IDH1 Mutation is a Master Regulator of Epigenomic Remodeling and is Sufficient to Establish the Glioma Hypermethylator Phenotype
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE30339 | GEO | 2012/02/16
SECONDARY ACCESSION(S): PRJNA143653
REPOSITORIES: GEO
Similar Datasets
Project description:This SuperSeries is composed of the following subset Series: GSE30336: Expression analysis of 52 glioma clinical samples (36 CIMP+ and 16 CIMP-) and 6 cell line samples GSE30338: Methylation analysis of 81 glioma clinical samples (49 CIMP+ and 32 CIMP-) and 53 cell line samples Refer to individual Series
2012-02-16 | E-GEOD-30339 | biostudies-arrayexpress
Project description:Both genome-wide genetic and epigenetic alterations are fundamentally important for the development of cancers, but the interdependence of these aberrations is poorly understood. Glioblastomas and other cancers with the CpG island methylator phenotype (CIMP) constitute a subset of tumours with extensive epigenomic aberrations and a distinct biology. Glioma CIMP (G-CIMP) is a powerful determinant of tumour pathogenicity, but the molecular basis of G-CIMP remains unresolved. Here we show that mutation of a single gene, isocitrate dehydrogenase 1 (IDH1), establishes G-CIMP by remodelling the methylome. This remodelling results in reorganization of the methylome and transcriptome. Examination of the epigenome of a large set of intermediate-grade gliomas demonstrates a distinct G-CIMP phenotype that is highly dependent on the presence of IDH mutation. Introduction of mutant IDH1 into primary human astrocytes alters specific histone marks, induces extensive DNA hypermethylation, and reshapes the methylome in a fashion that mirrors the changes observed in G-CIMP-positive lower-grade gliomas. Furthermore, the epigenomic alterations resulting from mutant IDH1 activate key gene expression programs, characterize G-CIMP-positive proneural glioblastomas but not other glioblastomas, and are predictive of improved survival. Our findings demonstrate that IDH mutation is the molecular basis of CIMP in gliomas, provide a framework for understanding oncogenesis in these gliomas, and highlight the interplay between genomic and epigenomic changes in human cancers.
| S-EPMC3351699 | biostudies-literature
Project description:IDH1 Mutation is a Master Regulator of Epigenomic Remodeling and is Sufficient to Establish the Glioma Hypermethylator Phenotype
| PRJNA143653 | ENA
Project description:Coordinated experiments focused on transcriptional responses and chromatin states are well-equipped to capture different epigenomic and transcriptomic levels governing the circuitry of a regulatory network. We propose a workflow for the genome-wide identification of epigenomic and transcriptional cooperation to elucidate transcriptional networks in cancer. Gene promoter annotation in combination with network analysis and sequence-resolution of enriched transcriptional motifs in epigenomic data reveals transcription factor families that act synergistically with epigenomic master regulators. By investigating complementary omics levels, a close teamwork of the transcriptional and epigenomic machinery was discovered. The discovered network is tightly connected and surrounds the histone lysine demethylase KDM3A, basic helix-loop-helix factors MYC, HIF1A, and SREBF1, as well as differentiation factors AP1, MYOD1, SP1, MEIS1, ZEB1, and ELK1. In such a cooperative network, one component opens the chromatin, another one recognizes gene-specific DNA motifs, others scaffold between histones, cofactors, and the transcriptional complex. In cancer, due to the ability to team up with transcription factors, epigenetic factors concert mitogenic and metabolic gene networks, claiming the role of a cancer master regulators or epioncogenes. Significantly, specific histone modification patterns are commonly associated with open or closed chromatin states, and are linked to distinct biological outcomes by transcriptional activation or repression. Disruption of patterns of histone modifications is associated with the loss of proliferative control and cancer. There is tremendous therapeutic potential in understanding and targeting histone modification pathways. Thus, investigating cooperation of chromatin remodelers and the transcriptional machinery is not only important for elucidating fundamental mechanisms of chromatin regulation, but also necessary for the design of targeted therapeutics.
