Direct ChIP-bisulfite sequencing reveals a role of H3K27me3 mediating aberrant hypermethylation of promoter CpG islands in cancer cells (ChIP-BS)
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE43094 | GEO | 2014/07/01
SECONDARY ACCESSION(S): PRJNA184403
REPOSITORIES: GEO
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Project description:The model describing that aberrant CpG island (CGI) methylation leads to transcription repression of tumor suppressor genes and thereby is implicated in tumor progression has been established in many cancers. However, recent studies indicated aberrantly hypermethylated genes in multiple cancers are already repressed in pre-cancerous tissues despite their promoters are hypomethylated. Here, we hypothesized that the occurrence of CGI promoter hypermethylation in cancers are associated with Polycomb-repressive complex and the associated H3K27me3 mark in pre-cancerous tissues. By using a ChIP-BS-seq technology that examines methylation of the DNA fragments precipitated by the antibodies to histone modifications, we provided direct evidences showing that genes highly enriched with H3K27me3 marks both in cancer and normal cells became aberrantly hypermethylated in CGI promoters in cancer cells in comparison with normal cells. Furthermore, we confirmed that these genes consistently were significantly hypermethylated in TCGA primary cancer in comparison with normal tissues. Thus, we provided direct evidences supporting that the presence of H3K27m3 may serve as a guide to promoter hypermethylation. This will spur future work on epigenetic signature of combined histone and DNA methylation that could define a cancerM-bM-^@M-^Ys epigenetic abnormalities, therefore helping distinguish subtypes of cancers and aiding future diagnosis and therapeutics of cancers. We applied ChIP-BS technology to examine H3K27me3 marks, which are catalyzed by the SET domain histone methyltransferase EZH2 and have a repressive function with 50bp pair-end sequencing. found H3K27me3 marks were enriched preferentially at CpG islands, (+/-500) transcription start sites (TSSs) and exons in two GC cell lines (BGC-823 and AGS). In YH cells, H3K27me3 marks were only preferentially enriched at CpG islands. In contrast, Hela cells presented a reverse pattern with highest H3K27me3 enrichment in intergenic regions. To confirm this result in Hela cells, we performed two independent replicates of ChIP-Seq and ChIP-BS-seq. Cause of useful was relative small. we still sequenced one 100bp pe reads replicate for H3K4me3 and two replicate for H3K27me3 ChIP-BS-seq.
2014-07-01 | E-GEOD-43094 | biostudies-arrayexpress
Project description:Aberrant DNA hypermethylation of CpG island (CGI) promoters are associated with transcriptional repression of many tumor suppressor genes and lead to tumor progression in many cancers. Most recently, one research group observed that aberrantly hypermethylated genes in multiple cancers are already repressed, but their promoters are maintained in a hypomethylated state in pre-cancerous tissues.Their studies didn't provide a clue to explain by what mechanisms those genes were repressed in pre-cancerous tissues. Another research group found that many genes with de novo promoter hypermethylation in colon cancer were among the subset of genes "bivalently" marked in embryonic stem cells and adult stem/progenitor cells by repressive Polycomb group proteins (PcG), which are known for maintaining low, but poised, transcription.These observations provide a clue that CGI promoter hypermethylation in cancers is associated with PcG target genes in pre-cancerous tissues.we took advantage of ChIP-BS-seq technology and applied it to examine H3K27me3 and H3K4me3 profiles for one normal lymphoblastoid cell line (YH) and three cancer cell lines including one cervical cancer cell line (Hela) and two gastric cancer (GC) cell lines (BGC-823 and AGS).
