Mammary Epithelial Cell Spheroid: Stabilization Through Vascular-Wall Mesenchymal Stem Cells and Endothelial Cells...

Over the past decade, the interest in using 3D cell culture models for studying the mammary gland in biomedical and veterinary fields has increased, but a fully functional in vitro model for domestic species is still lacking. Multiple cellular components, including epithelial cells, vascular endothelial cells, and stromal/stem cells, sustain the secretory mammary gland tissue in a well-organized 3D architecture. Considering the Göttingen Minipigs widely used for translational lactation studies, this work aimed to establish a 3D culture protocol to generate mammary heterogeneous multicellular spheroids composed of three different Göttingen Minipigs primary cells: mammary epithelial cells (mpMECs), aortic endothelial cells (mpAECs), and vascular-wall mesenchymal stem cells (mpVW-MSCs). Cells were cultured with hanging-drop (HD) and ultra-low-adherence plate (ULA) methods, evaluating aggregate formation in both monocultures and co/triple co-cultures. Brightfield area, eccentricity, viability, and cell distribution were analyzed. Results showed mpMECs formed irregular aggregates in both HD and ULA, while more compact and viable spheroids were formed when co-cultured with mpVW-MSCs and mpAECs by ULA. A well-organized cellular distribution was demonstrated by cytokeratin-18, vimentin, and e-NOS immunofluorescence analysis. In conclusion, this study established a stable 3D mammary multicellular spheroid model, representing a promising tool for future studies on hormonal modulation and mammary gland physiology.