Epigenome analysis in HPV(-) and HPV(+) squamous cell carcinoma cell lines
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ABSTRACT: Human papillomavirus (HPV)-associated head and neck cancers (HNSCCs) have a distinct risk profile and appreciate a prognostic advantage compared to HPV-negative HNSCC. Promoter hypermethylation has been widely recognized as an important mechanism in the progression of HNSCC, but the extent to which this mechanism is consistent between HPV(+) and HPV(-) tumors is unknown. To assess the genome-wide methylation changes in HPV(+) and HPV(-) tumors, we analyzed DNA methylation and expression patterns in two HPV(+) and two HPV(-) cell lines. HPV(+) tumors have overall higher DNA methylation in genic and LINE1 regions than HPV(-) tumors, and polycomb repressive complex 2 (PRC2) targets tend to be much more highly methylated in HPV(+) cells. Bisulphite-converted DNA from 4 squamous cell carcinoma (SCC) cell lines were hybridized to the Illumina Infinium 27k Human Methylation Beadchip.
Project description:Idiopathic Pulmonary Fibrosis (IPF) is a chronic progressive lung disease that affects more than 5 million people worldwide with a steady increase in both incidence and mortality. There is currently no effective therapy and the median survival without transplant is 2-5 years. The etiological factor is unknown, but several observational and pathogenesis studies suggest that environmental agents may cause IPF. DNA methylation is a type of chemical modification of DNA such environmental and occupational factors, that can induced a changes in the regulation of biological processes and link to diseases such as a cancer. We hypothesize that the global changes in methylation patterns of IPF lungs caused by environmental factors. In this study we will identify the global methylation signatures of the IPF lung and to compare to methylation signature of lung cancer. The DNA methylation profiles of IPF lung tissue differs from control lung but it shares great similarity with that of lung cancer. Immunoprecipitated methylated DNA from 12 IPF lungs, 10 lung adenocarcinomas and 10 normal histology lungs obtained from the same group of adenocarcinoma patients was hybridized to Agilent human CpG Islands Microarrays. Only probes with a hybridization Tm value between 79 C and 93C were included in the analysis because these show higher quality signal. All probes were divided according to their Tm into 14 groups/bins differing by 1C. Probe signals in each bin were standardized to have an average of 0 and a standard deviation of 1. To work in a CpG island oriented manner, we scored each island for its likelihood to be methylated. For that purpose, each probe was mapped to the genome and the signals of the probes that were mapped to a single CpG island were averaged to obtain the islandM-bM-^@M-^Ys methylation score. Data analysis was performed using BRB-Array Tools and DAVID Bioinformatics Resources software packages.
Project description:We report whole tissue RNA-seq data captured from 25 AK, IEC or SCC lesions obtained from the skin of 17 individuals. We used RNA-seq to detect and measure HPV E7 transcription.
Project description:DNA methylation analysis using the Infinium HumanMethylation450 BeadChip platform (Illumina) of 96 Caucasian American, 96 Han Chinese American and 96 African American LCL samples determined differences in terms of differentially methylated sites. Importantly, the observed differences were confirmed in primary blood samples of 10 healthy Caucasian, 10 African American (GSE36064) and 10 Asian individuals. Genes associated to differentially methylated site suggest an influence of DNA methylation on phenotype differences. Interestingly, methylation differences could be partially traced back to genetic polymorphisms. DNA was quantified by Quant-iT PicoGreen dsDNA Reagent (Invitrogen) and the integrity was analyzed in a 1.3% agarose gel. Bisulfite conversion of 600 ng of each sample was perform according to the manufacturer's recommendation for Illumina Infinium Assay. Effective bisulphite conversion was checked for three controls that were converted simultaneously with the samples. 4 ul of bisulfite converted DNA were used to hybridize on Infinium HumanMethylation 450 BeadChip, following Illumina Infinium HD Methylation protocol. Chip analysis was performed using Illumina HiScan SQ fluorescent scanner. The intensities of the images are extracted using GenomeStudio (2010.3) Methylation module (1.8.5) software. Methylation score of each CpG is represented as beta value.
