Project description:Loss-of-function mutations in EZH2 are associated with worse outcomes in patients with primary myelofibrosis (PMF). To understand how EZH2 insufficiency is involved in the pathogenesis of PMF, we generated mice compound for Ezh2 conditional deletion and a JAK2V617F transgene. The total bone marrow cells isolated from Cre-ERT2, Ezh2flox/flox;Cre-ERT2, JAK2V617F;Cre-ERT2 and JAK2V617F;Ezh2flox/flox;Cre-ERT2 mice were transplanted into lethally irradiated CD45.1+ wild-type recipient mice. As we deleted Ezh2 at four weeks post transplantation, we performed gene-expression analysis of LSKs and MEPs isolated from the recipient mice at 2 months post transplantation.
Project description:Loss-of-function mutations in EZH2 are associated with worse outcomes in patients with primary myelofibrosis (PMF). To understand how EZH2 insufficiency is involved in the pathogenesis of PMF, we generated mice compound for Ezh2 conditional deletion and a JAK2V617F transgene. The total bone marrow cells isolated from JAK2V617F;Ezh2flox/flox;Cre-ERT2 mice were transplanted into lethally irradiated CD45.1+ wild-type recipient mice. Post the deletion of Ezh2, we administered JAK2V617F/Ezh2?/? mice with JQ1 or control DMSO for two weeks, and performed gene-expression analysis of bone marrow LSKs and MEPs immediately after completion of JQ1 treatment.
Project description:Loss-of-function mutations in EZH2 are associated with worse outcomes in patients with primary myelofibrosis (PMF). To understand how EZH2 insufficiency is involved in the pathogenesis of PMF, we generated mice compound for Ezh2 conditional deletion and a JAK2V617F transgene.
Project description:Loss-of-function mutations in EZH2 are associated with worse outcomes in patients with primary myelofibrosis (PMF). To understand how EZH2 insufficiency is involved in the pathogenesis of PMF, we generated mice compound for Ezh2 conditional deletion and a JAK2V617F transgene.
Project description:Primary mielofibrosis (PMF) is a rare chronic myeloproliferative disorder characterized by the accumulation of abnormal megakaryocytes (Mks) in the bone marrow (BM), variable degrees of BM fibrosis, osteosclerosis and angiogenesis, immature myeloid and erythroid cells, and tear-drop erythrocytes in the peripheral blood (PB), and extramedullary hematopoiesis. The identification of the JAK2V617F mutation represented a seminal discovery in the field of Philadelphia-chromosome–negative chronic myeloproliferative neoplasms (MPNs), providing clues to the pathogenesis, prompting a revision of the diagnostic criteria, and culminating in the development of clinical trials with JAK2 (and JAK1) inhibitors. The JAK2V617F mutation occurs in almost all patients with polycythemia vera (PV) and in 50%-70% of those with essential thrombocythemia (ET) and primary myelofibrosis (PMF). Soon after the identification of the JAK2V617F mutation, mutations in JAK2 exon 12 were described in rare patients with JAK2V617F-negative PV and mutations in MPL were reported in 5%-10% of ET or PMF subjects. The complexity of the molecular pathogenesis of MPNs is reinforced by discovery of additional mutations in TET2, ASXL1, CBL, IDH1/IDH2, EZH2 and IKZF1. These mutations are detected in a minority of patients at different phases of the disorder, including leukemic transformation, and are variably associated each other and with JAK2 or MPL mutations. In order to better characterize biological differences between mutated and wild-type PMF cell populations we performed a gene expression profiling on 9 samples carrying at least one mutation in ASXL1, SRSF2 or EZH2 genes and 11 wild-type samples using the Affymetrix GeneChip technology. After data preprocessing and filtering a supervised analysis approach was used to define a gene expression signature for mutated samples. PMF samples carrying at least one mutation in ASXL1, SRSF2 or EZH2 genes exhibit a specific molecular signature as compared with WT samples. Gene expression profile (GEP) of CD34+ cells from 20 PMF patients (1 replicate for each sample). In particular, GEP was performed on 9 samples carrying at least one mutation in ASXL1, SRSF2 or EZH2 genes and 11 wild-type samples.
Project description:Primary mielofibrosis (PMF) is a rare chronic myeloproliferative disorder characterized by the accumulation of abnormal megakaryocytes (Mks) in the bone marrow (BM), variable degrees of BM fibrosis, osteosclerosis and angiogenesis, immature myeloid and erythroid cells, and tear-drop erythrocytes in the peripheral blood (PB), and extramedullary hematopoiesis. The identification of the JAK2V617F mutation represented a seminal discovery in the field of Philadelphia-chromosome–negative chronic myeloproliferative neoplasms (MPNs), providing clues to the pathogenesis, prompting a revision of the diagnostic criteria, and culminating in the development of clinical trials with JAK2 (and JAK1) inhibitors. The JAK2V617F mutation occurs in almost all patients with polycythemia vera (PV) and in 50%-70% of those with essential thrombocythemia (ET) and primary myelofibrosis (PMF). Soon after the identification of the JAK2V617F mutation, mutations in JAK2 exon 12 were described in rare patients with JAK2V617F-negative PV and mutations in MPL were reported in 5%-10% of ET or PMF subjects. The complexity of the molecular pathogenesis of MPNs is reinforced by discovery of additional mutations in TET2, ASXL1, CBL, IDH1/IDH2, EZH2 and IKZF1. These mutations are detected in a minority of patients at different phases of the disorder, including leukemic transformation, and are variably associated each other and with JAK2 or MPL mutations. In order to better characterize biological differences between mutated and wild-type PMF cell populations we performed a gene expression profiling on 9 samples carrying at least one mutation in ASXL1, SRSF2 or EZH2 genes and 11 wild-type samples using the Affymetrix GeneChip technology. After data preprocessing and filtering a supervised analysis approach was used to define a gene expression signature for mutated samples. PMF samples carrying at least one mutation in ASXL1, SRSF2 or EZH2 genes exhibit a specific molecular signature as compared with WT samples.
Project description:Pediatric high-grade gliomas, specifically diffuse intrinsic pontine gliomas (DIPG), account for 20% of clinical cases but have a 100% fatality rate. A majority of DIPG cases are characterized by the signature H3K27M mutation that is predicted to oppose EZH2, the methyltransferase enzyme of the Polycomb Repressor Complex 2 (PRC2). However, a clear understanding of EZH2’s role in DIPG is lacking. In this study, by incorporating Ezh2 loss and gain of function into our DIPG mouse models we demonstrate its tumor suppressor function. Genetic ablation of Ezh2 increased cell proliferation and tumor grade while expression of an Ezh2 gain of function mutation significantly reduced tumor incidence, increased tumor latency. Transcriptomic analysis revealed that EZH2 deletion upregulates an inflammatory response with upregulation of immunoproteasome genes such as Psmb8, Psmb9, and Psmb10 while EZH2 deletion an enrichment of the oxidative phosphorylation/mitochondrial metabolic pathway namely the isocitrate dehydrogenase Idh1/2/3 genes. Pharmacological inhibition of EZH2 augmented neural progenitor cell proliferation, supporting the tumor suppressive role of EZH2. In vivo treatment of DIPG tumor bearing Ntv-a;p53fl/fl; abcb1a-/-; abcb1b-/-; abcg2-/- (ABC knockout, ABC KO) mice with EZH2 inhibitor, EPZ-6438 did not alter proliferation or significantly impact survival. Together our results suggest that EZH2 has a tumor suppressor function in DIPG and warrants caution in clinical translation of these inhibitors to treat patients with DIPG.