ABSTRACT: Transcriptome analysis of leukemic granulocyte/macrophage progenitors (L-GMPs) from MLL-AF9-transduced Jmjd3+/+ and Jmjd3-/- cells (Jmjd3-/- L-GMPs vs Jmjd3+/+ L-GMPs)
Project description:We report the genome wide distribution of the three states of H3K79 methylation (H3K79me1/me2/me3) and H3K27me3 in mouse lineage negative Sca-1 positive Kit positive cells (LSKs), granulocyte macrophage progenitors (GMPs) and LSK derived MLL-AF9 leukemias in the presence or absence of the Af10 OM-LZ domain. Legend- MIT:MSCV-IRES-tdTomato (Empty vector control) and CRE (MIT vector with the Cre recombinase). We examined the H3K79 me1,me2,me3 and H3K27me3 profiles by ChIP-seq in lineage negative Sca-1 positive, Kit positive (LSK) cells, granulocyte macrophage progenitors (GMPs) and bone marrow cells from sacrificed terminally ill secondary MLL-AF9 positive leukemic mice. In case of the MLL-AF9 leukemias, the ChIP-seq experiments were performed in 2 conditions in the presence or absence of the Dot1l interacing octapeptide-motif leucine zipper (OM-LZ) domain of Af10. For the leukemia experiments, leukemias derived from the Af10 OM-LZ homozygous floxed background were transduced with MSCV-IRES-tdTomato control vector (MIT) or its Cre-recombinase expressing counterparts (CRE). Subsequently, we sorted tdTomato positive cells and injected them into sub-lethally irradiated syngenic secondary recipient mice. Seconday leukemias obtained from these MIT or CRE expressing cells were used for ChIP -seq studies.
Project description:Leukemia initiating cells (LICs) of acute myeloid leukemia (AML) may arise from self-renewing hematopoietic stem cells (HSCs) and from committed progenitors. However, it remains unclear how leukemia-associated oncogenes instruct LIC formation from cells of different origins and if differentiation along the normal hematopoietic hierarchy is involved. Here, using murine models with the driver mutations MLL-AF9 or MOZ-TIF2, we found that regardless of the transformed cell types, myelomonocytic differentiation to the granulocyte macrophage progenitor (GMP) stage is critical for LIC generation. Blocking myeloid differentiation through disrupting the lineage-restricted transcription factor C/EBPa eliminates GMPs, blocks normal granulopoiesis, and prevents AML development. In contrast, restoring myeloid differentiation through inflammatory cytokines “rescues” AML transformation. Our findings identify myeloid differentiation as a critical step in LIC formation and AML development, thus guiding new therapeutic approaches. Primary KSL, CMP, and GMP cells from wildtype controls and C/Ebpa knockouts were used for RNA extraction and hybridization on Affymetrix microarrays. We also compared the microarray samples of leukemic granulocyte macrophage progenitor compartments (L-GMPs) from MLL-AF9 transformed control or cytokine rescued C/EBPa KO leukemic mouse bone marrow and their secondary recipients with those non-Leukemia KSLs and CMPs from MLL-AF9 transduecd KO recipients with no leukemia development.
Project description:Leukemia initiating cells (LICs) of acute myeloid leukemia (AML) may arise from self-renewing hematopoietic stem cells (HSCs) and from committed progenitors. However, it remains unclear how leukemia-associated oncogenes instruct LIC formation from cells of different origins and if differentiation along the normal hematopoietic hierarchy is involved. Here, using murine models with the driver mutations MLL-AF9 or MOZ-TIF2, we found that regardless of the transformed cell types, myelomonocytic differentiation to the granulocyte macrophage progenitor (GMP) stage is critical for LIC generation. Blocking myeloid differentiation through disrupting the lineage-restricted transcription factor C/EBPa eliminates GMPs, blocks normal granulopoiesis, and prevents AML development. In contrast, restoring myeloid differentiation through inflammatory cytokines “rescues” AML transformation. Our findings identify myeloid differentiation as a critical step in LIC formation and AML development, thus guiding new therapeutic approaches. Primary KSL, CMP, and GMP cells from wildtype controls and C/Ebpa knockouts were used for RNA extraction and hybridization on Affymetrix microarrays. We also compared the microarray samples of leukemic granulocyte macrophage progenitor compartments (L-GMPs) from MLL-AF9 transformed control or cytokine rescued C/EBPa KO leukemic mouse bone marrow and their secondary recipients with those non-Leukemia KSLs and CMPs from MLL-AF9 transduecd KO recipients with no leukemia development.
Project description:Transcriptome analysis of leukemic granulocyte/macrophage progenitors (L-GMPs) from MLL-AF9-transduced Fbxl10+/+ and Fbxl10-/- cells (Fbxl10-/- L-GMPs vs Fbxl10+/+ L-GMPs)
Project description:The pathways by which oncogenes, such as MLL-AF9, initiate transformation and leukemia in humans and mice are incompletely defined. In a study of target cells and oncogene dosage, we found that Mll-AF9, when under endogenous regulatory control, efficiently transformed LSK (Lin- Sca1+ c-kit+) stem cells while committed granulocyte-monocyte progenitors (GMPs) were transformation-resistant and did not cause leukemia. Mll-AF9 was expressed at higher levels in hematopoietic stem (HSC) than GMP cells. Mll- AF9 gene dosage effects were directly shown in experiments where GMPs were efficiently transformed by the high dosage of Mll-AF9 resulting from retroviral transduction. Mll-AF9 up-regulated expression of 196 genes in both LSK and progenitor cells, but to higher levels in LSKs than in committed myeloid progenitors. Experiment Overall Design: Comparison of gene expression profiles among four types of hematopoietic cells (GMP, CMP, CLP and HSC), FACS sorted from wild type and Mll-AF9 knock-in mice. The goal was to identify genes differentially expressed in each Mll-AF9 cell type compared to the corresponding wild type cells.
