Me-DIP-chip data from osteosarcoma tumours
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE12864 | GEO | 2009/09/08
SECONDARY ACCESSION(S): PRJNA114171
REPOSITORIES: GEO
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Project description:Malignant cells show major disruptions in DNA methylation profiles which manifest as aberrant hypermethylation and hypomethylation of gene promoters as well as global genomic hypomethylation. To date, many genes with aberrant promoter hypermethylation have been identified in essentially all forms of cancer including cell cycle regulators, DNA repair genes, genes associated with apoptosis, hormonal regulation, detoxification, metastasis, angiogenesis, and many others We developed an effective high-resolution approach for mapping genome-wide, and cancer-specific DNA methylation profiles. We have used this approach to provide first genomic DNA methylation profiling in osteosarcoma cells Keywords: comparative profiling
2009-05-01 | GSE11413 | GEO
Project description:DNA (cytosine-5) methyltransferase 1 (DNMT1) is essential for mammalian development and maintenance of DNA methylation following DNA replication in cells. The DNA methylation process generates S-adenosyl-L-homocysteine, a strong inhibitor of DNMT1. Here we report that S-adenosylhomocysteine hydrolase (SAHH/AHCY), the only mammalian enzyme capable of hydrolyzing S-adenosyl-L-homocysteine binds to DNMT1 during DNA replication. SAHH activates DNMT1 in vitro and its overexpression in mammalian cells leads to hypermethylation of the genome, whereas its inhibition by adenosine periodate resulted in hypomethylation of the genome. Hypermethylation was consistent in both gene bodies and repetitive DNA elements leading to both down- and up-regulation of genes. Similarly, hypomethylation led to both up- and down-regulation of genes suggesting methylated regions influence gene expression either positively or negatively. Cells overexpressing SAHH specifically up-regulated metabolic pathway genes and down-regulated PPAR and MAPK signaling pathways genes. Therefore, we suggest that alteration of SAHH level in the cell leads to aberrant DNA methylation, altered metabolite levels and gene expression.
2018-06-06 | PXD006476 | Pride
Project description:Mitotic cell division increases tumour mutation burden and copy number load, predictive markers of the clinical benefit of immunotherapy. Cell division correlates also with genomic demethylation involving methylation loss in late-replicating partial methylation domains. Here we find that immunomodulatory pathway genes are concentrated in these domains and transcriptionally repressed in demethylated tumours with CpG island promoter hypermethylation. Global methylation loss correlated with immune evasion signatures independently of mutation burden and aneuploidy. Methylome data of our cohort (n = 60) and a published cohort (n = 81) in lung cancer and a melanoma cohort (n = 40) consistently demonstrated that genomic methylation alterations counteract the contribution of high mutation burden and increase immunotherapeutic resistance. Higher predictive power was observed for methylation loss than mutation burden. We also found that genomic hypomethylation correlates with the immune escape signatures of aneuploid tumours. Hence, DNA methylation alterations implicate epigenetic modulation in precision immunotherapy.
2019-08-02 | GSE135222 | GEO
Project description:Mitotic cell division increases tumour mutation burden and copy number load with a positive and inverse correlation, respectively, with the clinical benefit of immunotherapy. Markers of cell division correlate also with genomic demethylation involving methylation loss in late-replicating partial methylation domains. Here we find that immunomodulatory pathway genes are concentrated in these domains and transcriptionally repressed in demethylated tumours with CpG island promoter hypermethylation. Global methylation loss correlated with immune evasion signatures independently of mutation burden and aneuploidy. Methylome data of our cohort (n = 60) and a published cohort (n = 81) in lung cancer and a melanoma cohort (n = 40) consistently demonstrated that genomic methylation alterations counteract the contribution of high mutation burden and increase immunotherapeutic resistance. Higher predictive power was observed for methylation loss than mutation burden. We also found that genomic hypomethylation correlates with the immune escape signatures of aneuploid tumours. Hence, DNA methylation alterations implicate epigenetic modulation as a combination regimens for precision immunotherapy.
