Abstract B031: Exploring CDKN2A mediated metabolic alterations as an immunotherapy resistance mechanism in non-small cell lung cancer

Abstract Lung cancer is the leading cause of cancer-related death in the world. Immunotherapy is a promising treatment option for patients with late-stage non-small cell lung cancer (NSCLC). Lung tumors harboring Kras/p53 (KP) mutations express higher levels of PD-L1 and respond better to anti-PD-1/-PD-L1 (αPD-(L)1) therapy than other Kras subsets. However, tumors can gain acquired resistance through mechanisms that are not well understood. Therefore, our goal was to use αPD-1 therapy resistant models to elucidate the mechanisms of intrinsic and acquired resistance in NSCLC. We developed a panel of anti-PD-(L)1 sensitive and resistant cell lines from the mesenchymal 344SQ cell line previously derived from KP GEMM tumors. We then subcutaneously injected mice with either 344SQ (sensitive) or PD1R1 (resistant) and treated them with either αPD-1or IgG over 6 weeks. We harvested tumors at week 4 (when 344SQ remained sensitive) and at week 6 (when 344SQ gained resistance). We performed single-cell RNA sequencing (scRNA-seq) and obtained a list of differentially expressed genes (DEGs) in the malignant cell population between treatments. We identified CDKN2A expression as significantly lost in the resistant tumor cells. CDKN2A loss strongly associates with decreased response to αPD-(L)1 and KRAS inhibitors in patients, but its mechanism is poorly understood. Our scRNA-seq showed high OXPHOS activation in the resistant tumor cells. We found that CDKN2A knockdown increased OXPHOS activity, mitochondrial mass, and ROS production, potentially via a SIRT1-dependent pathway. We are currently exploring how CDKN2A-deficient malignant cell metabolism negatively impacts T cell metabolic fitness. Overall, there is a lack of clear mechanistic studies on how CDKN2A loss drives cancer immune escape despite it being one of the most common genomic deletions in human cancers. Thus, this study aims to identify vulnerabilities in CDKN2A-lost tumors so that such malignancies can be targeted in combination with αPD-1 to overcome immunotherapy resistance. Citation Format: Haoyi Wu, Jessica M. Konen, Bertha L. Rodriguez, Yanhua Tian, Shucheng Miao, Jared J. Fradette, Don L. Gibbons. Exploring CDKN2A mediated metabolic alterations as an immunotherapy resistance mechanism in non-small cell lung cancer abstract. In: Proceedings of the AACR Immuno-Oncology Conference (AACR IO): Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2026 Feb 18-21; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2026;14(2 Suppl):Abstract nr B031.