Project description:Here we show that pan-haematopoietic ERG expression driven by the Vav promoter induces an early progenitor myeloid leukemia in transgenic mice. Integrated genome-scale analysis of gene expression and ERG binding profiles revealed that ERG activates a transcriptional program similar to human AML stem/progenitor cells and human AML with high ERG expression. We further show that ERG induces expression of the Pim1 kinase oncogene through a novel enhancer element validated in transgenic mice, and Pim1 inhibition disrupts growth and induces apoptosis of ERG-driven leukemic cells. In addition, ERG indirectly induces the RAS pathway and direct RAS inhibition by a RAS inhibitor blocks growth of leukemia cells in vitro and in vivo. Thus, integrative genomic analysis of transgenic ERG leukemias reveals mechanisms and potential therapeutic targets of high ERG expressing AML.
Project description:Here we show that pan-haematopoietic ERG expression driven by the Vav promoter induces an early progenitor myeloid leukemia in transgenic mice. Integrated genome-scale analysis of gene expression and ERG binding profiles revealed that ERG activates a transcriptional program similar to human AML stem/progenitor cells and human AML with high ERG expression. We further show that ERG induces expression of the Pim1 kinase oncogene through a novel enhancer element validated in transgenic mice, and Pim1 inhibition disrupts growth and induces apoptosis of ERG-driven leukemic cells. In addition, ERG indirectly induces the RAS pathway and direct RAS inhibition by a RAS inhibitor blocks growth of leukemia cells in vitro and in vivo. Thus, integrative genomic analysis of transgenic ERG leukemias reveals mechanisms and potential therapeutic targets of high ERG expressing AML. Spleen cells were fixed with 1% formaldehyde and ChIP assays were performed as previously described (Wilson NK et al., 2010 Cell Stem Cell) using polyclonal antibodies against ERG-1/2/3 (clone C-17, Sc354X, Santa Cruz) and control nonspecific rabbit IgG (I5006, Sigma).
Project description:The Ets transcription factor, ERG, plays a central role in definitive hematopoiesis and its overexpression in acute myeloid leukemia is associated with a stem cell signature and bad prognosis. However, little is known about the underlying mechanism by which ERG causes leukemia. Therefore we sought to identify ERG targets that participate in development of leukemia by integration of expression arrays and Chromatin immunoprecipitation. Bone marrow was collected from three transgenic ERG mice harboring a myeloid leukemia and twelve wild type mice. Nine wild type bone marrow samples were lineage depleted and pooled into 3 samples (each one consisting of three lineage negative wild type bone marrows). The resulting 9 samples were used for RNA extraction and hybridization on affymetrix microarrays.
Project description:The Ets transcription factor, ERG, plays a central role in definitive hematopoiesis and its overexpression in acute myeloid leukemia is associated with a stem cell signature and bad prognosis. However, little is known about the underlying mechanism by which ERG causes leukemia. Therefore we sought to identify ERG targets that participate in development of leukemia by integration of expression arrays and Chromatin immunoprecipitation.
Project description:ERG is an Ets-transcription factor required for normal blood stem cell development. High ERG expression in acute myeloid leukemia (AML) and acute T-cell lymphoblastic leukemia (T-ALL) is associated with a stem cell signature and poor prognosis. In murine over-expression models, human ERG is a potent oncogene that induces both T-ALL and AML. However the functional and molecular consequences of high ERG expression in normal hematopoietic stem/progenitors (HSPCs), and how this contributes to leukemia development, are unknown. Here we show that retroviral transduction of ERG into human CD34+ cells and maintenance of ERG at levels present in high ERG AML results in altered myeloid and T cell differentiation and an increase in the self-renewal capacity of transduced progenitors but not the more primitive stem cell compartment. Integrated analysis of genome-wide expression in high ERG CD34+ and ERG binding profiles in HSPCs revealed that these functional characteristics were accompanied by an expression signature that was enriched in normal HSCs, high ERG AMLs, early T-cell precursor (ETP)-ALLs and leukemic stem cell signatures associated with poor clinical outcome. The proliferative advantage of high ERG progenitors may provide a cellular context for the acquisition and propagation of mutations that contribute to the pathogenesis of leukaemia. RNA sequencing in ERG overexpressing human CD34+ cells
