Gene Expression Profiling of the MLL-AF4 and Flt3 tyrosine kinase domain (TKD) genes in 32Dc cell
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE14236 | GEO | 2009/03/31
SECONDARY ACCESSION(S): PRJNA111157
REPOSITORIES: GEO
Similar Datasets
Project description:The tumorigenesis capacity of MLL-AF4 alone is insufficient for causing leukemia. Based on the finding that an Flt3 gene mutation in the tyrosine kinase domain (TKD) was observed in approximately 15% of MLL leukemia, we investigated synergistic leukemogenesis effects of the two genes in vitro. In a mouse IL3-dependent cell line, 32Dc, the expression of MLL-AF4 and Flt3 TKD was induced using a lentiviral vector. We performed gene expression profiling in the MLL-AF4 and the Flt3 TKD+MLL-AF4 expressing 32Dc cells. The enhancement of Hox genes expression was not identified. However, instead, the expression of S100A6, which was involved in the control of cell proliferation, was synergistically enhanced in the presence of both MLL-AF4 and Flt3 TKD genes. We performed gene expression profiling: 32Dc vs. MLL-AF4 expressing 32Dc, 32Dc vs. Flt3 TKD+MLL-AF4 expressing 32Dc, and MLL-AF4 expressing 32Dc vs. Flt3 TKD+MLL-AF4 expressing 32Dc. A single sample for each expressing cells was analyzed.
2009-03-31 | E-GEOD-14236 | biostudies-arrayexpress
Project description:MLL-AF4 is a hallmark genomic aberration which arises prenatally in high-risk infant acute lymphoblastic leukemia (ALL). In human embryonic stem cells (hESCs), MLL-AF4 skewed hemato-endothelial specification but was not sufficient for transformation. Additional cooperating genetic insults seem required for MLL-AF4-mediated leukemogenesis. FLT3 is highly expressed in MLL-AF4+ ALL through activating mutations (FLT3-TKD or FLT3-ITD) or increased transcriptional expression, being therefore considered a potential cooperating event in MLL-AF4+ ALL. Here, we explored the developmental impact of FLT3 activation on its own or in cooperation with MLL-AF4 in the hematopoietic fate of hESCs. FLT3 activation did not impact specification of CD45-CD31+ hemogenic precursors but significantly enhanced the formation of CD45+CD34+ and CD45+ blood cells and blood progenitors with clonogenic potential. Importantly, FLT3 activation through FLT3 mutations or FLT3-WT overexpression completely abrogated hematopoietic differentiation from MLL-AF4-expressing hESCs, indicating that FLT3 activation cooperates with MLL-AF4 to inhibit human embryonic hematopoiesis. Cell cycle/apoptosis analyses suggest that FLT3 activation directly impacts hESC specification rather than selective proliferation/survival of hESC-emerging hematopoietic derivatives. Transcriptional profiling supported the limited impact of FLT3 activation on hESC specification towards CD45-hemogenic precursors and the enhanced hematopoiesis upon FLT3 activation, and inhibited hematopoiesis upon MLL-AF4 expression in FLT3-activated hESCs which was associated to large transcriptional changes and regulation of master early hematopoietic genes. Also, although FLT3 activation and MLL-AF4 cooperate to inhibit embryonic hematopoiesis the underlying molecular/genetic mechanisms differ depending on how FLT3 activation is achieved. Finally, FLT3 activation did not cooperate with MLL-AF4 to immortalize/transform hESC-derived hematopoietic cells. 18 samples were analyzed. CD45- hemogenic precursors EV, 2 biological rep CD45- hemogenic precursors FLT3-TKD, 2 biological rep CD45- hemogenic precursors FLT3-WT, 2 biological rep CD45- hemogenic precursors FLT3-TKD/MLLAF4, 2 biological rep CD45- hemogenic precursors FLT3-WT/MLLAF4, 2 biological rep CD45+ blood cells EV, 1 biological rep CD45+ blood cells FLT3-TKD, 2 biological rep CD45+ blood cells FLT3-WT, 2 biological rep CD45+ blood cells FLT3-TKD/MLLAF4, 2 biological rep CD45+ blood cells FLT3-WT/MLLAF4, 1 biological rep
