Abstract 1538: Impact of MCT1 inhibition on NSCLC metabolism and sensitivity to therapy

Abstract Introduction: Despite the advent of targeted therapies, prognosis of lung of non-small cell lung cancer (NSCLC) remains poor. Thus, identifying metabolic programs in aggressive disease may allow for the development of novel treatment strategies. Prior work in early-stage NSCLC has demonstrated that lactate import via monocarboxylate transporter 1 (MCT1) is associated with higher recurrence and mortality. However, the potential for targeting MCT1 in treatment efficacy and resistance remains unknown. Methods: NSCLC cells were cultured in standard RPMI or, to better model in vivo metabolism, human plasma-like media (HPLM). MCT1 was inhibited genetically (CRISPR-KO) or pharmacologically (AZD3965). Isotope tracing experiments were performed using [U-13C]glucose or [U-13C]lactate. DNA damage was assessed via the protein expression of γH2AX. MCT1 inhibition was combined with pemetrexed, and cell viability/cell death was measured using annexin V/propidium iodide. Combinatorial/synergy effects were assessed using synergyfinderplus.org. Results: H1299 cells incorporate lactate into tricarboxylic acid cycle (TCA) intermediates in both standard and physiologic culture media. Lactate incorporation into the TCA was decreased by treatment with AZD3965. Both genetic and pharmacologic inhibition of MCT1 increased the expression of the DNA damage marker γH2AX. Following 24 hours of pemetrexed treatment, pemetrexed alone significantly decreased cell viability in RPMI but not HPLM. The addition of AZD3965 decreased cell viability in both conditions, but decreases were less pronounced in HPLM cultured cells. In both media conditions, combinatorial dosing of AZD3965 and pemetrexed led to increases in cell death, and these were more pronounced at increasing doses of AZD3965. AZD3965 did not confer additional cytotoxic effect to cells treated with paclitaxel. Conclusions: MCT1 inhibition decreases lactate import and oxidation in vitro and causes DNA damage to enhance the cytotoxic effects of pemetrexed. Metabolic reprogramming in NSCLC leads to the use of alternate carbon sources, such as lactate, and this can be modeled in both standard and physiologic culture conditions. Notably, this does not appear to be a general sensitization to cell death. Further studies are ongoing to identify the metabolic underpinnings of these effects and how they translate to in vivo systems. Citation Format: Robert Cameron, Massar Alsamraae, Maia G. Clare, Nia G. Hammond, Christine Bestvina, Marina Chiara Garassino, Brandon Faubert. Impact of MCT1 inhibition on NSCLC metabolism and sensitivity to therapy [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 1538.