Quantitative metabolome analysis profiles activation of glutaminolysis in glioma with IDH1 mutation

Abstract

Isocitrate dehydrogenase 1 (IDH1), which localizes to the cytosol and peroxisomes, catalyzes the oxidative decarboxylation of isocitrate to α-ketoglutarate (α-KG) and in parallel converts NADP(+) to NADPH. IDH1 mutations are frequently detected in grades 2-4 gliomas and in acute myeloid leukemias (AML). Mutations of IDH1 have been identified at codon 132, with arginine being replaced with histidine in most cases. Mutant IDH1 gains novel enzyme activity converting α-KG to D-2-hydroxyglutarate (2-HG) which acts as a competitive inhibitor of α-KG. As a result, the activity of α-KG-dependent enzyme is reduced. Based on these findings, 2-HG has been proposed to be an oncometabolite. In this study, we established HEK293 and U87 cells that stably expressed IDH1-WT and IDH1-R132H and investigated the effect of glutaminase inhibition on cell proliferation with 6-diazo-5-oxo-L-norleucine (DON). We found that cell proliferation was suppressed in IDH1-R132H cells. The addition of α-KG restored cell proliferation. The metabolic features of 33 gliomas with wild type IDH1 (IDH1-WT) and with IDH1-R132H mutation were examined by global metabolome analysis using capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). We showed that the 2-HG levels were highly elevated in gliomas with IDH1-R132H mutation. Intriguingly, in gliomas with IDH1-R132H, glutamine and glutamate levels were significantly reduced which implies replenishment of α-KG by glutaminolysis. Based on these results, we concluded that glutaminolysis is activated in gliomas with IDH1-R132H mutation and that development of novel therapeutic approaches targeting activated glutaminolysis is warranted.

Cancer-associated Isocitrate Dehydrogenase 1 (IDH1) R132H Mutation and d-2-Hydroxyglutarate Stimulate Glutamine Metabolism under Hypoxia

“…IDH1 mutations have been associated with several effects on cellular metabolism. IDH1 mutation is associated with lower levels of glutamine and other metabolites in primary glioma tissues (10,11). Cancer cells expressing mutant IDH1 are dependent on glutamine and are sensitive to inhibition of glutaminase, presumably because D-2HG production drains glutamine to sensitize cells to deficiencies in the production of these metabolites (11)(12)(13).…”

“…IDH1 mutation is associated with lower levels of glutamine and other metabolites in primary glioma tissues (10,11). Cancer cells expressing mutant IDH1 are dependent on glutamine and are sensitive to inhibition of glutaminase, presumably because D-2HG production drains glutamine to sensitize cells to deficiencies in the production of these metabolites (11)(12)(13). Also, in gliomas, IDH1 mutation is associated with silencing of the lactate dehydrogenase A (LDHA) gene and decreased glycolysis (14).…”

“…12-207CV) supplemented with 25 mM glucose, 4 mM glutamine, 16 M palmitate, and 20 mM HEPES. Half of the total molar concentration of either glucose, glutamine, or palmitate was supplied as [1,[2][3][4][5][6][7][8][9][10][11][12][13] C 2 ]glucose, [U-13 C]glutamine, or [U- 13 C]palmitate, respectively. Cells were pulsed with the isotope for 24 h, either in 21% oxygen (normoxia) or in 1% oxygen (hypoxia) in a hypoxia C-Chamber (BioSpherix, Lacona, NY, Part No.…”

O6-methyl-guanine-DNA methyltransferase methylation and IDH1/2 mutation in small cell lung cancer

“…IDH catalyzes the conversion of isocitrate to α-ketoglutarate (α-KG). Mutations in the active site of IDH1 at position R132 and an analogous mutation in the IDH2 gene at position R172 have been identified (16). IDH1 catalyzes the oxidative decarboxylation of isocitrate to α-KG and in parallel converts nicotinamide adenine dinucleotide phosphate (NADP + ) to NADPH.…”

“…The 5-year survival rate of limited stage SCLC is 15% or less and the 2-year survival of extensive stage SCLC is 5. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19].5% (1,2). Temozolomide, a chemotherapeutic drug, is a suitable option for relapsed SCLC, particularly when brain metastases are present (3,4), and it has been recommended for second-line treatment of SCLC in the National Comprehensive Cancer Network guidelines (5).…”