Single-cell transcriptomic analysis identifies MMP11-positive cancer-associated fibroblasts associated with bladder cancer progression and extracellular matrix remodeling

Cancer-associated fibroblasts (CAFs) play critical roles in bladder cancer progression, yet their heterogeneity and functional contributions during the transition from non-muscle-invasive bladder cancer (NMIBC) to muscle-invasive bladder cancer (MIBC) remain incompletely understood. Here, we integrated multiple single-cell RNA sequencing datasets comprising 21 bladder tumors and 4 adjacent normal tissues to characterize CAF heterogeneity and identify progression-associated subpopulations. A high-risk (HR) gene signature associated with invasive progression was first established using the Lund bladder cancer cohort. HR gene expression was predominantly enriched in CAFs, and reclustering analysis identified an MMP11⁺ myofibroblastic CAF (myCAF) subtype with the highest HR signature activity. Functional analyses revealed that MMP11⁺ myCAFs were strongly associated with extracellular matrix (ECM) remodeling, collagen metabolism, epithelial–mesenchymal transition, and angiogenesis. Multi-cohort deconvolution analyses demonstrated that MMP11⁺ myCAFs increased with tumor stage and were associated with significantly worse survival outcomes. Cell–cell communication analysis suggested that these CAFs interact with tumor epithelial cells through FN1- and collagen-related signaling pathways. Based on the expression levels of MMP11, FN1, COL1A1, and COL1A2, we developed an MMP11⁺ myCAF signature score, which was associated with advanced tumor stage and shorter overall survival (OS) and cancer-specific survival (CSS) in univariate analyses. However, the association between the signature score and survival was not significant after adjustment for tumor stage and invasiveness, indicating that its prognostic information was largely captured by established clinical variables. Immunohistochemistry further confirmed elevated expression of these markers in MIBC tissues. These findings identify MMP11⁺ myCAFs as a progression-associated CAF subpopulation in bladder cancer and suggest that their ECM remodeling programs and inferred epithelial communication pathways may contribute to tumor progression.