| Literature DB >> 29144447 |
Simon Raffel1,2,3, Mattia Falcone1,2, Niclas Kneisel4, Jenny Hansson5, Wei Wang4, Christoph Lutz3, Lars Bullinger6, Gernot Poschet7, Yannic Nonnenmacher8,9, Andrea Barnert1,2, Carsten Bahr1,2, Petra Zeisberger1,2, Adriana Przybylla1,2, Markus Sohn1,2, Martje Tönjes4, Ayelet Erez10, Lital Adler10, Patrizia Jensen11, Claudia Scholl12,13, Stefan Fröhling11,14,13, Sibylle Cocciardi6, Patrick Wuchter3,15, Christian Thiede16, Anne Flörcken17, Jörg Westermann17, Gerhard Ehninger17, Peter Lichter4,13, Karsten Hiller8,9, Rüdiger Hell7, Carl Herrmann18,19, Anthony D Ho3, Jeroen Krijgsveld5, Bernhard Radlwimmer4,13, Andreas Trumpp1,2,13.
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.Entities:
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Year: 2017 PMID： 29144447 DOI： 10.1038/nature24294
Source DB: PubMed Journal: Nature ISSN： 0028-0836 Impact factor: 49.962