Spatial Profiling Identified Senescent Cancer-Associated Fibroblasts Localized in the Border Region of Human Pancreatic Ductal Adenocarcinoma

BACKGROUND & AIMS: Pancreatic ductal adenocarcinoma is a highly aggressive malignancy characterized by a fibroblast-rich tumor microenvironment. Cancer-associated fibroblasts closely interact with tumor cells and play a pivotal role in cancer pathogenesis. Single-cell analyses have identified distinct cancer-associated fibroblast subsets that exert either tumor-promoting or tumor-suppressive effects in pancreatic ductal adenocarcinoma. Senescent cancer-associated fibroblasts have recently been linked to poor prognosis through their senescence-associated secretory phenotype. However, the dynamics of senescent cancer-associated fibroblast induction and their spatial distribution in pancreatic ductal adenocarcinoma remain largely unclear. This study aimed to investigate the heterogeneity and spatial organization of cancer-associated fibroblasts in pancreatic ductal adenocarcinoma, with a specific focus on the induction and localization of senescent cancer-associated fibroblasts. METHODS: We performed immunostaining and spatial transcriptomic analyses covering unbiased regions of tumor architecture to map cancer-associated fibroblast subpopulations and characterize senescent cancer-associated fibroblast induction and localization. RESULTS: Senescent cancer-associated fibroblasts were found to accumulate preferentially at the gross tumor edge, and their abundance was associated with poor patient prognosis. Chemotherapy further promoted senescence in myofibroblastic cancer-associated fibroblasts within the tumor core, resulting in an increased population of senescent cancer-associated fibroblasts. Spatial transcriptomic profiling identified gene signatures specific to senescent cancer-associated fibroblasts and revealed their distinct interactions with neighboring cells. Notably, senescent cancer-associated fibroblasts exhibited enhanced transforming growth factor-β signaling activity and upregulation of downstream genes, such as CCN2 and PLAU, which may contribute to tumor proliferation and invasion. CONCLUSIONS: This study reveals that senescent cancer-associated fibroblasts preferentially localize near the gross tumor edge and could impact tumor progression through their senescence-associated secretory phenotype. These findings highlight the spatial plasticity of pancreatic cancer-associated fibroblasts and underscore the pathological significance of senescent cancer-associated fibroblasts in human pancreatic ductal adenocarcinoma.