Project description:We report the global methylation patterns by MBDCap-seq for total 232 primary samples in endometrial cohorts, breast cancer cohorts and breast cancer cell lines. We found total 1,007 differentially methylated regions (DMRs) include CpG islands and shores in endometrial cohorts, and 2529 for Breast Cancer cohorts. We also identified 153 regions that are distinctly different from regular CpG islands at the 5'-ends of genes. Those regions, always contain a chain of 1-2 main islands and a few satellites alone on GC-poor and gene-less region. Majority of CpG atolls contain lowly transcribed or silenced genes in normal controls. This phenomenon provides a new opportunity to develop sensitive biomarkers for cancer diagnosis and prognosis
Project description:DNA methylation plays a key role in demarcation of regulatory regions, including promoter-associated CpG islands. While CpG islands are typically maintained in an unmethylated state in normal cells, a proportion of CpG islands are subject to hypermethylation in cancer cells. It still remains elusive how the exquisite demarcation of the bimodal methylation state is established and maintained at the CpG island flanks and conversely what triggers the erosion of CpG island DNA methylation in tumorigenesis. Here, we applied whole-genome bisulphite sequencing to study the comprehensive methylation patterns of prostate normal and cancer tissues. Alongside we performed TET-assisted bisulphite sequencing to study genome-wide DNA hydroxymethylation patterns of normal prostate and prostate cancer tissues.
Project description:DNA methylation plays a key role in demarcation of regulatory regions, including promoter-associated CpG islands. While CpG islands are typically maintained in an unmethylated state in normal cells, a proportion of CpG islands are subject to hypermethylation in cancer cells. It still remains elusive how the exquisite demarcation of the bimodal methylation state is established and maintained at the CpG island flanks and conversely what triggers the erosion of CpG island DNA methylation in tumorigenesis. Here, we applied whole-genome bisulphite sequencing to study the comprehensive methylation patterns of prostate normal and cancer tissues. Alongside we performed TET-assisted bisulphite sequencing to study genome-wide DNA hydroxymethylation patterns of normal prostate and prostate cancer tissues.
Project description:Methylation of CpG islands associated with genes can affect the expression of the proximal gene, and methylation of non associated CpG islands correlates to genomic instability. This epigenetic modification has been shown to be important in many pathologies, from development and disease to cancer. We report the development of a novel high-resolution microarray that detects the methylation status of over 25,000 CpG islands in the human genome. Experiments were performed to demonstrate low system noise in the methodology and that the array probes have a high signal to noise ratio. Methylation measurements between different cell lines were validated demonstrating the accuracy of measurement. We then identified alterations in CpG islands, both those associated with gene promoters, as well as non-promoter associated islands in a set of breast and ovarian tumors. We demonstrate that this methodology accurately identifies methylation profiles in cancer and in principle it can differentiate any CpG methylation alterations and can be adapted to analyze other species. We have developed a method to profile genome wide methylation. 12 breast normal samples and matching tumors from these individuals and an additional 28 tumor samples from other individuals were analyzed for CpG methylation. After inter array normalization, the tumor samples were taken together and the methylation compared to that of the normal samples to identify regions of the CpG islands that are significantly altered between the two datasets. Some of these regions were validated for their methylation as a proof of principle for the method.
Project description:Methylation of CpG islands associated with genes can affect the expression of the proximal gene, and methylation of non associated CpG islands correlates to genomic instability. This epigenetic modification has been shown to be important in many pathologies, from development and disease to cancer. We report the development of a novel high-resolution microarray that detects the methylation status of over 25,000 CpG islands in the human genome. Experiments were performed to demonstrate low system noise in the methodology and that the array probes have a high signal to noise ratio. Methylation measurements between different cell lines were validated demonstrating the accuracy of measurement. We then identified alterations in CpG islands, both those associated with gene promoters, as well as non-promoter associated islands in a set of breast and ovarian tumors. We demonstrate that this methodology accurately identifies methylation profiles in cancer and in principle it can differentiate any CpG methylation alterations and can be adapted to analyze other species. We have developed a method to profile genome wide methylation. 7 ovarian normal samples and 11 tumor samples from other individuals were analyzed for CpG methylation. After inter array normalization, the tumor samples were taken together and the methylation compared to that of the normal samples to identify regions of the CpG islands that are significantly altered between the two datasets. Some of these regions were validated for their methylation as a proof of principle for the method.
