Dependence on Myb expression is attenuated in myeloid leukemia with N-terminal CEBPA mutations
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA488821 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR7775320.fastq.gz | Fastqsanger.gz | |||
| SRR7775330.fastq.gz | Fastqsanger.gz | |||
| SRR7775321.fastq.gz | Fastqsanger.gz | |||
| SRR7775331.fastq.gz | Fastqsanger.gz | |||
| SRR7775322.fastq.gz | Fastqsanger.gz |
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Project description:Mutations altering the normal function of C/EBPα are frequent in acute myeloid leukaemia with normal karyotype. MYB, a cooperating partner of C/EBPα, is likewise heavily implicated in AML. Here we investigate how the relative requirement for the transcription factor MYB in AML relates to the particular combinations of wild type and mutated alleles of CEBPA. Through knockdown of Myb in murine cell lines modelling the spectrum of CEBPA mutations we show that the consequences of reduced Myb depend on the mutational status of Cebpa. Importantly, Myb knockdown fails to override the block in myeloid differentiation in cells with biallelic N-terminal C/EBPα mutations, demonstrating for the first time that the dependency on Myb observed in AML is much lower in leukaemia with this combination of mutations. By comparing genome-wide analyses of gene expression following Myb knockdown and ChIP-seq data for the binding of C/EBPα isoforms, we provide evidence for a functional cooperation between C/EBPα and Myb in the maintenance of the leukaemia state. This co-dependency breaks down when both alleles of CEBPA harbour N-terminal mutations, as a subset of C/EBPα-regulated genes only bind the short p30 C/EBPα isoform and, unlike other C/EBPα regulated genes, do so without a requirement for Myb.
2019-03-13 | GSE119348 | GEO
Project description:Mutations at the N- or C-terminus of C/EBPα are frequent in acute myeloid leukaemia (AML) with normal karyotype. Here, we investigate the role of the transcription factor Myb in AMLs driven by different combinations of CEBPA mutations. Using knockdown of Myb in murine cell lines modelling the spectrum of CEBPA mutations, we show that the effect of reduced Myb depends on the mutational status of the two Cebpa alleles. Importantly, Myb knockdown fails to override the block in myeloid differentiation in cells with biallelic N-terminal C/EBPα mutations, demonstrating for the first time that the dependency on Myb is much lower in AML with this mutational profile. By comparing gene expression following Myb knockdown and chromatin immunoprecipitation sequencing data for the binding of C/EBPα isoforms, we provide evidence for a functional cooperation between C/EBPα and Myb in the maintenance of AML. This co-dependency breaks down when both alleles of CEBPA harbour N-terminal mutations, as a subset of C/EBPα-regulated genes only bind the short p30 C/EBPα isoform and, unlike other C/EBPα-regulated genes, do so without a requirement for Myb.
| S-EPMC6421631 | biostudies-literature
Project description:Earlier we have shown important roles of MYB in pancreatic tumor pathobiology. To better understand the role of MYB in the tumor microenvironment and identify MYB-associated secreted biomarker proteins, we conducted mass spectrometry analysis of the secretome from MYB-modulated and control pancreatic cancer cell lines. We also performed in silico analyses to determine MYB-associated biofunctions, gene networks and altered biological pathways. We further investigated the secreted proteins for their potential biomarker properties.
2021-09-08 | PXD015126 | Pride
Project description:Most E2F-binding sites repress transcription through the recruitment of Retinoblasoma (RB) family members until the end of the G1 cell-cycle phase. Although the MYB promoter contains an E2F-binding site, its transcription is activated shortly after the exit from quiescence, before RB family members inactivation, by unknown mechanisms. We had previously uncovered a nuclear factor distinct from E2F, Myb-sp, whose DNA-binding site overlapped the E2F element and had hypothesized that this factor might overcome the transcriptional repression of MYB by E2F-RB family members. We have purified Myb-sp and discovered that Myc-associated zinc finger proteins (MAZ) are major components. We show that various MAZ isoforms are present in Myb-sp and activate transcription via the MYB-E2F element. Moreover, while forced RB or p130 expression repressed the activity of a luciferase reporter driven by the MYB-E2F element, co-expression of MAZ proteins not only reverted repression, but also activated transcription. Finally, we show that MAZ binds the MYB promoter in vivo, that its binding site is critical for MYB transactivation, and that MAZ knockdown inhibits MYB expression during the exit from quiescence. Together, these data indicate that MAZ is essential to bypass MYB promoter repression by RB family members and to induce MYB expression.
2017-10-04 | PXD006857 | Pride
Project description:The transcriptional activities of c-Myb and its oncogenic variant v-Myb were compared by expressing them in primary human monocytes using recombinant adenovirus vectors. All the samples were compared to cells infected with a control adenovirus expressing only GFP. The results showed that v-Myb, which differs from c-Myb only by N- and C-terminal deletions and eleven amino acid substitutions, has a qualitatively different transcriptional activity. Experiment Overall Design: 2 replicates of each type were analyzed. Replicates were performed independently, more than a week apart.