| S-EPMC6026491 | biostudies-literature
Project description:Glioma is the most frequent central nervous system tumor in adults. The overall survival of glioma patients is disappointing, mostly due to the poor prognosis of glioblastoma (Grade IV glioma). Isocitrate dehydrogenase (IDH) is a key factor in metabolism and catalyzes the oxidative decarboxylation of isocitrate. Mutations in IDH genes are observed in over 70% of low-grade gliomas and some cases of glioblastoma. As the most frequent mutation, IDH1(R132H) has been served as a predictive marker of glioma patients. The recently developed droplet digital PCR (ddPCR) technique generates a large amount of nanoliter-sized droplets, each of which carries out a PCR reaction on one template. Therefore, ddPCR provides high precision and absolute quantification of the nucleic acid target, with wide applications for both research and clinical diagnosis. In the current study, we collected 62 glioma tissue samples (Grade II to IV) and detected IDH1 mutations by Sanger direct sequencing, ddPCR, and quantitative real-time PCR (qRT-PCR). With the results from Sanger direct sequencing as the standard, the characteristics of ddPCR were compared with qRT-PCR. The data indicated that ddPCR was much more sensitive and much easier to interpret than qRT-PCR. Thus, we demonstrated that ddPCR is a reliable and sensitive method for screening the IDH mutation. Therefore, ddPCR is able to applied clinically in predicting patient prognosis and selecting effective therapeutic strategies. Our data also supported that the prognosis of Grade II and III glioma was better in patients with an IDH mutation than in those without mutation.
| S-EPMC4741852 | biostudies-other
Project description:PurposeNumerous studies have reported that glioma patients with isocitrate dehydrogenase 1(IDH1) R132H mutation are sensitive to temozolomide treatment. However, the mechanism of IDH1 mutations on the chemosensitivity of glioma remains unclear. In this study, we investigated the role and the potential mechanism of Nrf2 in IDH1 R132H-mediated drug resistance.MethodsWild type IDH1 (R132H-WT) and mutant IDH1 (R132H) plasmids were constructed. Stable U87 cells and U251 cells overexpressing IDH1 were generated. Phenotypic differences between IDH1-WT and IDH1 R132H overexpressing cells were evaluated using MTT, cell colony formation assay, scratch test assay and flow cytometry. Expression of IDH1 and its associated targets, nuclear factor-erythroid 2-related factor 2 (Nrf2), NAD(P)H quinine oxidoreductase 1 (NQO1), multidrug resistant protein 1 (MRP1) and p53 were analyzed.ResultsThe IDH1 R132H overexpressing cells were more sensitive to temozolomide than WT and the control, and Nrf2 was significantly decreased in IDH1 R132H overexpressing cells. We found that knocking down Nrf2 could decrease resistance to temozolomide. The nuclear translocation of Nrf2 in IDH1 R132H overexpressing cells was lower than the WT and the control groups after temozolomide treatment. When compared with WT cells, NQO1 expression was reduced in IDH1 R132H cells, especially after temozolomide treatment. P53 was involved in the resistance mechanism of temozolomide mediated by Nrf2 and NQO1.ConclusionsNrf2 played an important role in IDH1 R132H-mediated drug resistance. The present study provides new insight for glioma chemotherapy with temozolomide.
| S-EPMC5438698 | biostudies-literature
Project description:Isocitrate dehydrogenase 1 (IDH1) is the most frequently mutated gene in World Health Organization grade II-III and secondary glioma. The majority of IDH1 mutation cases involve the substitution from arginine to histidine at codon 132 (IDH1-R132H). Although the oncogenic role of IDH1-R132H has been confirmed, patients with IDH1-R132H brain tumors exhibit a better response to radiotherapy compared with those with wild-type (WT) IDH1. In the present study, the potential mechanism of radiosensitization mediated by IDH1-R132H was investigated by overexpressing IDH1-R132H in U87MG glioma cells. The results demonstrated decreased clonogenic capacity of IDH1-R132H-expressing cells, as well as delayed repair of DNA double-strand breaks compared with IDH1-WT. Data from The Cancer Genome Atlas were analyzed, which demonstrated that the expression of TP53-induced glycolysis and apoptosis regulator (TIGAR) was lower in patients with glioma harboring IDH1 mutations compared with that in patients with IDH1-WT. TIGAR-knockdown increases the radiosensitivity of glioma cells; in U87MG cells, IDH1-R132H suppressed TIGAR expression. Chromatin immunoprecipitation assays revealed increased levels of repressive H3K9me3 markers at the TIGAR promoter in IDH1-R132H compared with IDH1-WT. These data indicated that IDH1-R132H may overcome radioresistance in glioma cells through epigenetic suppression of TIGAR expression. However, these favorable effects were not observed in U87MG glioma stem-like cells. The results of the present study provide an improved understanding of the functionality of IDH1 mutations in glioma cells, which may improve the therapeutic efficacy of radiotherapy.
