Single-Cell Dissection of Therapy-Induced Remodeling Uncovers a Fibroblast-Driven Immunosuppressive Niche and...

Therapy resistance in prostate cancer arises from coordinated remodeling of malignant and stromal compartments, yet the mechanisms orchestrating this ecosystem adaptation remain elusive. Here, single-cell RNA sequencing of longitudinal biopsies obtained before and after androgen-deprivation therapy (ADT) delineated a therapy-induced stromal lineage bifurcation toward APOD⁺ and DPT⁺ fibroblast states. DPT⁺ fibroblasts activated a C3-ITGAX/ITGB2 complement signaling axis targeting macrophages, coinciding with suppression of M1 inflammatory programs, amplification of immune-checkpoint signaling, and a shift of CD8⁺ T cells from cytotoxic to exhausted phenotypes. Concomitantly, we identified pre-existing malignant epithelial subpopulations characterized by reduced AR/KLK3 activity and heightened chromosomal instability that preferentially persisted following therapy. Integrative multi-omic analyses nominated TSPAN1 as a functional effector of castrate resistant prostate cancer (CRPC) and NRXN1 as a regulator of neuroendocrine plasticity through calcium-dependent signaling programs. Genetic silencing of either gene suppressed proliferation, clonogenicity, migration, and tumor growth, while attenuating neuroendocrine features in vitro and in vivo. Spatial mapping, functional perturbation, and stromal-epithelial co-culture experiments mechanistically established a therapy-induced DPT⁺ fibroblast-complement circuit that enforced immune evasion and channels epithelial trajectories toward CRPC or neuroendocrine prostate cancer. Collectively, these findings defined the DPT⁺-complement-macrophage axis as an actionable vulnerability and position TSPAN1 and NRXN1 as therapeutic entry points to disrupt ADT-driven tumor ecosystem remodeling in prostate cancer.