Senescence-associated prostate cancer cells promote fibroblast reprogramming and extracellular matrix remodeling

Cellular senescence influences tumor progression via the senescence-associated secretory phenotype (SASP), yet whether senescence-associated alterations in prostate epithelial cells contribute to stromal remodeling remains poorly understood.

Human prostate cancer specimens, public single-cell RNA-sequencing datasets, a prostate-specific Pten conditional knockout (Pten-cKO) mouse model, mouse single-cell transcriptomic analysis, and mechanistic in vitro experiments were integrated to investigate senescence and stromal remodeling. Histopathological analysis, multiplex immunofluorescence staining, transcriptomic profiling, conditioned medium experiments, senolytic intervention, and pharmacological inhibition assays were employed to characterize epithelial-fibroblast interactions and their underlying mechanisms.

Senescence-associated phenotypes were progressively enriched across increasing PCa grades and were predominantly localized to the epithelial compartment. Human single-cell transcriptomic analysis revealed concurrent activation of epithelial senescence/SASP programs and fibroblast ECM-remodeling programs, along with the enrichment of fibrogenic secretory signatures linked to epithelial-stromal communication. Consistently, Pten-cKO mouse prostates exhibited increased epithelial senescence-associated phenotypes, collagen deposition, and fibroblast ECM-remodeling activity. Mechanistically, DOX-induced senescence-associated RM1 prostate cancer cells acquired a fibrogenic secretory phenotype characterized by augmented TGF-β1 secretion. Senolytic treatment with ABT-263 reduced the senescence-associated cell population and TGF-β1 secretion, while conditioned medium collected after ABT-263 treatment exhibited diminished fibroblast-remodeling activity. DOX-RM1 conditioned medium reprogrammed NIH/3T3 fibroblasts into an ECM-remodeling CAF-like state, which was manifested by enhanced collagen deposition and upregulated expression of matrix-associated genes and proteins. Pharmacological inhibition of TGF-β signaling attenuated SMAD2 phosphorylation and partially reversed fibroblast activation and ECM remodeling.

These findings identify epithelial senescence-associated signaling as a mechanism linking prostate epithelial alterations to fibroblast reprogramming and ECM remodeling. A fibrogenic tumor-cell secretory program promotes fibroblast acquisition of an ECM-remodeling CAF-like phenotype, at least in part through TGF-β/SMAD2 signaling, and contributes to fibrotic remodeling of the prostate tumor microenvironment.