Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA290069 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Gain-of-function IDH mutations define major clinical and prognostic classes of gliomas. Mutant IDH protein produces a novel onco-metabolite, 2-hydroxyglutarate (2-HG), that interferes with iron-dependent hydroxylase enzymes, including the TET family of 5'-methylcytosine hydroxylases. TET enzymes are critical for the dynamic regulation of DNA methylation. IDH mutant gliomas thus manifest a CpG island methylator phenotype (G-CIMP), though the functional significance of this altered epigenetic state remains unclear. Here we show that IDH1 mutant gliomas exhibit hyper-methylation at CTCF binding sites, leading to reduced binding of this methylation-sensitive insulator protein. Loss of CTCF binding is associated with a loss of insulation between topological domains and aberrant gene activation. We specifically demonstrate that loss of CTCF at a domain boundary permits a constitutive enhancer to aberrantly interact with the receptor tyrosine kinase gene PDGFRA, a prominent glioma oncogene. Treatment of IDH mutant gliomaspheres with demethylating agent partially restores insulator function and reduces PDGFRA expression. Conversely, CRISPR-mediated disruption of the CTCF binding sequence in IDH wildtype gliomaspheres induces PDGFRA expression and increases proliferation. Our study suggests that IDH mutations promote gliomagenesis by disrupting chromosomal topology and allowing aberrant regulatory interactions that induce oncogene expression. CTCF occupancy characterization and histone H3K27 acetylation profiling in IDH1 mutant and wild-type glioma patient specimens and culture models. ChIP-seq raw data is to be made available through dbGaP (controlled access) due to patient privacy concerns.
2015-12-23 | E-GEOD-70991 | biostudies-arrayexpress
Project description:Gain-of-function IDH mutations define major clinical and prognostic classes of gliomas. Mutant IDH protein produces a novel onco-metabolite, 2-hydroxyglutarate (2-HG), that interferes with iron-dependent hydroxylase enzymes, including the TET family of 5'-methylcytosine hydroxylases. TET enzymes are critical for the dynamic regulation of DNA methylation. IDH mutant gliomas thus manifest a CpG island methylator phenotype (G-CIMP), though the functional significance of this altered epigenetic state remains unclear. Here we show that IDH1 mutant gliomas exhibit hyper-methylation at CTCF binding sites, leading to reduced binding of this methylation-sensitive insulator protein. Loss of CTCF binding is associated with a loss of insulation between topological domains and aberrant gene activation. We specifically demonstrate that loss of CTCF at a domain boundary permits a constitutive enhancer to aberrantly interact with the receptor tyrosine kinase gene PDGFRA, a prominent glioma oncogene. Treatment of IDH mutant gliomaspheres with demethylating agent partially restores insulator function and reduces PDGFRA expression. Conversely, CRISPR-mediated disruption of the CTCF binding sequence in IDH wildtype gliomaspheres induces PDGFRA expression and increases proliferation. Our study suggests that IDH mutations promote gliomagenesis by disrupting chromosomal topology and allowing aberrant regulatory interactions that induce oncogene expression.
2015-12-23 | GSE70991 | GEO
Project description:Affymetrix OncoScan data for IDH and TP53 mutant gliomas
| PRJNA371737 | ENA
Project description:Recent single-cell transcriptomic studies report that IDH-mutant gliomas share a common hierarchy of cellular phenotypes, independent of genetic subtype. However, the genetic differences between IDH-mutant glioma subtypes are prognostic, predictive of response to chemotherapy, and correlate with distinct tumor microenvironments. To reconcile these findings, we profiled 22 human IDH-mutant gliomas via single-cell assay for transposase-accessible chromatin (scATAC-seq). We determined the cell-type specific differences in transcription-factor expression and associated regulatory grammars between IDH-mutant glioma subtypes. We find that while IDH-mutant gliomas do share a common distribution of cell types, there are significant differences in the expression and targeting of transcription factors that regulate glial identity and cytokine elaboration. We knocked out the chromatin-remodeler ATRX, which suffers loss-of-function alterations in most IDH-mutant astrocytomas, in an IDH-mutant immunocompetent intracranial murine model. We find that both human ATRX-mutant gliomas and murine ATRX-knockout gliomas are more heavily infiltrated by immunosuppressive monocytic-lineage cells derived from circulation than ATRX-intact gliomas, in an IDH-mutant background. ATRX knockout in murine glioma recapitulates gene expression and open-chromatin signatures that are specific to human ATRX-mutant astrocytomas, including drivers of astrocytic lineage and immune-cell chemotaxis. ATRX knockout in murine glioma recapitulates gene expression and open chromatin signatures that are specific to human ATRX-mutant astrocytomas, including drivers of astrocytic lineage and immune-cell chemotaxis. Through single-cell cleavage under targets and tagmentation assays and meta-analysis of public data, we show that ATRX loss leads to a global depletion in CCCTC-binding factor association with DNA, gene dysregulation along associated chromatin loops, and protection from therapy-induced senescence.
