Culture of human breast cancer cell line (MDA-MB-231) on fibronectin-coated surface induces pro-matrix metalloproteinase-9 expression and activity

Abstract

Interaction between cell surface integrin receptors with extracellular matrix (ECM) plays an important role in cell survival, proliferation, and migration including tumor development and invasion. Binding of ECM to integrins initiates intracellular signaling cascades, modulating expression and activity of different matrix metalloproteinases (MMPs) which is important in ECM degradation. The present study investigates fibronectin-integrin-mediated signaling and thereby modulation of MMPs expression and activity in human breast cancer cell line, MDA-MB-231. Culture of MDA-MB-231 cells on fibronectin (FN) induced expression and activity of pro-matrixmetalloproteinase-9 (MMP-9). Appreciable reduction of FN-induced pro-MMP-9 activity was observed in anti-α5 antibody treated cells. Inhibitor studies revealed that inhibitors of phosphatidyl inositiol-3-kinase (PI-3K), and nuclear factor kappa B (NF-κB) inhibited FN-induced pro-MMP-9 activity. FN increased tyrosine phosphorylation of focal adhesion kinase (FAK), integrin linked kinase (ILK), and PI-3K in MDA-MB-231 cells. FN-induced the transactivation of MMP-9 promoter by enhancing DNA binding activity of NF-κB and Sp1. Wound healing assay showed faster migration of MDA-MB-231cells grown on fibronectin-coated as surface as compared to control. Our findings indicated that culture of MDA-MB-231 on fibronectin perhaps send signals via fibronectin-integrin-mediated signaling pathways recruiting FAK, PI-3K, ILK, NF-κB, and modulate expression and activation of pro-MMP-9. These observations may enrich fundamental aspects of cancer biology especially role of α5β1 integrin in regulation of MMPs expression and activity.

Studies on Focal Adhesion Kinase in human breast cancer cell MDA-MB-231

“…Consistent with previous report [40] we found enhanced phosphorylation of ERK and PI3K in FN-treated MDA-MB-231 breast cancer cells. The importance of FAK in the phosphorylation of these effectors was noted through their down regulated phosphorylation after the depletion of FAK with specific SiRNA.…”

“…Our current findings clearly indicate FAK plays the pivotal role in regulation of cell migration in FN induced MDA-MB-231 breast cancer cells. Consistent with earlier reports we found an increased expression and phosphorylation (Tyr 397) of FAK, increased expression and activity of MMP-9, and reduced expression of TIMP-1 in this model [40]. So, FN induces FAK and MMP-9 but negatively regulate the inhibitor of MMP-9.…”

“…Involvement FAK in regulation of MMP-9 has also been reported in different cell type [16,22]. Our lab has shown induction of MMP-9 expression and activity in FN induced MDA-MB-231 [40]. In this communication we have used FN-treated MDA-MB-231 model to study the participation of FAK in regulation of MMP-9 and thereby cell migration.…”

Induction of fibronectin by HER2 overexpression triggers adhesion and invasion of breast cancer cells

“…FN is a secreted matrix protein whose production is potently increased upon induction of EMT [32,33]. Furthermore, FN dramatically augments the secretion of MMP-9 through the MEK1/ERK and the PI-3K/Akt-dependent pathways in breast and ovarian cancer cells, thereby triggering metastasis of tumor cells [8,34]. Consistent with these reports, our results showed that the adhesion and invasion of breast cancer cells increased significantly in response to rhFN treatment.…”

β1 integrin

“…Previous studies have shown that fibronectin can induce MMP-9 expression in a a5 integrin-dependent manner in both breast and laryngeal carcinoma cells supporting this hypothesis. 52,53 In conjunction with suppressing the expression of the endogenous MMP inhibitor TIMP-2, this would result in an overall enhancement of protease activity and invasive capabilities. Although we were unable to find published evidence that β1 integrinfibronectin interaction controls TIMP-2 expression in tumor cells, this has been shown to be the case in T-cells where fibronectin engagement significantly inhibited TIMP-2 expression.…”