Abstract 1375: Amlexanox inhibits FGF-mediated paracrine and autocrine activity of tumor-derived melanoma cell lines and cell strains

Abstract

Abstract Melanoma is a highly invasive disease characterized by widespread lymphatic and systemic metastases. Although angiogenesis is critical for this to occur, the responsible mechanisms within melanoma cells remain unclear. The purpose of this study is to identify factors secreted by tumor-derived melanoma cells which can mediate these processes. Serum-free conditioned medium (CM) isolated from two melanoma cell lines and four newly derived melanoma cell strains promote both the growth in culture and angiogenic outgrowth activity of HUVEC and HMEC1 in 3-dimensional (3-D) collagen gel culture. Substantial amounts of both FGF1 (acidic) and FGF2 (basic) are found in the conditioned medium (CM). The addition of neutralizing antibodies to FGF1 (5 μg/ml) and FGF2 (3 μg/ml) to the melanoma CM significantly decreased the proliferation of HUVEC and HMEC1 by (20%) and (40%), respectively, and the angiogenic activity of HMEC1 by (20%). Amlexanox (AMX) is an anti-inflammatory agent that binds intracellular S100A13, one component of the putative FGF1-secretion complexes. AMX suppresses constitutive release of FGF1, but not FGF2, from these melanoma cells. AMX-treated melanoma-CM results in significant reduction of: HUVEC mitogenic activity, endothelial migration into 3-D collagen gel as well as melanoma cell proliferation. These AMX-mediated effects correlate with a concomitant decrease of FGFR1 phosphorylation in melanoma cells. The sum of these results point to the importance of the FGF-1 pathway and nominate AMX as a significant anti-melanoma agent by virtue of its impact on both paracrine and autocrine activity. 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 1375.