2019-07-31 | GSE119144 | GEO
Project description:Mammalian cells contain copious amounts of RNA including both coding and non-coding RNA (ncRNA). Generally the ncRNAs function to regulate gene expression at the transcriptional and post-transcriptional level. Among ncRNA, the long ncRNA and small ncRNA can affect histone modification, DNA methylation targeting and gene silencing. Here we show that endogenous DNA methyltransferase 1 (DNMT1) co-purifies with inhibitory ncRNAs. MicroRNAs (miRNAs) binds directly to DNMT1 with high affinity. The binding of miRNAs, such as miR-155, leads to inhibition of DNMT1 enzyme activity. Exogenous miR-155 in cells induces aberrant DNA methylation of the genome, resulting in hypomethylation of low to moderately methylated regions. And small shift of hypermethylation of previously hypomethylated region was also observed. Furthermore, hypomethylation led to activation of genes. Based on these observations, we propose that overexpression of specific miRNAs in human cancer may lead to aberrant DNA methylation and altered gene-expression. Examine of the DNA methylation and mRNA profile of HCT 116 cells transfected by random 23-mer or miR-155 RNA
2015-04-21 | E-GEOD-68027 | biostudies-arrayexpress
Project description:Background Thousands of mammalian promoters are defined by co-enrichment of the histone tail modifications H3K27me3 (repressive) and H3K4me3 (activating) and are thus termed bivalent. It was previously observed that bivalent genes in human ES cells (hESC) are frequent targets for hypermethylation in human cancers, and depletion of DNA methylation in mouse embryonic stem cells has a marked impact on H3K27me3 distribution at bivalent promoters. However, only a fraction of bivalent genes in stem cells are targets of hypermethylation in cancer, and it is currently unclear whether all bivalent promoters are equally sensitive to DNA hypomethylation and whether H3K4me3 levels play a role in the interplay between DNA methylation and H3K27me3. Results We report the sub-classification of bivalent promoters into two groups—promoters with a high H3K27me3:H3K4me3 (hiBiv) ratio or promoters with a low H3K27me3:H3K4me3 ratio (loBiv). HiBiv are enriched in canonical Polycomb components, show a higher degree of local intrachromosomal contacts and are highly sensitive to DNA hypomethylation in terms of H3K27me3 depletion from broad Polycomb domains. In contrast, loBiv promoters are enriched in non-canonical Polycomb components, show lower intrachromosomal contacts and are less sensitive to DNA hypomethylation at the same genomic resolution. Multiple systems reveal that hiBiv promoters are more depleted of Polycomb complexes than loBiv promoters following a reduction in DNA methylation, and we demonstrate that H3K27me3 re-accumulates at promoters when DNA methylation is restored. In human cancer, we show that hiBiv promoters lose H3K27me3 and are more susceptible to DNA hypermethylation than loBiv promoters. Conclusion We conclude that bivalency as a general term to describe mammalian promoters is an over-simplification and our sub-classification has revealed novel insights into the interplay between the largely antagonistic presence of DNA methylation and Polycomb systems at bivalent promoters. This approach redefines molecular pathologies underlying disease in which global DNA methylation is aberrant or where Polycomb mutations are present.
2020-02-23 | GSE135638 | GEO
Project description:In our study we applied a genome-wide DNA methylation analysis approach, MethylCap-seq, to map the differentially methylated regions in 24 tumor and matched normal colon samples. In total, 2687 frequently hypermethylated and 468 frequently hypomethylated regions were identified, which include potential biomarkers for CRC diagnosis. Hypermethylation in the tumor samples was enriched at CpG islands and gene promoters, while hypomethylation was distributed throughout the genome. Using epigenetic data from human embryonic stem cells, we show that frequent differentially methylated regions (DMRs) coincide with bivalent loci in human embryonic stem cells. DNA methylation is commonly thought to lead to cancer gene related silencing, however integration of publically available expression analysis shows that 75% of the frequently hypermethylation genes were most likely already lowly or not expressed in normal tissue. Collectively, our study provides genome-wide DNA methylation maps of colon cancer, comprehensive lists of DMRs, and gives further clues on the role of aberrant DNA methylation in CRC formation.
