Optimizing a 3D culture system to study the interaction between epithelial breast cancer and its surrounding fibroblasts

Abstract

Stromal fibroblasts are suggested to be a key determinant in the malignant progression of breast cancer. To find an in vitro culture model that best mimics the in vivo tumor microen-vironment so we can study the effects of stromal fibroblasts on breast cancer progression, we evaluated several three-dimensional (3D) co-culture models in order to identify the most suitable culture model for our study. The purpose of our study is to co-culturing malignant mouse breast cancer 4T1 cells and murine embryonic fibroblasts (MEF) to form spheroids with matrigel. We found the best culture model for forming the 4T1 aggregates/spheroids was, in the absence of fibroblast, by growing 4T1 cells in the culture wells precoated with matrigel and in the overlay medium containing 2% matrigel. We chose this model as our standard 3D culture to co-culture 4T1 and MEF cells at different ratios. We found that the amount of MEF in the 4T1/MEF mixture affects the morphology of 4T1/MEF aggre-gates/spheroids: the higher the ratio of MEF in the mixture, the more ductal structures formed among the aggregates, and the more polarized-like alveolar structures they tended to become. Fibroblasts produced protection for the breast cancer cells in the 3D culture, as aggregates/spheroids formed by breast-cancer cells alone were more sensitive to cytotoxic chemo-agents than aggregates formed by the breast-cancer/fibroblast mixture. These results indicate that the selection of a suitable 3D culture model for a particular research focus may be critical to collecting clinically relevant information about tumor progression that involves interplay between different cell types. This 3D co-culture model demonstrated that tumor-surrounding fibroblasts play important roles in distributing and connecting epithelial breast cancer cells in a tumor microenvironment, as well as providing protection for breast cancer cells from chemo-agent killing. © Ivyspring International Publisher.