Senescent cancer-associated fibroblasts drive perineural invasion and pain in pancreatic ductal adenocarcinoma

Background Pain in pancreatic ductal adenocarcinoma (PDAC) correlates with perineural invasion (PNI), severely impairs quality of life, and predicts poor prognosis. The mechanisms driving this PNI-pain axis, particularly the role of senescent cancer-associated fibroblasts (senCAFs), and effective therapies remain elusive. Methods We correlated pain scores (NRS) with PNI (IHC/IF) in two PDAC cohorts. Single-cell/spatial transcriptomics and lipidomics were performed and cross-validated with external datasets. Human/murine senCAFs were co-cultured with tumor cells, dorsal root ganglion (DRG) neurons, and patient-derived organoids (PDOs), with neuronal activity assessed via patch-clamp electrophysiology. In vivo studies utilized orthotopic models with fibroblast-specific knockouts, evaluated by behavioral and nociceptive analyses. Results Higher pain grades strongly correlated with increased PNI, nerve density, and poor prognosis. scRNA-seq and spatial analyses revealed p16+ senCAFs enriched near nerves, confirmed by flow cytometry in painful tumors. Orthotopic co-inoculation with senCAFs induced nociceptive hypersensitivity prior to differences in tumor burden. Mechanistically, senCAFs activated an IL-6-JAK2/STAT3 feedback loop, sensitizing DRG neurons. JAK2 blockade normalized neuronal excitability and reduced pain behaviors. This neural-stromal crosstalk was bidirectional: senCAFs sensitize DRGs via IL-6-JAK2/STAT3, while activated DRGs release ATP, triggering P2RX7-mediated tumor cell depolarization to promote invasion. This loop is stabilized by tumor-derived, SPHK2-dependent S1P signaling via S1PR2 on CAFs, reinforcing the senescent phenotype. In vivo, JAK2 inhibition combined with nab-paclitaxel/gemcitabine significantly improved pain control and overall survival. Conclusion p16+ senCAFs orchestrate a vicious cycle by activating the IL-6-JAK2/STAT3 pathway, enhancing neuronal firing and pain; this in turn amplifies ATP/P2RX7-driven tumor cell depolarization and progression. This cycle is stabilized by tumor-derived sphingolipid reprogramming of CAFs. Targeting this senCAF-driven neural-stromal axis via JAK2 inhibition, combined with standard chemotherapy, provides a translationally potent therapeutic strategy for PDAC-related pain.