Abstract 5778: A three-dimensional RAFT™ co-culture as advanced model for breast cancer drug discovery
Authors: Nie Ying , Garner Krista L. , D'Souza Theresa 
Published: July 2017

Abstract
High-throughput screening (HTS) using two-dimensional (2D) cell culture models (2D HTS) is essential for rapid identification of drug candidates from chemical libraries. However, it often results in a large number of poorly qualified leads that exert extra burden on the downstream, preclinical animal studies and that cannot be translated into clinical success, because 2D culture cannot represent the complexity of the tumor microenvironment in vivo.
The progression of tumors and their response to drugs in vivo are regulated by their interactions with neighboring cells, and the natural gradients of nutrients, cytokines, wastes, oxygen, which can be better mimicked with three-dimensional (3D) cell-culture models.
We constructed a breast cancer model using the RAFTTM 3D Cell Culture System. The essential component of this system is a collagen matrix condensed to the physiologically-relevant collagen density by removing the majority of the liquid from the collagen hydrogel with specialized absorbers.
Our 3D model is a co-culture of human mammary fibroblasts (HMFs), embedded in the RAFT™ Collagen matrix, and the MCF7 human breast cancer epithelial cells, overlaying on top of the matrix, to model the interaction of breast cancer cells and stromal cells in vivo. As non-tumorous control, human mammary epithelial cells (nHMECs), isolated from normal breast tissue, were used to replace MCF7 cells in such a co-culture. A medium formulation combining fibroblast medium FGM2™ and mammary epithelial cell medium MEGM™ was optimized to grow both cell types in the co-culture. The RAFT™ co-cultures were stained with standard immunocytochemistry protocol to reveal the morphology of the cells. After three days in culture, the HMFs, evenly interspersed in the matrix, fully stretched out in the collagen matrix, and the nHMECs grew to reach above 90% confluence on the collagen matrix.
The cell proliferation in the co-culture was quantified with the ViaLight™ Plus Cell Proliferation and Cytotoxicity BioAssay, which measures cell viability with bioluminescent detection of cellular ATP. Based on this assay, the viabilities of the RAFT™ cultures of single cell types, as well as those of the co-cultures, increased from Day 1 to Day 3. Normal HMECs proliferated much faster than MCF7 cells on the matrix.
We demonstrate here the feasibility of co-culturing HMFs and mammary epithelial cells, in the RAFT™ System, as a 3D breast cancer model. The efficacy of anti-cancer drugs can be assessed by measuring the cell viability with the ViaLight™ Assay. This 3D model can be used to bridge the gap between 2D HTS and preclinical animal studies. It may provide physiologically-relevant data and better prediction of the in vivo efficacy and dosage of the drug candidates identified in HTS, and reduce the burden of animal studies in breast cancer drug discovery.
Citation Format: Ying Nie, Krista L. Garner, Theresa D'Souza. A three-dimensional RAFT™ co-culture as advanced model for breast cancer drug discovery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5778. doi:10.1158/1538-7445.AM2017-5778