Detection of aberrant DNA methylation in undifferentiated and differentiated mouse ES cells compared to normal tissues
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ABSTRACT:
ORGANISM(S): Mus musculus
SUBMITTER: guy ludwig
PROVIDER: E-GEOD-54664 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:Embryonic stem cells can be differentiated in vitro to produce a variety of somatic cell types. We have employed the mDIP method combined with hybridization to a tiling microarray to obtain a genome-wide methylation analysis of all UnMethylated Regions(UMRs). We show that this differentiation is accompanied by an intrinsic process of extensive aberrant CpG island de novo methylation that includes developmental and cancer target genes. CpG-methylated genomic DNA was enriched using a methyl-DNA immunoprecipitation (mDIP) assay. DNA from the input and bound (enriched) DNA for each sample were labeled and hybridized on the array to define the methylation state of each region.
2014-02-04 | E-GEOD-24270 | biostudies-arrayexpress
Project description:Following erasure in the early animal embryo, a new bimodal DNA methylation pattern is regenerated at the time of implantation in each individual through a wave of generalized de novo modification with CpG islands specifically left unmethylated. In this paper, we ask whether CpG islands are M-bM-^@M-^\protectedM-bM-^@M-^] from de novo methylation or, alternatively, acquire their unmodified state through M-bM-^@M-^\demethylation.M-bM-^@M-^] Using a genetic approach, we demonstrate that ES cells indeed have the ability to specifically demethylate CpG islands through pathways involving hydroxymethylation (Tet1), deamination (Aid), glycosylation (Mbd4) and excision repair (Gadd45a) genes. Surprisingly, this demethylation system is not actually necessary for generating the overall bimodal methylation pattern in ES cells. This general activity does, however, appear to be involved both in somatic cell reprogramming, as well as the normal methylation reprogramming that takes place in the early embryo. CpG-methylated genomic DNA was enriched using a methyl-DNA immunoprecipitation (mDIP) assay. DNA from the input and bound (enriched) DNA for each sample were labeled and hybridized on the array to define the methylation state of each region.
2013-11-17 | E-GEOD-48923 | biostudies-arrayexpress
Project description:De novo methylation of CpG islands is seen in many tumors, but the general rules governing this process are not known. By analyzing DNA from tumors, as well as normal tissues, and by utilizing a wide range of published data, we have been able to identify a well-defined set of tumor targets, each of which has its own M-bM-^@M-^\coefficientM-bM-^@M-^] of methylation that is largely determined by its inherent relative ability to recruit the polycomb complex. This pattern is initially formed by a slow process of de novo methylation that occurs during aging and then undergoes expansion early in tumorigenesis, where it may play a role as an inhibitor of development-associated gene activation. We also demonstrate that DNA methylation patterns can be used to diagnose the primary tissue source of tumor metastases. CpG-methylated genomic DNA was enriched using a methyl-DNA immunoprecipitation (mDIP) assay. DNA from the input and bound (enriched) DNA for each sample were labeled and hybridized on the array to define the methylation state of each region.
2014-03-26 | E-GEOD-38142 | biostudies-arrayexpress
Project description:Colorectal carcinoma (CRC) is often characterized by chromosomal instability (CIN) which has been associated with a poor prognosis. Disease-related de novo methylation often causes gene repression that may complement chromosomal losses or mutations. To compare CpG island methylation and chromosomal abnormalities in colorectal cancer, we determineded unbalanced chromosomal changes by aCGH of CRCs that were also profiled for aberrant de novo DNA methylation at 23,000 CpG islands of the human genome (Gebhard et al. 2010; and unpublished data). Refer to individual Series. This SuperSeries is composed of the following subset Series: GSE25221: CpG island methylation in colorectal cancer GSE25228: Chromosomal abnormalities in colorectal cancer
2012-11-01 | E-GEOD-25229 | biostudies-arrayexpress
Project description:To globally define methylation-M-bM-^@M-^YproneM-bM-^@M-^Y and -M-bM-^@M-^YprotectedM-bM-^@M-^Y CpG islands in cancer, we analyzed the methylation status of 23,000 CpG islands of the human genome in 19 colorectal carcinoma samples as well as normal colon using our previously described methyl-CpG immunoprecipitation (MCIp) technique (Gebhard et al. 2006; Schilling and Rehli 2007). This method enriches for highly CpG methylated DNA that can be directly applied to fluorescent labeling and oligonucleotide microarray hybridization without an additional amplification step. CpG-methylated genomic DNA was enriched using methyl-CpG immunoprecipitation (MCIp). On each microarray, the enriched material from colorectal carcinoma samples was compared to the enriched material from normal colon to identify aberrantly methylated regions.
