of breast cancer,and the improvement of treatment methods,we have successfully improved the survival rate of breast cancer patients.However,the invasion and metastasis of breast cancer is still one of the important factors affecting the survival rate and prognosis of breast cancer patients.At present,targeted therapy for breast cancer has achieved certain results,but due to the lack of therapeutic targets,the progress of targeted therapy has been slow.Therefore,the search for effective biomarkers and therapeutic targets has become an urgent problem to be solved in clinical treatment of breast cancer.In the preliminary work of the project,we found that Legumain(asparagine endopeptidase,AEP)is highly expressed in a variety of solid tumors including breast cancer,and is expected to become a new target for tumor therapy.We found in the study that high expression of Legumain is a poor prognosis for breast cancer patients,and Legumain has significant correlation with clinical pathological parameters and molecular typing of lymph node metastasis,clinical stage,and PR status.In order to further study the relationship between Legumain and the development,invasion and metastasis of breast cancer,we intend to explore the effects of Legumain on breast cancer through in vitro and in vivo experiments,and to study the molecular mechanism of Legumain affecting the invasion and metastasis of breast cancer.Methods: We studied the effects of Legumain on invasion and metastasis of breast cancer by in vitro and in vivo experiments,and initially investigated the relationship between Legumain and tumor-associated PI3K/Akt signaling pathway at the cellular level.Firstly,Western Blot was used to detect the expression of Legumain in various breast cancer cell lines,and the MDA-MB-231 breast cancer cell line with high expression of Legumain was screened to establish stable overexpressing and knockdown Legumain breast cancer cell lines in vitro..The effects of Legumain on the invasion and metastasis of breast cancer cells were analyzed by functional studies such as scratches,migration and invasion.Then,breast cancer cells expressing and knocking down Legumain were inoculated in BALB/c mice to observe tumor formation and metastasis in mice.Finally,functional interactions between Legumain and PI3K/Akt and other tumor-associated signaling pathway proteins were initially explored at the cellular level by functional studies such as Western Blot experiments,scratches,migration and invasion.Results: Legumain was highly expressed in a variety of breast cancer cell lines.Overexpression of Legumain in MDA-MB-231 breast cancer cells enhanced the ability of cells to invade and metastasize,whereas this ability was reduced after intervention with Legumain small molecule inhibitors(AEPIs).Mice vaccinated with Legumain breast cancer cells showed significantly tumorigenic ability compared with other groups(inoculated with low Legumain breast cancer cells and overexpressed to the AEPIs group),and the number of lung metastatic nodules was significantly different.In breast cancer cells overexpressing Legumain,the expression levels of p-PI3 K and p-Akt were significantly increased in the PI3K/Akt pathway,and the expression of Legumain was decreased after intervention of Legumain and PI3 K small molecule inhibitors(AEPIs and PI3KIs).The ability of breast cancer cells to invade and metastasize is reduced.Conclusion: Legumain enhances the invasion and metastasis of breast cancer at levels in vitro and in vivo,and this ability is inhibited by Legumain small molecule inhibitors.Our preliminary study showed that the molecular mechanism of Legumain promoting breast cancer invasion and metastasis is related to the activation of PI3K/Akt signaling pathway.Inhibition of this pathway can reduce the expression of Legumain,thereby reducing the invasion and metastasis of breast cancer cells.