Epigenetic vulnerabilities of leukemia harboring inactivating EZH2 mutations
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PROVIDER: PRJNA1043177 | ENA |
REPOSITORIES: ENA
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Project description:We investigated the epigenetic vulnerabilities of acute myeloid leukemia (AML) and myelodysplastic/myeloproliferative disorders (MDS/MPN) by performing a chemical probe screen in patient cells. Paradoxically, we observed increased sensitivity to EZH2 and EED inhibitors in AML and MDS/MPN patient cells harboring EZH2 mutations. Expression analysis indicated that EZH2 inhibition elicited upregulation of pathways responsible for cell death and growth arrest, specifically in patient cells with mutant EZH2. The identified EZH2 mutations had drastically reduced catalytic activity, resulting in lower cellular H3K27me3 levels and were associated with decreased EZH2 and PRC2 component EED protein levels. Overall, this study provides an important understanding of the role of EZH2 dysregulation in blood cancers and may indicate disease etiology for these poor prognosis AML and MDS/MPN cases
2025-01-31 | GSE248296 | GEO
Project description:The EZH2 histone methyltransferase is highly expressed in germinal center (GC) B-cells and targeted by somatic mutations in B-cell lymphomas. Here we find that EZH2 deletion or pharmacologic inhibition suppresses GC formation and functions in mice. EZH2 represses proliferation checkpoint genes and helps establish bivalent chromatin domains at key regulatory loci to transiently suppress GC B-cell differentiation. Somatic mutations reinforce these physiological effects through enhanced silencing of EZH2 targets in B-cells, and in human B-cell lymphomas. Conditional expression of mutant EZH2 in mice induces GC hyperplasia and accelerated lymphomagenesis in cooperation with BCL2. GCB-type DLBCLs are mostly addicted to EZH2, regardless of mutation status, but not the more differentiated ABC-type DLBCLs, thus clarifying the therapeutic scope of EZH2 targeting. RNA sequencing and H3K27me3 ChIP sequencing of human DLBCL cell lines and murine BCL1 cell line. RNA sequencing, H3K27me3 and H3K4me3 ChIP sequencing of B cells from de-identified human tonsills.
2013-05-13 | E-GEOD-45982 | biostudies-arrayexpress
Project description:The epigenetic modifier EZH2 is part of the polycomb repressive complex that suppresses gene expression via histone methylation. Activating mutations in EZH2 are found in a subset of melanoma that contributes to disease progression by inactivating tumor suppressor genes. In this study we have targeted EZH2 with a specific inhibitor (GSK126) or depleted EZH2 protein by stable shRNA knockdown. We show that inhibition of EZH2 has potent effects on the growth of both wild-type and EZH2 mutant human melanoma in vitro particularly in cell lines harboring the EZH2Y646 activating mutation. This was associated with cell cycle arrest, reduced proliferative capacity in both 2D and 3D culture systems, and induction of apoptosis. The latter was caspase independent and mediated by the release of apoptosis inducing factor (AIFM1) from mitochondria. Gene expression arrays showed that several well characterized tumor suppressor genes were reactivated by EZH2 inhibition. This included activating transcription factor 3 (ATF3) that was validated as an EZH2 target gene by ChIP-qPCR. These results emphasize a critical role for EZH2 in the proliferation and viability of melanoma and highlight the potential for targeted therapy against EZH2 in treatment of patients with melanoma. Tiffen JC, Gunatilake D, Gallagher SJ, Gowrishankar K, Heinemann A, Cullinane C, et al. Targeting activating mutations of EZH2 leads to potent cell growth inhibition in human melanoma by derepression of tumor suppressor genes. Oncotarget 2015;12:12
2019-11-15 | GSE140394 | GEO
Project description:The EZH2 histone methyltransferase is highly expressed in germinal center (GC) B-cells and targeted by somatic mutations in B-cell lymphomas. Here we find that EZH2 deletion or pharmacologic inhibition suppresses GC formation and functions in mice. EZH2 represses proliferation checkpoint genes and helps establish bivalent chromatin domains at key regulatory loci to transiently suppress GC B-cell differentiation. Somatic mutations reinforce these physiological effects through enhanced silencing of EZH2 targets in B-cells, and in human B-cell lymphomas. Conditional expression of mutant EZH2 in mice induces GC hyperplasia and accelerated lymphomagenesis in cooperation with BCL2. GCB-type DLBCLs are mostly addicted to EZH2, regardless of mutation status, but not the more differentiated ABC-type DLBCLs, thus clarifying the therapeutic scope of EZH2 targeting.
2013-05-13 | GSE45982 | GEO
Project description:Inactivating EZH2 mutations have been associated with myelofibrosis (MF). Moreover, EZH2 mutations co-exist with the JAK2V617F mutation in a significant cases of MF. To determine the effects of concomitant loss of EZH2 and JAK2V617F mutation in hematopoiesis, we generated Ezh2-deficient Jak2V617F-expressing mice. To identify the Ezh2 target genes that are regulated by H3K27me3 in MF, we performed H3K27me3 ChIP-sequencing in sorted LSK cells from control, MxCre;Jak2VF/+ and MxCre;Jak2VF/+ EZH2-/- mice.
