Chromosome-specific retention of cancer-associated DNA hypermethylation following pharmacological inhibition of DNMT1
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ABSTRACT:
PROVIDER: PRJNA755307 | ENA |
REPOSITORIES: ENA
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Project description: Not available
| S-EPMC9163065 | biostudies-literature
Project description:The DNA methylation status of the X-chromosome in cancer cells is often overlooked because of computational difficulties. Most of the CpG islands on the X-chromosome are mono-allelically methylated in normal female cells and only present as a single copy in male cells. We treated two colorectal cancer cell lines from a male (HCT116) and a female (RKO) with increasing doses of a novel DNA methyltransferase 1 (DNMT1)-specific inhibitor (GSK3685032/GSK5032) over a long time period to remove as much non-essential CpG methylation as possible. Analysis of the residual methylation patterns in the heavily treated cells showed a very surprising non-uniform distribution of retained methylation on specific chromosomes. For example, probes on the X-chromosome preferentially retained methylation 2-3-fold more frequently compared to those on autosomes. This was true for probes methylated on the active X chromosome in normal cells such as XIST and also for genes which acquired methylation in cancer such as ARMCX2 and MAGEH1. The maintenance of high DNA methylation on a subset of probes after such exhaustive treatment suggests that it might have functional significance for cell survival. Importantly, the same X-linked probes we found in the treated cells were also methylated in a large number of colorectal/rectal cancers in the TCGA data set and to a lesser extent in other cancer types. These results suggest that a re-examination of tumors for X-linked DNA methylation changes may enable greater understanding of the importance of epigenetic silencing of cancer related genes.
2022-06-23 | GSE182209 | GEO
Project description:Site-specific hypermethylation of tumor suppressor genes accompanied by genome-wide hypomethylation are epigenetic hallmarks of malignancy. However, molecular mechanisms that drive these linked changes in DNA methylation remain obscure. DNA methyltransferase 1 (DNMT1), the principle enzyme responsible for maintaining methylation patterns is commonly dysregulated in tumors. Replication foci targeting sequence (RFTS) is an N-terminal domain of DNMT1 that inhibits DNA-binding and catalytic activity, suggesting that RFTS deletion would result in gain of DNMT1 function. However, earlier data suggested that RFTS is required for DNMT1 activity. Here, we determined cellular consequences of RFTS deletion from DNMT1 in immortalized human bronchial epithelial cells. Compared to full-length DNMT1, ectopic expression of DNMT1- ?RFTS caused greater malignant transformation and enhanced promoter methylation that silenced DAPK and DUOX1 gene expression and increased intensity of promoter methylation across the genome. Strikingly, DNMT1-?RFTS also produced genomic hypomethylation and demethylation of Satellite 2 repeat sequences. Because deletion of RFTS is sufficient to induce focal hypermethylation and global hypomethylation in parallel, evidence suggests that the RFTS domain is a target responsible for epigenetic changes in cancer. DNA samples from HBEC3 cells transfected with vector control and HBEC3 cells with full-length and RFTS-deleted DNMT1 were assessed for genome-wide methylation using the microarray-based high resolution HpaII tiny fragment enriched by ligation-mediated PCR (HELP) assay.
2014-09-30 | E-GEOD-57829 | biostudies-arrayexpress
Project description:Site-specific hypermethylation of tumor suppressor genes accompanied by genome-wide hypomethylation are epigenetic hallmarks of malignancy. However, molecular mechanisms that drive these linked changes in DNA methylation remain obscure. DNA methyltransferase 1 (DNMT1), the principle enzyme responsible for maintaining methylation patterns is commonly dysregulated in tumors. Replication foci targeting sequence (RFTS) is an N-terminal domain of DNMT1 that inhibits DNA-binding and catalytic activity, suggesting that RFTS deletion would result in gain of DNMT1 function. However, earlier data suggested that RFTS is required for DNMT1 activity. Here, we determined cellular consequences of RFTS deletion from DNMT1 in immortalized human bronchial epithelial cells. Compared to full-length DNMT1, ectopic expression of DNMT1- ΔRFTS caused greater malignant transformation and enhanced promoter methylation that silenced DAPK and DUOX1 gene expression and increased intensity of promoter methylation across the genome. Strikingly, DNMT1-ΔRFTS also produced genomic hypomethylation and demethylation of Satellite 2 repeat sequences. Because deletion of RFTS is sufficient to induce focal hypermethylation and global hypomethylation in parallel, evidence suggests that the RFTS domain is a target responsible for epigenetic changes in cancer.
2014-09-30 | GSE57829 | GEO
Project description:Multiple endocrine neoplasia type 1 (MEN1) syndrome is the result of mutations in the MEN1 gene and results in tumor formation via mechanisms that are not well understood. Using a novel genome-wide methylation analysis, we studied tissues from patients with MEN1-parathyroid tumors, tissues from Men1 knockout (KO) mouse models, and mouse Men1 null mouse embryonic fibroblast (MEF) cell lines. Tissues from KO mice were used to confirm and assess the findings from the MEN1 clinical samples and further explore the molecular mechanisms of global epigenetic changes following the inactivation of menin. We demonstrated that the inactivation of menin results in enhanced activity of DNA (cytosine-5)-methyltransferase 1 (DNMT1) by retinoblastoma-binding protein 5 (Rbbp5) activation in MEN1 tumor tissues. The increased activity of DNMT1 mediated global DNA hypermethylation, which in turn resulted in aberrant activation of the Wnt/β-catenin signaling pathway through inactivation of Sox regulatory genes. Our study provides important insights into the possible regulatory role of menin in DNA methylation and its impact on the pathogenesis of MEN1 tumor development. Global DNA methylation in tissues from patients with MEN1-parathyroid tumors. Thirty-eight human parathyroid specimens were used: 13 sporadic (non-MEN1) parathyroid adenomas, 12 MEN1-parathyroid tumors, 4 parathyroid carcinomas, and 9 normal parathyroids.
