Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

A tumor suppression role for EZH2 in Diffuse Intrinsic Pontine Glioma pathogenesis

ABSTRACT: 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.

ORGANISM(S): Mus musculus

PROVIDER: GSE188450 | GEO | 2022/01/01

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Similar Datasets

Proteomic analysis of chemical and genetic EZH2 inhibition in diffuse intrinsic pontine glioma cell lines

Project description:Diffuse Intrinsic Pontine Glioma (DIPG) is a rare and highly aggressive pediatric tumor. The average survival time after diagnosis is less than one year. Currently, there are no effective treatments. Characteristic of DIPG is a mutation in histone H3 which leads to a substitution of Lysine 27 to Methionine (H3K27M) which deregulates Polycomb Repressive Complex 2 (PRC2), including enzymatic activity of EZH2. Previous studies have shown that inhibition of EZH2 by chemical agents decreases DIPG cell proliferation and inhibits tumor growth in vivo. My thesis project aims to confirm that EZH2 could be a therapeutic target using chemical EZH2 inhibitors, small interfering RNAs and a CRISPR/Cas9 approach in a series of DIPG tumor cell lines and to determine underlying molecular mechanisms of action.

2022-04-01 | PXD017525 | Pride

Genome-wide Analyses of Diffuse Intrinsic Pontine Gliomas

Project description:Purpose: More than 90% of children with diffuse intrinsic pontine glioma (DIPG) die within 2 years of diagnosis. There is a dire need to identify therapeutic targets, however lack of patient material for research has limited progress. We evaluated a large cohort of diffuse intrinsic pontine gliomas (DIPGs) to identify recurrent genomic abnormalities and gene expression signatures underlying DIPG. Patients and Methods: We used single nucleotide polymorphism arrays to evaluate genomic copy number imbalances in 43 DIPGs from 40 patients and in 8 low-grade exophytic brainstem gliomas. Gene expression arrays were used to evaluate expression signatures from 27 DIPGs, 6 low-grade exophytic brainstem gliomas and 66 low-grade gliomas arising outside the brainstem. Results: Frequencies of specific large-scale and focal imbalances varied significantly between DIPGs and pediatric glioblastomas outside the brainstem. Focal amplifications of genes within the receptor tyrosine kinase-Ras-PI3-kinase signaling pathway were found in 47% of DIPG, with PDGFRA and MET showing the highest frequency. 30% of DIPG contained focal amplifications of cell-cycle regulatory genes controlling RB phosphorylation, and 21% had concurrent amplification of genes from both pathways. Some tumors showed heterogeneity in amplification patterns. DIPGs showed distinct gene expression signatures relating to developmental processes compared to pediatric glioblastomas arising outside the brainstem, while expression signatures of low-grade exophytic brainstem gliomas were similar to low-grade gliomas outside the brainstem. Copy number analaysis: 43 DIPG samples, 8 Low Grade Gliomas using SNP6.0. Available matched normals are also profiled with SNP6.0. Expression analysis: 29 DIPG samples, 6 Low grade samples Please contact Suzanne Baker at Suzanne.Baker@stjude.org for CEL files and genotype calls.

2011-09-20 | E-GEOD-26576 | biostudies-arrayexpress

Genome-wide Analyses of Diffuse Intrinsic Pontine Gliomas

2011-09-21 | GSE26576 | GEO

Generation of diffuse intrinsic pontine glioma mouse models by brainstem targeted in utero electroporation

Project description:Diffuse intrinsic pontine gliomas (DIPGs) are highly lethal childhood brain tumors. Their unique genetic makeup, pathological heterogeneity, and brainstem location all present challenges to treatment. Developing mouse models that accurately reflect each of these distinct features will be critical to advance our understanding of DIPG development, progression, and therapeutic resistance. The aim of this study was to generate new mouse models of DIPG, and characterize the role of specific oncogenic combinations in DIPG pathogenesis. We used in utero electroporation (IUE) to transfect neural stem cells in the developing brainstem with PiggyBac DNA transposon plasmids. Combinations of PDGFB or PdgfraD842V, dominant negative Trp53 (DNp53), and H3.3K27M expression induced fully penetrant brainstem gliomas. IUE enabled the targeted transfection of brainstem neural stem cells. PDGFB + DNp53 induced the rapid development of grade-IV gliomas. PdgfraD842V + DNp53 produced slower forming grade-III gliomas. Addition of H3.3K27M only significantly accelerated PdgfraD842V DIPG development. Glioma subgroup molecular signatures were associated with differences in bulk PDGFB and PdgfraD842V tumor composition. H3.3K27M induced both overlapping and unique gene expression changes in PDGFB and PdgfraD842V tumors. Paracrine effects of PDGFB promote disruption of pericyte-endothelial interactions and angiogenesis in PDGFB DIPG mouse models. Brainstem targeted in utero electroporation provides a rapid and flexible system to generate diverse DIPG mouse models. Using IUE to investigate mutation and pathohistological heterogeneity of DIPG will provide a valuable tool for future genetic and preclinical studies.

