TRMT1-Mediated tRNA m22G Modification Drives Osimertinib Resistance via the ATXN3/USP25 Axis in Lung Adenocarcinoma

Acquired resistance to Osimertinib, a third-generation EGFR tyrosine kinase inhibitor (TKI), remains a critical challenge in lung adenocarcinoma. Here, we identify ATXN3, a deubiquitinating enzyme, as a driver of Osimertinib resistance and a predictor of poor patient survival. Osimertinib treatment dynamically upregulates ATXN3 transcription, which stabilizes USP25 through deubiquitination, activating an ATXN3-USP25-TRMT1 signaling cascade. This axis enhances TRMT1-mediated tRNA m²2G modifications, enabling selective translation of redox-regulating enzymes (e.g., GPX4, SOD2) that scavenge reactive oxygen species (ROS) and mitigate drug-induced oxidative stress. Genetic ablation of TRMT1 or pharmacological targeting of USP25 with the small-molecule inhibitor AZ1 disrupted this pathway, restored ROS accumulation, and re-sensitized resistant tumors to Osimertinib in patient-derived organoids and in vivo models. Our findings reveal tRNA epitranscriptomic reprogramming as a novel mechanism of EGFR-TKI resistance and position the ATXN3/USP25/TRMT1 axis as a therapeutically actionable target to overcome Osimertinib resistance in lung cancer.