2012-11-01 | E-GEOD-25221 | biostudies-arrayexpress
Project description:Using glutathione peroxidase, Gpx1 and Gpx2, double knockout (Gpx1/2-KO) mice as a model of inflammatory bowel disease predisposing to intestinal cancer, we analyzed genome-wide DNA methylation and chromatin changingM-bM-^@M-^Ys in the mouse ileum during chronic inflammation, aging and cancer. We found that inflammation leads to aberrant DNA methylation in Polycomb target genes, with 70% of the ~250 genes methylated in the inflamed tissue being PcG targets in embryonic stem cells and 58% of the methylated genes being marked by H3K27 trimethylation in the ileum of adult wildtype mice. Acquisition of DNA methylation at CpG islands in the ileum of Gpx-1/2-KO mice frequently correlated with loss of H3K27 trimethylation at the same loci. Inflammation-associated DNA methylation occurs preferentially in tissue-specific silent genes and, importantly, is much more frequently represented in tumors than is age-dependent DNA methylation. 60% of aberrant methylation found in tumors is also present in the inflamed tissue. In summary, inflammation creates a signature of aberrant DNA methylation, which is observed later in the malignant tissue and is directed by the PcG complex. In our study we used mice Gpx1/2-ko with B6 and B6.129 genetic background which are characterized by different level of inflammation in ileum and different tumor susceptibility. DNA methylation was analyzed by using MIRA-assisted Microarrays approach. Changing of the DNA methylation in intestinal epithelium during inflammation and tumorgenesis in Gpx1/2-KO mice were compared to healthy control mice with matching age. Aged dependent DNA methylation was study by comparing DNA methylation between 28-days-old healthy control mice with 8-month-old mice. To detect DKO-specific DNA methylation, we compared the changing DNA methylation in liver from Gpx1/2-KO mice with liver from control mice at age 28 days and 8 month. Association of the inflammation dependent DNA methylation with Polycomb targets and loss of H3K27me3 were verified by ChIp-on-ChIp experiments using H3K27me3 antibodies.
2008-12-31 | E-GEOD-12315 | biostudies-arrayexpress
Project description:The aim of the study was to address the concept of field cancerization in oral cancer. The presence of genomic aberrations, indicative of chromosomal instability (CIN), in oral distant fields (ODFs) of visually normal and non-dysplastic mucosa at the mirror image from concomitant oral potentially malignant lesions (OPMLs) was investigated. This pilot study comprised 16 OPMLs (8 without dysplasia, nd-OPMLs; 8 with dysplasia, d-OPMLs) and 16 ODFs. DNA diploid (DNA Index, DI=1) and aneuploid (DIM-bM-^IM- 1) sublines were detected by high resolution DNA-flow cytometry (FCM) at (hr DNA-FCM) using DAPI stained nuclei suspensions. Nuclei with different DIs were FCM-sorted in order to enrich the epithelial component and to obtain genomic DNA for high resolution oligonucleotide array-Comparative Genomic Hybridization (a-CGH) analysis to provide a genome-wide measurement of DNA copy number aberrations (CNAs). The frequencies of DNA aneuploidy in ODFs and OPMLs were 6.2% and 43.8%, respectively (p=0.037). ODFs and nd-OPMLs were all near-diploid (DIM-bM-^IM- 1 and DIM-bM-^IM-$1.4), while d-OPMLs were also high-aneuploid (DI>1.4). CNA averages were 2.3 in ODFs (1.5 for nd-OPMLs and 3.1 for d-OPMLs), and 7.325 in OPMLs (3.0 in nd-OPMLs; 11.6 in d-OPMLs). CNAs were present in the DNA diploid sublines and often the same CNAs were observed in both ODFs and corresponding OPMLs DNA aneuploid sublines and CNAs in the present series of 16 ODFs are likely to represent early events of the natural history of oral carcinogenesis and to indicate an early onset of the field effect cancerization. Moreover, gains within 20q13.33-qter, 7p22.2-pter and 16p13.3-pter chromosomal regions in ODFs and in the relative OPMLs suggest that specific genes localized in these regions (RTEL1, MAD1L1 and TEL2) might contribute to the ODF/d-OPML transition. We analyzed: 8 samples of oral potentially malignant lesions with dysplasia, 8 samples of oral potentially malignant lesions without dysplasia and for each patient a corresponding oral distant field of visually normal mucosa.
