Abstract

‍

Standard two-dimensional model systems are limited in their ability to accurately capture the molecular mediators underlying breast cancer, and cannot be used to study interactions between multiple cell types. Previous studies have shown that three-dimensional systems provide a more physiologically relevant platform to study cancer progression in a structurally appropriate context¹. However, these systems do not capture the interactions between tumor cells and the angiogenic component, an essential step in tumor progression². Here we describe, a novel three-dimensional co-culture system combining angiogenic endothelial cells and breast epithelial cells in a three-dimensional tumor matrix. Endothelial cells underwent angiogenic tubulogenesis on a matrigel matrix. Addition of metastatic green fluorescent protein+ve MDA-MB-231 resulted in a unique phenotype characterized by the alignment of the tumor cells on the endothelial tubes. We demonstrate FAK and B1 integrin signaling are important mediators of the observed phenotypes. Inhibiting FAK-B1 signaling disrupted the architecture, reducing the ability of the MDA-MB-231 cells to migrate and adhere to cultured vessels. Furthermore, treatment with small molecule inhibitors of phosphatidylinositol 3 kinase, LY294002 1.6uM, and mitogen activated protein kinase (MAPK), PD98059 20uM, also perturbed this architecture, indicating that these signaling pathways play a key role in controlling the observed phenotype. Furthermore, the inhibition of the PI3K and MAPK pathways, destroyed the tumor vasculature and inhibited progression and invasion of the MDA-MB-231 by 86% (p<0.001) while enhancing the cells’ susceptibility to the cytotoxic agent doxorubicin. Our study shows that a three-dimensional co-culture system provides a powerful in vitro model system to study the mechanisms underlying tumor metastasis and is a powerful tool to screen combination therapies. Supported by DoD BCRP.

‍

¹Lee GY, et al. Nat Methods. 2007 Apr;4(4):359-65.

²Sengupta S, et al. FASEB J. 2004 Oct;18(13):1565-7.

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 4813.