Castration-resistant Lgr5(+) cells are long-lived stem cells required for prostatic regeneration.

The adult prostate possesses a significant regenerative capacity that is of great interest for understanding adult stem cell biology. We demonstrate that leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) is expressed in a rare population of prostate epithelial progenitor cells, and a castration-resistant Lgr5(+) population exists in regressed prostate tissue. Genetic lineage tracing revealed that Lgr5(+) cells and their progeny are primarily luminal. Lgr5(+) castration-resistant cells are long lived and upon regeneration, both luminal Lgr5(+) cells and basal Lgr5(+) cells expand. Moreover, single Lgr5(+) cells can generate multilineage prostatic structures in renal transplantation assays. Additionally, Lgr5(+) cell depletion revealed that the regenerative potential of the castrated adult prostate depends on Lgr5(+) cells. Together, these data reveal insights into the cellular hierarchy of castration-resistant Lgr5+ cells, indicate a requirement for Lgr5(+) cells during prostatic regeneration, and identify an Lgr5(+) adult stem cell population in the prostate.