Spatial transcriptomics and single cell profiling reveal the dynamics of antigen presenting cancer associated fibroblasts during prostate cancer progression

Abstract Prostate cancer (PCa) is characterized by an immunosuppressive "cold" tumor microenvironment (TME), contributing to therapy resistance. Cancer-associated fibroblasts (CAFs) are pivotal in shaping this TME, but their heterogeneity and spatial dynamics remain poorly understood. Here, we integrated single-cell RNA sequencing (scRNA-seq; GSE181294) and spatial transcriptomics (GSE245389) to delineate CAF subpopulations in PCa, identifying three functionally distinct subsets: inflammatory (iCAF), myofibroblastic (myCAF), and antigen-presenting CAFs (apCAF). Notably, the apCAF subset (C11_HLA-DRA) exhibited high expression of PSCA and MHC-II genes, spatially co-localizing with PSCA⁺ tumor cells. Pseudotime analysis revealed dynamic CAF differentiation trajectories, with apCAFs enriched in pathways linked to angiogenesis (PTN-NCL), immune suppression (HLA-DRA), and KRAS/p53 signaling. Mendelian randomization (SMR) identified PSCA as a causal hub gene associated with PCa progression. Spatial analysis further uncovered heterotypic interactions between PSCA + tumor cells and C11_HLA-DRA via pro-angiogenic ligand-receptor pairs (SPP1-CD44, PTN-NCL), forming localized "communication hubs" within the TME. Our findings highlight HLA-DRA⁺ apCAFs as key mediators of immune evasion and propose PSCA as a therapeutic target to disrupt tumor-stroma crosstalk in immunosuppressive PCa. This study provides a spatially resolved blueprint of CAF-immune-tumor interactions, offering novel strategies to overcome immunotherapy resistance.