The Mechanism Of Breast Cancer Cells Recruiting And Altering The Phenotype Of Mesenchymal Stem Cells By Secreting TGF-? And The Role Of TGF-? In Breast Cancer Metastasis

Objective:Breast cancer is one of the most common malignant tumors,ranking first in female tumor deaths.MSCs play an important role in regulating the progression of breast cancer,but the mechanism is not entirely understood.Our previous study found that TGF-? is highly expressed in the supernatant of breast cancer,recruites more BMSCs and changes the phenotype.This study will validate how BMSCs are recruited toward tumor sites and changed the phenotype by TGF-? secreted of breast cancer cells and to further explore the molecular mechanism of TGF-? regulating P38MAPK/NF?B/ICAM-1 by binding to EGFR.At the same time,the effect of TGF-? on breast cancer was clarified,and its roles of migration and mechanism in breast cancer were explored,which provided new therapeutic ideas for predicting and preventing distant metastasis of breast cancer.Methods:1.The Cytokine antibody arrays,transwell,and breast cancer nude mouse model were used to screen and determine the effect of TGF-?secreted by breast cancer cells on BMSCs.2.Bioinformatics analysis was performed using BMSCs chips and combined with Q-PCR and western blot to identify the molecular mechanism of TGF-? recruitment and alteration of BMSCs phenotype.3.Immunohistochemistry was used to detect the expression of TGF-? in 67 cases of breast cancer and 15 cases of breast fibroadenoma,and to analyze the correlation with prognosis.Combined with transwell and western blot to identify the role of TGF-? in migration and mechanism in breast cancer.4.Using breast cancer nude mouse model,BMSCs were injected into the tail vein to determine the collective effects of TGF-? combined with BMSCs on breast cancer metastasis.Results:1.Breast cancer cells secrete TGF-? to recruit BMSCs to breast cancer in situ.(1)According to the recruitment of BMSCs in breast cancer supernatant,the results of the Cytokine antibody arrays and chemotaxis experiments,TGF-?secreted by breast cancer cells could recruit BMSCs,and high expression of TGF-? enhanced the recruitment ability of BMSCs.In contrary Blocking TGF-? could weaken the recruitment ability.(2)The result of breast cancer nude mouse model has showed TGF-? mediates the localization of BMSCs to BC tumor primary sites in vivo.2.TGF-? activates the P38MAPK/NF?B/ICAM-1 pathway to regulate the migration of BMSCs and alter their phenotype.(1)Combined with bioinformatics analysis and Q-PCR,TGF-? alters the phenotype of BMSCs and promotes the secretion of more pro-metastatic cytokines.(2)Combined with western blot,Q-PCR and transwell experiments,TGF-? acts on the receptor EGFR of BMSCs and activates P38MAPK and NF?B by phosphorylation,which causes the phenotypic changes of BMSCs,and up-regulates ICAM-1 to regulate the migration of BMSCs.3.The role of TGF-? in migration of breast cancer cell.(1)Immunohistochemical results showed that compared with normal breast epithelial tissues and breast fibroadenoma,TGF-? was significantly up-regulated in breast cancer tissues,especially in advanced breast cancer tissues.At the same time,high expression of TGF-? is closely related to OS and DFS of breast cancer patients.(2)Combined with transwell experiments and western blot,high expression of TGF-? in breast cancer cells can cause EMT transformation and promote cell migration ability.4.Effect of TGF-? and BMSCs on metastasis of breast cancerTGF-? can promote lung metastasis in breast cancer cells.And in the case of high expression of TGF-?,BMSCs can further promote lung metastasis of breast cancer cells in vivo.Conclusion:1.Breast cancer cells could recruit BMSCs toward the tumor microenvironment by secreting TGF-? and alter its phenotype.2.TGF-? acts on the receptor EGFR of BMSCs and activates P38MAPK and NF?B by phosphorylation,which causes the phenotypic changes of BMSCs,and up-regulates ICAM-1 to regulate the migration of BMSCs.3.Overexpressed TGF-? in BC is relevant to the poor prognosis of patients and cause EMT transformation and promote cell migration ability.4.While promoting the metastasis of breast cancer cells,TGF-? can also recruit BMSCs into the tumor microenvironment to further assist breast cancer cells to metastasize.