2016-04-19 | GSE79319 | GEO
Project description:We describe inactivating somatic mutations in the histone lysine demethylase, UTX, in human cancers pointing to the deregulation of histone H3 lysine methylation in the development of multiple tumour types. Gene expression was analysed on Illumina Human WG-6 v2 BeadChips following standard protocols. Data quality test and normalization were performed using the Lumi package implemented in R.
2009-02-16 | E-MTAB-84 | biostudies-arrayexpress
Project description:We studied transcriptional changes by Affymetrix human microarrays in DLBCL cell lines as a result of treatment with GSK126, a potent, highly-selective, SAM-competitive, small molecule inhibitor of EZH2 In eukaryotes, epigenetic post-translational modification of histones is critical for regulation of chromatin structure and gene expression. EZH2 is the catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) and is responsible for repressing target gene expression through methylation of histone H3 on lysine 27 (H3K27). Over-expression of EZH2 is implicated in tumorigenesis and correlates with poor prognosis in multiple tumor types. Recent reports have identified somatic heterozygous mutations of Y641 and A677 residues within the catalytic SET domain of EZH2 in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). The Y641 residue is the most frequently mutated residue, with 22% of GCB (Germinal Cell B-cell) DLBCL and FL harboring mutations at this site. These lymphomas exhibit increased H3K27 tri-methylation (H3K27me3) due to altered substrate preferences of the mutant enzymes. However, it is unknown whether direct inhibition of EZH2 methyltransferase activity alone will be effective in treating lymphomas carrying activating EZH2 mutations. Herein, we demonstrate that GSK126, a potent, highly-selective, SAM-competitive, small molecule inhibitor of EZH2 methyltransferase activity, decreases global H3K27me3 levels and reactivates silenced PRC2 target genes. GSK126 effectively inhibits the proliferation of EZH2 mutant DLBCL cell lines and dramatically inhibits the growth of EZH2 mutant DLBCL xenografts in mice. Together, these data demonstrate that pharmacological inhibition of EZH2 activity may provide a promising treatment for EZH2 mutant lymphoma. 10 DLBCL cell lines (7 mutant and 3 wild type EZH2), that were differentially sensitive to GSK126 in proliferation assays, were treated for 72 hours, in duplicate (n=2), with either DMSO (vehicle) or 500nM of GSK126, a potent selective EZH2 inhibitor. EZH2 mutant cell lines are Pfeiffer, KARPAS-422, WSU-DLCL2, SU-DHL-10, SU-DHL-6, DB and SU-DHL-4. EZH2 wildtype cell lines are HT, OCI-LY-19 and Toledo.
2012-10-12 | E-GEOD-40971 | biostudies-arrayexpress
Project description:Comparison of mRNA expression profiles of MEPs with or without mutations in JAK2 and Ezh2 by RNA sequencing. MEPs mRNA was extracted from six different transgenic mice (SclCre, SclCre;Ezh2+/-, SclCre;Ezh2-/-, SclCre; JAK2V617F, SclCre; JAK2V617F;Ezh2+/-, SclCre; JAK2V617F;Ezh2-/-) 10 weeks after tamoxifen injection. Our study represents the first detailed analysis of mRNA expression profile of MEP with or without mutations in JAK2 and Ezh2 , with biologic replicates, generated by RNA-seq technology. Our results revealed that mRNA expression profile of MEP with different genotype showed specific gene expression patterns, which allows to do biological comprehensive and quantitative analysis for hematopoiesis. MEPs mRNA profiles six different transgenic mice (SclCre, SclCre;Ezh2+/-, SclCre;Ezh2-/-, SclCre; JAK2V617F, SclCre; JAK2V617F;Ezh2+/-, SclCre; JAK2V617F;Ezh2-/-) were generated by deep sequencing.
2016-06-24 | E-GEOD-82072 | biostudies-arrayexpress
Project description:EZH2 and H3K27me3 ChIP-seq in E14 mouse embryonic stem cells harboring wildtype or mutant EZH2.
| PRJNA436988 | ENA
Project description:Inactivating EZH2 mutations have been associated with myelofibrosis (MF). Moreover, EZH2 mutations co-exist with the JAK2V617F mutation in a significant cases of MF. To determine the effects of concomitant loss of EZH2 and JAK2V617F mutation in hematopoiesis, we generated Ezh2-deficient Jak2V617F-expressing mice. To gain insights into the mechanisms by which Ezh2 deficiency promotes the development of MF in Jak2V617F knock-in mice, we performed microarray gene expression analysis on sorted LT-HSC from control, MxCre;Jak2VF/+ and MxCre;Jak2VF/+ EZH2-/- mice.
2016-04-19 | GSE79198 | GEO