2019-11-14 | GSE128807 | GEO

EZH2 inhibition as a targeted therapy for H3K27M mutant pediatric gliomas [RNA-Seq]

Project description:Diffuse intrinsic pontine glioma (DIPG) is a highly aggressive brain tumour that is located in the pons and primarily affects children. Whole-exome sequencing studies have identified recurrent driver mutations in H3F3A and HIST1H3B, leading to the expression of histone H3 in which lysine 27 is substituted with methionine (H3K27M) in nearly 80% of DIPGs. H3K27M inhibits Polycomb Repressive Complex 2 (PRC2) activity by binding to its catalytic subunit EZH2 and although DIPGs with H3K27M mutation show global loss of H3 with trimethylated lysine 27 (H3K27me3), several genomic loci are still H3K27me3 positive. Here, we describe a new mouse DIPG model in which H3K27M potentiates tumourigenesis. Using this model and primary patient-derived DIPG cell lines, we show that H3K27M expressing tumours require PRC2 for proliferation. Furthermore, we demonstrate that small molecule EZH2 inhibitors abolish in vitro and in vivo tumour cell growth through a mechanism involving induction of the tumour suppressor protein p16INK4A. In agreement with this, we show that tumour cells with inactivated p16INK4A function do not respond to EZH2 inhibitors. By analysing genome-wide H3K27me3 enrichment profile in mouse DIPG model, we highlight distinct features of the loci that lose or retain H3K27me3 in H3K27M expressing cells. Taken together these results show that residual PRC2 activity is required for the proliferation of H3K27M positive DIPGs, and we propose a therapeutic strategy for these tumours using EZH2 inhibitors and expression of p16INK4A as a marker for stratifying potential responding tumours.

2017-08-31 | GSE71387 | GEO

Combination of CBL0137 and Panobinostat in DIPG

Project description:Diffuse intrinsic pontine glioma (DIPG) is an aggressive and incurable childhood brain tumor for which new treatments are needed. A high throughput drug screen of 3600 pharmaceutical compounds found that anti-malarials, including quinacrine had potent activity against DIPG neurospheres. CBL0137 is a novel anti-cancer compound developed from quinacrine, which targets Facilitates Chromatin Transcription (FACT), a chromatin remodelling complex involved in transcription, replication, and DNA repair. We have found that CBL0137 displays profound cytotoxic activity against a panel of patient derived DIPG cultures, inhibiting cell proliferation and clonogenic potential, restoring tumor suppressor TP53 and Rb activity and inducing cell death through induction of apoptosis. Moreover, in an orthotopic model of DIPG, treatment with CBL0137 significantly extended animal survival. Histone mutations leading to the loss of histone trimethylation result in epigenetic dysregulation driving DIPG tumorigenesis. Treatment with CBL0137 targets this epigenetic defect, restoring both histone H3.3 acetylation and trimethylation and leading to tumor cell death. Combined epigenetic treatment with the histone deacetylase (HDAC) inhibitor panobinostat led to inhibition of the Rb/E2F1 pathway, and increased the enzymatic activity of enhancer of zeste homolog 2 (EZH2), leading to the restoration of H3K27 trimethylation. This combination therapy had synergistic activity against DIPG neurospheres with induction of apoptosis. Consistent with the in vitro results, the combination of CBL0137 and panobinostat significantly prolonged the survival of mice bearing DIPG orthografts suggesting a potential treatment strategy for DIPG.

2021-02-12 | GSE153441 | GEO

Effect of CBL0137 on DIPG cells

2021-03-07 | GSE153883 | GEO

Modeling Malignant Progression in Glioma

Project description:Gliomas are the most common primary brain tumor in humans. Low-grade gliomas (WHO grade II) invariably progress to high-grade gliomas (WHO grade III or IV). Although malignant progression may take many years, the survival rate after transformation to a high-grade glioma is poor, often only 12-15 months. In this data set, we have identified low-grade gliomas that have progressed to high-grade gliomas or high-grade gliomas that have progressed from low-grade gliomas. Some cases are matched pairs (meaning we have both the original low-grade tumor and the subsequent high-grade tumor). The samples deposited have been analyzed with bulk-RNA sequencing. They are also de-identified but are clinically annotated. When available, genetic information including IDH mutation status, 1p/19q deletion and histological subtype are also included.

2021-09-30 | GSE184941 | GEO

H3.3K27M mutant proteins reprogram epigenome by sequestering the PRC2 complex to poised enhancers

Project description:Expression of histone H3.3K27M mutant proteins in diffuse intrinsic pontine glioma (DIPG) results in a global reduction of tri-methylation of H3K27 (H3K27me3), and paradoxically, H3K27me3 peaks remain at hundreds of genomic loci, a dichotomous change that lacks mechanistic insights. Here we show that the PRC2 complex is sequestered at poised enhancers, but not at active promoters with high levels of H3.3K27M proteins, thereby contributing to the global reduction of H3K27me3. Moreover, the levels of H3.3K27M proteins are low at the retained H3K27me3 peaks and consequently having minimal effects on the PRC2 activity at these loci. H3K27me3-mediated silencing at specific tumor suppressor genes, including Wilms Tumor 1, promotes proliferation of DIPG cells. These results support a model in which the PRC2 complex is redistributed to poised enhancers in H3.3K27M mutant cells and supports the proliferation of DIPG cells in part through silencing of tumor suppressor gene WT1.

2018-07-02 | GSE94834 | GEO

iTRAQ-based quantitative proteomic analysis of nuclear fractions of glioma (WHO grade II, III and IV) tissues to identify altered transcriptional regulatory proteins

Project description:Glioma tumors arise from normal glial cells (astrocytes). Gliomas are morphologically and clinically classified into four malignancy grades as Grade I, II, III and IV. Grade I and II comprise low grade gliomas that grow slowly, are well differentiated and have a better prognosis and survival compared to grades III and IV. In contrast, grade III-IV lack endothelial proliferation and are highly vascular with a tendency to infiltrate and have areas of extensive necrosis and hypoxia. In the present study, we used iTRAQ (isobaric tags for relative and absolute quantitation) - based quantitative proteomic approach followed by online liquid chromatography and high resolution tandem mass spectrometry (LC-MS/MS) to identify differential nuclear proteins enriched with transcriptional regulatory function from three different grades of astrocytoma tumors (WHO Grade II, III and IV) compared to control.

2019-08-06 | PXD014111 | Pride

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data