Dissecting the early steps of MLL induced leukaemogenic transformation using a new mouse model of AML
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PROVIDER: PRJNA590993 | ENA |
REPOSITORIES: ENA
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Project description:Dissecting the early steps of MLL induced leukaemogenic transformation using a new mouse model of AML [ATAC-seq]
| PRJNA593208 | ENA
Project description:Leukaemogenic mutations commonly disrupt cellular differentiation and/or enhance proliferation, thus perturbing the regulatory programs that control self-renewal and differentiation of stem and progenitor cells. Translocations involving the Mll1 (Kmt2a) gene generate powerful oncogenic fusion proteins, predominantly affecting infant and paediatric AML and ALL patients. The early stages of leukaemogenic transformation are typically inaccessible from human patients and conventional mouse models. Here, we took advantage of cells conditionally blocked at the multipotent haematopoietic progenitor stage to develop a new MLL-r model capturing the early cellular and molecular consequences of MLL-ENL expression based on a clear clonal relationship between the parental and leukaemic cells. Through a combination of scRNA-seq, ATAC-seq and genome-scale CRISPR-Cas9 screening, we identified pathways and genes likely to drive the early phases of leukaemogenesis. Finally, we demonstrated the broad utility of using matched parental and transformed cells for small molecule inhibitor studies by validating both known and new potential therapeutic targets.
2020-02-07 | GSE140807 | GEO
Project description:Leukaemogenic mutations commonly disrupt cellular differentiation and/or enhance proliferation, thus perturbing the intricate regulatory programs that control multi-lineage differentiation and self-renewal in haematopoietic stem and progenitor cells. Translocations involving the Mll1 gene generate particularly powerful oncogenic fusion proteins, predominantly affecting infant and paediatric AML and ALL patients. The early stages of leukaemogenic transformation are typically inaccessible from human patient samples, and are not captured by conventional mouse models. Here, we took advantage of conditionally immortalised multipotent haematopoietic progenitor cells to develop a new MLL-r model capturing the early cellular and molecular consequences of MLL-ENL expression based on a clear clonal relationship between the parental and MLL-leukaemic cells. Through a combination of scRNA-seq, ATAC-seq and genome-scale CRISPR-Cas9 screening, we identified pathways and genes likely to be important during the early phases of leukaemogenesis. Finally, we demonstrate the broad utility of using matched parental and transformed cells for small molecule inhibitor studies by validating both known and new potential therapeutic targets.
2020-02-07 | GSE141353 | GEO
Project description:Leukaemogenic mutations commonly disrupt cellular differentiation and/or enhance proliferation, thus perturbing the regulatory programs that control self-renewal and differentiation of stem and progenitor cells. Translocations involving the Mll1 (Kmt2a) gene generate powerful oncogenic fusion proteins, predominantly affecting infant and paediatric AML and ALL patients. The early stages of leukaemogenic transformation are typically inaccessible from human patients and conventional mouse models. Here, we take advantage of cells conditionally blocked at the multipotent haematopoietic progenitor stage to develop a MLL-r model capturing early cellular and molecular consequences of MLL-ENL expression based on a clear clonal relationship between parental and leukaemic cells. Through a combination of scRNA-seq, ATAC-seq and genome-scale CRISPR-Cas9 screening, we identify pathways and genes likely to drive the early phases of leukaemogenesis. Finally, we demonstrate the broad utility of using matched parental and transformed cells for small molecule inhibitor studies by validating both previously known and other potential therapeutic targets.
| S-EPMC7075888 | biostudies-literature
Project description:Acute Myeloid Leukemia (AML) is associated with a number of genetic and epigenetic events that result in malignant transformation of hematopoietic cells. In particular, transcription factors essential for normal hematopoiesis and stem cell function are often found mutated leading to the formation of leukemic stem cells and the accumulation of immature blasts. Among them, translocations involving the mixed lineage leukemia (MLL) gene at chromosome band 11q23 are one of the most commonly events (~10 %) and is associated with poor prognosis in human leukemias. Whereas the downstream effects of MLL-fusion proteins are well established, the modes on which these effects are mediated are still unclear and whether MLL-fusion proteins are dependent on other transcriptional regulators or act alone remains elusive. To investigate this we searched gene expression profiles from patients with MLL-rearranged AML compared with normal hematopoietic progenitor cells for transcriptional regulators and found targets of C/EBPα to be up-regulated in the AML samples, suggesting that C/EBPα might collaborate with MLL-fusion proteins in the initial transformation process. We could show that transformation by MLL-fusion proteins is dependent on C/EBPα activity both in early progenitors as well as in GMPs. In contrast, C/EBPα was found to be indispensable in an already established leukemia. These finding led us to study the early transcriptional changes induced by MLL-ENL expression and we identified a combined C/EBPα / MLL-ENL transcriptional signature. Collectivly, our data shows that C/EBPα configure a proper chromatin state required for MLL-fusions to induce malignant transformation. Histone modification profiles (H3K4me3 and H3K27me3) in haematopoietic progenitor cells (preGM, wild type and Cebpa knock out), and C/EBPα binding in GMP cells
2013-12-10 | E-GEOD-47003 | biostudies-arrayexpress
Project description:Acute Myeloid Leukemia (AML) is associated with a number of genetic and epigenetic events that result in malignant transformation of hematopoietic cells. In particular, transcription factors essential for normal hematopoiesis and stem cell function are often found mutated leading to the formation of leukemic stem cells and the accumulation of immature blasts. Among them, translocations involving the mixed lineage leukemia (MLL) gene at chromosome band 11q23 are one of the most commonly events (~10 %) and is associated with poor prognosis in human leukemias. Whereas the downstream effects of MLL-fusion proteins are well established, the modes on which these effects are mediated are still unclear and whether MLL-fusion proteins are dependent on other transcriptional regulators or act alone remains elusive. To investigate this we searched gene expression profiles from patients with MLL-rearranged AML compared with normal hematopoietic progenitor cells for transcriptional regulators and found targets of C/EBPα to be up-regulated in the AML samples, suggesting that C/EBPα might collaborate with MLL-fusion proteins in the initial transformation process. We could show that transformation by MLL-fusion proteins is dependent on C/EBPα activity both in early progenitors as well as in GMPs. In contrast, C/EBPα was found to be indispensable in an already established leukemia. These finding led us to study the early transcriptional changes induced by MLL-ENL expression and we identified a combined C/EBPα / MLL-ENL transcriptional signature. Collectivly, our data shows that C/EBPα configure a proper chromatin state required for MLL-fusions to induce malignant transformation.
