title: 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.
authors.affiliation: Department of Neurosurgery, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan, fohka@med.nagoya-u.ac.jp.
authors.forename: Fumiharu
authors.initials: F
authors.lastname: Ohka
authors.forename: Maki
authors.initials: M
authors.lastname: Ito
authors.forename: Melissa
authors.initials: M
authors.lastname: Ranjit
authors.forename: Takeshi
authors.initials: T
authors.lastname: Senga
authors.forename: Ayako
authors.initials: A
authors.lastname: Motomura
authors.forename: Kazuya
authors.initials: K
authors.lastname: Motomura
authors.forename: Kaori
authors.initials: K
authors.lastname: Saito
authors.forename: Keiko
authors.initials: K
authors.lastname: Kato
authors.forename: Yukinari
authors.initials: Y
authors.lastname: Kato
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Wakabayashi
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Soga
authors.forename: Atsushi
authors.initials: A
authors.lastname: Natsume
mesh_terms: D001932:Brain Neoplasms / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D003606:Dacarbazine / Q000031:analogs & derivatives / Q000494:pharmacology; D005910:Glioma / Q000235:genetics* / Q000378:metabolism; D005972:Glutaminase / Q000037:antagonists & inhibitors; D005973:Glutamine / Q000378:metabolism*; D005977:Glutarates / Q000032:analysis; D057809:HEK293 Cells; D006801:Humans; D007521:Isocitrate Dehydrogenase / Q000235:genetics*; D007656:Ketoglutaric Acids / Q000494:pharmacology; D055442:Metabolome; D009154:Mutation; D000077204:Temozolomide
chemical_list: D005977:Glutarates; D007656:Ketoglutaric Acids; D005973:Glutamine; C019417:alpha-hydroxyglutarate; D003606:Dacarbazine; D007521:Isocitrate Dehydrogenase; C543588:IDH1 protein, human; D005972:Glutaminase; D000077204:Temozolomide