Abstract 3001: Angiogenesis-related cytokine secretion pattern in tumor interstitial fluid and its relationship with VEGF expression and metastatic profile

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA The tumor microenvironment (TME) contributes significantly to the phenotypic characteristics of cancer. Unraveling the roles of the TME in cancer growth and treatment, as well as mining the TME for treatment strategies is increasingly occupying center-stage. One of the least examined, and yet critically important factors in the TME is the tumor interstitial fluid (IF). This fluid surrounds cancer and stromal cells within the tumor, and contains various cytokines, and nutritional and molecular factors that shape the outcome of nearly all aspects of tumor growth, metastasis, and response to treatment. Here we have characterized IF from human breast cancer xenografts in SCID mice. The IF was obtained from the tumor using a small custom-built diffusion chamber (outer diameter 6.2 mm, inner volume approx. 40 µl) implanted in the subcutaneous space. The chamber was surrounded by 4-6 tumor pieces that were allowed to grow for 4-6 weeks that resulted in the chamber being incorporated within the tumor. Three different human breast carcinoma cell lines were used to analyze tumor IF content: invasive, highly metastatic MDA-MB-231 cells, less invasive MCF-7 cells and MCF-7 cells engineered to overexpress vascular endothelial growth factor (VEGF). After IF, plasma and tumor collection, IF samples were analyzed using a multiple cytokine assay (Proteome Profiler Human Angiogenesis Kit, R & D Systems Inc., Minneapolis MN). With this kit, 55 human angiogenesis-related cytokines were investigated for relative secretion levels. Our results identified differences in cytokine content in tumors derived from these cells. Out of the 55 cytokines tested, 24 were detected in the IF. Of these, more than 80% (20) were detected in MDA-MB-231 tumors only. Additionally, MDA-MB-231 derived tumor IF showed increased levels of TIMP metallopeptidase inhibitor 1 (TIMP-1), urokinase plasminogen activator (uPA) and Serpin E1 compared to MCF-7 cells. As expected, high VEGF levels were detected in the IF of tumors derived from VEGF-overexpressing MCF-7 cells compared to wild type cells. VEGF overexpression also influenced the levels of TIMP-1, Serpin E1 and uPA in the IF. Variations in IF cytokine content of cancers with different metastatic and angiogenic abilities provide further understanding of the TME. Measurement of cytokine content is only the first step towards the correlation of tumor IF cytokine levels with tumor vascular properties and anti-angiogenic treatments. A better understanding of the TME through characterization of the IF may identify new targets for cancer treatment and allow for optimization of therapeutic strategies. Supported by NIH R01CA138264 and R01CA136576. Citation Format: Louis Dore-Savard, Esak Lee, Aleksander S. Popel, Zaver M. Bhujwalla. Angiogenesis-related cytokine secretion pattern in tumor interstitial fluid and its relationship with VEGF expression and metastatic profile. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3001. doi:10.1158/1538-7445.AM2014-3001