Identification of multipotent luminal progenitor cells in the human prostate in a novel epithelial culture system

The prostate gland consists of basal and luminal cells arranged as pseudo-stratified epithelium. In tissue recombination models, only basal cells reconstitute a complete prostate gland, yet murine lineage-tracing experiments show that luminal cells generate basal cells. It has remained challenging to address the molecular details of these transitions and whether they apply to humans, due to the lack of culture conditions that recapitulate prostate gland architecture. Here we describe a 3D culture system that supports long-term expansion of primary mouse and human prostate organoids, composed of fully differentiated CK5-expressing basal and CK8-expressing luminal cells. Organoids are genetically highly stable, reconstitute prostate glands in recombination assays and can be experimentally manipulated. Single human luminal and basal cells give rise to organoids, yet luminal cell-derived organoids more closely resemble prostate glands. These data support a luminal multilineage progenitor cell model for prostate tissue and establish a robust, scalable system for mechanistic studies.