2007-12-12 | E-GEOD-2816 | biostudies-arrayexpress
Project description:The transcriptional activities of c-Myb and its oncogenic variant v-Myb were compared by expressing them in human MCF7 cells using recombinant adenovirus vectors. A hybrid construct, 3Mutc, which is a variant of c-Myb harboring three v-Myb-derived DNA binding domain mutations was also analyzed. All the samples were compared to cells infected with a control adenovirus. The results showed that v-Myb, which differs from c-Myb only by N- and C-terminal deletions and eleven amino acid substitutions, has a qualitatively different transcriptional activity. Experiment Overall Design: 2 replicates of each type were analyzed. Replicates were performed independently, more than a week apart.
2007-12-12 | E-GEOD-2815 | biostudies-arrayexpress
Project description:The c-Myb transcription factor is highly expressed in immature hematopoietic cells and down-regulated during differentiation. To define the role of c-Myb during the terminal differentiation of hematopoietic precursors, we studied the effects of its silencing in human primary CD14-myeloblasts, which maintain a granulo-monocyte differentiation bipotentiality. c-Myb-silenced myeloblasts were blocked in the G1 phase of the cell cycle at 24 hours post-nucleofection and subsequently were forced towards macrophage differentiation, as demonstrated by immunophenotypic and morphological analysis. Indeed, c-Myb-silenced CD14- cells differentiate to macrophage even after the treatment with ATRA 10-6 M, demonstrating that the c-Myb knockdown strongly impairs the ability of myeloblasts to differentiate to granulocytes. Gene expression profiling of c-Myb-silenced CD14- cells identified some potential c-Myb targets that can account for these effects.
2010-07-14 | GSE21943 | GEO
Project description:Aberrant gene expression is a hallmark of acute leukemias. However, therapeutic strategies for its blockade are generally lacking, in large part due to the pharmacologic challenges of drugging transcription factors. MYB-driven gene trans-activation with CREB-binding protein (CBP) is required for the initiation and maintenance of a variety of acute lymphoblastic and myeloid leukemias, including refractory MLL-rearranged leukemias. Using structure-guided molecular design, we developed a prototypical peptidomimetic inhibitor MYBMIM that interferes with the assembly of the molecular MYB:CBP complex at ¼M concentrations and rapidly accumulates in the nuclei of AML cells. We found that treatment of AML cells with MYBMIM, but not with its inactive near-isosteric analogue TG3, led to the displacement and dissociation of MYB:CBP complex in cells, displacement of MYB from oncogenic enhancers and promoters enriched for MYB binding sites, and rapid downregulation of MYB-dependent gene expression, including of MYC and BCL2 oncogenes. Both human MLL-rearranged and non-rearranged AML cells, but not normal CD34+ umbilical cord blood progenitor cells, underwent sustained mitochondrial apoptosis in response to MYBMIM treatment, an effect that could be partially rescued by ectopic expression of BCL2. We observed that MYBMIM treatment impeded leukemia growth and extended survival of immunodeficient mice engrafted with primary patient-derived MLL-rearranged leukemia cells. These findings emphasize the exquisite dependence of human AML on MYB:CBP transcriptional dysregulation, and establish a pharmacologic approach for its therapeutic blockade.
2018-02-23 | GSE94240 | GEO
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.
2019-08-08 | PXD011359 | Pride
Project description:The c-Myb transcription factor is highly expressed in immature hematopoietic cells and down-regulated during differentiation. To define the role of c-Myb during the terminal differentiation of hematopoietic precursors, we studied the effects of its silencing in human primary CD14-myeloblasts, which maintain a granulo-monocyte differentiation bipotentiality. c-Myb-silenced myeloblasts were blocked in the G1 phase of the cell cycle at 24 hours post-nucleofection and subsequently were forced towards macrophage differentiation, as demonstrated by immunophenotypic and morphological analysis. Indeed, c-Myb-silenced CD14- cells differentiate to macrophage even after the treatment with ATRA 10-6 M, demonstrating that the c-Myb knockdown strongly impairs the ability of myeloblasts to differentiate to granulocytes. Gene expression profiling of c-Myb-silenced CD14- cells identified some potential c-Myb targets that can account for these effects. To maximize siRNA transfection efficiency, we utilized the NucleofectorTM technology (Amaxa). CD14- cells were transfected with a mixture of 3 siRNAs targeting c-Myb mRNA, with a non-targeting siRNA as a negative control (NegCTR) and without siRNA (MOCK). c-Myb siRNAs were transfected at days 1 to 3 after the CD14- myeloblasts purification based on the observation that this timing represented a phase of phisiological increase in c-Myb expression in myeloblasts. Western Blot analysis at 24 hours post-nucleofection demonstrated the c-Myb protein knockdown in MYBsiRNA CD14- cells as compared with control samples (MOCK, NegCTR).
2010-07-14 | E-GEOD-21943 | biostudies-arrayexpress