Cancer-associated Isocitrate Dehydrogenase Mutations Inactivate NADPH-dependent Reductive Carboxylation

Leonardi, Roberta; Subramanian, Chitra; Jackowski, Suzanne; Rock, Charles O.

doi:10.1074/jbc.c112.353946

Cited by 150 publications

(146 citation statements)

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“…3a). Employing previously reported reaction conditions with Tris-based buffers 31 , we detected substantial non-enzymatic production of 2HG that was equally distributed as D- and L- enantiomers (Supplementary Fig. 6).…”

Section: Resultsmentioning

confidence: 64%

L-2-Hydroxyglutarate production arises from noncanonical enzyme function at acidic pH

et al. 2017

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The metabolite 2-hydroxyglutarate (2HG) can be produced as either a D(R)- or L(S)- enantiomer, each of which inhibits alpha-ketoglutarate (αKG)-dependent enzymes involved in diverse biologic processes. Oncogenic mutations in isocitrate dehydrogenase produce D-2HG, which causes a pathologic blockade in cell differentiation. On the other hand, oxygen limitation leads to accumulation of L-2HG, which can facilitate physiologic adaptation to hypoxic stress in both normal and malignant cells. Here we demonstrate that purified lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) catalyze stereospecific production of L-2HG via ‘promiscuous’ reduction of the alternative substrate αKG. Acidic pH enhances production of L-2HG by promoting a protonated form of αKG that binds to a key residue in the substrate-binding pocket of LDHA. Acid-enhanced production of L-2HG leads to stabilization of hypoxia-inducible factor 1 alpha (HIF-1α) in normoxia. These findings offer insights into mechanisms whereby microenvironmental factors influence production of metabolites that alter cell fate and function.

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Section: Resultsmentioning

confidence: 64%

L-2-Hydroxyglutarate production arises from noncanonical enzyme function at acidic pH

et al. 2017

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“…Previous studies have demonstrated that IDH1 R132H human gliomas maintain normal concentrations of α-KG but have not identified a mechanism that compensates for diverted flux of α-KG into 2-HG (8,9,18,19). In human tumors, mutations in IDH1 and IDH2 are mutually exclusive and invariably heterozygous (7).…”

Section: Idh1mentioning

confidence: 99%

Hominoid-specific enzyme GLUD2 promotes growth of IDH1 ^R132H glioma

Chen¹,

Nishimura²,

Kharbanda³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Somatic mutation of isocitrate dehydrogenase 1 (IDH1) is now recognized as the most common initiating event for secondary glioblastoma, a brain tumor type arising with high frequency in the frontal lobe. A puzzling feature of IDH1 mutation is the selective manifestation of glioma as the only neoplasm frequently associated with early postzygotic occurrence of this genomic alteration. We report here that IDH1 R132H exhibits a growth-inhibitory effect that is abrogated in the presence of glutamate dehydrogenase 2 (GLUD2), a hominoid-specific enzyme purportedly optimized to facilitate glutamate turnover in human forebrain. Using murine glioma progenitor cells, we demonstrate that IDH1R132H exerts a growth-inhibitory effect that is paralleled by deficiency in metabolic flux from glucose and glutamine to lipids. Examining human gliomas, we find that glutamate dehydrogenase 1 (GLUD1) and GLUD2 are overexpressed in IDH1-mutant tumors and that orthotopic growth of an IDH1-mutant glioma line is inhibited by knockdown of GLUD1/2. Strikingly, introduction of GLUD2 into murine glioma progenitor cells reverses deleterious effects of IDH1 mutation on metabolic flux and tumor growth. Further, we report that glutamate, a substrate of GLUD2 and a neurotransmitter abundant in mammalian neocortex, can support growth of glioma progenitor cells irrespective of IDH1 mutation status. These findings suggest that specialization of human neocortex for high glutamate neurotransmitter flux creates a metabolic niche conducive to growth of IDH1 mutant tumors.tumor metabolism | astrocytoma | oligodendroglioma

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“…Mutant mice overexpressing IDH1 in liver and adipose tissue are obese, have fatty livers, and show elevated plasma triglycerides (TG) and cholesterol (7). In tumor cells, IDH1 contributes to de novo lipogenesis by generating acetyl-CoA building blocks via the NADPH-dependent reductive carboxylation of α-KG to isocitrate (8)(9)(10)(11). However, IDH1-null mice at steady-state are healthy and fertile, maintain normal body weight, and show no inflammatory symptoms (12).…”

mentioning

confidence: 99%

IDH1 deficiency attenuates gluconeogenesis in mouse liver by impairing amino acid utilization

