Fibronectin is a multi-functional matrix glycoprotein protein that has been linked to tumor progression. We previously demonstrated that cellular fibronectin (cFN) increased non-small cell lung carcinoma (NSCLC) cell growth through signals mediated by the integrin α5β1. Here, we explore the role of integrin-linked kinase (ILK), an integrin β1 subunit cytoplasmic domain interactor in cFN induced cell growth. We found that cFN increases ILK expression and kinase activity, promotes protein-protein interactions between ILK and integrin β1. Silencing of ILK attenuated the effect of cFN on cell proliferation. Knockdown of the integrin β1 subunit, but not the integrin α5, blocked the effect of cFN on ILK expression. In addition, the inhibitor of p38MAPK, SB239063, and the inhibitor of PI3-K, wortmannin, abrogated the effect of cFN on ILK expression, whereas the inhibitor of ERK, PD98059, had no effect. Taken together, our results demonstrate that fibronectin induces the expression of ILK through integrin β1-mediated signals that include p38 MAPK and PI3-K. This in turn, promotes lung carcinoma cell proliferation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1223.