Abstract 1287: Anastellin, the fibronectin-derived angiogenesis inhibitor, activates a proangiogenic signature in stromal fibroblasts

Abstract

Abstract Fibronectin is an extracellular matrix protein that is important in the regulation of angiogenesis, tumor progression and tumor metastasis. Anastellin, a peptide fragment derived from the first Type III repeat in Fibronectin (III1c), has been shown to prevent tumor angiogenesis in mouse models of human cancer and to inhibit serum-dependent growth of endothelial microvessel cells. To determine whether anastellin might have additional roles in the tumor microenvironment, we evaluated the effect of anastellin on gene expression in human dermal fibroblasts. Microarray analysis (Human Cancer PathwayFinder RT2 Profiler PCR Array) indicated that addition of anastellin to fibroblasts induced the expression of several genes including the proangiogenic inflammatory mediators, IL-8 and TNF-α. PCR analysis confirmed that expression of both TNF-α and IL-8 were markedly increased within 2 hrs suggesting a direct effect of anastellin on fibroblast gene expression. ELISA assay of the conditioned medium of anastellin treated cells indicated that the increased gene expression was accompanied by the secretion of IL-8 and TNF-α protein, which was detected between 2-4 hrs of anastellin treatment. Changes in gene expression were preceded by increased phosphorylation of c-Jun N-terminal kinase (JNK) and p38 MAPK as well as the nuclear translocation of NF-κB. PCR and ELISA analysis showed that the NF-κB inhibitor (BAY 11-7082) completely inhibited the induction of IL-8 and TNF-α. The inhibitor of p38 MAPK activity (SB 203580) and the inhibitor of JNK (SP600125) each partially attenuated the induction of IL-8 and TNFα while the combination of inhibitors completely blocked gene expression and the nuclear translocation of NF-κB in response to anastellin. Taken together, these data indicate that treatment of dermal fibroblasts with anastellin causes activation of the p38 and JNK MAPK pathways which converge downstream to promote the NF-κB dependent expression of IL-8 and TNF-α. These data suggest that fibronectin matrix remodeling induces the expression of proangiogenic cytokines by stromal cells present in the tumor microenvironment. This mechanism may represent a novel pathway of tumor resistance to angiogenesis blockade. This work is supported by NIH grant CA69612. 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 1287.