Project description:The key myeloid transcription factor (TF) CEBPA is frequently mutated in acute myeloid leukemia (AML), but the molecular ramifications of this leukemic driver mutation remain elusive. To investigate CEBPA mutant AML, we compared gene expression changes in human CEBPA mutant AML and in the corresponding CebpaLp30 mouse model, and identified a conserved cross-species transcriptional program. ChIP-seq revealed aberrantly activated enhancers, exclusively occupied by the leukemia-associated CEBPA-p30 isoform. One leukemic-enhancer upstream of Nt5e, encoding CD73, was physically and functionally linked to this conserved AML gene, and could be activated by CEBPA. Targeting of CD73-adenosine signaling increased AML survival in transplanted mice. Our data indicate a first-in-class link between a TF cancer driver mutation and a druggable, direct transcriptional target.
Project description:Human histone deacetylase 3 (HDAC3) plays an important role in gene transcription in diseased human cells, such as leukemia. The t(8;21) chromosomal translocation is one of the most commonly observed genetic abnormalities associated with acute myeloid leukemia. This translocation generates the AML1-ETO fusion protein between the wild-type RUNX1 transcription factor and wild-type ETO transcriptional corepressor. To better understand the role of HDAC3 in t(8;21) leukemogenesis, the human HDAC3-containing complexes were isolated from stably-transfected HeLa cells by using anti-FLAG immunoprecipitation. The resulting complexes were resolved in SDS-PAGE. The components of the complexes were identified using LC-MS/MS. We report here that the human RUNX1 transcription is a component of the HDAC3 complexes. We demonstrate that HDAC3 and RUNX1 collaboratively repress AML1-ETO-mediated transcription. These results reveal new insight into how AML1-ETO, RUNX1, and HDAC3 crosstalk to deregulate gene transcription in t(8;21) leukemia cells.
Project description:C/EBPalpha is an important myeloid transcription factor that is inactivated in approximately 50% of acute myeloid leukemia cases. We were interested in microRNAs that are regulated by C/EBPalpha during myeloid differentiation.
Project description:Chromosomal rearrangements deregulating hematopoietic transcription factors are common leukemia-initiating lesions in acute lymphoblastic leukemia (ALL). Here, we show that deregulation of the homeobox transcription factor gene DUX4 and the ETS transcription factor gene ERG are hallmarks of a subtype of B-progenitor ALL with a distinct gene expression profile that comprises up to 7% of B-ALL. DUX4 rearrangement and overexpression is present in all cases, and is accompanied by profound transcriptional deregulation of ERG, frequent ERG deletion and expression of a truncated ERG isoform, ERGalt. ERGalt utilizes a non-canonical first exon that is bound by DUX4 and induces its expression....
