Overexpression of N-terminal amino acid of RI3K p55γ regulatory subunit inhibits cell adhesion of breast cancer cell line MDA-MB-231

QI Xiaodan; GUO Hongyan; ZHANG Chunjing; YI Tonghui; SUN Xiaojie

doi:10.13431/j.cnki.immunol.j.20160062

Abstract：This study was performed to investigate the effects of overexpression of the N-terminal 24-amino acid of p55γ regulatory subunit of phosphoinositide 3-kinase (PI3K) on cell adhesion of breast cancer cellMDA-MB-231.MDA-MB-231 cell lines expressing GFP-N24 fusion protein or green fluorescence protein (GFP) protein alone were generated by transient transfection with pEGFPN24 plasmid and control plasmid pEGFPC1,respectively.The expression of GFP and fusion protein GFP-N24 were observed by fluorescence microscope and Western blotting.The adhesion of the transfected cells in collagen and fibronectin was detected by cell adhesion assay.The expression of E-cadherin and phospho-Akt were analyzed by Western blotting.The expression and secretion of matrix metalloproteinase-9 (MMP9) and urokinase plasminogen activator (uPA) were detected by zymography.Under fluorescence microscope,the green fluorescence was observed in the transfected cells,and the secretory granules increased obviously.The results of Western blot showed that the expression level of the fusion protein GFP-N24 was slightly lower than GFP expression in the empty vector.Compared with the control cells,the adhesion of MDA-MB-231 cells to fibronectin and collagen was decreased in N24p55γ over expressing group.Overexpression of N24p55γdecreased the expression of phosphor-Akt but not effected the expression of E-cadherin in MDA-MB-231 cells.The activation and secretion of MMP9 and uPA were inhibited by GFP-N24 expression in MDAMB-231 cells.In conclusion,overexpression of N24p55γ inhibits cell adhesion of MDA-MB-231 by influencingPI3K/Akt signaling pathway and the expression of tumor metastasis associated gene uPA and MMP9.