2015-12-22 | E-GEOD-64412 | biostudies-arrayexpress
Project description:Multiple endocrine neoplasia type 1 (MEN1) syndrome is the result of mutations in the MEN1 gene and results in tumor formation via mechanisms that are not well understood. Using a novel genome-wide methylation analysis, we studied tissues from patients with MEN1-parathyroid tumors, tissues from Men1 knockout (KO) mouse models, and Men1 null mouse embryonic fibroblast (MEF) cell lines. We demonstrated that the inactivation of menin (the protein product of MEN1) results in increased activity of DNA (cytosine-5)-methyltransferase 1 (DNMT1) by retinoblastoma-binding protein 5 (Rbbp5) activation in MEN1 tumor tissues. The increased activity of DNMT1 mediated global DNA hypermethylation, which in turn resulted in aberrant activation of the Wnt/β-catenin signaling pathway through inactivation of Sox regulatory genes. Our study provides important insights into the possible regulatory role of menin in DNA methylation and its impact on the pathogenesis of MEN1 tumor development.
2015-12-22 | GSE64412 | GEO
Project description:DNMT1 loss leads to hypermethylation of a subset of late replicating domains by DNMT3A.
| PRJNA1266419 | ENA
Project description:DNMT1 loss leads to hypermethylation of a subset of late replicating domains by DNMT3A (WGBS)
| PRJNA1266162 | ENA
Project description:Loss of DNA methylation is a hallmark of cancer that is proposed to promote carcinogenesis through gene expression alterations, retrotransposon activation and induction of genomic instability. Cancer-associated hypomethylation does not occur across the whole genome but leads to the formation of partially methylated domains (PMDs). However, the mechanisms underpinning PMD formation remain unclear. PMDs replicate late in S-phase leading to the proposal that they become hypomethylated due to incomplete re-methylation by the maintenance methyltransferase DNMT1 during cell division. Here we investigate the role of DNMT1 in the formation of PMDs in cancer by conducting whole genome bisulfite sequencing (WGBS), repli-seq and ChIP-seq on DNMT1 knockout HCT116 colorectal cancer cells (DNMT1 KO cells). We find that DNMT1 loss leads to preferential hypomethylation in late replicating, heterochromatic PMDs marked by the constitutive heterochromatic mark H3K9me3 or the facultative heterochromatic mark H3K27me3. However, we also observe that a subset of H3K9me3-marked PMDs gain methylation in DNMT1 KO cells. We find that, in DNMT1 KO cells, these hypermethylated PMDs remain late replicating but gain DNMT3A localisation. This is accompanied by loss of heterochromatic H3K9me3 and specific gain of euchromatic H3K36me2. Our observations suggest that hypermethylated PMDs lose their heterochromatic state, enabling their methylation by DNMT3A and the establishment of a hypermethylated, non-PMD state, despite their late replication timing. More generally, our findings suggest that the de novo DNMTs play a key role in establishing domain level DNA methylation patterns in cancer cells.
2026-03-26 | GSE297777 | GEO
Project description:Loss of DNA methylation is a hallmark of cancer that is proposed to promote carcinogenesis through gene expression alterations, retrotransposon activation and induction of genomic instability. Cancer-associated hypomethylation does not occur across the whole genome but leads to the formation of partially methylated domains (PMDs). However, the mechanisms underpinning PMD formation remain unclear. PMDs replicate late in S-phase leading to the proposal that they become hypomethylated due to incomplete re-methylation by the maintenance methyltransferase DNMT1 during cell division. Here we investigate the role of DNMT1 in the formation of PMDs in cancer by conducting whole genome bisulfite sequencing (WGBS), repli-seq and ChIP-seq on DNMT1 knockout HCT116 colorectal cancer cells (DNMT1 KO cells). We find that DNMT1 loss leads to preferential hypomethylation in late replicating, heterochromatic PMDs marked by the constitutive heterochromatic mark H3K9me3 or the facultative heterochromatic mark H3K27me3. However, we also observe that a subset of H3K9me3-marked PMDs gain methylation in DNMT1 KO cells. We find that, in DNMT1 KO cells, these hypermethylated PMDs remain late replicating but gain DNMT3A localisation. This is accompanied by loss of heterochromatic H3K9me3 and specific gain of euchromatic H3K36me2. Our observations suggest that hypermethylated PMDs lose their heterochromatic state, enabling their methylation by DNMT3A and the establishment of a hypermethylated, non-PMD state, despite their late replication timing. More generally, our findings suggest that the de novo DNMTs play a key role in establishing domain level DNA methylation patterns in cancer cells.
2026-03-26 | GSE297778 | GEO