Abstract 5435: OXPHOS as a driver of treatment resistance in NSCLC? From computational analysis to preclinical validation

Abstract Lung cancer is the leading cause of cancer deaths in the U.S. and worldwide. Up to 90% of all lung cancer cases are non-small cell lung cancer (NSCLC); a complex and highly aggressive disease typical for poor prognosis and high rates of treatment resistance. Clinical management of NSCLC varies according to the stage. High-dose stereotactic body radiation therapy (SBRT) is the standard of care for localized non-resectable NSCLC. In the last decade, first line NSCLC treatment has been substantially reinforced with the introduction of immunotherapy targeting immune checkpoints such as programmed cell death 1 (PD-1). However, despite initial good response, up to 75% of NSCLC patients may experience disease progression and the reasons for this heterogeneity are not fully understood. Several lines of evidence suggest that the highly hypoxic tumor microenvironment in NSCLC contributes to the high rates of treatment resistance. The basis of tumor hypoxia has traditionally been attributed to the oxygen supply deficit as malformed tumor vasculature fails to meet the high demand of the rapidly proliferating tumor mass. However, our preliminary analysis of NSCLC patient datasets in the Cancer Genome Atlas (TCGA) PanCancer dataset revealed a significant correlation between high-level expression of nuclear genes encoding mitochondrial subunits essential for oxidative phosphorylation (OXPHOS), and high-level expression of hypoxia-regulated genes (Buffa hypoxia score). Furthermore, we have observed a direct correlation between copy number amplification (CNA) of several OXPHOS genes and hypoxia levels in patient samples. Because mitochondrial function consumes up to 90% of available cellular oxygen, its activity may be indirectly regulating oxygen availability in the tumor microenvironment by rapidly consuming oxygen upon its delivery to the tumor. Moreover, we have identified that almost 70% of NSCLC patients harbor CNA of these essential OXPHOS genes. To provide mechanistic insight into these clinical observations, we have generated mouse syngeneic NSCLC cell lines with modified mRNA expression levels of OXPHOS genes (representing deletion, diploid and amplified number of copies) identified in our screen and observed a direct effect on the rates of mitochondrial oxygen consumption in vitro and hypoxia levels in vivo, leading to increased resistance to anti-cancer therapy in preclinical mouse model of NSCLC. Our study investigates the previously unknown role of OXPHOS gene copy number in driving mitochondrial oxygen demand and thus contributing to tumor hypoxia and treatment resistance in NSCLC. Citation Format: Katarina Benejova, McKenzie Kreamer, Nicholas Denko, Martin Benej. OXPHOS as a driver of treatment resistance in NSCLC? From computational analysis to preclinical validation [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 5435.