Implications of epigenetic drift in colorectal neoplasia
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PROVIDER: PRJNA454447 | ENA |
REPOSITORIES: ENA
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Project description:Many normal tissues undergo age-related DNA methylation drift providing a quantitative measure of tissue age. However this drift has not been demonstrated in neoplastic tissues. Here we identify and validate 781 CpG-islands (CGIs) that undergo significant methylomic drift in normal colorectal tissues continue to drift in neoplasia and remain significantly correlated with one another across tissue samples. However compared with normal colon this drift advances (~3-4 fold) faster in neoplasia consistent with increased cell proliferation during neoplastic progression. Furthermore we show that the observed drift patterns are broadly consistent with modeled adenoma-carcinoma sojourn time distributions from colorectal cancer (CRC) incidence data. These results support the hypothesis that beginning with the founder premalignant cell cancer precursors frequently sojourn for decades before turning into cancer which implies that the founder cell typically arises early in life. We estimate that at least 77-89% of the observed drift variance in distal and rectal tumors is explained by stochastic variability associated with neoplastic progression while only 55% of the variance is explained for proximal tumors. However >50% of identified gene-CGI pairs in the proximal colon that undergo drift are significantly and mainly negatively correlated with cancer gene expression suggesting that methylomic drift participates in the clonal evolution of CRCs. Significance: Methylomic drift advances in colorectal neoplasia consistent with extended sojourn time distributions explaining a significant fraction of epigenetic heterogeneity in CRCs. Importantly the estimated long-duration premalignant sojourn times suggest that early dietary and lifestyle interventions may be more effective than later changes in reducing CRC incidence.
2019-04-19 | GSE113904 | GEO
Project description: Not available
| S-EPMC6359943 | biostudies-literature
Project description:Mutational profiling across premalignant colorectal neoplasia
| PRJEB28577 | ENA
Project description:Our analysis reveals an extensive methylomic drift between normal squamous esophagus and BE tissues in nonprogressed BE patients, with differential drift affecting 4024 (24%) of 16,984 normally hypomethylated cytosine-guanine dinucleotides (CpGs) occurring in CpG islands. The majority (63%) of islands that include drift CpGs are associated with gene promoter regions. Island CpGs that drift have stronger pairwise correlations than static islands, reflecting collective drift consistent with processive DNA methylation maintenance. Individual BE tissues are extremely heterogeneous in their distribution of methylomic drift and encompass unimodal low-drift to bimodal high-drift patterns, reflective of differences in BE tissue age. Further analysis of longitudinally collected biopsy samples from 20 BE patients confirm the time-dependent evolution of these drift patterns. Drift patterns in EAC are similar to those in BE, but frequently exhibit enhanced bimodality and advanced mode drift. To better understand the observed drift patterns, we developed a multicellular stochastic model at the CpG island level. Importantly, we find that nonlinear feedback in the model between mean island methylation and CpG methylation rates is able to explain the widely heterogeneous collective drift patterns. Using matched gene expression and DNA methylation data in EAC from TCGA and other publically available data, we also find that advanced methylomic drift is correlated with significant transcriptional repression of ~ 200 genes in important regulatory and developmental pathways, including several checkpoint and tumor suppressor-like genes. Taken together, our findings suggest that epigenetic drift evolution acts to significantly reduce the expression of developmental genes that may alter tissue characteristics and improve functional adaptation during BE and EAC progression.
2017-10-31 | GSE104707 | GEO
Project description:During the last decades, our knowledge about the genetic architecture of sporadic ALS has significantly increased. However, besides the recognized genetic risk factors, also the environment is supposed to have a role in disease pathogenesis. Epigenetic modifications reflect the results of the interaction between environmental factors and genes and may play a role in the development and progression of ALS. A recent large epigenome-wide association study (EWAS) in blood identified differentially methylated positions mapping to 42 different genes involved in cholesterol biosynthesis and immune-related pathways. Here we performed a genome-wide DNA methylation analysis in peripheral blood cells on an Italian cohort of 61 sporadic ALS patients and 61 healthy controls. Initially, a conventional genome-wide association analysis was performed, and results were subsequently integrated with the findings from the previous EWAS using a meta-analytical approach. To delve deeper into the significant outcomes, over-representation analysis (ORA) was employed. Moreover, the epigenetic signature obtained from the meta-analysis was examined to determine potential associations with chemical compounds, utilizing the Toxicogenomic Database. Expanding the scope of the epigenetic analysis, we explored both epigenetic drift and rare epivariations. Notably, we observed an elevated epigenetic drift in individuals with ALS compared to the control group, both at a global and single gene level. Interestingly, epigenetic drift at a single gene level revealed an enrichment of genes related to the neurotrophin signaling pathway. Moreover, for the first time rare we identified epivariations exclusively enriched in ALS cases associated with 153 genes, 88 of whom with a strong expression in cerebral areas. Overall, our study reinforces the evidence that epigenetics may contribute to the pathogenesis of ALS and that epigenetic drift may be a useful diagnostic marker. Further research is needed to determine the role of epivariations in the identified candidate genes.
