ALKBH5 in Cancer-associated Fibroblasts Facilitates Pancreatic Cancer Metastasis via HSF1–LIF Axis [ATAC-seq]

Cancer-associated fibroblasts (CAFs) are principal determinants of pancreatic ductal adenocarcinoma (PDAC) progression, yet the epitranscriptomic mechanisms governing tumor–stroma crosstalk remain poorly understood. Here, we identify N6-methyladenosine (m6A) remodeling as a hallmark of CAF activation and define a critical role for the m6A demethylase AlkB homolog 5 (ALKBH5) in PDAC metastasis. Activated CAFs exhibit a global reduction in m6A abundance, with ALKBH5 emerging as a key regulator of the CAF epitranscriptome. Functionally, CAF-derived ALKBH5 enhances pancreatic cancer cell migration and invasion in vitro and promotes epithelial–mesenchymal transition–associated gene expression in tumor cells in an m6A-dependent manner. In vivo, orthotopic co-implantation models and host genetic ablation models demonstrate that ALKBH5 plays a critical role in metastatic dissemination, with minimal impact on primary tumor growth. Mechanistically, ALKBH5 enhances the m6A-dependent translation of heat shock factor 1 (HSF1) in CAFs, at least in part by relieving insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3)-associated translational constraints. Elevated HSF1 subsequently activates leukemia inhibitory factor (LIF) transcription through distal enhancer elements, establishing an ALKBH5–HSF1–LIF signaling axis that mediates pro-metastatic CAF–tumor cell communication. Clinically, enrichment of ALKBH5⁺/HSF1⁺ CAFs independently predicts poor prognosis and is preferentially observed in metastatic PDAC. Collectively, these findings uncover a CAF-intrinsic epitranscriptomic program that drives PDAC metastasis and highlight stromal m6A regulation as a potential therapeutic vulnerability.