Abstract 2407: Snail 1 regulates invasion through uPA-uPAR and MMP-9 signaling in prostate cancer cells

Abstract

Abstract Epithelial-mesenchymal transition (EMT) is a process by which cancer cells acquire mesenchymal properties, such as induction of N-cadherin, while epithelial-associated genes like E-cadherin are lost. This enables the cells to be more invasive, migratory and metastatic. Factors that can induce EMT include growth factors like transforming growth factor -α (TGF-β) and epidermal growth factor (EGF), and transcription factors like Snail1. Snail1-induced EMT promotes migration and invasion and we hypothesized that this may be mediated by urokinase (uPA) and its receptor (uPAR) activities. uPA, a serine protease, may be activated by integrin engagement to bind to its receptor, uPAR, and initiate a signaling cascade that regulates a variety of biological pathways including invasion. Since Snail1 can induce matrix metalloproteinases (MMP 2 and 9) which are also involved in cell invasion, we also examined MMP activity. Androgen-dependent LNCaP, and 22Rv1 and androgen-independent ARCaP human prostate cancer (PC) cells were stably transfected with empty vector control (Neo) or constitutively active Snail1 which led to increased cell migration and invasion. The levels of Snail1, uPA, and uPAR were measured by Western Blot analysis. uPA activity in conditioned media was measured using the Elisa uPA activity assay kit. Additionally, cells were treated with MAPK inhibitor, UO126, at set time points. Gelatin zymography analysis was utilized to detect MMP-9 activity in the conditioned media. Currently, ARCaP-Snail cells are being transiently transfected with uPAR siRNA to assay for the effects of uPAR knockdown on uPA and MMP activity. The data suggests that overexpression of Snail1 increased uPA and uPAR protein levels, while uPA activity was elevated in conditioned media from LNCaP, 22Rv1 and ARCaP cells. Also, MAPK inhibited MAPK expression in the cell and decreased uPA activity. In addition gelatin zymography showed higher MMP 9 activity in ARCaP-Snail overexpressing cells that was inhibited by MAPK inhibitor. Therefore, Snail-mediated cell migration and invasion in human prostate cancer cells may occur via the regulation of uPA and uPAR activities in addition to MMPs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2407. doi:1538-7445.AM2012-2407