Exploring the molecular mechanism of osimertinib resistance in EGFR-mutated lung cancer through organoids
Background: Osimertinib is a first-line targeted therapy for EGFR-mutant non-small cell lung cancer (NSCLC), but acquired resistance limits its clinical efficacy. Patient-derived tumor organoids retaining tumor heterogeneity are ideal models for exploring resistance mechanisms. This study aimed to clarify the osimertinib resistance mechanism mediated by key genes in EGFR-mutant lung cancer using organoid models.Methods: EGFR-mutant lung cancer organoids were constructed and tested for osimertinib sensitivity. Transcriptome sequencing and TCGA data cross-analysis were performed to screen resistance-related genes and pathways. SPC25 function was verified via organoid overexpression and knockdown assays, and ferroptosis-related protein (NRF2, SLC7A11, GPX4) expression was assessed through Western blot.Results: Lung cancer organoids with epithelial phenotype and proliferative activity were successfully constructed. The IC50 of osimertinib-sensitive organoids was 0.49 uM, while that of osimertinib-resistant organoids was 8.51 uM. Transcriptome sequencing combined with TCGA analysis identified 522 common differentially expressed genes. KEGG enrichment showed that the ferroptosis pathway was significantly enriched. Among them, SPC25 expression was most markedly upregulated in resistant organoids. Overexpression of SPC25 in sensitive organoids markedly reduced the sensitivity to osimertinib, while upregulating the expressions of NRF2, SLC7A11, and GPX4; knockdown of SPC25 in resistant organoids restored the sensitivity to osimertinib and downregulated the expressions of the above ferroptosis inhibitory proteins.Conclusions: SPC25 inhibited the ferroptosis pathway to mediate the resistance of EGFR-mutated lung cancer organoids to osimertinib. Targeting SPC25 or inducing ferroptosis in combination may be a new strategy to reverse osimertinib resistance.