IRP1/ARID3A complex identified as a new epigenetic driver of pancreatic cancer chemoresistance

Pancreatic cancer remains among the deadliest malignancies, in part because tumors often withstand chemotherapy and later acquire resistance. In recent years, ferroptosis—an iron-dependent, lipid-peroxidation-driven cell death—has emerged as a potential strategy to bypass conventional resistance mechanisms. Yet many pancreatic cancers still evade ferroptosis, leaving a crucial gap in understanding the molecular circuitry behind treatment failure.

Now, a study in Genes & Diseases reports a previously unrecognized epigenetic route through which the iron-responsive protein IRP1 collaborates with the transcription factor ARID3A to suppress ferroptosis and promote chemoresistance. The work links iron sensing to chromatin regulation and identifies a pathway that could be exploited therapeutically.

Across pancreatic cancer specimens, the authors find that both IRP1 and ARID3A are highly expressed and correlate with poor chemotherapy outcomes and unfavorable patient survival. In cell-based functional assays, elevating either protein enhances proliferation and increases resistance to gemcitabine, while silencing IRP1 or ARID3A restores chemosensitivity and suppresses tumor growth in models.

Mechanistically, intracellular iron accumulation drives IRP1 into the nucleus, where it physically associates with ARID3A. Rather than altering transcription solely through classic repression, the IRP1–ARID3A complex remodels chromatin dynamics to reduce accessibility at the cytoglobin (CYGB) promoter. This epigenetic shift suppresses CYGB expression without relying on direct transcriptional shutdown.

CYGB, in turn, plays a role in maintaining redox balance and regulating oxidative stress responses. When CYGB is diminished, pancreatic cancer cells show reduced lipid peroxidation, less reactive oxygen species accumulation, and stronger survival under ferroptosis-inducing conditions. The study connects these biochemical changes directly to the observed drug-resistant phenotype.

Crucially, restoring CYGB or disrupting the IRP1–ARID3A interaction reverses the ferroptosis-resistant state, resensitizing cells to ferroptosis and improving gemcitabine efficacy. In vivo, combining ferroptosis-relevant interventions with suppression of this signaling axis markedly restricts tumor progression.

The findings position the IRP1–ARID3A–CYGB axis as a central determinant of ferroptosis resistance in pancreatic cancer. By uniting iron metabolism, epigenetic control, and regulated cell death, the work offers a mechanistic basis for pairing chemotherapy with ferroptosis-targeting strategies in patients who do not respond to standard treatment.

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Web References: http://dx.doi.org/10.1016/j.gendis.2025.101866

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