DNA Methylation and RNA Expression Profiles in Lung Adenocarcinomas
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Zhifu Sun
PROVIDER: E-GEOD-62950 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Lung cancer occurs in never-smokers. Epigenetic changes in lung cancer potentially represent important diagnostic, prognostic, and therapeutic targets. We compared DNA methylation profiles of 28 adenocarcinomas of the lungs of never-smokers with paired adjacent nonmalignant lung tissue. We correlated differential methylation changes with gene expression changes from the same 28 samples. We observed a distinct separation in methylation profiles between tumor and adjacent nonmalignant lung tissue using principal component analysis. Tumors were generally hypomethylated compared with adjacent nonmalignant tissue. Of 1,906 differentially methylated CpG sites between tumor and nonmalignant tissue, 1,198 were within classically defined CpG islands where tumors were hypermethylated compared with nonmalignant tissue. A total of 708 sites were outside CpG islands where tumors were hypomethylated compared with nonmalignant tissue. There were significant differences in expression of 351 genes (23%) of the 1,522 genes matched to the differentially methylated CpG sites. Genes that were not significantly differentially expressed and were hypermethylated within CpG sites were enriched for homeobox genes. These results suggest that the methylation profiles of lung adenocarcinomas of never-smokers and adjacent nonmalignant lung tissue are significantly different. Despite the differential methylation of homeobox genes, no significant changes in expression of these genes were detected. Twenty eight pairs of tumor and adjacent normal lungs were profiled for lung adenocarcinoma patients by gene expression and DNA methylation microarray
2015-02-03 | E-GEOD-62948 | biostudies-arrayexpress
Project description:Preeclampsia (PE), a hypertensive disorder of pregnancy, is hypothesized to be associated with, if not mechanistically related to abnormal placental function. However, the exact mechanisms regulating the pathogenesis of PE remain unclear. While many studies have investigated changes in gene expression in the PE placenta, the role of epigenetics in PE associated placental dysfunction remains unclear. Using the genome-wide Illumina Infinium Methylation 450 BeadChip array, we analyzed gene-specific alterations in DNA methylation in placental biopsies collected from normal pregnant women delivering at term (n=14), with term PE (≥37 weeks; n=19) or with preterm PE (<37 weeks, n=12). Of the 485,582 gene loci on the array, compared to controls, 229 loci were differentially methylated in PE placentas and 3411 loci were differentially methylated in preterm PE (step up p-value <0.05 and >5% methylation difference). Functional annotation of the differentially methylated genes in preterm PE placentas revealed a 32 gene cluster in the cadherin and cell adhesion functional groups (Benjamini p<0.00001). Hypermethylation of CDH11 (p=0.0143), COL5A1 (p=0.0127) and TNF (p=0.0098) and hypomethylation of NCAM1 (p=0.0158) was associated with altered mRNA expression in preterm PE placentas. These studies demonstrate aberrant methylation, correlating with disease severity, in PE placentas. Bisulphite converted DNA from the 45 samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip v1.2
2014-05-20 | E-GEOD-57767 | biostudies-arrayexpress
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2014-09-11 | E-GEOD-51287 | biostudies-arrayexpress
Project description:Using the Illumina Infinium Human Methylation27 BeadChip, we performed a genome-wide analysis of DNA methylation in right coronary artery in the area of advanced atherosclerotic plaques, atherosclerotic-resistant internal mammary arteries, and great saphenous veins obtained from same patients with coronary heart disease. The resulting DNA methylation patterns were markedly different between all the vascular tissues. The genes hypomethylated in athero-prone arteries to compare with atherosclerotic-resistant arteries were predominately involved in regulation of inflammation and immune processes, as well as development. The great saphenous veins exhibited an increase of the DNA methylation age in comparison to the internal mammary arteries. Gene ontology analysis for genes harboring hypermethylated CpG-sites in veins revealed the enrichment for biological processes associated with the development. Four CpG-sites located within the MIR10B gene sequence and about 1 Kb upstream of the HOXD4 gene were also confirmed as hypomethylated in the independent dataset of right coronary arteries in the area of advanced atherosclerotic plaques in comparison with the other vascular tissues. Bisulfite converted genomic DNA from 24 samples was denatured, whole-genome amplified, fragmented and subsequently hybridized to the Illumina Infinium 27k Human Methylation Beadchip.
2014-10-31 | E-GEOD-62867 | biostudies-arrayexpress
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2014-03-26 | E-GEOD-50220 | biostudies-arrayexpress
Project description:Mutations of IDH1 (R132) and IDH2 (R172 and R140), which produce an oncometabolite 2-hydroxyglutarate (2HG), have been identified in several tumors including acute myeloid leukemia (AML). Recent studies have shown that expression of the IDH mutant enzymes results in high levels of 2HG and a block in cellular differentiation that can be reversed with IDH-mutant specific small molecule inhibitors. To further understand the role of IDH mutations in cancer, we conducted mechanistic studies in the TF-1/IDH2 R140Q erythroleukemia model system and found that IDH2 mutant expression caused both histone and genomic DNA methylation changes that can be reversed when IDH2 mutant activity is inhibited. Specifically, histone hypermethylation is rapidly reversed within days whereas reversal of DNA hypermethylation proceeds in a progressive manner over the course of weeks. Pathway enrichment analysis revealed several pathways involved in tumorigenesis of leukemia and lymphoma, indicating a selective modulation of relevant cancer genes by IDH mutations. As methylation of DNA and histones is closely linked to mRNA expression and differentiation, these results indicate that IDH2 mutant inhibition may function as a cancer therapy via short-term histone demethylation and long-term DNA demethylation at genes involved in differentiation and tumorigenesis. TF-1 cells with and without IDH2/R140Q expression were treated with DMSO or AGI-6780, an inhibitor of IDH2/R140Q for 7 to 28 days. Genomic DNA was extracted and analyzed by the Illumina 450k Methylation array.
