Mast cell CRFR1 contributes to pancreatic cancer pain via MAPK/SPHK1 signaling
Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer often accompanied by persistent abdominal pain and stress, significantly compromising patients' quality of life. Previous studies have identified mast cells as crucial contributors to pancreatic cancer related pain. This study aimed to investigate the role of the mast cell receptor CRFR1 and delineate its underlying mechanisms in mediating pancreatic pain. In the current study, we demonstrated that painful PDAC patients exhibited markedly increased mast cell infiltration in peritumoral tissues, but not in tumor tissues, along with elevated levels of CRF and mast cell-specific CRFR1 expression, compared to asymptomatic patients. Consistently, in orthotopic PDAC mice models, flow cytometry and immunofluorescence staining confirmed increased CRFR1 expression in mast cells. Both pharmacological inhibition of CRFR1 and mast cell specific CRFR1 knockout suppressed mast cell degranulation and alleviated cancer pain in male and female mice. Mechanistically, RNA sequencing, western blotting, and ELISA indicated that CRFR1 activated MAPK pathway signaling, upregulated SPHK1 expression, and increased S1P levels. A rescue experiment revealed that MAPK inhibition blocked CRFR1-induced SPHK1 upregulation in vitro. Importantly, the SPHK1 inhibitor PF543 reduced abdominal hyperalgesia in mice, while this effect was abolished in mast cell deficient mice. Moreover, SPHK1 knockdown by siRNA abolished CRFR1-induced mast cell degranulation. These findings highlight the critical role of mast cell CRFR1 in mediating abdominal hyperalgesia and identify the MAPK/SPHK1/S1P axis as an essential pathway, suggesting that targeting mast cell CRFR1 may be a promising therapeutic strategy for managing pancreatic cancer pain. Overall design: Para-tumor tissues were randomly selected from CRFR1 CKO and WT PDAC mice for RNA sequencing to explore the downstream signaling pathways of CRFR1.