BCAT1 restricts αKG levels in AML stem cells leading to IDHmut-like DNA hypermethylation

Research output: Contribution to journalArticle

Abstract

The branched-chain amino acid (BCAA) pathway and high levels of BCAA transaminase 1 (BCAT1) have recently been associated with aggressiveness in several cancer entities. However, the mechanistic role of BCAT1 in this process remains largely uncertain. Here, by performing high-resolution proteomic analysis of human acute myeloid leukaemia (AML) stem-cell and non-stem-cell populations, we find the BCAA pathway enriched and BCAT1 protein and transcripts overexpressed in leukaemia stem cells. We show that BCAT1, which transfers α-amino groups from BCAAs to α-ketoglutarate (αKG), is a critical regulator of intracellular αKG homeostasis. Further to its role in the tricarboxylic acid cycle, αKG is an essential cofactor for αKG-dependent dioxygenases such as Egl-9 family hypoxia inducible factor 1 (EGLN1) and the ten-eleven translocation (TET) family of DNA demethylases. Knockdown of BCAT1 in leukaemia cells caused accumulation of αKG, leading to EGLN1-mediated HIF1α protein degradation. This resulted in a growth and survival defect and abrogated leukaemia-initiating potential. By contrast, overexpression of BCAT1 in leukaemia cells decreased intracellular αKG levels and caused DNA hypermethylation through altered TET activity. AML with high levels of BCAT1 (BCAT1high) displayed a DNA hypermethylation phenotype similar to cases carrying a mutant isocitrate dehydrogenase (IDHmut), in which TET2 is inhibited by the oncometabolite 2-hydroxyglutarate. High levels of BCAT1 strongly correlate with shorter overall survival in IDHWTTET2WT, but not IDHmut or TET2mut AML. Gene sets characteristic for IDHmut AML were enriched in samples from patients with an IDHWTTET2WTBCAT1high status. BCAT1high AML showed robust enrichment for leukaemia stem-cell signatures, and paired sample analysis showed a significant increase in BCAT1 levels upon disease relapse. In summary, by limiting intracellular αKG, BCAT1 links BCAA catabolism to HIF1α stability and regulation of the epigenomic landscape, mimicking the effects of IDH mutations. Our results suggest the BCAA-BCAT1-αKG pathway as a therapeutic target to compromise leukaemia stem-cell function in patients with IDHWTTET2WT AML.

Details

Authors
  • Simon Raffel
  • Mattia Falcone
  • Niclas Kneisel
  • Wei Wang
  • Christoph Lutz
  • Lars Bullinger
  • Gernot Poschet
  • Yannic Nonnenmacher
  • Andrea Barnert
  • Carsten Bahr
  • Petra Zeisberger
  • Adriana Przybylla
  • Markus Sohn
  • Martje Tönjes
  • Ayelet Erez
  • Lital Adler
  • Patrizia Jensen
  • Claudia Scholl
  • Stefan Fröhling
  • Sibylle Cocciardi
  • Patrick Wuchter
  • Christian Thiede
  • Anne Flörcken
  • Jörg Westermann
  • Gerhard Ehninger
  • Peter Lichter
  • Karsten Hiller
  • Rüdiger Hell
  • Carl Herrmann
  • Anthony D Ho
  • Jeroen Krijgsveld
  • Bernhard Radlwimmer
  • Andreas Trumpp
Organisations
External organisations
  • University Hospital Heidelberg
  • German Cancer Research Centre
  • European Molecular Biology Laboratory Heidelberg
  • University Hospital of Ulm
  • Heidelberg University
  • University of Luxembourg
  • Weizmann Institute of Science Israel
  • University Hospital Carl Gustav Carus
  • Charité Universitätsmedizin Berlin
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Cell and Molecular Biology

Keywords

  • Amino Acids, Branched-Chain, Animals, Cell Proliferation, DNA Methylation, DNA-Binding Proteins, Epistasis, Genetic, Female, Humans, Hypoxia-Inducible Factor 1, alpha Subunit, Hypoxia-Inducible Factor-Proline Dioxygenases, Isocitrate Dehydrogenase, Ketoglutaric Acids, Leukemia, Myeloid, Acute, Mice, Molecular Targeted Therapy, Mutation, Neoplastic Stem Cells, Prognosis, Proteolysis, Proteomics, Proto-Oncogene Proteins, Transaminases, Journal Article, Research Support, U.S. Gov't, Non-P.H.S.
Original languageEnglish
Pages (from-to)384-388
Number of pages5
JournalNature
Volume551
Issue number7680
Publication statusPublished - 2017 Nov 16
Publication categoryResearch
Peer-reviewedYes