Aberrant DNA methylation in rhabdomyosarcoma
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE61150 | GEO | 2014/10/22
SECONDARY ACCESSION(S): PRJNA260353
REPOSITORIES: GEO
Similar Datasets
Project description:Many pediatric malignancies are embryonal in nature, and one hypothesis for the origin of embryonal tumors is that they arise from a defect in differentiation, either by an inability to terminally differentiate or a reversion to a pluripotent state. There is emerging evidence that epigenetic regulation plays an important role in the transition from embryonic stem cell to a more committed cell fate, utilizing both de novo DNA methylation and poised M-bM-^@M-^XbivalentM-bM-^@M-^Y chromatin domains (H3K27me3 and H3K4me3) to abolish pluripotency and gain lineage- and cell-type-specific characteristics as a cell differentiates. Thus inappropriate epigenetic silencing by aberrant DNA methylation of bivalent genes required for differentiation could lead to the uncontrolled cell growth observed in cancer. Our broad hypothesis is that aberrant DNA methylation in cancer is targeted to a non-random subset of critical pathways used in normal development. This dysregulation of the normal epigenetic program used in development promotes cellular proliferation and provides a mechanism to block differentiation in pediatric cancers, such as rhabdomyosarcoma. Examination of DNA methylation in fourteen human rhabdomyosarcoma patient samples using RRBS. In addition, RRBS was used to examine DNA methylation in one human rhabdomyosarcoma cell line (RD) forced to terminally differentiate by expression of the forced heterodimer MyoD~E12 (MDE). Lastly, RRBS was used to examine DNA methylation changes during normal differentiation in one primary human normal myoblast cell line
2014-10-22 | E-GEOD-61150 | biostudies-arrayexpress
Project description:Because it excises thymine from GM-bM-^@M-"T mismatches, TDG was proposed to counter mutagenesis by 5-methylcytosine deamination. Yet, TDG was also observed to attack 5-methycytosine itself, making it a candidate DNA demethylase, and interactions with transcription factors implicated additional functions in gene regulation. Unlike other DNA glycosylases, TDG is essential for embryonic development. Fibroblasts from Tdg null embryos show massively impaired gene regulation, and this correlates with imbalanced histone modification and CpG methylation. TDG associates with the promoters of affected genes in MEFs and in embryonic stem cells, but epigenetic aberrations appear only in differentiated cells. TDG also contributes to the maintenance of active and bivalent chromatin during cell differentiation, using its DNA glycosylase activity to counter aberrant de novo methylation. Thus, TDG dependent DNA repair stabilizes epigenetic states during cell differentiation. Comparison of 3 Tdg+/- MEF replicates with 3 Tdg-/- MEF replicates. Comparison of Tdg+/- and Tdg-/- ES cells and respective in vitro differentiated neuronal progenitors. Each condition is represented by 3 replicas.
2011-01-31 | E-GEOD-20693 | biostudies-arrayexpress
Project description:Epigenetic priming factors establish a permissive epigenetic landscape which is not required until a later developmental or physiological time point, temporally uncoupling the presence of these factors with their phenotypic effects. One classic example of epigenetic priming is in the context of bivalent chromatin, found in pluripotent stem cells and early embryos at key developmental gene promoters marked by both activating-associated H3K4me3 and repressive-associated H3K27me3 histone modifications. It is currently unknown how these bivalent domains are targeted, or precisely how they impact on lineage commitment. Here we show that the small heterodimerising non-enzymatic DNA binding proteins Developmental Pluripotency Associated 2 (Dppa2) and 4 (Dppa4) act as epigenetic priming factors to establish bivalency at a subset of developmental genes. Dppa2/4 localise to the +1 nucleosome position of bivalent genes and while they are not required for pluripotency in embryonic stem cells (ESCs), double knockout cells fail to exit pluripotency and to differentiate efficiently, with delays in upregulating bivalently marked lineage genes. Proteomics reveal that Dppa2/4 interact on chromatin with members of the COMPASS and Polycomb complexes important for H3K4me3 and H3K27me3 deposition, respectively. Epigenetic profiling reveals a striking loss of H3K4me3, H3K27me3, and their associated enzymatic machinery at a significant subset of bivalent promoters in Dppa2/4 mutants, in addition to loss of H2A.Z and chromatin accessibility. In wild-type ESCs, these “Dppa2/4-dependent” bivalent promoters are characterised by low H3K4me3 enrichment and breadth, near-absent expression levels and initiating but not elongating RNA polymerase. Notably, Dppa2/4-dependent promoters are less evolutionarily conserved suggesting that they lack additional safeguard measures to maintain bivalency at these genes in the absence of Dppa2/4. Concomitantly with the loss of bivalency, Dppa2/4-dependent bivalent promoters gain DNA methylation and consequently are no longer able to be effectively activated upon ESC differentiation, leading to defects in cell fate acquisition. Our findings reveal a targeting principle for bivalency to developmental gene promoters poising them for future lineage specific gene activation.
