Endothelial-rich microenvironment supports growth and branching morphogenesis of prostate epithelial cells

BACKGROUND Development of epithelial organs depends on interaction between the epithelium and the underlying mesenchyme including the vasculature. The aim of this study was to explore the morphogenic effect of endothelial cells on prostate epithelial cell lines in 3D culture and to establish an in vitro model for prostate branching morphogenesis. METHODS A panel of eleven cell lines originating in normal or malignant prostate and primary prostate epithelial cells were cultured in reconstituted basement membrane (rBM) matrix with or without non‐proliferating but metabolically active endothelial cells. Morphogenesis was evaluated by phase contrast microscopy and further characterized by immunocyto/histocemistry and confocal microscopy. RESULTS Endothelial cells induced clonogenic potential of most prostate cell lines and formation of branching and mesenchymal‐like colonies. One of the normal‐derived cell lines in the panel (PZ‐HPV‐7) displayed unique properties in rBM culture by forming large and complex branching structures resembling the ductal architecture of the prostate. This ability was highly dependent on epithelial seeding density and soluble factors derived from the endothelial cells. High seeding density suppressed branching of PZ‐HPV‐7 but survival was compromised at low density in the absence of endothelium. CONCLUSIONS We have generated an endothelial‐based clonogenic assay to study prostate epithelial morphogenesis in three‐dimensional context. This assay will be important tool to study prostate epithelial–endothelial interactions in 3D context and open up possibilities to study molecular regulation of prostate morphogenesis and cancer progression. Prostate 73: 884–896, 2013. © 2012 Wiley Periodicals, Inc.