2014-07-01 | GSE43093 | GEO
Project description:Aberrant DNA hypermethylation of CpG island (CGI) promoters are associated with transcriptional repression of many tumor suppressor genes and lead to tumor progression in many cancers. Most recently, one research group observed that aberrantly hypermethylated genes in multiple cancers are already repressed, but their promoters are maintained in a hypomethylated state in pre-cancerous tissues.Their studies didn't provide a clue to explain by what mechanisms those genes were repressed in pre-cancerous tissues. Another research group found that many genes with de novo promoter hypermethylation in colon cancer were among the subset of genes "bivalently" marked in embryonic stem cells and adult stem/progenitor cells by repressive Polycomb group proteins (PcG), which are known for maintaining low, but poised, transcription.These observations provide a clue that CGI promoter hypermethylation in cancers is associated with PcG target genes in pre-cancerous tissues.we took advantage of ChIP-BS-seq technology and applied it to examine H3K27me3 and H3K4me3 profiles for one normal lymphoblastoid cell line (YH) and three cancer cell lines including one cervical cancer cell line (Hela) and two gastric cancer (GC) cell lines (BGC-823 and AGS). We aplied ChIP-BS technology to examine H3K27me3 marks, which are catalyzed by the SET domain histone methyltransferase EZH2 and have a repressive function with 50bp pair-end sequencing. found H3K27me3 marks were enriched preferentially at CpG islands, (+/-500) transcription start sites (TSSs) and exons in two GC cell lines (BGC-823 and AGS). In YH cells, H3K27me3 marks were only preferentially enriched at CpG islands. In contrast, Hela cells presented a reverse pattern with highest H3K27me3 enrichment in intergenic regions. To confirm this result in Hela cells, we performed two independent replicates of ChIP-Seq and ChIP-BS-seq. Cause of useful was relative small. we still sequenced one 100bp pe reads replicate for H3K4me3 and two replicate for H3K27me3 ChIP-BS-seq.
2014-07-01 | E-GEOD-43093 | biostudies-arrayexpress
Project description:While promoter epigenetic modifications have been linked to tumor suppressor silencing in cancers, modifications in gene body regions has been largely neglected. Using a genetic setting in which subtle enhanced levels of non-oncogenic receptor tyrosine kinases (RTKs) become progressively pathological, we show that reprogrammed CpG island (CGI) methylation locks cells into tumorigenicity. By focusing on gene bodies, we found an enrichment of hypermethylated CGI similar to that reported in cancer patients. Gene body CGI hypermethylation correlates with decreased H3K27me3 modification and enhanced transcription for a proportion of genes, which act as oncogenes in cancer cells. Collectively, our results illustrate that tumorigenesis is ensured by an increase dosage of a set of oncogenes through an epigenetic reprogramming involving gene body CGI hypermethylation.
2018-08-15 | GSE90093 | GEO
Project description:CpG islands (CGIs) including those at imprinting control regions (ICRs) are protected from de novo methylation in somatic cells. However, many cancers often exhibit CGI hypermethylation, implying that the machinery is impaired in cancer cells. Here, we conducted a comprehensive analysis of CGI methylation during the somatic cell reprogramming. Although most CGIs remain hypomethylated, a small subset of CGIs, particularly at several ICRs, were often de novo methylated in reprogrammed pluripotent stem cells (PSCs). Such de novo ICR methylation was linked with the silencing of reprogramming factors, which occurs at a late stage of reprogramming. The ICR-preferred CGI hypermethylation was similarly observed in human PSCs. Mechanistically, ablation of Dnmt3a prevented PSCs from de novo ICR methylation. Notably, the ICR-preferred CGI hypermethylation was observed in pediatric cancers, while adult cancers exhibit genome-wide CGI hypermethylation. These results may have important implications in the pathogenesis of pediatric cancers and the application of PSCs.
2019-06-18 | GSE111173 | GEO
Project description:Determination of the profile of genes commonly aberrantly methylated in colorectal cancer (CRC) has substantial potential value for diagnostic and therapeutic application. However, our knowledge of the DNA methylation pattern in CRC is currently limited. Therefore, we analyzed the methylation profile of 27,578 CpG sites spanning more than 14,000 genes in CRC and in adjacent normal mucosa using beadchip array-based technology. We identified 621 CpG sites located in promoter region and CpG islands that were significantly hypermethylated in CRC compared to normal mucosa. Genes on chromosome 18 showed promoter hypermethylation most frequently. According to gene ontology analysis, the most common biologically relevant class of genes affected by methylation was the class associated with the cadherin signaling pathway. In comparison with genome-wide expression array, mRNA expression was more like to be down-regulated in the genes demonstrating promoter hypermethylation, although this was not statistically significant. We validated 10 CpG sites that were shown to be hypermethylated in the array studies (ADHFE1, BOLL, SLC6A15, ADAMTS5, TFPI2, EYA4, NPY, TWIST1, LAMA1, GAS7) and 2 CpG sites showing hypomethylaion (MAEL, SFT2D3) in CRC compared to normal mucosa using pyrosequencing. The methylation status measured by pyrosequencing was consistent with the methylation array data. In conclusion, we have shown that methylation profiling based on beadchip arrays is an effective method for screening for aberrantly methylated genes in CRC. In addition, we identified novel methylated genes that are candidate diagnostic or prognostic markers for CRC. We measured the methylation status of the 27,578 CpG sites (Human Methylation27 DNA Analysis BeadChip) in 22 pairs of CRC tissue and adjacent normal mucosa to identify genes that are commonly aberrantly methylated in CRC.
