Abstract 5393: Cancer cells surviving chemotherapy reprogram glucose and glutamine metabolism to combat oxidative stress

Therapy resistance is the leading cause of cancer-related deaths across all tumor types. Our group has discovered a novel resistance mechanism where cancer cells enter a reversible non-proliferative state in response to chemotherapy. These cells exhibit a 40-fold increase in cell size and an increase in DNA content when compared to their proliferative counterparts. Cells surviving in this state eventually produce progeny that can repopulate the tumor, modeling cancer recurrence. This resistant phenotype has been reported in cell culture, pre-clinical mouse models, and in human patients. The surviving cells exhibited increased levels of reactive oxygen species (ROS) when compared to the untreated parental controls. It is well known that ROS is produced during oxidative metabolism, and cancer cells utilize a variety of mechanisms to neutralize oxidative radicals. Metabolic reprogramming is one of the main responses to oxidative stress, where cancer cells can better obtain resources from the extracellular environment and repurpose them to replenish their antioxidant defense systems. We hypothesize that cancer cells surviving in this non-proliferative state in response to cisplatin treatment alter their metabolism of major carbon sources to fuel antioxidant-generating pathways. Cells surviving chemotherapy exhibited an increase in glucose and glutamine consumption, but a decrease in lactate excretion and an increase in glutamate excretion when compared to the untreated parental population. We performed parallel labeling experiments with a variety of 13C glucose and glutamine tracers to investigate how these carbon sources are broken down. We observed that surviving cells utilize glucose to fuel the pentose phosphate pathway (PPP), which is one of the major pathways to generate NADPH for ROS detoxification, rather than breaking it down through glycolysis. In addition, surviving cells exhibited decreased glutamine metabolism into the TCA cycle when compared to the parental cells. Thus, we hypothesize that cells surviving chemotherapy are consuming glutamine to generate glutamate for excretion. Single cell RNA sequencing data demonstrated that surviving cells exhibit an enrichment in NRF2 target genes such as SLC7A11, which encodes for a cystine-glutamate antiporter (system Xc) that exchanges glutamate for cystine, a major component in glutathione biosynthesis to combat oxidative stress. We are further characterizing these changes with mathematical modeling-based 13C-metabolic flux analysis. Additionally, we are currently testing if cells surviving chemotherapy are susceptible to PPP and system Xc inhibitors. Our goal is to identify mechanisms of how cells in this resistant state reprogram their metabolism to survive therapeutic stress. Leveraging these key findings will provide insight for better treatment of therapy-resistant cancers and improve patient outcomes. Citation Format: Melvin Li, Luke V. Loftus, Sarah R. Amend, Kenneth J. Pienta. Cancer cells surviving chemotherapy reprogram glucose and glutamine metabolism to combat oxidative stress [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 5393.