Glioblastoma, the most aggressive and least treatable form of malignant glioma, is the most common human brain tumor. Although many regions of allelic loss occur in glioblastomas, relatively few tumor suppressor genes have been found mutated at such loci. To address the possibility that epigenetic alterations are an alternative means of glioblastoma gene inactivation, we coupled pharmacological manipulation of methylation with gene profiling to identify potential methylation-regulated, tumor-related genes. Triplicates of three short-term cultured glioblastomas were exposed to 5M 5-aza-dC for 96 hours followed by cRNA hybridization to an oligonucleotide microarray (Affymetrix U133A). We based candidate gene selection on bioinformatics, RT-PCR, bisulfite sequencing, methylation-specific PCR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Two genes identified in this manner, RUNX3 and Testin (TES), were subsequently shown to harbor frequent tumor-specific epigenetic alterations in primary glioblastomas. This overall approach therefore provides a powerful means to identify candidate tumor suppressor genes for subsequent evaluation and may lead to the identification of genes whose epigenetic dysregulation is integral to glioblastoma tumorigenesis.
Downregulation of RUNX3 and TES by hypermethylation in glioblastoma.
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View SamplesAs a result of ancestral whole genome and small-scale duplication events, the genome of Saccharomyces cerevisiae's, and of many eukaryotes, still contain a substantial fraction of duplicated genes. In all investigated organisms, metabolic pathways, and more particularly glycolysis, are specifically enriched for functionally redundant paralogs. In ancestors of the Saccharomyces lineage, the duplication of glycolytic genes is purported to have played an important role leading to S. cerevisiae current lifestyle favoring fermentative metabolism even in the presence of oxygen and characterized by a high glycolytic capacity. In modern S. cerevisiae, the 12 glycolytic reactions leading to the biochemical conversion from glucose to ethanol are encoded by 27 paralogs. In order to experimentally explore the physiological role of this genetic redundancy, a yeast strain with a minimal set of 14 paralogs was constructed (MG strain). Remarkably, a combination of quantitative, systems approach and of semi-quantitative analysis in a wide array of growth environments revealed the absence of phenotypic response to the cumulative deletion of 13 glycolytic paralogs. This observation indicates that duplication of glycolytic genes is not a prerequisite for achieving the high glycolytic fluxes and fermentative capacities that are characteristic for S. cerevisiae and essential for many of its industrial applications and argues against gene dosage effects as a means for fixing minor glycolytic paralogs in the yeast genome. MG was carefully designed and constructed to provide a robust, prototrophic platform for quantitative studies, and is made available to the scientific community. Overall design: The goals of the present study are to experimentally explore genetic redundancy in yeast glycolysis by cumulative deletion of minor paralogs and to provide a new experimental platform for fundamental yeast research by constructing a yeast strain with a functional 'minimal glycolysis'. To this end, we deleted 13 minor paralogs, leaving only the 14 major paralogs for the S. cerevisiae glycolytic pathway. The cumulative impact of deleting all minor paralogs was investigated by two complementary approaches. A first, quantitative analysis focused on the impact on glycolytic flux under a number of controlled cultivation conditions that, in wild-type strains, result in different glycolytic fluxes. These quantitative growth studies were combined with transcriptome, enzyme-activity and intracellular metabolite assays to capture potential small phenotypic effects. A second, semi-quantitative characterization explored the phenotype of the 'minimal glycolysis' strain under a wide array of experimental conditions to identify potential context-dependent phenotypes
The Genetic Makeup and Expression of the Glycolytic and Fermentative Pathways Are Highly Conserved Within the <i>Saccharomyces</i> Genus.
Cell line, Subject
View SamplesThe four transcription factors Oct4, Sox2, Klf4, and c-Myc can induce pluripotency in mouse and human fibroblasts. We previously described direct reprogramming of adult mouse neural stem cells (NSCs) by Oct4 and either Klf4 or c-Myc. NSCs endogenously express Sox2, c-Myc, and Klf4 as well as several intermediate reprogramming markers. Here we report that exogenous expression of the germline-specific transcription factor Oct4 is sufficient to generate pluripotent stem cells from adult mouse NSCs. These one-factor induced pluripotent stem (1F iPS) cells are similar to embryonic stem cells in vitro and in vivo. Not only can these cells be efficiently differentiated into NSCs, cardiomyocytes and germ cells in vitro, but they are also capable of teratoma formation and germline transmission in vivo. Our results demonstrate that Oct4 is required and sufficient to directly reprogram NSCs to pluripotency.
Oct4-induced pluripotency in adult neural stem cells.
No sample metadata fields
View SamplesInhibition of the costimulatory CD40-CD40L receptor/ligand dyad drastically reduces atherosclerosis. However, its long-term blockage can result in immune suppression. We recently identified small molecule inhibitors that block the interaction between CD40 and TNF Receptor Associated Factor (TRAF) 6 (TRAF-STOPs), while leaving CD40-TRAF2/3/5 interactions intact, thereby preserving CD40-mediated immunity. Here we further characterized the working mechanisms of TRAF-STOPs 6877002 and 6860766 in atherogenesis.
Targeting CD40-Induced TRAF6 Signaling in Macrophages Reduces Atherosclerosis.
