The Prostate Basal Cell (BC) Heterogeneity and the p63-Positive BC Differentiation Spectrum in Mice

Abstract

The prostate epithelium is composed of basal (BC), luminal (LEC), and neuroendocrine (NEC) cells. It is unclear how many subtypes of BCs in the prostate and which subtype of BCs contains the main stem cell niche in the adult prostate. Here we report seven BC subpopulations according to their p63, cytokeratin 14 (K14) and K5 expression patterns, including p63-positive/K14-negative/K5-negative (p63+/K14-/K5-), p63-/K14+/K5-, p63-/K14-/K5+, p63+/K14+/K5-, p63+/K14-/K5+, p63-/K14+/K5+, and p63+/K14+/K5+ BCs. We generated a p63-CreERT2 knock-in mouse line that expresses tamoxifen-inducible Cre activity in the p63-expressing cells, including the prostate BCs. We then crossbred this line with ROSA26R mice, and generated p63-CreERT2×ROSA26R bi-genic mice harboring the Cre-activated β-galactosidase reporter gene. We treated these bi-genic mice with tamoxifen to mark the p63+ BCs at different ages or under different hormonal conditions, and then traced the lineage differentiation of these genetically labeled BCs. We discovered that these p63+ BCs contain self-renewable stem cells in culture and efficiently differentiated into LECs, NECs and BCs in the postnatal, adult and re-generating mouse prostates. Therefore, BC population contains heterogeneous BCs that express different combinations of the p63, K14 and K5 differentiation markers. Because K14+ and K5+ BCs were previously shown to be extremely inefficient to produce LECs in adulthood, we propose that the p63+/K5-/K14- subpopulation of BCs contains most stem-like cells, especially in adult animals.

Prostate Sphere-forming Stem Cells Are Derived from the P63-expressing Basal Compartment

“…1B showed that prostaspheres are derived from the Nkx3.1 lineage. Lineage tracing also demonstrates that both basal and luminal cells in mouse prostate are derived from the cells that express P63 (20). Therefore, both basal and luminal cells are derived from the lineage.…”

“…However, it has been reported that P63, a basal cell marker, is required for prostate epithelial lineage commitment and prostate development (5,31). Recent reports with P63 CreERT2 lineage tracing reveal that both luminal and basal cells are derived from P63-expressing cells (20,24 CreERT2 -mediated activation of reporter genes demonstrates that both basal and luminal compartments contain P-SCs. Both luminal and basal P-SCs give rise to multiple lineages of cells either in a tumor microenvironment or coimplanted with urogenital mesenchymal cells.…”

Transitional basal cells at the squamous–columnar junction generate Barrett’s oesophagus

“…R26 tdTomato , R26 LacZ , R26 rtTA mice were purchased from the Jackson Laboratory. p63-CreER mice were kindly provided by Dr. Jianmin Xu of Baylor College of Medicine 30 . The otet-CDX2-T2A-mCherry transgenic line was generated by pronuclear injection of linearized DNA.…”

Prostate organogenesis: tissue induction, hormonal regulation and cell type specification

“…Notably, androgen deprivation by castration results in significant epithelial cell death in the prostate, whereas subsequent testosterone supplementation results in rapid tissue regeneration. During androgen-mediated regeneration, luminal castration-resistant Nkx3.1-expressing cells (CARNs) as well as basal cell populations can display bipotency and self-renewal indicative of stem cell activity (Lee et al, 2014;Wang et al, 2009Wang et al, , 2013bWang et al, , 2015. Furthermore, during tissue damage and repair, such as in mouse models of prostatitis or luminal-specific anoikis, basal cells show significant capability to replace lost luminal cells Toivanen et al, 2016).…”