Abstract 4172: Differential angiogenesis-related cytokines release in tumor interstitial fluid and plasma in ER-positive and triple-negative breast cancers overexpressing VEGF

Abstract

Abstract Interstitial fluid (IF) is a key component of the tumor microenvironment (TME) that has been largely overshadowed by proteomic and genomic analysis of the cancer cell and stromal compartments of the TME. Early studies of tumor IF by Gullino and colleagues showed elevated protein and lactic acid levels and the absence of glucose. Modern analytical methods allow for comprehensive characterization of IF proteins to better understand the TME. We modified Gullino's model and created a collection chamber adapted to collect IF from mouse tumors. We used ER-positive MCF-7 and triple negative MDA-MB-231 breast cancer cells in SCID mice. Additionally, we created VEGF-overexpressing cells from each cell line to evaluate the effect of VEGF overexpression on angiogenic cytokines in tumor IF. The chamber was implanted with small tumor pieces in the subcutaneous space until the tumor encompassed the chamber (4 to 12 weeks depending on cell types). The tumor was then removed and the tumor IF (approximate volume 40μl) and blood plasma were collected. IF and plasma samples were analyzed using a multiple cytokine immunoassay (Proteome Profiler Human Angiogenesis Kit, R & D Systems Inc., Minneapolis MN). Among the 55 human angiogenesis-related cytokines tested, only 4 were detected in MCF-7 tumors IF, and 24 were detected in MDA-MB-231 IF sample. As anticipated, high VEGF levels were detected in MCF-7 overexpressing cells. Additionally, we observed a tendency to an elevated level of TIMP metallopeptidase inhibitor 1 (TIMP-1). All 4 cytokines detected in MCF-7 IF were also detected in MDA-MB-231 IF. VEGF overexpression had minimal effect on the tested cytokines. However, decreased levels of angiogenin and endostatin were observed. In plasma of tumor-bearing mice, 5 cytokines were detected. For instance, Serpin E1 (PAI-1) and TIMP-1 were detected in the plasma of both MCF-7 and MDA-MB-231, at lower levels than in IF. However, urokinase plasminogen activator was present only in mice with triple negative MDA-MB-231 tumors. We anticipate that a better understanding of the TME, via the characterization of the IF, will help identify new targets for diagnosis and therapy of cancer. We intend to examine correlations between the present data and human databanks to confirm the relevance of our model systems. Citation Format: Louis Dore-Savard, Esak Lee, Aleksander S. Popel, Zaver M. Bhujwalla. Differential angiogenesis-related cytokines release in tumor interstitial fluid and plasma in ER-positive and triple-negative breast cancers overexpressing VEGF. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4172. doi:10.1158/1538-7445.AM2015-4172