2014-11-19 | E-GEOD-51352 | biostudies-arrayexpress
Project description:The recent discovery of mutations in metabolic enzymes has rekindled interest in harnessing the altered metabolism of cancer cells for cancer therapy. One potential drug target is isocitrate dehydrogenase 1 (IDH1) which is mutated in multiple human cancers. Here, we examine the role of mutant IDH1 in fully transformed cells with endogenous IDH1 mutations. A selective R132H-IDH1 inhibitor (AGI-5198) identified through a high-throughput screen dose-dependently blocked the ability of the mutant enzyme (mIDH1) to produce R-2-hydroxyglutarate (R-2HG). Under conditions of near complete R-2HG inhibition, the mIDH1 inhibitor induced demethylation of histone H3K9M3 and expression of genes associated with gliogenic differentiation. Blockade of mIDH1 impaired the growth of IDH1-mutant - but not IDH1-wildtype – glioma cells without appreciable changes in genome wide DNA methylation. These data suggest that mIDH1 may promote glioma growth through mechanisms beyond its well-characterized epigenetic effects. Xenograft experiments were carried out with treatment cohorts of vehicle, 150mg/kg/day, 450mg/kg/day. After the indicated tumors were harvested and genomic DNA was extracted and analyzed by the Illumina 450k Methylation array.
2013-04-04 | E-GEOD-45198 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2013-04-04 | E-GEOD-45200 | biostudies-arrayexpress
Project description:The recent discovery of mutations in metabolic enzymes has rekindled interest in harnessing the altered metabolism of cancer cells for cancer therapy. One potential drug target is isocitrate dehydrogenase 1 (IDH1) which is mutated in multiple human cancers. Here, we examine the role of mutant IDH1 in fully transformed cells with endogenous IDH1 mutations. A selective R132H-IDH1 inhibitor (AGI-5198) identified through a high-throughput screen dose-dependently blocked the ability of the mutant enzyme (mIDH1) to produce R-2-hydroxyglutarate (R-2HG). Under conditions of near complete R-2HG inhibition, the mIDH1 inhibitor induced demethylation of histone H3K9M3 and expression of genes associated with gliogenic differentiation. Blockade of mIDH1 impaired the growth of IDH1-mutant - but not IDH1-wildtype – glioma cells without appreciable changes in genome wide DNA methylation. These data suggest that mIDH1 may promote glioma growth through mechanisms beyond its well-characterized epigenetic effects. Samples were maintained in either DMSO or 1.5uM 5198 for 2 passages up to 20 passages. Biological replicates for each passage and treatment was collected and genomic DNA was extracted and analyzed on the Illumina 450K Methylation platform for a total of 16 samples.
2013-04-04 | E-GEOD-45199 | biostudies-arrayexpress
Project description:Introduction: Although High Grade Serous Ovarian Cancer (HGSOC) is considered a chemo-responsive disease, a proportion of patients do not respond to platinum-based chemotherapy at presentation or have progression-free survival of <6 months. Validated biomarkers of lack of response would enable alternative treatment stratification for these patients and identify novel mechanisms of resistance. Methods: Differential DNA methylation was investigated in independent tumour sets using Illumina 27K HumanMethylation arrays and validated by bisulphite pyrosequencing. Gene expression was by Affymetrix arrays and qRT-PCR. The role of Msh homeobox 1 (MSX1) in drug sensitivity was investigated by gene reintroduction into ovarian cancer cell lines. Results: CpG sites at contiguous genomic locations within the MSX1 gene have significantly lower levels of methylation in HGSOC which recur by 6 months compared to after 12 months and/or with RECIST response (p<0.05, q<0.05). A decrease in methylation at these intragenic CpG sites was significantly correlated with decreased MSX1 gene expression. Low expression of MSX1 was associated with poor progression-free survival independent of known clinical prognostic features (p=0.014). Three mutant or wild-type TP53 expressing ovarian cancer cell lines, resistant to cisplatin, have reduced MSX1 expression compared to matched parental, platinum sensitive, lines. Re-expression of MSX1 in resistant lines led to cisplatin sensitisation, increased apoptosis, increased p21 and BAX expression. However, in two TP53-null cell lines, MSX1 failed to change cisplatin sensitivity. Conclusion: Hypomethylation of MSX1 is a biomarker of resistant HGSOC disease at presentation and identifies a novel mechanism of platinum drug resistance. Bisulphite converted DNA from the 86 samples were hybridised to the Illumina Infinium 27k Human Methylation Beadchip v1.2
2015-11-26 | E-GEOD-75414 | biostudies-arrayexpress