Abstract 1001: Effects of matrix compositions on the development of breast acini and ducts in a 3D in-vitro culture model

Abstract

Abstract Background: Epithelial cells of the breast respond to cues from the stromal components and develop into polarized and highly organized functional acinar and ductal structures. Extracellular matrix components and increased stiffness in particular have been shown to promote breast cancer. The stroma - cell interactions that determine the cellular organization and differentiation are in part reproduced in a 3D environment. Whether alterations of the microenvironment in 3D cultures could mimic phenotypic alterations observed during breast cancer progression remain to be fully determined. Here we present the effects of various stroma physical compositions on the ability of heterotypic 3D cultures of epithelial and mesenchymal stem cells to organize into acinar and tubular structures. Material & Methods: The normal murine mammary gland (NMuMG) cells were cultured either alone or in combination (30:70) with mouse mesenchymal stem cells (D1), in 3D cell culture conditions generated by agarose, collagen and Matrigel® alone or a combination thereof. After 3-5 days in culture, cell distribution, organization and the presence of acinus-like and tubule-like structures were determined. Results: By immunohistochemistry, NMuMG cells co-cultured with D1 cells were shown to form acinar structures with the NMuMG epithelial cells surrounding a lumen composed of dead cells whereas the D1 cells were mostly peripheral. Immuno-staining for laminin indicated the presence of basement membrane when NMuMG cells were grown in Matrigel® alone or co-cultured with D1 cells in a combination of Matrigel® and collagen I. The number of acinar structures was significantly higher in cultures grown in combination of agarose with Matrigel® or collagen I when compared to the cultures grown in Matrigel® or collagen I alone (P<0.05). No tubular structures were formed when agarose was included in the matrix, regardless of the combination. In Matrigel® but not in collagen I/ Matrigel® microenvironment the number of tubular structures was significantly increased in NMuMG /D1 co-culture when compared to culture of NMuMG cells alone (P<0.05). Conclusion: These results indicate that the physical and biochemical properties of the matrix and cellular composition alter the organization of the mammary gland. Furthermore, they underline the likely critical role of the extracellular matrix in breast cancer progression. Supported by grants from the Department of Defense Era of Hope Program and the National Science Foundation. 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 1001.