Abstract 912A: Cadherins control Src kinase induced fibroblast cell motility
Authors: Sheehan Stephanie A. , Retzbach Edward P. , Shen Yongquan , Goldberg Gary S. 
Published: July 2017

Cancer associated fibroblasts (CAFs) are a part of the tumor microenvironment, and help remodel the extracellular matrix to pave the way for tumor cells to forge invasive fronts. Src tyrosine kinase activity is often increased in the tumor microenvironment, and has been shown to induce cell motility and disrupt adherens junctions. Adherens junctions are formed by cadherin proteins that mediate intercellular adhesion and control cell migration. Previous studies have found correlations between cadherin expression and cancer cell motility. However, effects of cadherin expression on CAF motility have not been thoroughly elucidated. We are investigating how junctions formed by E-cadherin (ECAD) and N-cadherin (NCAD) affect individual and collective migration of fibroblasts expressing different levels of Src kinase activity. We are utilizing fluorescently tagged ECAD or NCAD to study the localization and effects of cadherin proteins in real time by live cell imaging along with wound healing and Transwell migration assays. Results from these studies indicate that ECAD and NCAD have different effects on migration of cells depending on Src kinase activity. Src kinase activity did not affect collective cell migration, but increased individual cell migration by over 4 fold (p&lt;0.0001 by t-test) in the absence of forced cadherin expression. In addition, our data indicate that ECAD increases collective cell motility, while NCAD decreases collective cell migration in the absence of strong Src kinase activity. Collective migration by ECAD expressing cells was over 4 fold higher than cells expressing NCAD or control transfectants (p&lt;0.0001 by t-test) in the absence of strong Src activity. Conversely, collective migration of cells expressing NCAD was over 5 fold lower than control transfectants, and over 30 fold lower than cells expressing ECAD (p&lt;0.005 by t-test) without strong Src kinase activity. In contrast, both cadherins decrease individual cell motility promoted by Src kinase activity. ECAD and NCAD transfected cells migrated over 4 fold less than control transfectants with high levels of Src kinase expression (p&lt;0.0001 by t-test). Interestingly, human oral squamous cell carcinoma (OSCC) cells that express high levels of both ECAD and NCAD exhibit collective migration equal to cells with low Src kinase activity, but individual migration over 5 fold higher than nontransformed cells (p&lt;0.0001 by t-test). This system should prove useful to elucidate how cadherins and Wnt signaling pathways affect motility of CAFs and tumor cells. For example, western blotting analysis suggest that both ECAD and NCAD may protect β-catenin from destruction initiated by Src kinase activity. Taken together this work should elucidate how cadherins affect the ability of the Src kinase to increase CAF motility, and identify mechanisms that can be exploited to identify potential chemotherapeutic targets.

Citation Format: Stephanie A. Sheehan, Edward P. Retzbach, Yongquan Shen, Gary S. Goldberg. Cadherins control Src kinase induced fibroblast cell motility [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 912A. doi:10.1158/1538-7445.AM2017-912A