| S-EPMC6956398 | biostudies-literature
Project description:With recent approval of the first dendritic cell (DC) vaccine for patient use, many other DC vaccine approaches are now being tested in clinical trials. Many of these DC vaccines employ tumor cell lysates (TL) generated from cells cultured in atmospheric oxygen (?20% O?) that greatly exceeds levels found in tumors in situ. In this study, we tested the hypothesis that TLs generated from tumor cells cultured under physiologic oxygen (?5% O?) would be more effective as a source for DC antigens. Gene expression patterns in primary glioma cultures established at 5% O? more closely paralleled patient tumors in situ and known immunogenic antigens were more highly expressed. DCs treated with TLs generated from primary tumor cells maintained in 5% O? took up and presented antigens to CD8 T cells more efficiently. Moreover, CD8 T cells primed in this manner exhibited superior tumoricidal activity against target cells cultured in either atmospheric 20% O? or physiologic 5% O?. Together, these results establish a simple method to greatly improve the effectiveness of DC vaccines in stimulating the production of tumoricidal T cells, with broad implications for many of the DC-based cancer vaccines being developed for clinical application.
| S-EPMC3360979 | biostudies-literature
Project description:Astrocytoma, oligodendroglioma, oligoastrocytoma, and ependymoma are the main histologic subtypes of glioma. The molecular character of these subtypes has profound implications for understanding their causes and treatment. We describe the epigenetic landscape of these tumor types using novel DNA methylation profiling tools. There is a robust association of methylation profile with tumor histology and IDH1 mutation status. Furthermore, tumors with IDH1 mutation independently predict a tumor hypermethylator phenotype, histology, TP53 mutation status, patient age, and survival. Integrating tumor epigenetic and genetic alterations, this work provides a critical step toward better defining the somatic nature of glioma which will have great potential to impact clinical approaches to disease. This work provides an important step forward in classification of malignant brain tumors using DNA methylation profiling, integrating knowledge regarding IDH1 mutation in gliomas. The epigenetic homogeneity of the IDH1 mutant subclass despite histologic diversity implies that IDH1 mutation is a “driver” or functional determinant of a distinct DNA methylation phenotype, suggesting a novel role for an altered metabolic profile in the brain. This association occurs across histologic subtypes and demonstrates a clear relationship between genetic alteration and epigenetic profile. Fresh frozen tumor tissues were obtained from the University of California San Francisco (UCSF) Brain Tumor Research Center tissue bank with appropriate institutional review board approval. Tumors were diagnosed between 1990 and 2003. Tumor samples were defined as secondary GBM if the patients had prior histological diagnosis of a low-grade glioma. Tumors had previously been reviewed by UCSF neuropathologists to assign histologic subtype and grade. Normal brain tissue samples were from cancer-free patients who underwent temporal lobe resection as treatment for epilepsy at UCSF.
2010-12-20 | E-GEOD-20395 | biostudies-arrayexpress
Project description:Cancer-specific changes in DNA methylation can alter genetic stability, genomic structure, and gene expression. Promoter CpG island methylation can result in transcriptional silencing and plays an important role in the oncogenic process. We used genome-wide analysis to characterize the methylomes of breast cancers with diverse metastatic behavior. Here, we describe the identification of novel groups of breast tumors characterized by the presence or absence of coordinate hypermethylation at a large number of genes, demonstrating the existence of a breast-CpG island methylator phenotype (B-CIMP). B-CIMP imparts a distinct epigenomic profile and is a strong determinant of metastatic potential. Gene Expression Samples (GSM647057-GSM647077): Twenty-one breast cancer primary samples were analyzed. There are 10 CIMP positive and 11 CIMP negative samples. Methylation Profiling Samples (GSM651372-GSM651410): Thirty-nine breast cancer primary samples were analyzed. There are 17 CIMP positive and 22 CIMP negative samples.
| S-ECPF-GEOD-26349 | biostudies-other