Abstract
Introduction
Three-dimensional (3D) bioprinting provides an important approach for modeling mammary gland development and epithelial morphogenesis in a physiologically relevant environment. Mammary epithelial cells have a strong response to their extracellular matrix (ECM), which can influence cell organization, proliferation, polarity, and tissue-like structure formation (1, 2). The murine mammary epithelial cell line EpH4 provides a useful model for researching these processes. Combining 3D bioprinting with tunable hydrogel environments allows for the precise placement of these mammary cells within a defined matrix while evaluating ECM conditions that promote organoid formation.
Methods
We hypothesize that incorporation of a basement membrane such as Geltrex will promote epithelial cell polarization and improve the efficiency of luminal organoid formation compared to collagen alone. To test this hypothesis, EpH4 cells were 3D bioprinted within hydrogel constructs, with initial experiments using rat-tail collagen as a matrix lacking basement membrane components. Cell morphology and organization were evaluated following printing. Geltrex will subsequently be evaluated as an alternative matrix condition.
Results
The preliminary experiments using rat-tail collagen demonstrate that EpH4 cells can establish 3D cellular structures within the printed matrix. However, the cultures have not consistently developed the organized, branching morphologies characteristic of a mammary organoid model. These findings provide a foundation for determining whether addition of a basement membrane matrix improves luminal organoid formation.
Conclusion
Establishing an optimized 3D culture environment will provide a reproducible platform for investigating mammary epithelial morphogenesis along with the cellular and extracellular mechanisms that regulate tissue organization. This system could support studies of mammary gland development, epithelial remodeling, and disease-associated changes in tissue architecture.