2011-12-21 | E-GEOD-28906 | biostudies-arrayexpress
Project description:The mucosae of the oral cavity are different at the histological level but are all exposed to common genotoxic agents. As a result of this exposure, changes in the mucosal epithelia develop giving rise to Oral Potentially Malignant Lesions (OPMLs), which with time may in turn progress to Oral Squamous Cell Carcinomas (OSCCs). Therefore, much effort should be devoted to identify features able to predict the likeliness of progression associated with an OPML. Such features may be helpful in assisting the clinician to establish both appropriate therapies and follow-up schedules. Here, we report a pilot study that compared the anatomical subsites of OPMLs development with occurrence of DNA aneuploidy and chromosomal copy number aberrations (CNAs). Multiple samples from histologically diagnosed OPMLs were processed for high resolution DNA flow cytometry (hr DNA-FCM) in order to determine the relative DNA content expressed by the DNA index (DI). Additionally, array-Comparative Genomic Hybridization (a-CGH) analysis was performed on FCM-sorted nuclei subpopulations based on DI values. Tongue OPMLs were more frequently associated with DNA aneuploidy and CNAs than OPMLs arising from all the other mucosal subsites. We suggest that the follow-up and the management of the patients with tongue OPMLs should receive a distinctive special attention. Clearly, this conclusion should be validated in a prospective clinical study. exposed to common genotoxic agents. As a result of this exposure, changes in the mucosal epithelia develop giving rise to Oral Potentially Malignant Lesions (OPMLs), which with time may in turn progress to Oral Squamous Cell Carcinomas (OSCCs). Therefore, much effort should be devoted to identify features able to predict the likeliness of progression associated with an OPML. Such features may be helpful in assisting the clinician to establish both appropriate therapies and follow-up schedules. Here, we report a pilot study that compared the anatomical subsites of OPMLs development with occurrence of DNA aneuploidy and chromosomal copy number aberrations (CNAs). Multiple samples from histologically diagnosed OPMLs were processed for high resolution DNA flow cytometry (hr DNA-FCM) in order to determine the relative DNA content expressed by the DNA index (DI). Additionally, array-Comparative Genomic Hybridization (a-CGH) analysis was performed on FCM-sorted nuclei subpopulations based on DI values. Tongue OPMLs were more frequently associated with DNA aneuploidy and CNAs than OPMLs arising from all the other mucosal subsites. We suggest that the follow-up and the management of the patients with tongue OPMLs should receive a distinctive special attention. Clearly, this conclusion should be validated in a prospective clinical study. We analyzed: 19 samples (4 aneuploid and 15 diploid components) deriving from oral potentially malignant lesions without dysplasia obtained of 16 patients; 14 samples (2 aneuploid and 12 diploid components) deriving from oral potentially malignant lesions with dysplasia obtained from 11 patients (two patients had multiple dysplastic lesions); 2 samples from visually normal mucosa in the near field obtained from two patients with dysplastic lesions. All the aneuploid samples had a purity of at least 90%.
2011-10-19 | E-GEOD-28868 | biostudies-arrayexpress
Project description:Chinese and Philippine strains of the blood fluke Schistosoma japonicum present clear and distinctive phenotypes in areas of fecundity, pathology, drug sensitivity and immunology. Despite these differences large scale sequencing efforts have focused solely on Chinese mainland strain of the parasite. We have undertaken a comparative genomic hybridisation (CGH) approach to highlight some of the structural differences in the genome of two of the major geographical isolates of S. japonicum. We identified seven distinct regions of the S. japonicum genome that present differential CGH between Chinese and Philippine strains of the blood fluke Schistosoma japonicum, representing either deletion or duplication regions in the Philippine strain. Within these regions, genes that may be related to phenotypical differences are identified and discussed. Genomic DNA was isolated from adult (7 week post cercarial challenge) Schistosoma japonicum Chinese and Philippine isolates and separate maleand femalesamples comparatively hybridised on an Agilent customn designed oligo microarray.
2012-07-13 | E-GEOD-39329 | biostudies-arrayexpress
Project description:Abstract: DNA methylation is an essential epigenetic modification that plays a key role associated with the regulation of gene expression during differentiation but in disease states such as cancer, the DNA methylation landscape is often deregulated. There are now numerous technologies available to interrogate DNA methylation status of CpG sites in a targeted or genome-wide fashion but each method, due to intrinsic biases, potentially interrogates different fractions of the genome. In this study, affinity-purification of methylated DNA using two popular genome-wide techniques: methylated DNA immunoprecipitation (MeDIP) and methyl-CpG binding domain-based capture (MBDCap) were evaluated, highlighting that each technique operates in a different domain of the CpG density landscape. The effect of whole genome amplification was explored, illustrating that it can reduce sensitivity for detecting DNA methylation in GC-rich regions of the genome. Using MBDCap, microarray- and sequencing-based readouts were compared, highlighting the impact that copy number variation (CNV) can make in differential comparisons of methylomes. These studies reveal that the analysis of DNA methylation data and genome coverage is highly dependent on the method employed and consideration must be made in light of GC content, extent of DNA amplification and copy number. Comparison of MeDIP/MBD for DNA methylation profiling, comparison of whole genome amplification techniques, using tiling array for copy number aberration detection and comparisons of tiling array data to sequencing readouts
2010-10-08 | E-GEOD-24546 | biostudies-arrayexpress