Hypoxia Differentially Regulates Ferroptosis Sensitivity and Tumor Cell-Intrinsic Type I Interferon Signaling in Pancreatic Ductal Adenocarcinoma Cells.

Ferroptosis has emerged as a promising strategy to overcome resistance to conventional cancer therapies. Pancreatic ductal adenocarcinoma (PDAC) is characterized by hypoxia, therapy resistance, and an immunosuppressive microenvironment. Although hypoxia is likely to influence ferroptosis susceptibility and the associated inflammatory pathways that regulate antitumor immunity, their impact on ferroptosis sensitivity and innate immune responses remains poorly understood. In this study, we investigated the effects of hypoxia on the induction of ferroptosis and immune-related signaling in PDAC cell lines. We examined how hypoxia affects the responses of Panc-1, BxPC3, and Capan-1 cells to the ferroptosis inducers RAS-selective lethal 3 (RSL3)/Imidazole ketone erastin (IKE) under normoxic and hypoxic (0.1% O2) conditions. Cell viability assays were used to assess ferroptosis sensitivity, and rescue experiments were performed using liproxstatin-1 (LIP). Gene expression analysis was conducted to evaluate changes in immune, interferon, inflammatory, and hypoxia-related genes following ferroptosis induction. Panc-1 cells were the most sensitive, whereas Capan-1 cells were resistant, particularly under hypoxia. Ferroptosis triggered cell line-specific responses involving interferon signaling, inflammation, and stress pathways. Panc-1 cells showed over-expression of RIG-I, MAVS, IRF3/7/9, STAT1/2, and CXCL10, particularly under hypoxia, indicating activation of Type I interferon (IFN)-associated transcriptional program. BxPC3 cells demonstrated broader cytokine induction, including IL-8, CCL2, CXCL2, GM-CSF, and IL-11, whereas Capan-1 cells were minimally responsive. Hypoxia also increased ANGPTL4 and GDF15 expression following ferroptosis induction. These findings show that hypoxia differentially affects ferroptosis sensitivity and immune responses in PDAC, revealing complex interactions among ferroptosis, innate immunity, and the tumor microenvironment.