Abstract 4042: Mitochondrial electron transport chain inhibition suppresses NRF2 expression in NSCLC

Abstract Lung cancer is the leading cause of cancer-associated death in the US. Non-small cell lung cancer (NSCLC) accounts for 85% of all diagnosed lung cancer cases, which has a high frequency of mutations in the KEAP1/NRF2 circuit (15-34%). NRF2 is a stress-responsive transcription factor that regulates transcriptional programs in response to oxidative stress. KEAP1 directs NRF2 degradation, and accordingly, disruption of KEAP1 increases the abundance and activity of NRF2. KEAP1/NRF2 mutations result in constitutive NRF2 activation and chronic induction of a battery of NRF2 target genes, which confer profound resistance to chemo/radiation therapy. Although direct inhibition of NRF2 holds great therapeutic potential, NRF2 inhibitors have not yet existed in the clinic. Instead, our attempt to address this challenge focuses on targeting upstream NRF2 regulators in NSCLC. To this end, we leveraged CRISPR/Cas9-based genetic screening approaches. We found that electron transport chain (ETC) complex I/III component deletion or pharmacological inhibition results in complete loss of NRF2 protein expression in KEAP1 mutant NSCLC cells. Our results indicate that NRF2 destruction by ETC inhibition is associated with post-translational ubiquitination and degradation facilitated by an alternative E3 ligase within the Cullin complex and is controlled by AMPK. We also translate these findings in vivo using novel NRF2 active genetically engineered lung tumor mouse models LSL-KrasG12D; Lkb1flox/flox ; Nrf2D29H that mimic the common co-occurrence of KRAS and Lkb1 loss-of-function mutations in human lung adenocarcinoma. This work establishes the link between the mitochondria and NRF2 regulation in NSCLC and, more importantly, will lead to the discovery of novel mediators of this signaling, which can be targeted as a therapeutical strategy for NRF2 inhibition. Overall, our research has great implications in reversing the profound resistance of NSCLC with KEAP1/NRF2 mutations to chemo/radiotherapy, which can significantly improve treatment efficacy and patient survival. Citation Format: Chang Jiang, Ryan Martin, Yun Huang, Nicolas Prieto, Yun Pyo Kang, Mingxiang Teng, Gina DeNicola. Mitochondrial electron transport chain inhibition suppresses NRF2 expression in NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4042.