A novel Embryonic Stem Cell differentiation model for High‐Throughput Antivasculogenesis Screening

Abstract

Recent studies have implicated the contribution of stem cells towards tumor neovascularization through the process of de‐novo differentiation or vasculogenesis, thus establishing the need for an effective assay to screen antivasculogenesis agents. The goal of this work was to establish an in vitro system for the efficient differentiation of embryonic stem cells (ES) into endothelial cells (EC) with the aim of creating an effective model for high‐throughput vasculogenesis inhibitor screening. We and others have shown that ES cells associate into embryoid bodies, which can differentiate into EC when exposed to extracellular matrix and/or growth factors. Here we describe an effective model for ES cell differentiation into EC as an assay system for screening drugs. We established that matrix composition is critical for the differentiation of embryoid bodies into EC, as confirmed by immunohistochemistry and imaging for selective expression markers, and EB plated with no matrix exhibited no vascular phenotype. The addition of growth factors increased vasculogenic sprouting by up to 16.5 times as compared to control (P<0.01). This model was used to test various permutations of signal transduction inhibitors to explore downstream pathways. In conclusion, we have established a novel in vitro model for screening antivasculogenic agents for potential cancer therapies in preclinical trials.