2010-06-24 | E-GEOD-17648 | biostudies-arrayexpress
Project description:Chromatin immunoprecipitation with DNMT3B specific antibody followed by CGI microarray identified genes with or without CGIs, repeat elements and genomic contigs in RKO cells. ChIP-Chop analysis showed that majority of the target genes including P16, DCC, DISC1, SLIT1, CAVEOLIN1, TBX5, TBX18, HOXB13 and some histone variants, that harbor CGI in their promoters, were methylated in multiple colon cancer cell lines but not in normal colon epithelial cells. Further, these genes were reactivated in RKO cells after treatment with 5-aza-2â-deoxycytidine, a DNA hypomethylating agent. COBRA and bisulfite genomic sequencing showed that the CGIs encompassing the transcription start sites (TSS) of DCC, TBX5, TBX18, SLIT1 were also methylated in primary colorectal tumors compared to matching normal tissues whereas GNA11 was methylated in both. MassARRAY analysis demonstrated that the CGI located ~4.5 kb upstream of HOXB13 +1 site was tumor-specifically hypermethylated in primary colorectal cancers and cancer cell lines. Analysis of tumor suppressor properties of two aberrantly methylated transcription factors, HOXB13 and TBX18, revealed that both inhibited growth and clonogenic survival of colon cancer cells in vitro, but only HOXB13 abolished tumor growth in nude mice. Chromatin immunoprecipitation with DNMT3B specific antibody in RKO cells was compared to control antibody.
2010-05-06 | E-GEOD-18929 | biostudies-arrayexpress
Project description:Chromatin immunoprecipitation with DNMT3B specific antibody followed by CGI microarray identified genes with or without CGIs, repeat elements and genomic contigs in RKO cells. ChIP-Chop analysis showed that majority of the target genes including P16, DCC, DISC1, SLIT1, CAVEOLIN1, TBX5, TBX18, HOXB13 and some histone variants, that harbor CGI in their promoters, were methylated in multiple colon cancer cell lines but not in normal colon epithelial cells. Further, these genes were reactivated in RKO cells after treatment with 5-aza-2’-deoxycytidine, a DNA hypomethylating agent. COBRA and bisulfite genomic sequencing showed that the CGIs encompassing the transcription start sites (TSS) of DCC, TBX5, TBX18, SLIT1 were also methylated in primary colorectal tumors compared to matching normal tissues whereas GNA11 was methylated in both. MassARRAY analysis demonstrated that the CGI located ~4.5 kb upstream of HOXB13 +1 site was tumor-specifically hypermethylated in primary colorectal cancers and cancer cell lines. Analysis of tumor suppressor properties of two aberrantly methylated transcription factors, HOXB13 and TBX18, revealed that both inhibited growth and clonogenic survival of colon cancer cells in vitro, but only HOXB13 abolished tumor growth in nude mice.
