Primary prostate organoid transcriptomic profile in co-culture with primary prostate stroma

Organotypic in vitro culture is useful to model mammalian disease in numerous tissues. Normal epithelial differentiation and carcinogenesis both undergo in vivo regulation by stroma, but current culture methods exclude stroma. To mimic this in vivo environment, we developed and characterized a human 3D prostate organoid co-culture model that incorporates prostate stroma. Primary prostate stromal cells supported increased organoid formation and expressed growth factors and WNT-related genes involved in epithelial differentiation. Organoid branching occurred distal to physical contact with stromal cells, demonstrating non-random branching. Tumoroids derived from primary prostate cancer maintained differential expression of the prostate cancer marker AMACR only in the presence of stroma. Stroma-induced phenotypes were similar in all patients examined, yet maintained inter-patient heterogeneity in the degree of response. Addition of stroma to in vitro organoid culture recapitulated the in vivo microenvironment by inducing organization of benign organoids into branching structures and preserving prostate cancer phenotypes.

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