Project description:ERG is a transcription factor that is involved in leukomogenesis and its mRNA overexpression has been associated with poor prognosis in a subset of patients with T-cell acute lymphoblastic leukemia (T-ALL) and acute myeloid leukemia (AML). Herein, a genome-wide screen of ERG target genes was conducted by chromatin immunoprecipitation-on-chip (ChIP-chip) in Jurkat cells. 342 significant annotated regions were derived from ChIP-chip experiments. Seventeen candidate promoter regions resulted in at least two-fold enrichment by quantitative PCR. Notably, ERG potential targets included WNT signaling genes: WNT2, WNT9A, WNT11, CCND1, and FZD7. Functionally, expression of WNT11 was downregulated with siRNA ERG knockdown and substantially upregulated in a tet-on ERG-inducible assay in K562 cells. To investigate a role for ERG in WNT signaling, a WNT agonist was used to inhibit glycogen synthase kinase (GSK-3). This treatment resulted in an ERG-dependent proliferative growth advantage in the tet-on ERG-inducible system. Lastly, chromatin immunoprecipitation assays of primary leukemia blasts confirmed WNT11 promoter enrichment dependent on ERG mRNA expression. In conclusion, ERG transcriptional networks in leukemia are revealed. Specifically, WNT11 emerged as a target of ERG. We propose that overexpression of ERG in acute leukemia may lead to a proliferative advantage upon activation of WNT signals. ChIP-chip with ERG antibody C20 and combined C17/20 and nonspecificic IgG in Jurkat
Project description:Chromosomal rearrangements involving EVI1 (MECOM) define a subtype of acute myeloid leukemia (AML) that is associated with a two-year survival rate of <10%. Gene regulatory functions of EVI1 are largely elusive and no targeted therapeutics exist. We developed experimentally tractable murine and human leukemia models that recapitulate phenotypic and transcriptional features of EVI1-rearranged AML and enable large-scale loss-of-function screens. We characterize EVI1-controlled transcriptional programs in cell culture and in vivo, perform CRISPR screens and identify the ETS-related transcription factor ERG as the only gene that is specifically required for EVI1-driven AML. ERG is transcriptionally activated by EVI1 and overexpressed in EVI1-rearranged AML patients. ERG suppression selectively induces terminal differentiation of leukemia cells. EVI1 becomes dispensable for leukemia cells upon ectopic expression of ERG, indicating that key functions of EVI1 are mediated through aberrant activation of ERG. Interfering with this regulatory axis may therefore provide new entry points for rational therapies.
Project description:The ETS transcription factor ERG is involved in several cancers including leukemia. However, ERG domains and co-factors involved in leukemogenesis remain largely uncharacterized and as a transcription factor it is currently undruggable. Here, we report a critical role for the conserved amino-acid proline at position 199, at the 3’ end of the PNT domain, for ERG’s leukemogenic activity. Specifically, we demonstrate that it is required for ERG-induced self-renewal and restriction of myeloid differentiation in hematopoietic progenitor cells and for initiation of leukemia in mouse transduction/transplantation models. Mechanistically, we show that P199 facilitates the interaction of ERG with the NCoR-HDAC3 co-repressor complex. Inhibition of HDAC3 reduced in vitro and in vivo growth of human ERG-dependent leukemic cells as well as growth of ERG dependent prostate cancer cells. Thus, the interaction of ERG with the NCoR-HDAC3 co-repressor complex is required for its oncogenic activity and modulation of this interaction may provide an opportunity for therapeutic intervention.
Project description:The ETS transcription factor ERG is involved in several cancers including leukemia. However, ERG domains and co-factors involved in leukemogenesis remain largely uncharacterized and as a transcription factor it is currently undruggable. Here, we report a critical role for the conserved amino-acid proline at position 199, at the 3’ end of the PNT domain, for ERG’s leukemogenic activity. Specifically, we demonstrate that it is required for ERG-induced self-renewal and restriction of myeloid differentiation in hematopoietic progenitor cells and for initiation of leukemia in mouse transduction/transplantation models. Mechanistically, we show that P199 facilitates the interaction of ERG with the NCoR-HDAC3 co-repressor complex. Inhibition of HDAC3 reduced in vitro and in vivo growth of human ERG-dependent leukemic cells as well as growth of ERG dependent prostate cancer cells. Thus, the interaction of ERG with the NCoR-HDAC3 co-repressor complex is required for its oncogenic activity and modulation of this interaction may provide an opportunity for therapeutic intervention.
Project description:The ETS transcription factor ERG is involved in several cancers including leukemia. However, ERG domains and co-factors involved in leukemogenesis remain largely uncharacterized and as a transcription factor it is currently undruggable. Here, we report a critical role for the conserved amino-acid proline at position 199, at the 3’ end of the PNT domain, for ERG’s leukemogenic activity. Specifically, we demonstrate that it is required for ERG-induced self-renewal and restriction of myeloid differentiation in hematopoietic progenitor cells and for initiation of leukemia in mouse transduction/transplantation models. Mechanistically, we show that P199 facilitates the interaction of ERG with the NCoR-HDAC3 co-repressor complex. Inhibition of HDAC3 reduced in vitro and in vivo growth of human ERG-dependent leukemic cells as well as growth of ERG dependent prostate cancer cells. Thus, the interaction of ERG with the NCoR-HDAC3 co-repressor complex is required for its oncogenic activity and modulation of this interaction may provide an opportunity for therapeutic intervention.