Project description:Puropose: To detemine transcriptome profile of Evi1-overexpressing leukemia cells by RNA sequencing Method: RNA samples were isolated from GFP+Lin-c-kit+ mouse bone marrow cells
Project description:To infer enhancers and super enhancers in Acute Myeloid Leukemia (AML) Cell lines with a 3q-aberration we determined regions enriched for H3K27AC, H3K4ME3, H3K4ME1, P300, and BRD4 in MOLM1. Additionally we determined regions enriched for P300 and BRD4 in the cell line Mutz3 which also harbors a 3q-aberration. As an control we performed Chip-Seq to determine enrichment for BRD4 in K562, which overexpresses the proto-oncogene EVI1, but has no apparent 3q-aberration. Ultimately, the ChipSeq experiments were utilized to infer which enhancer or super enhancer drives the overexpression of EVI1 in AMLs with a 3q-aberration. Finally, the effect of the compound JQ1 on the inferred super enhancers and the overexpression of EVI1 is tested by treating the cell line MOLM1 for 6 hours and determining the residual binding of BRD4.
Project description:Ecotropic viral integration site 1 (EVI1/MECOM) overexpression is common in myeloid malignancies. We present a new Evi1 transgenic mouse model with inducible expression in hematopoietic stem cells (HSCs) and progenitor cells (HPCs) at lower levels. Upon exogenous Evi1 induction, mice displayed anemia, thrombocytopenia, lymphopenia, and dysplasia in erythroid and megakaryocyte cells with a significant expansion of committed myeloid progenitor cells, resembling human Myelodysplastic syndrome/Myeloproliferative neoplasm (MDS/MPN)-like disease. Methods: Lin-C-Kit+ cells were isolated from 2 Evi1 overexpressing mice for CUT&RUN assay using flag antibody and IgG. Lin-C-Kit+ cells were isolated from 2 pair of WT mice and Evi1 overexpressing mice for CUT&RUN assay using H3K27me3 antibody.Around 5X105 Lin-C-Kit+ cells for each group were used in CUT&RUN assay. About 10 ng of the purified CUT&RUN DNA was used for preparation of multiplexed libraries with the NEB Ultra II DNA Library Prep Kit per manufacturer's instruction (NEB #E7103). Sequencing was conducted using an Illumina NextSeq 500 Sequencing System. Results: Molecular pathways altered in Lin-C-Kit+ cells from Evi1-OE mice. Conclusions: Evi1 has a special binding profiling in Lin-C-Kit+ cells. The modification profile of H3K27me3 was altered in Evi1-OE hematopoietic stem and progenitor cells.
Project description:The overexpression of the ecotropic viral integration site-1 gene (EVI1/MECOM) marks the most lethal acute myeloid leukemia (AML) subgroup carrying chromosome 3q26 abnormalities. By taking advantage of the intersectionality of high-throughput cell-based and gene expression screens, we identified selective and pan-histone deacetylase inhibitors (HDACis) as potent repressors of EVI1. To understand the mechanism driving on-target anti-leukemia activity of this compound class, we dissected the expression dynamics of the bone marrow leukemia cells of patients treated with HDACi and reconstituted the EVI1 chromatin-associated co-transcriptional complex merging on the role of proliferation-associated 2G4 protein. PA2G4 overexpression rescues AML cells from the inhibitory effects of HDACis, while genetic and small molecule inhibition of PA2G4 abrogated EVI1 in 3q26 AML cells, including in patient-derived leukemia xenografts. This study positions PA2G4 at the crosstalk of the EVI1 leukemogenic signal for developing new therapeutics and urges the use of HDACi-based combination therapies in patients with 3q26 AML.
Project description:Evi1 is essential for proliferation of hematopoietic stem cells and implicated in the development of myeloid disorders. Particularly, high Evi1 expression defines one of the largest clusters in acute myeloid leukemia and is significantly associated with extremely poor prognosis. Improvement of the therapeutic outcome of leukemia with activated Evi1 is one of the most challenging issues. However, mechanistic basis of Evi1-mediated leukemogenesis has not been fully elucidated. Here we show that Evi1 directly represses PTEN transcription in the murine bone marrow, which leads to activation of AKT/mTOR signaling. In a murine bone marrow transplantation model, Evi1 leukemia showed remarkable sensitivity to an mTOR inihibitor rapamycin. Furthermore, we found that Evi1 binds to several polycomb group proteins and recruits polycomb repressive complexes for PTEN downregulation, which reveals a novel epigenetic mechanism of AKT/mTOR activation in leukemia. Expression analyses and chromatin immunoprecipitation assays using human samples indicate that our findings in mice models are recapitulated in human leukemic cells. Dependence of Evi1-expressing leukemic cells on AKT/mTOR signaling provides the first example of targeted therapeutic modalities that suppress the leukemogenic activity of Evi1. The PTEN/AKT/mTOR signaling pathway and the Evi1-polycomb interaction can be promising therapeutic targets for leukemia with activated Evi1. Gene expression analysis for the purpose of identifying the target genes of Evi1 in primary bone marrow. 5-FU-primed mononuclear bone marrow cells harvested from C57/B6 mice were retrovirally transduced with Evi1-GFP or GFP. GFP positive cells were sorted and analyzed by Affymetrix® Mouse Genome 430 2.0 Array® for gene expression. Four independent experiments were performed.
Project description:Evi1 is essential for proliferation of hematopoietic stem cells and implicated in the development of myeloid disorders. Particularly, high Evi1 expression defines one of the largest clusters in acute myeloid leukemia and is significantly associated with extremely poor prognosis. Improvement of the therapeutic outcome of leukemia with activated Evi1 is one of the most challenging issues. However, mechanistic basis of Evi1-mediated leukemogenesis has not been fully elucidated. Here we show that Evi1 directly represses PTEN transcription in the murine bone marrow, which leads to activation of AKT/mTOR signaling. In a murine bone marrow transplantation model, Evi1 leukemia showed remarkable sensitivity to an mTOR inihibitor rapamycin. Furthermore, we found that Evi1 binds to several polycomb group proteins and recruits polycomb repressive complexes for PTEN downregulation, which reveals a novel epigenetic mechanism of AKT/mTOR activation in leukemia. Expression analyses and chromatin immunoprecipitation assays using human samples indicate that our findings in mice models are recapitulated in human leukemic cells. Dependence of Evi1-expressing leukemic cells on AKT/mTOR signaling provides the first example of targeted therapeutic modalities that suppress the leukemogenic activity of Evi1. The PTEN/AKT/mTOR signaling pathway and the Evi1-polycomb interaction can be promising therapeutic targets for leukemia with activated Evi1.
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.