IER3 promotes non-small cell lung cancer malignancy by suppressing ferroptosis via the AKT/GSK3β/NRF2 pathway.

Non-small cell lung cancer (NSCLC) remains a lethal malignancy due to therapy resistance and recurrence. Ferroptosis, a regulated form of cell death, is a promising strategy to overcome cancer drug resistance, yet its mechanisms remain incompletely defined. Here, we report that Immediate Early Response 3 (IER3) is significantly upregulated in NSCLC tumors and linked to advanced stage and poor prognosis. Using IER3-overexpressing and knockout models in A549 and H1299 cells, we found that IER3 promotes NSCLC cell proliferation, migration, and invasion by suppressing ferroptosis. Conversely, IER3 knockout induced ferroptosis and reduced malignancy-effects reversed by the ferroptosis inhibitor Fer-1. Mechanistically, IER3 sustained AKT phosphorylation to inactivate GSK3β, both blocking GSK3β-dependent proteasomal degradation of NRF2 and enhancing its nuclear translocation, which collectively led to the transactivation of downstream ferroptosis-suppressive gene programs. This program maintained glutathione homeostasis, sequestered labile iron, scavenged ROS, and ultimately inhibited lipid peroxidation to counter ferroptosis. Rescue assays confirmed NRF2 overexpression or AKT/GSK3β activation reversed IER3 knockout-induced ferroptosis and viability loss. Additionally, low-IER3 NSCLC tumors were more sensitive to clinical/preclinical agents targeting survival/stress pathways. Collectively, our findings establish IER3 as an NSCLC oncogenic driver-suppressing ferroptosis via AKT/GSK3β/NRF2 to sustain malignancy-highlighting its potential as a prognostic biomarker and therapeutic target for improved NSCLC outcomes.