Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

DNA methylation data from pilocytic astrocytoma tumor samples and normal cerebellum controls

ABSTRACT: Pilocytic astrocytomas (PA) are the most common brain tumor in pediatric patients and can cause significant morbidity, including chronic neurological deficiencies. They are characterized by activating alterations in the mitogen-activated protein kinase (MAPK) pathway, but little else is known about their development. To map the global DNA methylation profiles of these tumors, we analysed 61 PAs and 6 normal cerebellum samples using Illumina's Infinium HumanMethylation450 BeadChips. These data revealed two subgroups of PA that separate according to tumor location (infratentorial versus supratentorial), and identified key neural developmental genes that are differentially methylated between the two groups. Integration with transcriptome microarray data highlighted significant expression differences, which were unexpectedly associated with a strong positive correlation between methylation and expression. Differentially methylated probes were often identified within the gene body and/or regions up- or downstream of the gene, rather than at the transcription start site. We also identified a large number of differentially methylated genes between cerebellar PAs and normal cerebellum, which included additional developmental genes. Bisulphite converted DNA from 61 PA tumours (fresh frozen) and 6 normal cerebellum (from commerical sources) were hybridised to the Illumina Infinium HumanMethylation450 BeadChips.

ORGANISM(S): Homo sapiens

SUBMITTER: Sally Lambert

PROVIDER: E-GEOD-44684 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Publications

Differential expression and methylation of brain developmental genes define location-specific subsets of pilocytic astrocytoma.

Lambert Sally R SR Witt Hendrik H Hovestadt Volker V Zucknick Manuela M Kool Marcel M Pearson Danita M DM Korshunov Andrey A Ryzhova Marina M Ichimura Koichi K Jabado Nada N Fontebasso Adam M AM Lichter Peter P Pfister Stefan M SM Collins V Peter VP Jones David T W DT

Acta neuropathologica 20130510 2

Pilocytic astrocytomas (PAs) are the most common brain tumors in pediatric patients and can cause significant morbidity, including chronic neurological deficiencies. They are characterized by activating alterations in the mitogen-activated protein kinase pathway, but little else is known about their development. To map the global DNA methylation profiles of these tumors, we analyzed 62 PAs and 7 normal cerebellum samples using Illumina 450K microarrays. These data revealed two subgroups of PA th ...[more]

PMID: 23660940

Similar Datasets

Project description:Treatment with recombinant human growth hormone (rhGH) has been consistently reported to induce transcriptional changes in various human tissues including peripheral blood. For other hormones it has been shown that the induction of such transcriptional effects is conferred or at least accompanied by DNA-methylation changes. To analyse effects of short term rhGH treatment on the DNA-methylome we investigated a total of 24 patients at baseline and after 4-day rhGH stimulation. We performed array-based DNA-methylation profiling of paired peripheral blood mononuclear cell samples followed by targeted validation using bisulfite pyrosequencing. Unsupervised analysis of DNA-methylation in this short-term treated cohort revealed clustering according to individuals rather than treatment. Supervised analysis identified 239 CpGs as significantly differentially methylated between baseline and rhGH-stimulated samples (p<0.0001, unadjusted paired t-test), which nevertheless did not retain significance after adjustment for multiple testing. An individualised evaluation strategy led to the identification of 2350 CpG and 3 CpH sites showing methylation differences of at least 10% in more than 2 of the 24 analysed sample pairs. To investigate the long term effects of rhGH treatment on the DNA-methylome, we analysed peripheral blood cells from an independent cohort of 36 rhGH treated children born small for gestational age (SGA) as compared to 18 untreated controls. Median treatment interval was 33 months. In line with the groupwise comparison in the short-term treated cohort no differentially methylated targets reached the level of significance in the long-term treated cohort. We identified marked intra-individual responses of DNA-methylation to short-term rhGH treatment. These responses seem to be predominately associated with immunologic functions and show considerable inter-individual heterogeneity. The latter is likely the cause for the lack of a rhGH induced homogeneous DNA-methylation signature after short- and long-term treatment, which nevertheless is well in line with generally assumed safety of rhGH treatment. Bisulfite converted DNA of PB from 36 SGA born children treated long-term with rhGH and 18 SGA born children with no rhGH treatment (controls) were hybridized to the Illumina Infinium HumanMethylation 450k Bead Chip.

Project description:Primary aldosteronism (PA) is the most common endocrine hypertension comprising 10% of hypertensive patients. A recent series of transcriptome analyses using DNA microarray has shown that neumerous genes are differentially expressed between aldosterone-producing adenoma (APA) and its adjacent adrenal gland (AAG) tissue from the same patient. However, the molecular mechanism(s) of pathogenesis of APA has not yet been fully clarified. Although growing body of evidence has shown that epigenetic abnormalities including DNA methylation play a key role in tumorigenesis, there are few studies with regard to DNA methylation in APA. In the present study, to elucidate the pathogenic relationship between gene expression and DNA methylation in PA, we conducted an integrated analysis of transcriptome and methylome data for paired APA-AAG samples from the same patient. Adrenal specimens were obtained from 7 Japanese patients with APA, who underwent adrenalectomy at Tokyo Medical and Dental University. RNA and DNA samples were extracted from those 7 paired APA and AAG tissues. Gene expression and genome-wide DNA methylation profiles were obtained using SurePrint G3 Human GE 8x60K Microarray (Agilent) and Infinium HumanMethylation450 Beadchip (Illumina), respectively. Transcriptome anlaysis identified 244 significantly (2 fold<) upregulated genes in APA compared to AAG. The upregulated genes include the previously studied genes such as PCP4, ALDH1A2, and CYP11B2, and other genes that have not been previously studied, such as HOXA9, HOXA11, and HOXB9. Gene ontology (GO) analysis for these upregulated genes identified the calcium signaling pathway to be most significantly enriched with the upregulated genes (8 genes). Methylome analysis revealed that APA was globally hypomethylated compared to AAG regardless of gene feature groups, namely, TSS1500, TSS200, 5’UTR, 1stExon, gene body, and 3’UTR. GO analysis for the genes showing hypomethylation at TSS1500/TSS200 regions in APA identified the term “cytokine-cytokine receptor interaction” to be most significantly enriched with hypomethylated genes (37 genes). Integrated analysis of gene expression and genome-wide DNA methylation profiles identified 18 genes that are upregulated and whose TSS1500/TSS200 regions are hypomethylated in APA compared to AAG. These genes include CYP11B2 and MC2R (ACTH receptor). In conclusion, this is the first genome-wide study for PA that integrated transcriptome and methylome data. Global DNA hypomethylation in APA and concordant transcriptional up-regulation of some key genes, such as CYP11B2 and MC2R, may play crucial roles in the pathophysiological significance in PA. Adrenal specimens were obtained from 7 Japanese patients with APA, who underwent adrenalectomy at Tokyo Medical and Dental University. RNA and DNA samples were extracted from those 7 paired APA and AAG tissues. Gene expression and genome-wide DNA methylation profiles were obtained using SurePrint G3 Human GE 8x60K Microarray (Agilent) and Infinium HumanMethylation450 Beadchip (Illumina), respectively.

Dataset Information

DNA methylation data from pilocytic astrocytoma tumor samples and normal cerebellum controls

Publications

Differential expression and methylation of brain developmental genes define location-specific subsets of pilocytic astrocytoma.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure