NRF2-CDH6-CEBPD axis suppresses ferroptosis and drives cisplatin resistance in non-small cell lung cancer.

Ferroptosis is a non-apoptotic form of programmed cell death driven by iron-dependent lipid peroxidation. Induction of ferroptosis has been shown to overcome chemoresistance in cancer cells. Given the importance of the nuclear factor erythroid 2-related factor 2 (NRF2) pathway in the regulation of cellular oxidative stress, this study was designed to search for NRF2-regulated genes involved in ferroptosis and chemoresistance in non-small cell lung cancer (NSCLC). Bioinformatics analysis and experimental validation indicated cadherin-6 (CDH6) as a candidate gene. The expression and role of CDH6 in NSCLC were explored. CDH6 protein partners were identified and investigated after CDH6 co-immunoprecipitation assays and mass spectrometry. Our data demonstrated that NRF2 binding to the promoter of the CDH6 gene inhibited RUNX2-mediated transcription of CDH6 in NSCLC. Clinically, CDH6 was downregulated in NSCLC tissues and correlated with more advanced tumor-node-metastasis (TNM) stage and shorter overall survival. Knockdown of CDH6 enhanced the proliferation, colony formation, tumorigenesis, and cisplatin (CDDP) resistance in NSCLC cells. Moreover, overexpression of CDH6 induced ferroptosis and increased CDDP sensitivity in CDDP-resistant NSCLC cells. Mechanistically, CDH6 associated with and sequestered CCAAT enhancer binding protein delta (CEBPD) protein in the cytoplasm and impaired the CEBPD-dependent transcription of target genes. Depletion of CEBPD increased CDDP sensitivity of CDH6-depleted NSCLC cells, whereas overexpression of CEBPD restored CDDP resistance in CDH6-overexpressing NSCLC cells. Additionally, CEBPD upregulation was associated with poor prognosis in NSCLC patients. In conclusion, our data underscore the critical role of the NRF2-CDH6-CEBPD axis in modulating CDDP sensitivity in NSCLC and offer a potential therapeutic target for improving chemotherapy.