2020-05-26 | PXD014981 | Pride
Project description:Because it excises thymine from G•T mismatches, TDG was proposed to counter mutagenesis by 5-methylcytosine deamination. Yet, TDG was also observed to attack 5-methycytosine itself, making it a candidate DNA demethylase, and interactions with transcription factors implicated additional functions in gene regulation. Unlike other DNA glycosylases, TDG is essential for embryonic development. Fibroblasts from Tdg null embryos show massively impaired gene regulation, and this correlates with imbalanced histone modification and CpG methylation. TDG associates with the promoters of affected genes in MEFs and in embryonic stem cells, but epigenetic aberrations appear only in differentiated cells. TDG also contributes to the maintenance of active and bivalent chromatin during cell differentiation, using its DNA glycosylase activity to counter aberrant de novo methylation. Thus, TDG dependent DNA repair stabilizes epigenetic states during cell differentiation.
2011-01-31 | GSE20693 | GEO
Project description:In adult cancers, epigenetic changes and aberrant splicing of the DNMT3B is commonly observed, and the pattern of gene methylation and expression has been shown to be modified by DNMT3B7, a truncated protein of DNMT3B. Much less is known about the mechanism of epigenetic changes in the pediatric cancer neuroblastoma. To investigate if aberrant DNMT3B transcripts alter DNA methylation, gene expression and tumor phenotype in neuroblastoma, we measured DNMT3B isoform expression in primary tumors and cell lines. Higher levels of DNMT3B7 were detected in differentiated ganglioneuroblastomas compared to undifferentiated neuroblastomas, suggesting that expression of DNMT3B7 may induce a less clinically aggressive tumor phenotype. To test this hypothesis, we investigated the effects of forced DNMT3B7 in neuroblastoma cells. We found that DNMT3B7 expression significantly inhibited neuroblastoma cell proliferation in vitro, and in neuroblastoma xenografts, DNMT3B7 decreased angiogenesis and tumor growth. DNMT3B7-positive cells had higher levels of total genomic methylation, and RNA-sequencing revealed a dramatic decrease in expression of FOS and JUN family members, AP1 complex components. Consistent with the established antagonistic relationship between AP1 expression and retinoic acid receptor activity, decreased proliferation and increased differentiation was seen in the DNMT3B7-expressing neuroblastoma cells following treatment with all trans retinoic acid (ATRA) compared to controls. Our results demonstrate that high levels of DNMT3B7 modify the epigenome in neuroblastoma cells, induce changes in gene expression, inhibit tumor growth, and increase sensitivity to ATRA. Further knowledge regarding mechanisms by which DNMT3B7 regulates gene methylation may ultimately lead to the development of therapeutic strategies that reverse the epigenetic aberrations that drive neuroblastoma pathogenesis. DNMT3B7, a truncated DNMT3B isoform, was stably transfected into an N-type neuroblastoma cell line (LA1-55n) using a Tet-off inducible system. DNMT3B7 expressing cells were compared to vector control cells after 21 days of induction.
2012-10-05 | E-GEOD-36350 | biostudies-arrayexpress
Project description:H3K4 methylation is associated with active genes and, along with H3K27 methylation, is part of a bivalent chromatin mark that typifies poised developmental genes in ESCs. However, its functional roles in ESC maintenance and differentiation are not established. Here we show that mammalian Dpy-30, a core subunit of SET1/MLL complexes, biochemically modulates H3K4 methylation in vitro, and directly regulates chromosomal H3K4me3 throughout the mammalian genome. Depletion of Dpy-30 does not affect ESC self-renewal, but significantly alters the differentiation potential of ESCs, particularly along the neural lineage. The differentiation defect is accompanied by defects in gene induction and H3K4 methylation at key developmental loci. Our results provide strong experimental evidence for the hypothesis that H3K4 methylation is an essential functional component of the bivalent mark during activation of developmental genes in ESCs. Total RNAs from control or knockdown cells before and after RA-mediated differentiation were subjected to Illumina microarray analyses. ChIP-enriched DNA from mouse ES cells was analyzed by Solexa sequencing.