2013-06-04 | E-GEOD-40103 | biostudies-arrayexpress
Project description:MLL-AF4 is a hallmark genomic aberration which arises prenatally in high-risk infant acute lymphoblastic leukemia (ALL). In human embryonic stem cells (hESCs), MLL-AF4 skewed hemato-endothelial specification but was not sufficient for transformation. Additional cooperating genetic insults seem required for MLL-AF4-mediated leukemogenesis. FLT3 is highly expressed in MLL-AF4+ ALL through activating mutations (FLT3-TKD or FLT3-ITD) or increased transcriptional expression, being therefore considered a potential cooperating event in MLL-AF4+ ALL. Here, we explored the developmental impact of FLT3 activation on its own or in cooperation with MLL-AF4 in the hematopoietic fate of hESCs. FLT3 activation did not impact specification of CD45-CD31+ hemogenic precursors but significantly enhanced the formation of CD45+CD34+ and CD45+ blood cells and blood progenitors with clonogenic potential. Importantly, FLT3 activation through FLT3 mutations or FLT3-WT overexpression completely abrogated hematopoietic differentiation from MLL-AF4-expressing hESCs, indicating that FLT3 activation cooperates with MLL-AF4 to inhibit human embryonic hematopoiesis. Cell cycle/apoptosis analyses suggest that FLT3 activation directly impacts hESC specification rather than selective proliferation/survival of hESC-emerging hematopoietic derivatives. Transcriptional profiling supported the limited impact of FLT3 activation on hESC specification towards CD45-hemogenic precursors and the enhanced hematopoiesis upon FLT3 activation, and inhibited hematopoiesis upon MLL-AF4 expression in FLT3-activated hESCs which was associated to large transcriptional changes and regulation of master early hematopoietic genes. Also, although FLT3 activation and MLL-AF4 cooperate to inhibit embryonic hematopoiesis the underlying molecular/genetic mechanisms differ depending on how FLT3 activation is achieved. Finally, FLT3 activation did not cooperate with MLL-AF4 to immortalize/transform hESC-derived hematopoietic cells.
2013-06-04 | GSE40103 | GEO
Project description:In our study, we found that MLL-AF4 transcriptionally induces IGF2BP3 and is required for MLL-Af4 mediated leukemogenesis. Deletion of murine Igf2bp3 significantly increased the survival of mice with MLL-Af4 driven leukemia and greatly attenuated disease. Furthermore, Igf2bp3 was necessary for the development of and the self-renewal capacity of MLL-Af4 leukemic initiating cells. eCLIP and transcriptome analysis of MLL-Af4 transformed stem and progenitor cells and primary cells from MLL-Af4 leukemic mice revealed an IGF2BP3-regulated post-transcriptional operon governing tumor cell survival and proliferation. Critical mRNA targets include the Hoxa locus and numerous genes within the Ras signaling pathway. Together, our findings show that IGF2BP3 is an essential positive regulator of MLL-AF4 mediated leukemogenesis and is a potential therapeutic target in this disease.
