Sox4 is a key oncogenic target in C/EBP? mutant Acute Myeloid Leukemia
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ABSTRACT: Mutation or epigenetic silencing of the transcription factor C/EBP? is observed in ~10% of patients with acute myeloid leukemia (AML). In both cases, a common global gene expression profile is observed, but down-stream targets relevant for leukemogenesis are not known. Here we identify Sox4 as a direct target of C/EBP? whereby its expression is inversely correlated with C/EBP? activity. Downregulation of Sox4 abrogated increased self-renewal of leukemic cells and restored their differentiation. Gene expression profiles of leukemia initiating cells (LICs) from both Sox4 overexpression and murine mutant C/EBP? AML models clustered together, but differed from other types of AML. Our data demonstrate that Sox4 overexpression resulting from C/EBP? inactivation contributes to the development of leukemias with a distinct LIC phenotype. K/L (bi-allelic Cebpa mutations) leukemic mice and Sox4 overexprssing leukemic mice were used for RNA extraction and hybridization on Affymetrix microarrays. We compared these microarray samples with the C57/BL6 wild type mice.
Project description:Mutation or epigenetic silencing of the transcription factor C/EBPa is observed in ~10% of patients with acute myeloid leukemia (AML). In both cases, a common global gene expression profile is observed, but down-stream targets relevant for leukemogenesis are not known. Here we identify Sox4 as a direct target of C/EBPa whereby its expression is inversely correlated with C/EBPa activity. Downregulation of Sox4 abrogated increased self-renewal of leukemic cells and restored their differentiation. Gene expression profiles of leukemia initiating cells (LICs) from both Sox4 overexpression and murine mutant C/EBPa AML models clustered together, but differed from other types of AML. Our data demonstrate that Sox4 overexpression resulting from C/EBPa inactivation contributes to the development of leukemias with a distinct LIC phenotype. A ChIP-seq sample of C/EBPa in Macrophages is used in this study
Project description:Mutation or epigenetic silencing of the transcription factor C/EBPa is observed in ~10% of patients with acute myeloid leukemia (AML). In both cases, a common global gene expression profile is observed, but down-stream targets relevant for leukemogenesis are not known. Here we identify Sox4 as a direct target of C/EBPa whereby its expression is inversely correlated with C/EBPa activity. Downregulation of Sox4 abrogated increased self-renewal of leukemic cells and restored their differentiation. Gene expression profiles of leukemia initiating cells (LICs) from both Sox4 overexpression and murine mutant C/EBPa AML models clustered together, but differed from other types of AML. Our data demonstrate that Sox4 overexpression resulting from C/EBPa inactivation contributes to the development of leukemias with a distinct LIC phenotype.
Project description:Mutation or epigenetic silencing of the transcription factor C/EBPα is observed in ~10% of patients with acute myeloid leukemia (AML). In both cases, a common global gene expression profile is observed, but down-stream targets relevant for leukemogenesis are not known. Here we identify Sox4 as a direct target of C/EBPα whereby its expression is inversely correlated with C/EBPα activity. Downregulation of Sox4 abrogated increased self-renewal of leukemic cells and restored their differentiation. Gene expression profiles of leukemia initiating cells (LICs) from both Sox4 overexpression and murine mutant C/EBPα AML models clustered together, but differed from other types of AML. Our data demonstrate that Sox4 overexpression resulting from C/EBPα inactivation contributes to the development of leukemias with a distinct LIC phenotype.
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:Leukemia initiating cells (LICs) self-renew indefinitely to fuel leukemic growth and spark disease relapse. Previously thought to be primitive and rare, the LIC state may actually be heterogeneous and dynamic, allowing LICs to evade therapy. Here, we use single cell transcriptomics to dissect the ontogeny of MLL-rearranged B-lymphoblastic leukemia (MLL-r B-ALL). Although we identify primitive, rare LICs, we also find more phenotypically differentiated LICs that possess the capability to replenish the full cellular diversity of MLL-r B-ALL. We find that activation of MYC-driven oxidative phosphorylation drives this process of cell state conversion, defining a new mechanism of LIC plasticity.
Project description:Leukemia initiating cells (LICs) self-renew indefinitely to fuel leukemic growth and spark disease relapse. Previously thought to be primitive and rare, the LIC state may actually be heterogeneous and dynamic, allowing LICs to evade therapy. Here, we use single cell transcriptomics to dissect the ontogeny of MLL-rearranged B-lymphoblastic leukemia (MLL-r B-ALL). Although we identify primitive, rare LICs, we also find more phenotypically differentiated LICs that possess the capability to replenish the full cellular diversity of MLL-r B-ALL. We find that activation of MYC-driven oxidative phosphorylation drives this process of cell state conversion, defining a new mechanism of LIC plasticity.
Project description:Leukemia initiating cells (LICs) self-renew indefinitely to fuel leukemic growth and spark disease relapse. Previously thought to be primitive and rare, the LIC state may actually be heterogeneous and dynamic, allowing LICs to evade therapy. Here, we use single cell transcriptomics to dissect the ontogeny of MLL-rearranged B-lymphoblastic leukemia (MLL-r B-ALL). Although we identify primitive, rare LICs, we also find more phenotypically differentiated LICs that possess the capability to replenish the full cellular diversity of MLL-r B-ALL. We find that activation of MYC-driven oxidative phosphorylation drives this process of cell state conversion, defining a new mechanism of LIC plasticity.
Project description:Leukemia initiating cells (LICs) self-renew indefinitely to fuel leukemic growth and spark disease relapse. Previously thought to be primitive and rare, the LIC state may actually be heterogeneous and dynamic, allowing LICs to evade therapy. Here, we use single cell transcriptomics to dissect the ontogeny of MLL-rearranged B-lymphoblastic leukemia (MLL-r B-ALL). Although we identify primitive, rare LICs, we also find more phenotypically differentiated LICs that possess the capability to replenish the full cellular diversity of MLL-r B-ALL. We find that activation of MYC-driven oxidative phosphorylation drives this process of cell state conversion, defining a new mechanism of LIC plasticity.
Project description:Leukemia initiating cells (LICs) self-renew indefinitely to fuel leukemic growth and spark disease relapse. Previously thought to be primitive and rare, the LIC state may actually be heterogeneous and dynamic, allowing LICs to evade therapy. Here, we use single cell transcriptomics to dissect the ontogeny of MLL-rearranged B-lymphoblastic leukemia (MLL-r B-ALL). Although we identify primitive, rare LICs, we also find more phenotypically differentiated LICs that possess the capability to replenish the full cellular diversity of MLL-r B-ALL. We find that activation of MYC-driven oxidative phosphorylation drives this process of cell state conversion, defining a new mechanism of LIC plasticity.