The Polycomb Repressive Complex 2 Is Required For MLL-AF9 Leukemia
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ABSTRACT: This SuperSeries is composed of the following subset Series: GSE34959: Expression profiling of primary wild type (WT), Ezh2-null and Eed-null murine MLL-AF9 AML GSE34961: Expression profiling of secondary wild type (WT) and Ezh2-null murine MLL-AF9 AML GSE34962: Epigenetic profiling of WT and Ezh2-null MLL-AF9 murine leukemic cells Refer to individual Series
Project description:We evaluated gene expression changes in secondary recipient murine leukemia caused by retroviral overexpression of MLL-AF9. We compared wild-type (WT) leukemia cells with mutant leukemia cells after cre-mediated inactivation of a homozygous conditional allele for Ezh2, a component of the Polycomb Repressive Complex2. For WT cells, 4 biological replicates were hybridized. For Ezh2-null cells, 5 biological replicates were hybridized.
Project description:We evaluated gene expression changes in murine leukemia caused by retroviral overexpression of MLL-AF9. We compared wild-type (WT) leukemia cells with mutant leukemia cells after cre-mediated inactivation of homozygous conditional alleles for Ezh2 or Eed, both of which are components of the Polycomb Repressive Complex2. For WT cells, 3 biological replicates were hybridized. For Ezh2-null cells, 4 biological replicates were hybridized. For Eed-cells, 3 biological replicates were hybridized.
Project description:MLL-fusions may induce leukemogenic gene expression programs by recruiting the histone H3K79 methyltransferase to MLL-target promoters. We evaluated gene expression changes after cre-mediated loss of Dot1l in leukemia cells obtained from mice injected with MLL-9 transformed lineage negative bone marrow cells. MLL-AF9 murine leukemia cells carrying two conditional Dot1l alleles were retrovirally transduced with Cre or empty control vector, and gene expression changes were monitored on day 3, 5, and 7 after transduction.
Project description:Chromatin immunoprecipitation (ChIP) for H3K27me3 followed by Solexa sequencing in WT and Ezh2-null leukemic cells from primary and secondary recipients. Leukemic cells from primary and secondary recipients of MLL-AF9-transduced WT and Ezh2-null cells were sorted for GFP and YFP expression and analyzed by Chip-Seq.
Project description:We investigated the role of the transcriptional regulator Id2 in the context of MLL-rearranged acute myeloid leukemia (AML). Using an AML mouse model driven by tet-regulated MLL-AF9 co-expressed with oncogenic NRASG12D (Tet-off MLL-AF9), we demonstrated that MLL-AF9 regulates the E protein pathway by suppressing Id2, while activating the expression of its target E2-2. Moreover, we found that Id2 over-expression in Tet-Off MLL-AF9 AML cells in vitro partially phenocopies MLL-AF9 depletion and results inhibition of leukemia growth, loss of leukemia stem cell-associated gene expression pattern and induction of differentiation. To compare gene expression changes associated with enforced Id2 expression and MLL-AF9 withdrawal, RNA sequencing analysis was performed on Tet-off MLL-AF9 cells transduced with an Id2 over-expressing or a control vector, or upon MLL-AF9 dox-inducible knock-down. Primary AMLs driven by Tet-off inducible MLL/AF9 expression linked to dsRED reporter, in association with oncogenic NRASG12D (Tet-off MLL-AF9) were generated by reconstituting lethally irradiated congenic mice with foetal liver cells co-transduced with a Tet-Off-MLL-AF9-dRED retroviral vector and a second vector co-expressing NRASG12D together with the Tet-Off responsive transcriptional activator. RNA sequencing analysis sequencing analysis was performed on Tet-Off MLL-AF9/dsRED+ AML cells treated in vitro with doxycycline (DOX) for 4 days to inactivate MLL-AF9 expression or left untreated (UT). For the Id2 over-expression experiment, Tet-Off MLL-AF9/dsRED+ AML cells were transduced in vitro with an Id2-GFP or a control-GFP retroviral vector. Viable GFP-positive cells were FACS-sorted 2 days after transduction and used for RNA sequencing analysis.
Project description:The Wnt/beta-catenin pathway is required for the development of leukemia stem cells in MLL-AF9 AML. We evaluated the dependance on beta-catenin for KrasG12DMLL-AF9 leukemia. Lin-Kit+ bone marrow cells obtained from mice transplanted with primary MLL-AF9 leukemia cells and KRasG12DMLL-AF9 leukemia cells were assessed for gene expression in the presence or absence of beta-catenin
Project description:We investigated the role of the transcriptional regulators Id2 and E2-2 (encoded by Tcf4) in the context of MLL-rearranged acute myeloid leukemia (AML). Using an AML mouse model driven by a Tet-off inducible MLL-AF9 allele co-expressed with oncogenic NRASG12D, we demonstrated that MLL-AF9 regulates the E protein pathway by suppressing Id2, while activating the expression of its target E2-2. Moreover, we found that Id2 over-expression in MLL-AF9 AML cells results inhibition of leukemia growth, loss of leukemia stem cell-associated gene expression pattern and induction of differentiation. E2-2 silencing phenocopies Id2 overexpression in MLL-AF9-AML cells. To study the gene expression changes associated with E2-2 depletion in the context of MLL-rearranged AML, RNA sequencing analysis was performed on MLL-AF9;NRAS AML cells transduced with vectors expressing hairpins against E2-2 (shTcf4#654 and shTcf4#3646) or a control hairpin against Renilla luciferase (shRen). Primary AMLs driven by MLL/AF9 expression linked to cherry reporter, in association with oncogenic NRASG12D (MLL/AF9;NRAS) were generated by reconstituting lethally irradiated congenic mice with fetal liver cells co-transduced with the MSCV-MLL/AF9-IRES-cherry retroviral vector and a second vector co-expressing NRASG12D together with luciferase (MSCV-luciferase-IRES-NRASG12D). RNA sequencing analysis sequencing analysis was performed on MLL-AF9;NRAS AML cells transduced in vitro with vectors expressing hairpins against E2-2 (shTcf4#654 and shTcf4#3646) or a control hairpin against Renilla luciferase (shRen) linked to the reporter GFP. Viable GFP-positive cells were FACS-sorted 2 days after transduction and used for RNA sequencing analysis. Two independent biological replicates of the experiment were used for the RNA sequencing (9-5-14 and 14-4-14).
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:Despite the advanced understanding of disease mechanisms, the current therapeutic regimens fail to cure most patients with acute myeloid leukemia (AML). In the present study, we address the role of protein synthesis control in leukemia function and leukemia propagation. Using a transgenic eIF6 mouse strain that permits inducible and graded regulation of ribosomal subunit joining, we have generated a murine model of MLL-AF9 acute myeloid leukemia where the expression of transgenic eIF6 is doxycycline-inducible. Using this model system, we have performed scRNA-seq expression analysis to study the impact of eIF6 overexpression on leukemia cell function. scRNA-seq was performed using the 10x Chromium Next GEM Single Cell 3ʹ platform. BM cells were harvested from leukemia-engrafted mice that were administered doxycycline for six days and viable GFP+ leukemia cells were sorted into PBS containing 0.05 % BSA following the manusfacturer’s protocol. 5 samples: 2 control and 3 eIF6 overexpression.