2021-08-11 | GSE156115 | GEO
Project description:B-cell acute lymphoblastic leukemia (B-ALL) is the most common pediatric cancer, with long-term overall survival rates of 80%. However, B-ALL harboring rearrangements of the MLL gene (also known as KTM2A), hereinafter termed MLLr B-ALL, is frequently seen in infants and is associated with poor 5-year survival (<30%), frequent relapses, and refractoriness to glucocorticoids (GC). GC are an essential part of the treatment backbone for B-ALL and GC resistance is a major clinical predictor of poor outcome. Unraveling the mechanisms of GC resistance in MLLr B-ALL is, therefore, crucial to guide therapeutic strategies that deepen response after induction therapy. Neuron-glial antigen-2 (NG2) expression is a hallmark of MLLr B-ALL and is minimally expressed in healthy hematopoietic cells. We recently reported that NG2 expression is associated with poor prognosis and that anti-NG2 immunotherapy strongly reduces/delays relapse in xenograft models of MLLr B-ALL. However, despite its contribution to MLLr B-ALL pathogenesis and its diagnostic utility, the role of NG2 in MLLr-mediated leukemogenesis/chemoresistance remains elusive. We show here that NG2 is an epigenetically regulated direct target gene of the leukemic MLL-AF4 fusion protein. NG2 negatively regulates the expression of the GC receptor NR3C1, conferring GC chemoresistance to MLLr B-ALL cells in vitro and in vivo. Mechanistically, NG2 interacts with FLT3 to render ligand-independent activation of FLT3 signaling (a hallmark of MLLr B-ALL) and downregulation of NR3C1 via AP-1-mediated transrepression. Collectively, our study elucidates the role of NG2 in GC resistance in MLLr B-ALL through a FLT3/AP-1-mediated downregulation of NR3C1, providing novel therapeutic avenues for MLLr B-ALL.
2024-07-12 | PXD041875 | Pride
Project description:Aberrant enhancer activation is a key mechanism driving oncogene expression in many cancers. While much is known about the regulation of larger chromosome domains in eukaryotes, the details of enhancer-promoter interactions remain poorly understood. Recent work suggests co-activators like BRD4 and Mediator have little impact on enhancer-promoter interactions. In leukemias controlled by the MLL-AF4 fusion protein, we use the ultra-high resolution technique Micro-Capture-C (MCC) to show that MLL-AF4 binding promotes broad, high-density regions of enhancer-promoter interactions at a subset of key targets. These enhancers are enriched for transcription elongation factors like PAF1C and FACT and loss of these factors abolishes enhancer-promoter contact. This work not only provides a new model for how MLL-AF4 is able to drive high levels of transcription at key genes in leukemia, but also suggests a more general model linking enhancer-promoter crosstalk and transcription elongation.
2023-08-18 | PXD043920 | Pride
Project description:ITD mutations in the FLT3 gene occur in the 30% of acute myeloid leukemia patients. The integration of ITD in the tyrosine kinase domain (TKD-ITD) of the FLT3 receptor has been shown to confer resistance to standard chemotherapy treatment. We applied state-of-the-art, high-sensitive, mass spectrometry (MS)-based (phospho)proteomics to investigate the molecular mechanisms underlying the sensitivity to cytarabine therapy in FLT3-ITD cells.
2023-07-20 | PXD038638 | Pride
Project description:The interaction of Menin (MEN1) and MLL (MLL1, KMT2A) is a dependency and potential therapeutic opportunity against NPM1 mutant (NPM1mut) and MLL-rearranged (MLL-r) leukemias. Concomitant activating driver mutations in the gene encoding the tyrosine kinase FLT3 occur in both leukemias and are particularly common in the NPM1mut subtype. Transcriptional profiling upon pharmacological inhibition of the Menin-MLL complex revealed specific changes in gene expression with downregulation of the MEIS1 transcription factor and its transcriptional target gene FLT3 being most pronounced. Combining Menin-MLL inhibition with specific small molecule kinase inhibitors of FLT3 phosphorylation resulted in a significantly superior reduction of phosphorylated FLT3 and transcriptional suppression of genes downstream to FLT3 signaling. The drug combination induced synergistic inhibition of proliferation as well as enhanced apoptosis and differentiation compared to single-drug treatment in models of human and murine NPM1mut and MLL-r leukemias harboring an FLT3 mutation. Primary AML cells harvested from patients with NPM1mut FLT3mut AML showed significantly better responses to combined Menin and FLT3 inhibition than to single-drug or vehicle control treatment, while AML cells with wildtype NPM1, MLL, and FLT3 were not affected by any of the two drugs. In vivo treatment of leukemic animals with MLL-r FLT3mut leukemia reduced leukemia burden significantly and prolonged survival compared to the single-drug and vehicle control groups. Our data suggest that combined Menin-MLL and FLT3 inhibition represents a novel and promising therapeutic strategy for patients with NPM1mut or MLL-r leukemia and concurrent FLT3 mutation.
