Abstract 271: MYC mediates enhanced lactate reutilization and resistance to anti-angiogenesis therapy in preclinical models of LKB1-deficient NSCLC
Authors: Qian Yu , Molkentine David , Yang Chendong , Cobo Ana Galan , Guijarro Irene , Dang Minghao , Poteete Alissa , Jiang Peixin , Skoulidis Ferdinandos , Wang Linghua , Reuben Alexandre , Minna John D. , DeBerardinis Ralph J. , Heymach John V. 
Published: April 2023

Abstract
Deletion or loss of function mutations of the STK11/LKB1 tumor suppressor are associated with primary resistance to immunotherapy in KRAS-mutant lung adenocarcinoma (LUAD) and drive metabolic reprogramming of tumor cells. We observed that LKB1-deficient tumors were resistant to anti-angiogenic therapy in the hypoxic and nutrient-depleted or acidic tumor microenvironment (TME). We determined that MYC which is elevated in LKB1-deficient cells, regulated the expression of the lactate transporter, MCT4. Moreover, knockdown of MYC decreases glycolysis and cell proliferation. Therefore, we hypothesize that metabolic changes in LKB1-deficient tumor cells is at least partially driven by MYC upregulation, and that depletion of MYC or targeting of key enzymes or transporters downstream of MYC such as MCT4 may abrogate lactate reutilization and sensitize LKB1-deficient tumors to anti-angiogenic therapy. To explore the impact of MYC on lactate metabolism in LKB1-deficient NSCLC cells, we performed isotope tracing in KRAS mutant (K) and KRAS mutant LKB1 knockout (KL) syngeneic murine lung cancer cells. 13C3-lactate tracing revealed that isotopologues were significantly enriched in TCA components such as pyruvate, citrate and a-ketoglutarate in KL cells. Meanwhile, lactate-treated KL cells shows less reactive oxygen species (ROS), suggesting that LKB1-deficient tumor cells reutilize lactate as an energy source more efficiently than LKB1-intact cells. MCT4 KO significantly abrogated lactate incorporation into TCA cycle. Similarly, MYC knockdown or MCT4 KO decreased lactate-induced oxygen consumption, but increased ROS levels. In contrast, exhausted T cells were inefficient at lactate reutilization, and high levels of lactate increased ROS in T cells. Hence, LKB1-deficient tumors have a survival advantage over T cells in the lactate-rich TME. We queried scRNAseq data from K, KL and KL MCT4KO syngeneic models and similarly observed that KL tumor cells exhibited elevated hypoxia and angiogenesis gene expression signatures, which was reversed by MCT4 KO. However, ROS detoxification was decreased in T cells from KL tumors but increased in MCT4 KO tumors. Finally, we injected KL murine tumor cells into immunocompetent mice, and randomly treated them with vehicle or the VEGF blocking antibody, DC101. MYC knockdown or MCT4 KO sensitized KL tumors to VEGF inhibition, and significantly increased overall survival. Collectively, our data indicates that in LKB1-deficient tumors, upregulation of MYC promotes tumor cell metabolic reprogramming and that targeting MYC or MCT4 can inhibit lactate reutilization and enhance the efficacy of anti-angiogenic agents. These findings provide insight into the mechanisms driving the aggressive phenotype of KRAS-mutant LKB1-deficient tumors and identify a novel therapeutic strategy for targeting this patient population.
Citation Format: Yu Qian, David Molkentine, Chendong Yang, Ana Galan Cobo, Irene Guijarro, Minghao Dang, Alissa Poteete, Peixin Jiang, Ferdinandos Skoulidis, Linghua Wang, Alexandre Reuben, John D. Minna, Ralph J. DeBerardinis, John V. Heymach. MYC mediates enhanced lactate reutilization and resistance to anti-angiogenesis therapy in preclinical models of LKB1-deficient NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 271.