Epigenetic regulation of protein translation in KMT2A-rearranged AML.
Exp Hematol
; 85: 57-69, 2020 05.
Article
em En
| MEDLINE
| ID: mdl-32437908
ABSTRACT
Inhibition of the H3K79 histone methyltransferase DOT1L has exhibited encouraging preclinical and early clinical activity in KMT2A (MLL)-rearranged leukemia, supporting the development of combinatorial therapies. Here, we investigated two novel combinations dual inhibition of the histone methyltransferases DOT1L and EZH2, and the combination with a protein synthesis inhibitor. EZH2 is the catalytic subunit in the polycomb repressive complex 2 (PRC2), and inhibition of EZH2 has been reported to have preclinical activity in KMT2A-r leukemia. When combined with DOT1L inhibition, however, we observed both synergistic and antagonistic effects. Interestingly, antagonistic effects were not due to PRC2-mediated de-repression of HOXA9. HOXA cluster genes are key canonical targets of both KMT2A and the PRC2 complex. The independence of the HOXA cluster from PRC2 repression in KMT2A-r leukemia thus affords important insights into leukemia biology. Further studies revealed that EZH2 inhibition counteracted the effect of DOT1L inhibition on ribosomal gene expression. We thus identified a previously unrecognized role of DOT1L in regulating protein production. Decreased translation was one of the earliest effects measurable after DOT1L inhibition and specific to KMT2A-rearranged cell lines. H3K79me2 chromatin immunoprecipitation sequencing patterns over ribosomal genes were similar to those of the canonical KMT2A-fusion target genes in primary AML patient samples. The effects of DOT1L inhibition on ribosomal gene expression prompted us to evaluate the combination of EPZ5676 with a protein translation inhibitor. EPZ5676 was synergistic with the protein translation inhibitor homoharringtonine (omacetaxine), supporting further preclinical/clinical development of this combination. In summary, we discovered a novel epigenetic regulation of a metabolic process-protein synthesis-that plays a role in leukemogenesis and affords a combinatorial therapeutic opportunity.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Biossíntese de Proteínas
/
Rearranjo Gênico
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Leucemia Mieloide Aguda
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Regulação Leucêmica da Expressão Gênica
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Epigênese Genética
Limite:
Humans
Idioma:
En
Revista:
Exp Hematol
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Panamá