Abstract 4171: The role of the Src kinase family in determining three-dimensional epithelial cell morphology of colorectal cancer cell lines

Abstract

Abstract Members of the Src kinase family are involved in numerous cellular signaling pathways that regulate cellular growth, survival, differentiation, adhesion and migration. Src family kinases (SFKs) associate with cellular membranes and function as molecular switches at the interface of various extracellular input signals (e.g., growth factors, cell-matrix adhesion) and intracellular signaling cascades. Deregulation of SFK expression levels and activity is implicated in a variety of human pathologies, including cancer, neurodegeneration, epilepsy and progression of HIV/AIDS. Elevation of c-Src activity is a common event in human colon cancer, and increases in c-Src activity are often associated with disease progression. In addition, upregulation of other Src-family members has been observed in colon cancer (e.g., c-Yes, Lck), suggesting that deregulation of SFKs may contribute to colorectal cancer progression. The three-dimensional culture of epithelial cells in a laminin-rich extracellular matrix (lrECM) has become increasingly popular in investigating the integration of cellular signaling pathways. Because the growth of cells in lrECM more closely recapitulates the microenvironment encountered by cells in vivo, three-dimensional cell culture is particularly useful in elucidating the biological roles of molecular components, such as SFKs, that function at the interface of extracellular and intracellular signals. In this study we use a three-dimensional culture system to study the role of SFKs in determining epithelial cell morphology of colorectal cancer cells. We tested a panel of ten commonly studied colorectal cancer cell lines for their ability to form organized cysts with established apical-basal polarity when grown in Matrigel in the presence or absence of broad-spectrum SFK inhibitors. We observed that Caco-2 and T84 cells, two lines capable of polarized cyst formation, show distinct sensitivity to SFK inhibition in three-dimensional culture but not in monolayer growth. Surprisingly, in Caco-2 cells, but not in T84 cells, global inhibition of SFK activity appears to interfere with cyst polarization, suggesting that one or more SFKs contribute to epithelial cell polarity. In addition, using RT-PCR and immunoblot techniques we demonstrate that SFK expression profiles are altered in Matrigel culture compared to monolayer culture. By comparing SFK expression profiles in cell lines displaying polarized versus unpolarized cell morphology we seek to identify individual members of the SFK family that contribute to three-dimensional epithelial morphology. 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 4171.