Therapeutic pressure drives the evolution of a protective ecotype characterized by AR-loss-induced senescence in prostate cancer.

Rationale: Prostate cancer treatment relies heavily on androgen deprivation therapy, yet the progression to a lethal treatment-resistant state presents a nearly universal clinical challenge. While tumor-intrinsic changes are well documented, the manner in which the broader tumor microenvironment dynamically reorganizes into distinct macroscopic ecological states under therapeutic pressure remains elusive. This underscores that dismantling specific therapy-induced TME niches may represent a promising strategy for CRPC treatment. Methods: We constructed a comprehensive single-cell atlas comprising 399,276 cells from 133 clinical samples to systematically investigate sample-level microenvironmental heterogeneity. Integrative bioinformatics and a meta-analysis of 1,259 patients were utilized to validate the clinical relevance. The upstream regulatory role of the androgen receptor on the NF-κB2/p52 pathway in cancer-associated fibroblasts was elucidated and validated using CRISPR-Cas9, ChIP-qPCR, and dual-luciferase reporter assays. Functional studies and therapeutic strategies targeting this axis were conducted using gain- and loss-of-function assays, and evaluated through Results: We demonstrated that hormonal therapy drives a convergent systemic evolution toward a specific treatment-refractory ecological state termed Ecotype 4. Rather than isolated cellular events, this highly malignant ecosystem is characterized by a TGF-β-driven rigid vascular-stromal barrier enforcing immune exclusion and the prominent accumulation of an androgen receptor-negative senescent fibroblast population. Mechanistically, we identified that the loss of the androgen receptor releases a physiological brake on the non-canonical NF-κB pathway, forcing these fibroblasts into a pro-tumorigenic senescence phenotype. Importantly, pharmacologically blocking this NF-κB2/p52 pathway with the inhibitor SN52 reverses the supportive nature of this niche and restores sensitivity to standard antiandrogens Conclusions: This study demonstrates that castration resistance is driven by the dynamic, systemic evolution of the microenvironment into a highly structured protective ecotype. Targeting the therapy-associated stromal p52 senescence switch effectively dismantles this ecological sanctuary and offers a new valued therapeutic strategy for advanced CRPC.