Abstract 3893: Endocan is upregulated on tumor vessels in invasive bladder cancer and mediates VEGF-A-induced angiogenesis.

Abstract

Abstract Tumor-associated blood vessels differ from normal vessels at the morphological and molecular level. Proteins that are only present on tumor vessels may serve as biomarkers and as therapeutic targets for inhibition of angiogenesis in cancer. To identify factors contributed by the tumor-associated endothelium, we performed immuno-laser capture microdissection (i-LCM) of blood vascular endothelial cells in conjunction with transcriptional profiling from surgically harvested cancer and normal matched bladder tissue of five patients with invasive bladder cancer. Comparing the transcriptional profiles of blood vascular endothelium from human invasive bladder cancer and from normal bladder tissue, we found that endocan (endothelial cell-specific molecule-1) was highly elevated on tumor vessels and associated with the filopodia of angiogenic endothelial tip cells in invasive bladder cancer. Notably, endocan expression on tumor vessels strongly correlated with the tumor stage and invasiveness and predicted a shorter recurrence-free survival time in non-invasive bladder cancers. Furthermore, both endocan and VEGF-A levels were significantly higher in plasma of patients with invasive bladder cancer (n=53) compared to healthy individuals (n=60). Using cultured blood vascular endothelial cells and an in vivo transgenic mouse model we found that endocan expression was strongly upregulated by VEGF-A activation of VEGFR-2. RNA interference-mediated knockdown of endocan in cultured blood vascular endothelial cells revealed that endocan was required for the promotion of cell migration and tube formation by VEGF-A. Furthermore, we found that endocan potentiates VEGFR-2 phosphorylation in response to VEGF-A. Therefore, blocking the interaction of endocan with either VEGFR-2 or VEGF-A might represent a promising approach for inhibiting tumor angiogenesis. Endocan might also serve as a novel biomarker for monitoring disease progression and the efficacy of VEGF-A-targeting therapies in patients with bladder cancer. Citation Format: Filip Roudnicky, Cedric Poyet, Peter J. Wild, Sarah Krampitz, Fabrizia Negrini, Reto Huggenberger, Anja Rogler, Robert Stöhr, Arndt Hartmann, Maurizio Provenzano, Vivianne I. Otto, Michael Detmar. Endocan is upregulated on tumor vessels in invasive bladder cancer and mediates VEGF-A-induced angiogenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3893. doi:10.1158/1538-7445.AM2013-3893