Zhang

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Although the enzymatic activity of isocitrate dehydrogenase 1 (IDH1) was defined decades ago, its functions in vivo are not yet fully understood. Cytosolic IDH1 converts isocitrate to α-ketoglutarate (α-KG), a key metabolite regulating nitrogen homeostasis in catabolic pathways. It was thought that IDH1 might enhance lipid biosynthesis in liver or adipose tissue by generating NADPH, but we show here that lipid contents are relatively unchanged in both IDH1-null mouse liver and IDH1-deficient HepG2 cells generated using the CRISPR-Cas9 system. Instead, we found that IDH1 is critical for liver amino acid (AA) utilization. Body weights of IDH1-null mice fed a high-protein diet (HPD) were abnormally low. After prolonged fasting, IDH1-null mice exhibited decreased blood glucose but elevated blood alanine and glycine compared with wildtype (WT) controls. Similarly, in IDH1-deficient HepG2 cells, glucose consumption was increased, but alanine utilization and levels of intracellular α-KG and glutamate were reduced. In IDH1-deficient primary hepatocytes, gluconeogenesis as well as production of ammonia and urea were decreased. In IDH1-deficient whole livers, expression levels of genes involved in AA metabolism were reduced, whereas those involved in gluconeogenesis were up-regulated. Thus, IDH1 is critical for AA utilization in vivo and its deficiency attenuates gluconeogenesis primarily by impairing α-KG-dependent transamination of glucogenic AAs such as alanine.isocitrate dehydrogenase 1 | α-ketoglutarate | gluconeogenesis | transamination | liver I socitrate dehydrogenases (IDH) convert isocitrate to α-ketoglutarate (α-KG) by reducing NADP + or NAD + . The recent discovery of IDH1 and IDH2 mutations in human cancers (1-4) has elicited new interest in defining IDH1's functions in vivo, which are still poorly understood. IDH1 is abundant in liver and was reported to participate in lipid biosynthesis in hepatocyte cytoplasm and peroxisomes (5, 6). Mutant mice overexpressing IDH1 in liver and adipose tissue are obese, have fatty livers, and show elevated plasma triglycerides (TG) and cholesterol (7). In tumor cells, IDH1 contributes to de novo lipogenesis by generating acetyl-CoA building blocks via the NADPH-dependent reductive carboxylation of α-KG to isocitrate (8-11). However, IDH1-null mice at steady-state are healthy and fertile, maintain normal body weight, and show no inflammatory symptoms (12).The liver maintains normal blood glucose levels through glycogenolysis and gluconeogenesis. Gluconeogenesis generates glucose from noncarbohydrate carbon substrates such as pyruvate, lactate, glycerol, and glucogenic amino acids (AAs). During prolonged fasting, the breakdown of skeletal muscle generates limited carbon resources in the form of AAs such as alanine. Hence, both fasting and feeding of a high-protein diet (HPD) can stimulate AA deamination and urea production in the liver (13), where AA carbon skeletons are converted into glucose or lipids. For most AAs, the amino group is transferred to α-KG to generate glutama...

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Cancer-associated Isocitrate Dehydrogenase Mutations Inactivate NADPH-dependent Reductive Carboxylation

Abstract: Background:Reductive carboxylation by isocitrate dehydrogenase (IDH) is required for hypoxic growth, and IDH mutations are associated with cancer. Results: Reductive carboxylation by IDH is inhibited by NADP ϩ and isocitrate and inactivated by cancer-associated mutations.

Cited by 150 publications

References 30 publications

L-2-Hydroxyglutarate production arises from noncanonical enzyme function at acidic pH

L-2-Hydroxyglutarate production arises from noncanonical enzyme function at acidic pH

Hominoid-specific enzyme GLUD2 promotes growth of IDH1 ^R132H glioma

IDH1 deficiency attenuates gluconeogenesis in mouse liver by impairing amino acid utilization

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Cancer-associated Isocitrate Dehydrogenase Mutations Inactivate NADPH-dependent Reductive Carboxylation

Abstract: Background:Reductive carboxylation by isocitrate dehydrogenase (IDH) is required for hypoxic growth, and IDH mutations are associated with cancer. Results: Reductive carboxylation by IDH is inhibited by NADP ϩ and isocitrate and inactivated by cancer-associated mutations.

Cited by 150 publications

References 30 publications

L-2-Hydroxyglutarate production arises from noncanonical enzyme function at acidic pH

L-2-Hydroxyglutarate production arises from noncanonical enzyme function at acidic pH

Hominoid-specific enzyme GLUD2 promotes growth of IDH1 R132H glioma

IDH1 deficiency attenuates gluconeogenesis in mouse liver by impairing amino acid utilization

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Hominoid-specific enzyme GLUD2 promotes growth of IDH1 ^R132H glioma