D-2-Hydroxyglutarate producing neo-enzymatic activity inversely correlates with frequency of the type of isocitrate dehydrogenase 1 mutations found in glioma

Acta Neuropathol Commun. 2014 Feb 14:2:19. doi: 10.1186/2051-5960-2-19.

Abstract

Background: IDH mutations frequently occur in diffuse gliomas and result in a neo-enzymatic activity that results in reduction of α-ketoglutarate to D-2-hydroxyglutarate. In gliomas, the frequency of IDH1 mutations in codon 132 increases in the order R132L-R132S-R132G-R132C-R132H with R132H constituting more than 90% of all IDH1 mutations.

Results: We determined the levels of D-2-hydroxyglutarate in glioma tissues with IDH1 mutations. D-2-hydroxyglutarate levels increased in the order of R132H-R132C-R132S/R132G/R132L. We expressed and purified IDH1 wild type and mutant protein for biochemical characterization. Enzyme kinetics of mutant IDH protein correlated well with D-2-hydroxyglutarate production in cells with R132H exhibiting the highest and R132L the lowest KM for α-ketoglutarate. Addition of D-2-hydroxyglutarate to the medium of cell lines revealed an inhibitory effect at higher concentrations. Migration of LN229 increased at lower D-2-hydroxyglutarate concentrations while higher concentrations showed no effect.

Conclusion: These findings may suggest natural selection against the rare IDH1R132 mutations in human glioma due to toxicity caused by high levels of D-2-hydroxyglutarate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brain Neoplasms / genetics*
  • Brain Neoplasms / metabolism
  • Cell Movement / genetics
  • Cell Survival / genetics
  • Glioma / genetics*
  • Glioma / metabolism
  • Glutarates / metabolism*
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • HEK293 Cells
  • Humans
  • Isocitrate Dehydrogenase / genetics*
  • Isocitrate Dehydrogenase / metabolism
  • Mutagenesis / genetics
  • Mutant Proteins
  • Mutation / genetics*
  • Transfection
  • Tumor Stem Cell Assay

Substances

  • Glutarates
  • Mutant Proteins
  • Green Fluorescent Proteins
  • alpha-hydroxyglutarate
  • Isocitrate Dehydrogenase
  • IDH1 protein, human