Specimen part, Treatment
View SamplesNo description.
Analysis of diet-induced differential methylation, expression, and interactions of lncRNA and protein-coding genes in mouse liver.
Sex, Age, Specimen part, Cell line
View SamplesAffymetrix Mouse Genome 430 2.0 arrays were used to measure genome-wide gene expression levels. The results show that high-risk human papillomavirus oncogenes E6 and E7 reprogram the cervical cancer microenvironment independently of and synergistically with estrogen, a critical co-factor in cervical cancer development and maintenance.
Human papillomavirus oncogenes reprogram the cervical cancer microenvironment independently of and synergistically with estrogen.
Specimen part, Treatment
View SamplesNasopharyngeal carcinoma is an Epstein-Barr virus-associated epithelial cancer with high prevalence in Southeast Asia. mRNA expression levels were measured for essentially all human genes and all latent Epstein-Barr virus (EBV) genes in nasopharyngeal carcinoma tissue samples and normal nasopharyngeal tissues. Data were analyzed for differential gene expression between tumor and normal tissue and for correlations with levels of viral gene expression. Primary publications: Sengupta et al, 2006, Cancer Research 66(16): 7999-8006. Dodd et al, 2006, Cancer Epidemiology, Biomarkers & Prevention 15(11): 2216-2225.
Genes involved in DNA repair and nitrosamine metabolism and those located on chromosome 14q32 are dysregulated in nasopharyngeal carcinoma.
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View SamplesHuman papillomaviruses (HPVs) are associated with nearly all cervical cancers (CCs), 20-30% of head and neck cancers (HNCs), and other cancers. Because HNCs also arise in HPV-negative patients, this type of cancer provides unique opportunities to define similarities and differences of HPV-positive versus HPV-negative cancers arising in the same tissue. Here, we describe genome-wide expression profiling of 84 HNCs, CCs and site-matched normal epithelial samples in which we used laser capture microdissection to enrich samples for tumor-derived versus normal epithelial cells. This analysis revealed that HPV+HNCs and CCs differed in their patterns of gene expression yet shared many changes compared to HPV-HNCs. Some of these shared changes were predicted, but many others were not. Notably, HPV+HNCs and CCs were found to be upregulated in their expression of a distinct and larger subset of cell cycle genes than observed in HPV-HNC. Moreover, HPV+ cancers over-expressed testis-specific genes that are normally expressed only in meiotic cells. Many, though not all, of the hallmark differences between HPV+HNC and HPV-HNC were a direct consequence of HPV and in particular the viral E6 and E7 oncogenes. This included a novel association of HPV oncogenes with testes specific gene expression. These findings in primary human tumors provide novel biomarkers for early detection of HPV+ and HPV- cancers, and emphasize the potential value of targeting E6 and E7 function, alone or combined with radiation and/or traditional chemotherapy, in the treatment of HPV+ cancers.
Fundamental differences in cell cycle deregulation in human papillomavirus-positive and human papillomavirus-negative head/neck and cervical cancers.
Sex, Age
View SamplesIn the present study, we studied chronic HCV patients who responded to IFN-based therapy as evidenced by absence of HCV RNA at the end of treatment, and focused on two issues that have not received much attention. Firstly, we evaluated whether specific genes or gene expression patterns in blood were able to distinguish responder patients with a viral relapse from responder patients who remained virus-negative after cessation of treatment. We found that chronic HCV patients who were sustained responders and relapsers to IFN-based therapy showed comparable baseline clinical parameters and immune composition in blood. However, at baseline, the gene expression profiles of a set of 18 genes predicted treatment outcome with an accuracy of 94%. Secondly, we examined whether patients with successful therapy-induced clearance of HCV still exhibited gene expression patterns characteristic for HCV, or whether normalization of their transcriptome was observed. We observed that the relatively high expression of IFN-stimulated genes (ISG) in chronic HCV patients prior to therapy was reduced after successful IFN-based antiviral therapy (at 24 weeks follow-up). These ISG included CXCL10, OAS1, IFI6, DDX60, TRIM5 and STAT1. In addition, 1428 differentially expressed non-ISG genes were identified in paired pre- and post-treatment samples from sustained responders, which included genes involved in TGF- signaling, apoptosis, autophagy, and nucleic acid and protein metabolism. Interestingly, 1424 genes were identified with altered expression in responder patients after viral eradication in comparison to normal expression levels in healthy individuals. Additionally, aberrant expression of a subset of these genes, including IL-32, IL-16, CCND3 and RASSF1, was also observed at baseline. Our findings indicate that successful antiviral therapy of chronic HCV patients does not lead to normalization of their blood transcriptional signature. The altered transcriptional activity may reflect HCV-induced liver damage in previously infected individuals.
Gene expression profiling to predict and assess the consequences of therapy-induced virus eradication in chronic hepatitis C virus infection.
Sex, Specimen part, Disease, Race
View SamplesAffymetrix-U133-plus2.0-based gene expression analysis of laser-captured epithelium from 128 cervical tissue specimens from women enrolled in SUCCEED
Molecular transitions from papillomavirus infection to cervical precancer and cancer: Role of stromal estrogen receptor signaling.
Specimen part, Treatment
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