Journal Article

Metabolic requirement for GOT2 in pancreatic cancer depends on environmental context

Long, Daniel, Lyssiotis, Costas A, Ackenhusen, Sarah E, Gao, Xiaohua, Robinson, Anthony, Sutton, Damien J, Pasca di Magliano, Marina, Crawford, Howard C, Lin, Lin, Sajjakulnukit, Peter, Hoffman, Megan T, Zhang, Yaqing, Myers, Amy L, Andren, Anthony, Steele, Nina G, Lombard, David B, Wen, Hui-Ju, Kemp, Samantha B, Nwosu, Zeribe C, Jiménez, Jennifer A, Nelson, Barbara S, Thurston, Galloway, Zhang, Li, Ying, Haoqiang, Kerk, Samuel A, Ramos, Johanna, Piwnica-Worms, David R, Galban, Stefanie, Chen, Brandon, Shah, Yatrik M, Halbrook, Christopher J

2022

Overview

Mitochondrial glutamate-oxaloacetate transaminase 2 (GOT2) is part of the malate-aspartate shuttle, a mechanism by which cells transfer reducing equivalents from the cytosol to the mitochondria. GOT2 is a key component of mutant KRAS (KRAS*)-mediated rewiring of glutamine metabolism in pancreatic ductal adenocarcinoma (PDA). Here, we demonstrate that the loss of GOT2 disturbs redox homeostasis and halts proliferation of PDA cells in vitro. GOT2 knockdown (KD) in PDA cell lines in vitro induced NADH accumulation, decreased Asp and α-ketoglutarate (αKG) production, stalled glycolysis, disrupted the TCA cycle, and impaired proliferation. Oxidizing NADH through chemical or genetic means resolved the redox imbalance induced by GOT2 KD, permitting sustained proliferation. Despite a strong in vitro inhibitory phenotype, loss of GOT2 had no effect on tumor growth in xenograft PDA or autochthonous mouse models. We show that cancer-associated fibroblasts (CAFs), a major component of the pancreatic tumor microenvironment (TME), release the redox active metabolite pyruvate, and culturing GOT2 KD cells in CAF conditioned media (CM) rescued proliferation in vitro. Furthermore, blocking pyruvate import or pyruvate-to-lactate reduction prevented rescue of GOT2 KD in vitro by exogenous pyruvate or CAF CM. However, these interventions failed to sensitize xenografts to GOT2 KD in vivo, demonstrating the remarkable plasticity and differential metabolism deployed by PDA cells in vitro and in vivo. This emphasizes how the environmental context of distinct pre-clinical models impacts both cell-intrinsic metabolic rewiring and metabolic crosstalk with the TME.

• Publisher: eLife Science Publications, Ltd,eLife Sciences Publications Ltd,eLife Sciences Publications, Ltd
• Subject: Adenocarcinoma / Analysis / Animal models / Animals / Aspartate / Aspartate Aminotransferase, Mitochondrial - genetics / Aspartate Aminotransferase, Mitochondrial - metabolism / Biochemistry and Chemical Biology / Cancer Biology / Carcinoma, Pancreatic Ductal - pathology / Cell culture / Cell proliferation / Cytosol / Enzymes / Fatty Acid-Binding Proteins / Fibroblasts / Glutamate / Glutamine / Glycolysis / Homeostasis / Humans / Instrument industry / International economic relations / Ketoglutaric acid / Lactates / Lactic acid / Metabolism / Metabolites / Mice / Mitochondria / NAD - metabolism / Pancreatic cancer / Pancreatic Neoplasms / Pancreatic Neoplasms - pathology / Phenotypes / Physiological aspects / Proto-Oncogene Proteins p21(ras) - metabolism / Pyruvic acid / Pyruvic Acid - metabolism / Transaminase / Tricarboxylic acid cycle / tumor metabolism / Tumor Microenvironment / Tumors / Xenografts