Project description:The pathways by which oncogenes, such as MLL-AF9, initiate transformation and leukemia in humans and mice are incompletely defined. In a study of target cells and oncogene dosage, we found that Mll-AF9, when under endogenous regulatory control, efficiently transformed LSK (Lin- Sca1+ c-kit+) stem cells while committed granulocyte-monocyte progenitors (GMPs) were transformation-resistant and did not cause leukemia. Mll-AF9 was expressed at higher levels in hematopoietic stem (HSC) than GMP cells. Mll- AF9 gene dosage effects were directly shown in experiments where GMPs were efficiently transformed by the high dosage of Mll-AF9 resulting from retroviral transduction. Mll-AF9 up-regulated expression of 196 genes in both LSK and progenitor cells, but to higher levels in LSKs than in committed myeloid progenitors. Keywords: mutant hematopoietic cells
Project description:We report the genome wide distribution of the three states of H3K79 methylation (H3K79me1/me2/me3) and H3K27me3 in mouse lineage negative Sca-1 positive Kit positive cells (LSKs), granulocyte macrophage progenitors (GMPs) and LSK derived MLL-AF9 leukemias in the presence or absence of the Af10 OM-LZ domain. Legend- MIT:MSCV-IRES-tdTomato (Empty vector control) and CRE (MIT vector with the Cre recombinase).
Project description:CB CD34+ cells were isolated by Miltenyi miniMACS column. Cells were prestimulated in HPGM with 100 ng/ml KITL, FLT#L and TPO for 48 hrs. Cells were transduced with control MiNR1 or STAT5A-ER in three rounds over 48 hrs. Hematopoietic stem cells (HSCs), common myeloid progenitors (CMPs), granulocyte/macrophage progenitors (GMPs), and megakaryocyte/erythroid progenitors (MEPs) were sorted (for details see Blood 2011, Fatrai et al). cells were stimulated with 100 ng/ml 4OHT for 24 hrs after which RNA was isolated for Illumina beadhchiop arrays HT12 v3 CB CD34+ cells were isolated by Miltenyi miniMACS column. Cells were prestimulated in HPGM with 100 ng/ml KITL, FLT#L and TPO for 48 hrs. Cells were transduced with control MiNR1 or STAT5A-ER in three rounds over 48 hrs. Hematopoietic stem cells (HSCs), common myeloid progenitors (CMPs), granulocyte/macrophage progenitors (GMPs), and megakaryocyte/erythroid progenitors (MEPs) were sorted (for details see Blood 2011, Fatrai et al). cells were stimulated with 100 ng/ml 4OHT for 24 hrs after which RNA was isolated for Illumina beadhchiop arrays HT12 v3
Project description:The molecular mechanism defining susceptibility of normal cells to oncogenic transformation may be a valuable therapeutic target. We characterized the cell of origin and its critical pathways in MN1 leukemias. Common myeloid (CMP), but not granulocyte-macrophage progenitors (CMP) could be transformed by constitutively overexpressed MN1. Complementation studies of CMP-signature genes in GMPs demonstrated that leukemogenicity of MN1 required the MEIS1/abdB-like HOX protein complex. Colocalization studies by ChIP-seq identified common chromatin targets of MN1 and MEIS1 that were associated with open chromatin and transcriptional activation. Transcriptional repression of MEIS1 target sites in established MN1 leukemias had antileukemic activity. As MN1 relies on but can not activate expression of MEIS1/abdB-like HOX proteins, transcriptional activity of these genes determines which cell is the cell of origin in MN1 leukemia. We have showed at the single cell level that CMPs, but not GMPs, are susceptible to MN1-induced transformation. To identify transcriptional differences between CMPs and GMPs that may explain this difference in susceptibilities to MN1 transformation we produced gene expression profiles (two biological replicates in each experimental arm) of bone marrow cells from MN1 leukemic mice and mature myeloid bone marrow cells (Gr1+/CD11b+) from healthy mice and compared those to already published gene expression profiles of CMPs and GMPs (Krivtsov, A.V., et al. (2006). Transformation from committed progenitor to leukaemia stem cell initiated by MLL-AF9. Nature 442, 818-822).
Project description:In this study, we use pre-malignant cells from different Cebpa mutant acute myeloid leukemia (AML) models. We have used conditional KO models (CreLoxP) and isolated hematopoietic cells shortly after induction of recombination, in order to look at pre-leukemic cells, which have acquired the first hit, but not yet undergone full malignant transformation. We have sorted granulocyte-macrophage progenitors (GMPs) and the more immature population pre-granulocyte-macrophages (preGMs) from pre-leukemic mice. We analyzed gene-expression profiles in order to find deregulated genes, which make the cells more prone to undergo transformation.