Interleukin‐1α‐Mediated Activation of TNF ‐α/ NF ‐ κB Signaling Confers Resistance to Osimertinib in EGFR ‐Mutant Non‐Small‐Cell Lung Cancer

BACKGROUND: Lung cancer is the leading cause of cancer-related deaths worldwide. Although osimertinib is more effective than previous-generation drugs, its efficacy is often limited by both primary and acquired resistance. Cycling cancer persister cells (CPCs) have recently emerged as a transient, drug-tolerant subpopulation that may contribute to early resistance to targeted therapies. However, their biological characteristics and role in osimertinib resistance remain poorly understood. METHODS: We established osimertinib-resistant CPCs derived from epidermal growth factor receptor (EGFR)-mutant non-small-cell lung cancer (NSCLC) cell lines PC9 and HCC827. RNA sequencing (RNA-seq) was performed to identify CPC-specific transcriptional programs. RESULTS: RNA-seq analyses demonstrated that the tumor necrosis factor alpha (TNF-α)/nuclear factor-κB (NF-κB) signaling pathway was upregulated in osimertinib-resistant PC9 cells (PC9-CPCs), with interleukin-1 alpha (IL-1α) being the most significantly overexpressed gene. Treatment with IL-1α increased TNF-α and NF-κB p65 expression in PC9 parental cells, whereas IL-1α inhibition decreased TNF-α expression in PC9-CPCs. Consequently, the inhibition of either IL-1α or TNF-α restored the sensitivity of EGFR-mutant NSCLC cells to osimertinib. Immunohistochemical analysis confirmed that NF-κB expression was higher in tumor specimens from patients who had developed osimertinib resistance than in specimens collected before treatment. CONCLUSION: CPCs exhibit a distinct inflammatory phenotype driven by IL-1α-driven activation of the TNF-α/NF-κB axis, representing an alternative mechanism underlying osimertinib resistance. Targeting IL-1α or TNF-α may provide a promising strategy to overcome resistance in patients with EGFR-mutant NSCLC.