2011-02-01 | E-GEOD-26136 | biostudies-arrayexpress
Project description:In pancreatic ductal adenocarcinoma (PDAC), no recurrent metastasis-specific mutation has been found, suggesting that epigenetic mechanisms, such as DNA methylation, are the major contributors of late-stage disease progression. Here, we performed the first whole genome bisulfite sequencing (WGBS) on mouse and human PDAC organoid models to identify stage-specific and subtype-specific DNA methylation signatures in PDAC. With this approach, we identified thousands of DMRs that can distinguish between the stages and subtypes of PDAC. Stage-specific DMRs are associated with genes related to nervous system development and cell-cell adhesions and are enriched in promoters and bivalent enhancers. Subtype-specific DMRs showed hypermethylation of GATA6 transcriptional networks in the squamous subtype and hypermethylation of EMT transcriptional networks in the progenitor subtype. These results indicate that aberrant DNA methylation contributes to both PDAC progression and subtype differentiation, resulting in significant and reoccurring DNA methylation patterns with diagnostic and prognostic potential.
2024-01-29 | GSE243528 | GEO
Project description:Many cancers may originate in stem or early progenitor cells 1-4 which depend on epigenetic modulation of gene expression for normal function (ref). We have studied whether epigenetic states in cancers, and particularly abnormal gene silencing associated with promoter DNA hypermethylation in CpG rich regions (refs), may represent links between cancer and stem cell epigenetic patterns. We studied embryonal carcinomas (EC) which are malignancies of embryonic stem (ES) cells, but retain high potential for multi-lineage differentiation 5-8. Surprisingly, genes DNA hypermethylated and silenced in adult cancers are unmethylated in ES and EC cells. Remarkably, the promoter chromatin of the genes in EC cells is virtually identical to the same genes in adult cancers when the latter are induced to de-methylate. This chromatin, as recently reported for CpG island promoters of low expression, developmentally related, genes in ES cells (refs), is “bivalent” and contains both active and repressive histone modifications. The latter includes trimethyl lysine 27 of histone H3 (H3K27me3), which may recruit DNA methylation (refs), and the promoter regions are enriched for polycomb group (PcG) proteins which place this H3K27me3 mark. Thus, many genes which undergo abnormal DNA methylation and permanent silencing in adult cancers may be programmed to do so by a pre-existent stem cell-like chromatin pattern inherent to the cells in which they arise. Keywords: Stem cell epigenetics expression microarray
2007-10-26 | GSE4809 | GEO
Project description:Atypical teratoid/rhabdoid tumors (AT/RTs) are pediatric brain tumors known for their aggressiveness, exceptionally low mutation rate, and aberrant but still unresolved epigenetic regulation. To evaluate methylation associated regulation in AT/RTs, we compared them to medulloblastomas and choroid plexus tumors by integrating DNA methylation (507 samples), gene expression (120 samples), and public transcription factor (TF) binding data. We showed that elevated DNA methylation masks the binding sites of TFs driving neural development and is associated with reduced transcription for specific neural regulators in AT/RTs. Hypermethylated sites largely behaved similarly in AT/RTs and pluripotent stem cells, revealing DNA methylation -driven halted cell differentiation. AT/RT-unique DNA hypermethylation was associated with polycomb repressive complex 2 members, like EZH2, and linked to suppressed genes with a role in neural development and tumorigenesis. The obtained results highlight and characterize these DNA methylation programs as drivers of AT/RT malignancy.
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Project description:In adult cancers, epigenetic changes and aberrant splicing of the DNMT3B is commonly observed, and the pattern of gene methylation and expression has been shown to be modified by DNMT3B7, a truncated protein of DNMT3B. Much less is known about the mechanism of epigenetic changes in the pediatric cancer neuroblastoma. To investigate if aberrant DNMT3B transcripts alter DNA methylation, gene expression and tumor phenotype in neuroblastoma, we measured DNMT3B isoform expression in primary tumors and cell lines. Higher levels of DNMT3B7 were detected in differentiated ganglioneuroblastomas compared to undifferentiated neuroblastomas, suggesting that expression of DNMT3B7 may induce a less clinically aggressive tumor phenotype. To test this hypothesis, we investigated the effects of forced DNMT3B7 in neuroblastoma cells. We found that DNMT3B7 expression significantly inhibited neuroblastoma cell proliferation in vitro, and in neuroblastoma xenografts, DNMT3B7 decreased angiogenesis and tumor growth. DNMT3B7-positive cells had higher levels of total genomic methylation, and RNA-sequencing revealed a dramatic decrease in expression of FOS and JUN family members, AP1 complex components. Consistent with the established antagonistic relationship between AP1 expression and retinoic acid receptor activity, decreased proliferation and increased differentiation was seen in the DNMT3B7-expressing neuroblastoma cells following treatment with all trans retinoic acid (ATRA) compared to controls. Our results demonstrate that high levels of DNMT3B7 modify the epigenome in neuroblastoma cells, induce changes in gene expression, inhibit tumor growth, and increase sensitivity to ATRA. Further knowledge regarding mechanisms by which DNMT3B7 regulates gene methylation may ultimately lead to the development of therapeutic strategies that reverse the epigenetic aberrations that drive neuroblastoma pathogenesis.
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