2020-07-01 | GSE144759 | GEO
Project description:Survival rates for children diagnosed with acute lymphoblastic leukemia (ALL) have drastically improved, but those carrying mutations in the Mixed Lineage Leukemia (MLL) gene continue to have a very poor prognosis. The most common MLL mutation in ALL is the t(4;11)(q21;q23) chromosome translocation that fuses MLL in frame with the AF4 gene producing MLL-AF4 and AF4-MLL fusion proteins. Previously, we showed that MLL-AF4 binds to the BCL-2 gene and directly activates it through DOT1L recruitment and increased H3K79me2/3 levels. We went on to show that MLL leukemias are particularly sensitive to treatment with the BCL-2 inhibitor venetoclax which synergizes with both standard chemotherapeutic agents as well as DOT1L inhibitors. Altered expression of other BCL-2 family members is a major cause of resistance to ventoclax, so here we perform a detalied analysis of MLL-AF4 regulation of the entire BCL-2 family. By measuring nascent RNA production, we find that of all the BCL-2 family genes, MLL-AF4 directly controls the transcription of both BCL-2 and MCL-1, but only BCL-2 shows a significant loss of steady state RNA levels. Interestingly however, both MCL-1 and BCL-XL protein levels are dependent on MLL-AF4 activity through an unknown and likely indirect mechanism. Finally, we analyze MLL-AF4 regulation of the BCL-2 gene in greater detail and using Capture C we identify a major BCL-2 specific enhancer consisting of two clusters of H3K27Ac. Loss of MLL-AF4 activity results in a reduction of H2K27Ac levels at the major BCL-2 enhancer, revealing a novel regulatory dependence on MLL-AF4 function at BCL-2.
2016-11-23 | GSE85988 | GEO
Project description:The MLL-AF4 fusion gene is a hallmark genomic aberration in high-risk acute lymphoblastic leukemia in infants. Although it is well-established that MLL-AF4 arises pre-natally during human development, its effects on hematopoietic development in utero remains unexplored. We have created a human-specific in vitro system to study early hemato-endothelial development in MLL-AF4-expressing human embryonic stem cells (hESCs). Differentiation and functional studies as well as clonal analyses and gene expression profiling reveal that expression of MLL-AF4 in hESCs has a phenotypic, functional and gene expression impact. It enhances the specification of hemogenic precursors from hESCs and impairs further hematopoietic commitment of these precursors in favour of the endothelial cell fate. Similar to that reported in cord blood CD34+ hematopoietic stem/progenitor cells (HSPCs), MLL-AF4 expression is not sufficient to transform hESC-derived hematopoietic cells in vitro or in vivo, indicating that additional events may be required to initiate leukemogenesis or that embryonic hematopoiesis is not the appropriate human cellular target for MLL-AF4-mediated leukemogenesis. This work illustrates how hESCs can provide unique insights into human development and further our understanding of how leukemic fusion genes known to arise pre-natally regulate human embryonic hematopoietic specification. MLL is involved in transcriptional regulation and most MLL translocations appear to result in increased expression of Hox genes and hematopoietic genes. We therefore assessed the impact of MLL-AF4 expression on the transcriptome of hESCs. Gene expression profiling performed in MLL-AF4 hESCs revealed that MLL-AF4 preferentially activates transcription. 1826 out of the 3001 genes (61%) expressed were up-regulated in MLL-AF4 hESCs. Human ESC samples were collected during the exponential cell growth phase and stabilized in RNA later. 500 ng of each total RNA sample was labelled with Cy3 using the Quick-Amp Labelling kit and hybridized with the Gene Expression Hybridization kit to a Whole Human Genome Oligo Microarray (Agilent Technologies) following the Manufacturer’s instructions. Each cell line was analyzed as independent duplicates. NEO-expressing (empty lentivector) hESC line was used as the baseline.
2011-06-09 | E-GEOD-29869 | biostudies-arrayexpress