Abstract 556: Extracellular matrix protein mixture isolated from cultures of human tumor and stromal cells supports growth of human tumor cells in vitro and in vivo

Carcinoma Associated Fibroblasts (CAFs) along with other cells present in the tumor milieu play a major role in tumor progression. We have previously demonstrated differentiation of human bone marrow derived mesenchymal stem cells to CAF like phenotype upon exposure to tumor conditioned medium. The present study evaluates the ability of these stromal components to support tumor progression. An in vitro system was used to study impact of the components of the tumor milieu on growth of luciferase expressing MDA MB 231 cells, representing basal subtype of human breast cancer. CAFs along with phorbol ester induced HL60 cells representing a macrophage like phenotype supported growth of MDAMB231 cells in vitro as measured by a luciferase assay. When injected subcutaneously in vivo in nu/nu mice, tumor cells comingled with CAFs or with differentiated HL60 cells showed almost similar tumor growth rate, whereas CAFs and differentiated HL60s when mixed together showed more than 4 fold increased tumor growth rate compared to the tumor cells alone and 2 fold compared to tumor cells plus MatrigelTM. Electrophoretic analysis of extracellular matrix protein mixture isolated from mixed cultures of CAFs plus MDAMB231 cells and differentiated HL60 cells (3 cells) using previously published methods showed presence of laminins and collagens, and demonstrated robust tumor cell growth compared to MatrigelTM. The ECM protein mixture derived from the three cell system offers a completely humanized substitute for MatrigelTM useful for study of tumor growth and response to therapy in vitro as well as in vivo. 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 556.