2013-12-10 | GSE47003 | GEO
Project description:MLL-rearrangements (MLL-r) are recurrent genetic events in acute myeloid leukemia (AML) and frequently associate with poor prognosis. In infants, MLL-r have been suggested to be sufficient to drive transformation. However, despite the prenatal origin of MLL-r, the incidence of congenital leukemia is very low with transformation usually occurring postnatally. The influence of prenatal signals on leukemogenesis, such as those mediated by the fetal-specific RNA binding protein LIN28B, remains controversial. Here, using a dual-transgenic mouse model that co-express MLL-ENL and LIN28B, we investigated the impact of LIN28B on AML. We show that LIN28B impedes the progression of MLL-r AML through a compromised leukemia initiating cell activity and a suppression of MYB signaling. Mechanistically, rather than involving the well-studied Lin28B-let7 miR axis, we found that LIN28B directly bound MYBBP1A mRNA, a co-repressor of MYB, and that positively correlated with MYBBP1A protein levels. Overexpression of MYBBP1A in MLL-ENL driven leukemogenesis largely phenocopied the tumor suppressor effects of LIN28B. Thereby, our work proposes that the developmentally-restricted expression of LIN28B during fetal development provides a protection against MYB-dependent AML.
2023-02-08 | GSE201083 | GEO
Project description:MIR139 is a critical tumor suppressor and commonly silenced in human cancer, including acute myeloid leukemia (AML). Here, we found that depletion of identified MIR139 targets affects AML outgrowth. We unraveled the mechanism of MIR139 gene inactivation in AML expressing the Mixed-Lineage Leukemia (MLL)-AF9 oncogene. Epigenetic analyses revealed two well-conserved putative enhancer regions in close proximity of transcriptional start sites (TSS) of MIR139. These regions were silenced by the Polycomb-Repressive Complex-2 (PRC2) downstream of MLL-AF9. Genomic deletion of these regions abolished MIR139 transcriptional regulation in normal and oncogenic conditions. Genome-wide knockout screens revealed the transcriptional pausing factor of RNA Polymerase-II, POLR2M, as a critical MIR139-silencing factor. Furthermore, direct POLR2M binding to the MIR139 TSS induced paused transcription, which was abrogated upon PRC2 inhibition. We present evidence for an oncogenic POLR2M-mediated MIR139 silencing mechanism, downstream of MLL-AF9 and PRC2. Together, our findings highlight the importance of POLR2M-mediated paused transcription in AML.
2021-11-11 | PXD022488 | Pride
Project description:AML/MDS patients carrying 11q amplifications involving the mixed lineage leukemia gene (MLL) locus are characterized by a complex aberrant karyotype (CAK) frequently including deletions within 5q, 17p and 7q, a later onset and fast progression of the disease with extremely poor prognosis. We and others have shown that the MLL gene is overexpressed in amplified cases; however, in most of the cases the amplified region is not restricted to the MLL locus. In the present study we investigated 19 patients with AML/MDS and MLL gain/amplification. By means of array CGH performed in 12 patients we were able to delineate the minimal deleted regions within 5q, 17p and 7q and identified three independent regions 11q/I-III that were amplified in all cases. Gene expression profiles established in 15 cases (GSE10258) were used to define candidate genes within these regions. Interestingly, analysis of our data suggests an interdependency of loss of 5q and 17p and expression of genes present in 11q23-25. Furthermore, we demonstrate that the gene expression signature can be used to discriminate AML/MDS with MLL amplification from several other types of AML, thus, indicating specific pathogenesis present in this entity. Keywords: comparative genomic hybridization; array CGH In this study, aCGH analysis performed on 12 DNA samples derived from patients with AML, preselected for the presence of MLL amplifications, were analysed on a submegabase resolution BAC array. No replicates, no dye swap was done. Gene expression profiling performed for 15 AML patients (GSE10258).
2008-06-30 | E-GEOD-9928 | biostudies-arrayexpress
Project description:Gene expression analysis identified a MLL translocation-specific signature of differentially expressed genes discriminating ALL and AML with and without MLL rearrangements. Gene expression signatures of acute lymphoblastic and myeloblastic leukemia samples with and without MLL rearrangements were analyzed using paired supervised analyses.
2009-07-22 | GSE14062 | GEO