Fig. 5. Androgen deprivation enhances the regenerative potential of human prostate luminal cells.

(A) Enhanced organoid formation by human luminal cells obtained post castration. Left: Relative organoid formation (mean ± standard deviation) of CD26/DPP4 luminal cells isolated from prostates obtained by radical prostatectomy from hormonally intact patients (N=5, blue) or patients treated with androgen deprivation therapy (N=5, red). Organoids were quantified 14 days after seeding of 200 cells. N=4. **designates p< 0.01, Welch’s t test. (B) Representative brightfield image (right), H&E stain (middle) and confocal image (right) of a human organoid derived a patient treated with ADT as in (A). For the confocal image: CK8 (red), CK5 (green), EPCAM (white) and DAPI (purple). Scale bar: 100μm. (C) Schematic of human prostate processing for scRNA-seq. (D) Top: PHATE map of luminal cells from all samples stratified by treatment (left) and by sample (right). Bottom: PHATE maps colored by correlation to RNA signatures derived from Henry et. al. (30). L1 (left); L2 “Club” (right). (E) Pairwise correlation of signature scores for L1 and L2 “Club” cells (30) per patient after CNA filtering. Signatures were generated using previously published human prostate luminal cell data (30). * designates significant change of the median correlation (p<0.05, Welch’s t-test, one-sided test). (F) Model of prostate regeneration. The prostate gland shrinks ~90% following androgen deprivation (castration) due to loss of luminal epithelial cells. During this process, the transcriptome of L1 cells closely resembles that of more stem-like L2 cells. Androgen addback stimulates production of growth factors by distinct populations of mesenchymal cells, which rapidly recruit nearly all persisting luminal cells into cell cycle. Each of these proliferating luminal cells collectively contributes to regeneration of the prostate gland, rather than a rare stem cell population.