2010-03-01 | GSE18929 | GEO
Project description:Genetic abnormalities of cholangiocarcinoma (CCA) have been widely studied; however, epigenomic changes related to cholangiocarcinogenesis have been less well characterized. We have profiled the DNA methylomes of 28 primary CCA and six matched adjacent normal tissues using Infinium’s HumanMethylation27 BeadChips with the aim of identifying gene sets aberrantly epigenetically regulated in CCA. Using a linear model for microarray data we identified 1610 differentially methylated autosomal CpG sites with 809 CpG sites (representing 603 genes) being hypermethylated and 801 CpG sites (representing 712 genes) being hypomethylated in CCA versus adjacent normal (false discovery rate ? 0.05). Gene Ontology and Gene Set Enrichment analyses identified gene sets significantly associated with hypermethylation at linked CpG sites in CCA including homeobox genes and target genes of PRC2, EED, SUZ12 and Histone H3 trimethylation at lysine 27. We confirmed frequent hypermethylation at the homeobox genes HOXA9 and HOXD9 by bisulfite pyrosequencing in a larger cohort of CCA (n = 103). Our findings indicate a key role for hypermethylation of multiple CpG sites at genes associated with a stem cell-like phenotype as a common molecular aberration in CCA. These data have implications for CCA carcinogenesis, as well as possible novel treatment options using histone methyltransferase inhibitors. Methods: Thirty-two primary CCA, 6 matched adjacent normal, 5 CCA cell lines and an immortal biliary cell line were analyzed for DNA methylation profiles using the Infinium HumanMethylation27 BeadChip. Differential methylation was statistically analyzed using LIMMA. Specific functional terms and Gene Set Enrichment Analysis were performed to identify specific function of aberrantly methylated genes. Results: We identified 711 and 590 autosomal CpG sites as being hypermethylated and hypomethylated representing 527 and 521 genes, respectively, in CCA compared to adjacent normal (false discovery rate 0.05). A number of gene sets were significantly associated with hypermethylation at linked CpG sites in CCA including homeobox genes and the target genes of PRC2, EED, SUZ12, and H3K27me3, whereas target genes of NOS and OCT4 were hypomethylated at linked CpG sites in tumors. Frequent aberrant DNA methylation at HOXA9 and HOXD9 was confirmed by bisulfite pyrosequencing in a larger cohort of CCA (n = 107). Conclusions: This is the first report of a DNA methylation profile of multiple CpG sites at genes associated with a stem cell-like phenotype as a common molecular aberration in CCA. These data have implications for CCA carcinogenesis, as well as possible novel treatment options using histone methyltransferase inhibitors. Array-based methylation profiling was performed using the Infinium HumanMethylation27 BeadChip in 28 primary cholangiocarcinomas and six matched adjacent normal tissues. The reproducibility of the Infinium HumanMethylation27 BeadChips was evaluated using five technical replicates of the ovarian cancer cell line PEO1. Differential methylation cutoff was estimated from five technical replicates by bootstrap resampling and set at ?? ? 0.15 corresponding to a FDR ? 0.05.
2013-01-01 | E-GEOD-38860 | biostudies-arrayexpress
Project description:Determination of the profile of genes commonly aberrantly methylated in colorectal cancer (CRC) has substantial potential value for diagnostic and therapeutic application. However, our knowledge of the DNA methylation pattern in CRC is currently limited. Therefore, we analyzed the methylation profile of 27,578 CpG sites spanning more than 14,000 genes in CRC and in adjacent normal mucosa using beadchip array-based technology. We identified 621 CpG sites located in promoter region and CpG islands that were significantly hypermethylated in CRC compared to normal mucosa. Genes on chromosome 18 showed promoter hypermethylation most frequently. According to gene ontology analysis, the most common biologically relevant class of genes affected by methylation was the class associated with the cadherin signaling pathway. In comparison with genome-wide expression array, mRNA expression was more like to be down-regulated in the genes demonstrating promoter hypermethylation, although this was not statistically significant. We validated 10 CpG sites that were shown to be hypermethylated in the array studies (ADHFE1, BOLL, SLC6A15, ADAMTS5, TFPI2, EYA4, NPY, TWIST1, LAMA1, GAS7) and 2 CpG sites showing hypomethylaion (MAEL, SFT2D3) in CRC compared to normal mucosa using pyrosequencing. The methylation status measured by pyrosequencing was consistent with the methylation array data. In conclusion, we have shown that methylation profiling based on beadchip arrays is an effective method for screening for aberrantly methylated genes in CRC. In addition, we identified novel methylated genes that are candidate diagnostic or prognostic markers for CRC.
2009-08-18 | GSE17648 | GEO