2023-11-23 | GSE239901 | GEO
Project description:Culture expansion of primary cells evokes highly reproducible DNA methylation (DNAm) changes These changes might be directly regulated or caused by gradual deregulation of the epigenetic state, which is often referred to as “epigenetic drift” We have identified CG dinucleotides (CpGs) that become continuously hyper- or hypomethylated in the course of culture expansion of mesenchymal stem cells (MSCs) and other cell types During reprogramming into induced pluripotent stem cells (iPSCs) particularly the culture-associated hypomethylation is reversed simultaneously with age-associated and pluripotency-associated DNAm changes Bisulfite barcoded amplicon sequencing (BBA-seq) demonstrated that upon passaging the DNAm patterns of neighboring CpGs become more complex without evidence of continuous pattern development and without association to oligoclonal subpolulations of MSCs at later passages Circularized chromatin conformation capture (4C) revealed reproducible changes in nuclear organization between early and late passages, while there was no preferential interaction with other genomic regions that also harbor culture-associated DNAm changes Chromatin immunoprecipitation of CTCF did not show significant differences during long-term culture of MSCs, however culture-associated hypermethylation was enriched at CTCF binding sites and hypomethylated CpGs were devoid of CTCF Taken together, our results indicate that DNAm changes during culture-expansion resembles epigenetic drift
2021-05-26 | GSE116375 | GEO
Project description:Culture expansion of primary cells evokes highly reproducible DNA methylation (DNAm) changes. These changes might be directly regulated or caused by gradual deregulation of the epigenetic state, which is often referred to as “epigenetic drift”. We have identified CG dinucleotides (CpGs) that become continuously hyper- or hypomethylated in the course of culture expansion of mesenchymal stem cells (MSCs) and other cell types. During reprogramming into induced pluripotent stem cells (iPSCs) particularly the culture-associated hypomethylation is reversed simultaneously with age-associated and pluripotency-associated DNAm changes. Bisulfite barcoded amplicon sequencing (BBA-seq) demonstrated that upon passaging the DNAm patterns of neighboring CpGs become more complex without evidence of continuous pattern development and without association to oligoclonal subpolulations of MSCs at later passages. Circularized chromatin conformation capture (4C) revealed reproducible changes in nuclear organization between early and late passages, while there was no preferential interaction with other genomic regions that also harbor culture-associated DNAm changes. Chromatin immunoprecipitation of CTCF did not show significant differences during long-term culture of MSCs, however culture-associated hypermethylation was enriched at CTCF binding sites and hypomethylated CpGs were devoid of CTCF. Taken together, our results indicate that DNAm changes during culture-expansion resembles epigenetic drift.
2021-05-26 | GSE165603 | GEO
Project description:Culture expansion of primary cells evokes highly reproducible DNA methylation (DNAm) changes at specific sites in the genome. These changes might be due to an directly regulated epigenetic process, or to gradual deregulation of the epigenetic state, which is often referred to as “epigenetic drift”. We have identified CG dinucleotides (CpGs) that become continuously hyper- or hypomethylated in the course of culture expansion of mesenchymal stem cells (MSCs) and other cell types. During reprogramming into induced pluripotent stem cells (iPSCs) the long-term culture-associated hypomethylation is reversed simultaneously with pluripotency-associated DNAm changes. Bisulfite barcoded amplicon sequencing (BBA-seq) demonstrated that upon passaging the DNAm patterns of neighboring CpGs become more complex without evidence of continuous pattern development and without association to dominant subclones at later passages. Circularized chromatin conformation capture (4C) revealed reproducible changes in nuclear organization between early and late passages, while there was no preferential interaction with other genomic regions that also harbor culture-associated DNAm changes. Chromatin immunoprecipitation of CTCF did not show significant differences during long-term culture of MSCs, however culture-associated hypermethylation was enriched at CTCF binding sites and hypomethylated CpGs were devoid of CTCF. Taken together, the DNAm changes during culture-expansion of cells cannot be attributed to cellular subsets, whereas they seem to resemble epigenetic drift in relation to chromatin conformation.
2021-05-26 | GSE144195 | GEO
Project description:Epigenetic drift during long-term culture of cells in vitro
| PRJNA603001 | ENA
Project description:Epigenetic drift during long-term culture of cells in vitro
| PRJNA478324 | ENA