Mitophagy-dependent mitochondrial DNA release links ionizing radiation to immunogenic cell death in pancreatic cancer

Abstract Ionizing radiation (IR) elicits both cytotoxic and immunomodulatory effects, yet the precise link between mitochondrial remodeling and immunogenic cell death (ICD) remains elusive. Here, we report that IR triggers robust mitophagy in pancreatic cancer cells, marked by mitochondrial damage, Parkin/BNIP3 upregulation, and increased autophagic flux. In parallel, IR induces key hallmarks of ICD, including calreticulin exposure, HMGB1 translocation, and the release of ATP and IFN-β. Notably, genetic or pharmacological inhibition of mitophagy attenuated this immunogenic profile, whereas mitophagy induction amplified it. We further demonstrate that mitophagy triggers the cytosolic release of mitochondrial DNA (mtDNA) to activate immune signaling, which can be reversed by blocking mtDNA replication. In murine models, Parkin overexpression enhanced mitophagy and ICD marker expression, leading to reduced tumor burden and prolonged survival following irradiation. Collectively, our findings indicate that mtDNA leakage downstream of mitophagy links mitochondrial remodeling to radiation-induced ICD, suggesting that modulation of mitochondrial dynamics may represent a strategy to enhance both radiosensitivity and the immunogenic potential of radiotherapy in pancreatic cancer.