Transcriptomic Signature and Growth Factor Regulation of Castration-Tolerant Prostate Luminal Progenitor Cells

Abstract

Background: The molecular and cellular mechanisms that drive castration-resistant prostate cancer (CRPC) remain poorly understood. LSCmed cells defines an FACS-enriched population of castration-tolerant luminal progenitor cells that has been proposed to promote tumorigenesis and CRPC in Pten-deficient mice. The goals of this study were to assess the relevance of LSCmed cells through the analysis of their molecular proximity with luminal progenitor-like cell clusters identified by single-cell (sc)RNA-seq analyses of mouse and human prostates, and to investigate their regulation by in silico-predicted growth factors present in the prostatic microenvironment. Methods: Several bioinformatic pipelines were used for pan-transcriptomic analyses. LSCmed cells isolated by cell sorting from healthy and malignant mouse prostates were characterized using RT-qPCR, immunofluorescence and organoid assays. Results: LSCmed cells match (i) mouse luminal progenitor cell clusters identified in scRNA-seq analyses for which we provide a common 15-gene signature including the previously identified LSCmed marker Krt4, and (ii) Club/Hillock cells of the human prostate. This transcriptional overlap was maintained in cancer contexts. EGFR/ERBB4, IGF-1R and MET pathways were identified as autocrine/paracrine regulators of progenitor, proliferation and differentiation properties of LSCmed cells. The functional redundancy of these signaling pathways allows them to bypass the effect of receptor-targeted pharmacological inhibitors. Conclusions: Based on transcriptomic profile and pharmacological resistance to monotherapies that failed in CRPC patients, this study supports LSCmed cells as a relevant model to investigate the role of castration-tolerant progenitor cells in human prostate cancer progression.

Integrated single-cell analysis defines the epigenetic basis of castration-resistant prostate luminal cells

“…Studying castration/regeneration responses in mouse prostate has great implications in understanding human PCa response to ADT/ARSIs and potential cell(s)-of-origin of CRPC. In both mouse and human prostate, the urethra-proximal prostate harbors quiescent epithelial stem/progenitor cells that are intrinsically refractory to castration 1,3,5,6,[25][26][27][53][54][55][56] . The proximal epithelial cells underexpress differentiation regulators AR and NKX3.1 but overexpress stem cell molecules such as Sca-1, SOX2 and RUNX1 53,54,57,58 ; this study).…”

“…In both mouse and human prostate, the urethra-proximal prostate harbors quiescent epithelial stem/progenitor cells that are intrinsically refractory to castration 1,3,5,6,[25][26][27][53][54][55][56] . The proximal epithelial cells underexpress differentiation regulators AR and NKX3.1 but overexpress stem cell molecules such as Sca-1, SOX2 and RUNX1 53,54,57,58 ; this study). Due to their intrinsically castration-resistant nature, the proximal progenitor cells have been thought of as the cells that would survive castration and mediate regeneration/recurrence.…”

Progéniteurs luminaux prostatiques

“…Les cellules LSC med expriment les gènes codant des kératines luminales (Krt8) mais aussi ceux codant des kératines spécifiques (Krt4, Krt7). Elles se caractérisent par une signature particulière de 110 gènes [24] qui sont spécifiquement enrichis dans la population de progéniteurs luminaux telle que définie in silico par scRNAseq (Figure 3), démontrant la correspondance de ces deux populations cellulaires [17,23]. In vitro, les cellules LSC med sont capables de former des sphéroïdes [25] et des organoïdes [26], mais aussi des structures glandulaires lorsqu'elles sont greffées dans une souris hôte [26].…”

“…La population luminale progénitrice (LumP, n° 5 entourée d'un cercle rouge) représente une faible proportion de l'épithélium glandulaire. Elle se caractérise par une signature de 15 marqueurs commune aux cinq études scRNAseq réanalysées dans notre étude [23]. Cette population cellulaire définie in silico est la seule significativement enrichie en transcrits de la signature des cellules LSC med [24], comme illustré par le « score LSC med » élevé (B), le « violin plot » (C) et la « heatmap » (D).…”

Integrated analysis of single-cell and bulk RNA sequencing identifies a signature based on macrophage marker genes involved in prostate cancer prognosis and treatment responsiveness

“…Nowadays, the growing research on scRNA-seq has led to the identi cation of a multitude of potentially predictive biomarkers in PCa, exploring tumor heterogeneity and mechanisms, effectively [16,17].…”