Project description:To improve our understanding of the effect of differential methylation on gene expression between normal and tumor breast cells, we employed high-throughput sequencing technology to determine and compare CpG methylation of normal breast and four breast tumor genomes at single-base resolution. By comparing the methylation profiles between normal and tumor, we identified large hypomethylated zones in associated with large tissue-specific genes and gene deserts. We identified small hypomethylated regions in the methylomes and termed these sites as unmethylated islands (UMI). The UMI are highly correlated with positive regulatory chromatin marks and exhibit differential methylation mainly at the island shores. Our analysis showed there is a complex relationship between genome-wide promoter differential methylation and gene expression. Four other data sets from this study were also deposited at ArrayExpress under accession numbers E-MTAB-1935, E-MTAB-1952, E-MTAB-1958 and E-MTAB-1961.
Project description:We have systematically profiled DNA methylation at promoter CpG islands (CGIs) in ovarian cancer. Epithelial ovarian tumours, excluding mucinous and clear cell cancers, prospectively collected through a cohort study, were analyzed by differential methylation hybridization (DMH) (Nouzova M et al, 2004) in duplicates. The loci targeted by the custom-designed microarray are the promoter CpG islands (Gardiner-Garden and Frommer, 1987) of the genes involved in the Wnt, p53, AKT/mTOR, BRCA1/2 and Redox pathways, DNA repair (HR, NHEJ and MMR), FA family and IgLON family.
Project description:COHCAP (City of Hope CpG Island Analysis Pipeline) is an algorithm to analyze single-nucleotide resolution DNA methylation data. It provides QC metrics, differential methylation for CpG Sites, differential methylation for CpG Islands, integration with gene expression data, and visualization of methylation values. COHCAP is currently the only DNA methylation package that can handle integration with gene expression data, and the results of this study show that COHCAP can identify regions of differential methylation with ~50% concordance with gene expression. COHCAP is scalable for analysis of both cell line data and heterogeneous patient data, and it can identify known cancer biomarkers as well as intriguing new roles of epigenetic regulation in cancer (such as methylation of estrogen receptor in breast cancer patients). This study also uses cell line data to show that COHCAP is capable of analyzing Illumina methylation array and targeted bisulfite sequencing data, with either 1-group or 2-group study designs. The accuracy of COHCAP is accessed using qPCR, EpiTect, and comparison of COHCAP regions of differential methylation with MIRA peaks. This software is freely available at https://sourceforge.net/projects/cohcap/. The following third-party datasets were utilized in the paper: BS-Seq data: GSE26826 Additional Microarray Data: GSE29290 This SuperSeries is composed of the SubSeries listed below. Refer to individual Series.
Project description:<p>Understanding and explaining hereditary predisposition to cancer has focused on the genetic etiology of the disease. However, mutations in known genes associated with breast cancer such as BRCA1 and BRCA2 account for less than 25% of familial cases of breast cancer. Heritable epigenetic modifications, in the form of hypermethylated MLH1 promoter alleles, have recently been shown to promote hereditary nonpolyposis colorectal cancer. We investigated the potential for an epigenetic basis for hereditary breast cancer by performing deep bisulfite sequencing of CpG islands and known promoter regions in germline DNA from 100 familial or early-onset breast or ovarian cancer patients.</p>
Project description:10% of methylation sites in CpG islands. In this study, the genome-wide CpG islands of human sperm, oocyte and pre-implantation embryos were analyzed using the almost complete coverage of promoters and CpG islands (most methylation-producing regions) methylation microarray method (MeDIP-Chip). Dynamic changes in methylation of sub-regions to understand the dynamic pattern of CpG island and promoter methylation, possible regulatory mechanisms of this methylation dynamic change, and function during early embryonic development.