2021-10-20 | GSE155430 | GEO
Project description:Epigenetic lesions that disrupt gene regulatory elements and expression are increasingly recognized as pervasive drivers of human cancers. However, we currently lack the in vitro and in vivo models required to functionally validate such lesions and their tumorigenic impact. Here we model aberrations that arise in Isocitrate Dehydrogenase mutant (IDHmut) lower-grade gliomas, which exhibit profound DNA hypermethylation. We initially focus on a CTCF insulator downstream of the PDGFRA oncogene that is recurrently disrupted in IDHmut gliomas. We demonstrate that disruption of the syntenic insulator in mouse oligodendrocyte-progenitor cells (OPCs) allows an OPC-specific enhancer to contact and induce PDGFRA, thereby increasing proliferation. In contrast, insulator disruption did not affect PDGFRA expression in neural progenitor cells (NPCs), which lack the enhancer. We also model a second recurrent epigenetic lesion in IDHmut gliomas, the methylation-dependent silencing of the CDKN2A tumor suppressor. We show that inactivation of CDKN2A/p19ARF by de novo promoter methylation or mutation drives OPC proliferation and synergizes with PDGFRA insulator loss. Finally, we use lentiviruses to coordinately inactivate the PDGFRA insulator and CDKN2A in mouse corpus callosum, resulting in low-grade gliomagenesis in vivo. Our study recapitulates recurrent epigenetic lesions in mouse models and demonstrates that combination of PDGFRA activation and CDKN2A silencing can transform OPCs in vitro and drive gliomagenesis in vivo.
2023-07-25 | GSE225732 | GEO
Project description:Adult-type diffuse gliomas comprise IDH-mutant astrocytomas, IDH-mutant 1p/19q codeleted oligodendrogliomas (ODG), and IDH-wildtype glioblastomas (GBM). GBM display genome instability, which may result from two genetic events leading to massive chromosome alterations: chromothripsis (CT) and whole-genome duplication (WGD). The better prognosis of the latter may be related to their genome stability compared to GBM. Pangenomic profiles of 297 adult diffuse gliomas were analyzed at initial diagnosis using SNP arrays, including 192 GBM and 105 IDH-mutant gliomas (61 astrocytomas and 44 ODG). Tumor ploidy was assessed with Genome Alteration Print and CT events with CTLPScanner and through manual screening.
2024-12-24 | E-MTAB-13542 | biostudies-arrayexpress
Project description:IDH and TP53 mutant gliomas are high recurrent tumor, and thus we aimed to detect malignant and recurent factors in this genetic type of gliomas
2017-09-01 | GSE94652 | GEO
Project description:Gliomas are immunologically cold tumors that can be broken into several categories based on either RNA expression profiles or methylation profiles, with isocitrate dehydrogenase (IDH) mutations defining a major segregration between types. IDH mutant gliomas often exhibit defects in the retinoic acid pathway. We treated mice harboring IDH mutant gliomas with all-trans retinoic acid, and found that this treatment cause reductions in tumor growth and a swith in immune profiles in the tumor microenvironment.
2024-04-19 | GSE172387 | GEO
Project description:Epigenetic lesions that disrupt gene regulatory elements and expression are increasingly recognized as pervasive drivers of human cancers. However, we currently lack the in vitro and in vivo models required to functionally validate such lesions and their tumorigenic impact. Here we model aberrations that arise in Isocitrate Dehydrogenase mutant (IDHmut) lower-grade gliomas, which exhibit profound DNA hypermethylation. We initially focus on a CTCF insulator downstream of the PDGFRA oncogene that is recurrently disrupted in IDHmut gliomas. We demonstrate that disruption of the syntenic insulator in mouse oligodendrocyte-progenitor cells (OPCs) allows an OPC-specific enhancer to contact and induce PDGFRA, thereby increasing proliferation. In contrast, insulator disruption did not affect PDGFRA expression in neural progenitor cells (NPCs), which lack the enhancer. We also model a second recurrent epigenetic lesion in IDHmut gliomas, the methylation-dependent silencing of the CDKN2A tumor suppressor. We show that inactivation of CDKN2A/p19ARF by de novo promoter methylation or mutation drives OPC proliferation and synergizes with PDGFRA insulator loss. Finally, we use lentiviruses to coordinately inactivate the PDGFRA insulator and CDKN2A in mouse corpus callosum, resulting in low-grade gliomagenesis in vivo. Our study recapitulates recurrent epigenetic lesions in mouse models and demonstrates that combination of PDGFRA activation and CDKN2A silencing can transform OPCs in vitro and drive gliomagenesis in vivo.
2023-07-25 | GSE225793 | GEO
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
| S-EPMC2531291 | biostudies-literature