Project description:We used deep sequencinge technology to profile the transcriptome, gene copy number, and CpG island methylation status simultaneously in eight commonly used breast cell lines to develop a model for how these genomic features are integrated in estrogen receptor positive (ER+) and negative breast cancer. Total mRNA sequence, gene copy number, and genomic CpG island methylation were carried out using the Illumina Genome Analyzer. Sequences were mapped to the human genome to obtain digitized gene expression data, DNA copy number in reference to the non-tumor cell line (MCF10A), and methylation status of 21,570 CpG islands to identify differentially expressed genes that were correlated with methylation or copy number changes. These were evaluated in a dataset from 129 primary breast tumors. Gene expression in cell lines was dominated by ER-associated genes. ER+ and ER- cell lines formed two distinct, stable clusters, and 1,873 genes were differentially expressed in the two groups. Part of chromosome 8 was deleted in all ER- cells and part of chromosome 17 amplified in all ER+ cells. These loci encoded 30 genes that were overexpressed in ER+ cells; 9 of these genes were overexpressed in ER+ tumors. We identified 149 differentially expressed genes that exhibited differential methylation of one or more CpG islands within 5kb of the 5' end of the gene and for which mRNA abundance was inversely correlated with CpG island methylation status. In primary tumors we identified 84 genes that appear to be robust components of the methylation signature that we identified in ER+ cell lines. Our analyses reveal a global pattern of differential CpG island methylation that contributes to the transcriptome landscape of ER+ and ER- breast cancer cells and tumors. The role of gene amplification/deletion appears to more modest, although several potentially significant genes appear to be regulated by copy number aberrations. 8 commonly used breast cancer cell lines were sequenced for mRNA expression, CpG methylation and DNA copy number
Project description:Bilateral retinoblastoma has served as a critical model for studying genetic predisposition to cancer, however international incidence of unilateral retinoblastoma is variable across populations suggesting the involvement of environmental factors. DNA from Human Papilloma Virus (HPV) has been found in human retinoblastoma tissue through polymerase chain reaction based methods in several independent reports. To search for HPV oncoproteins and characterize transcriptional profiles in retinoblastoma, we analyzed tumor tissue obtained after enucleation and cultured for one week from 13 previously untreated Mexican children with retinoblastoma. We identified the presence of E7 HPV oncoproteins using western blot analysis in HPV positive tumors, and using non-supervised methods of classification on gene expression microarrays data, tumors clustered according to the presence or absence of HPV DNA identified by PCR. These methods were unable to discriminate retinoblastoma tissues by laterality. 2,404 genes were differentially expressed between HPV positive and HPV negative retinoblastoma, including a group of genes involved in a transcriptional response to viral infection. This molecular evidence supports the hypothesis that HPV is involved in the molecular pathogenesis of these tumors. The 13 children and tumors examined here, are incident cases participating in a larger case-control study at two Pediatric Hospitals of third level of medical attention in Mexico City, that form part of the public health system. Nine different tumors positive and four negative to HPV by PCR were included in the experimental design. From these, seven are unilateral and six are bilateral and are considered biological replicas. Two unilateral and two bilateral cases were chosen to make technical replicas. From the surgical specimens, two tumor portions were obtained, one was frozen, DNA was extracted from it, and HPV status was assigned using MY09 and MY11 primers by PCR. Another portion of tumor tissue was used to grow in culture, separating viable cells from non viable cells through a ficoll gradient. In the eye, retinoblastoma usually grows into the vitreous which has no cells, and thus the tissue obtained is predominantly formed by tumor cells and few endothelial cells from capillaries in the tumor. Retinoblastoma grow in culture as non adherent cells, and when adherent cells were also present, cell suspension was moved to a new dish to keep retinoblastoma cells as the main or only cellular type as possible. We used a two channel platform with in house spotted microarrays. Since retinoblastoma has known classes: uni and bilateral, we sought to verify these classes or discover new, we used a class discovery approach and a reference experimental design. As the reference sample we used RNA form exponentially growing Saccharomyces cerevisiae because major signaling pathways and basic cellular processes among Saccharomyces cerevisiae and mammalian cells including cell cycle control and DNA repair mechanisms have a high degree of conservation. Also because yeast is easy to grow, and thus a reliable and robust source of reference RNA.
Project description:Analysis of genomic methylation differences between day workers and shift workers. We hypothesized that there would be differences in methylation patterns between day workers and shift workers, and that some of these differences may explain the association between long-term shift work and breast cancer. The array provides methylation data on more than 27,000 CpG sites spread across the genome. Bisulfite-converted DNA from 10 day workers and 10 shift workers were hybridised to the Illumina Infinium 27k Human Methylation Beadchip v1.2.
Project description:ChIP-Seq for H3K27 trimethylation was performed for two HPV-positive and two HPV-negative squamous cell carcinoma cell lines. The data served two purposes. First, the data were used as an example implementation of our novel ChIP-Seq Peak Prioritization pipeline, PePr. We have developed the PePr pipeline, a ChIP-Seq Peak Prioritization pipeline that accounts for the variation among replicates and peak location relative to a gene. We show, using a transcription factor dataset (which exhibited small variation among samples), that PePr performs favorably compared to commonly used peak callers and that it achieves balanced sensitivity and specificity. We also show, using histone modification data (which exhibited larger variation among samples), that PePr can improve the detection of differential H3K27me3 regions compared with a common current approach. Using data from ChIP-Seq and gene expression experiments performed in parallel on the same samples, we show that the incorporation of functional annotations can improve the prioritization of functional sites. Secondly, the data were used to assess real differences in the genome-wide H3K27me3 profiles between HPV-positive and HPV-negative carcinoma cell lines. Careful analysis and integration of the data with DNA methylation and gene expression data performed on the same cell lines demonstrated striking differences exist. ChIP-Seq for H3K27 trimethylation was performed for two HPV-positive and two HPV-negative squamous cell carcinoma (SCC) cell lines. Input DNA was also sequenced for each sample to serve as a control. The goal was to determine overall differences in H3K27me3 patterns observed between the HPV-positive and HPV-negative SCC cell lines.
Project description:Genome wide DNA methylation profiling of normal whole blood samples. The data consist of 100 samples with Illumina HumanMethylation450 BeadChip data. Bisulphite converted DNA from the 100 samples were hybridized to the Illumina HumanMethylation450 BeadChip
Project description:To broaden our understanding of the gene expression common to volar skin, we biopsied the dorsum of the hand, palm, dorsum of the foot and sole and collected DNA for methylation chip anlayses Total of 12 skin biopsy samples with 3 repeats from distinct individuals of each site: dorsum of hand, palm, dorstum of foot and sole. The samples below represent methylation data only.
Project description:Genome wide DNA methylation profiling of primary neuroblastomas. The Illumina 450k methylation array was used to obtain DNA methylation profiles across approximately 485,000 CpGs in 105 neuroblastomas. Tumors were derived from 40 low-risk, 9 intermediate-risk and 56 high-risk patients. Bisulphite converted DNA from the 105 samples were hybridised to the llumina HumanMethylation450 BeadChip