2012-10-26 | GSE39068 | GEO
Project description:Aberrant DNA methylation is frequently observed in breast cancer. However, the relationship between methylation patterns and the heterogeneity of breast cancer has not been comprehensively characterized. Whole-genome DNA methylation analysis using 450K Illumina BeadArrays was performed on 188 human breast tumors. Unsupervised bootstrap consensus clustering was performed to identify DNA methylation epigenetic subgroups (epitypes). The Cancer Genome Atlas data, incluing methylation profiles of 669 human breast tumors, was utilized for validation. The identified epitypes were characterized by integration with publicly available genome-wide data, including gene expression levels, DNA copy numbers, whole-exome sequencing data, and chromatin states. We identified seven breast cancer epitypes. One epitype was distinctly associated with basal-like tumors and with BRCA1 mutations, one epitype contained a subset of ERBB2-amplified tumors characterized by multiple additional amplifications and the most complex genomes, and one epitype displayed a methylation profile similar to normal epithelial cells. Luminal tumors were stratified into the remaining four epitypes, with differences in promoter hypermethylation, global hypomethylation, proliferative rates and genomic instability. We observed two dominant patterns of aberrant methylation in breast cancer. One pattern, constitutively methylated in both basal-like and luminal breast cancer, was linked to genes with promoters in a Polycomb-repressed state in normal epithelial cells and displayed no correlation to gene expression levels. The second pattern correlated with gene expression levels and was associated with methylation in luminal tumors and genes with active promoters in normal epithelial cells. Our results suggest that hypermethylation patterns in basal-like breast cancer may have limited influence on tumor progression and instead reflects the repressed chromatin state of the tissue of origin. On the contrary, hypermethylation patterns specific to luminal breast cancer influence gene expression, may contribute to tumor progression, and may present an actionable epigenetic alteration in some luminal breast cancers. Genome-wide DNA methylation analysis of 188 breast cancers using Illumina Human Methylation 450K Beadchips.
2016-02-29 | E-GEOD-75067 | biostudies-arrayexpress
Project description:In our study we applied a genome-wide DNA methylation analysis approach, MethylCap-seq, to map the differentially methylated regions in 24 tumor and matched normal colon samples. In total, 2687 frequently hypermethylated and 468 frequently hypomethylated regions were identified, which include potential biomarkers for CRC diagnosis. Hypermethylation in the tumor samples was enriched at CpG islands and gene promoters, while hypomethylation was distributed throughout the genome. Using epigenetic data from human embryonic stem cells, we show that frequent differentially methylated regions (DMRs) coincide with bivalent loci in human embryonic stem cells. DNA methylation is commonly thought to lead to cancer gene related silencing, however integration of publically available expression analysis shows that 75% of the frequently hypermethylation genes were most likely already lowly or not expressed in normal tissue. Collectively, our study provides genome-wide DNA methylation maps of colon cancer, comprehensive lists of DMRs, and gives further clues on the role of aberrant DNA methylation in CRC formation. To investigate DNA methylation in CRC in a genome-wide unbiased fashion, we applied MethylCap-seq. This method involves capture of methylated DNA using the MBD domain of MeCP2, and subsequent next-generation Illumina sequencing of eluted DNA. In addition, we compared MethylCap with RNA-seq and ChIP-seq profiles of H3K4me3 and H3K27me3 for the colon cancer tumor cell line HCT116 (HCT116 WT) and the cell line of HCT116 with DNMT1 and DNMT3b knockout (HCT116 DKO).
2012-10-26 | E-GEOD-39068 | biostudies-arrayexpress
Project description:Osteosarcomas (OS) arise more commonly during the rapid bone growth and remodeling, thus it is plausible to infer the relationship between their tumorigenesis and cell cycle disruption by genetic and epigenetic factors. Methylation data of 28 primary OS was obtained using the HM450K microarray, and compared with nine normal bone tissues. The tumor mutational burden was analyzed using data from the TruSight One sequencing panel. We identified 3,146 differentially methylated positions, and OS presented high methylation heterogeneity, with global hypomethylation and focal hypermethylation at CpG islands. There were 319 hypomethylated and 266 hypermethylated regions in tumors, located in the promoter regions of 172 and 178 genes, respectively. These genes were enriched for biological processes related to skeletal system morphogenesis, proliferation, inflammatory response and signal transduction. Six tumor suppressors presented deletions or hypermethylation (DLEC1, GJB2, HIC1, MIR149, PAX6, WNT5A), and four oncogenes presented gains or hypomethylation (ASPSCR1, NOTCH4, PRDM16, RUNX3). Most cases did not report mutations in DNMTs or TETs, but DNMT3B was recurrently gained, a possible explanation for the hypermethylation at CpG islands. Our analysis also revealed hypomethylation at 6p22, a region that contains several genes, including histones. Overall, aberrant DNA methylation was spread throughout the genome of osteosarcomas, presented with high variance, similar to other molecular alterations. While the open-sea hypomethylation likely contributes to genomic instability, enriched CpG island hypermethylation suggests the involvement of mechanisms related to silencing tumor suppressor genes in osteosarcoma tumorigenesis. These data also suggest DNMT3B probably impacting biological processes associated with early bone development.
2023-06-21 | GSE193000 | GEO