Methylated DNA binding protein 2 (MBD2) has been shown to bind specific methylated promoters and suppress transcription. Here we systematically investigate MBD2 suppression by overexpressing MBD2 in MCF-10A cells and generating gene expression profiles of overexpressing cells and normal MCF-10A cells.
Methylated DNA binding domain protein 2 (MBD2) coordinately silences gene expression through activation of the microRNA hsa-mir-496 promoter in breast cancer cell line.
Cell line, Treatment
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Definition of the landscape of promoter DNA hypomethylation in liver cancer.
Specimen part, Cell line, Subject
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A common promoter hypomethylation signature in invasive breast, liver and prostate cancer cell lines reveals novel targets involved in cancer invasiveness.
Sex, Disease, Disease stage, Cell line
View SamplesExtensive loss of DNA methylation is a hallmark of cancer. The role of hypomethylation in altering gene expression in cancer cells has been poorly understood. Hepatic cellular carcinoma (HCC) is one of the most common human cancers. We use HCC as a model to investigate hypomethylation in cancer by a combination of methylated DNA immunoprecipitation and hybridization with comprehensive promoter arrays. We identify approximately 2,800 promoters that are hypomethylated in tumor samples. The hypomethylated promoters appear in clusters across the genome suggesting a high-level organization behind the epigenomic changes in cancer. The genes whose promoters are demethylated are mainly involved in cell growth, cell adhesion and communication, signal transduction, mobility and invasion; functions that are essential for cancer progression and metastasis. Previous studies suggested that MBD2 was involved in demethylation of uPA and MMP2 genes in human breast and prostate cancer cell lines. We extend these results here showing that whereas MBD2 depletion in normal liver cells has little or no effect, its depletion in the human hepatocellular carcinoma cell line HepG2 and the adenocarcinoma cell line SkHep1 results in suppression of cell growth, anchorage-independent growth and invasiveness, as well as an increase in promoter methylation and silencing of several of the genes that are hypomethylated in tumors. Our studies establish for the first time the rules governing hypomethylation of promoters in liver cancer and define the potential functional role of hypomethylation in cancer.
Definition of the landscape of promoter DNA hypomethylation in liver cancer.
Specimen part, Subject
View SamplesCancer invasion and metastasis is the most morbid aspect of cancer and is governed by different cellular mechanisms than those driving the deregulated growth of tumors. We addressed here the question of whether a common DNA methylation signature of invasion exists in cancer cells from different origins that differentiates invasive from noninvasive cells. We identified a common DNA methylation signature consisting of hyper- and hypomethylation and determined the overlap of differences in DNA methylation with differences in mRNA expression using expression array analyses. A pathway analysis reveals that the hypomethylation signature includes some of the major pathways that were previously implicated in cancer migration and invasion such as TGF beta and ERBB2 triggered pathways. The relevance of these hypomethylation events in human tumors was validated by identification of the signature in several publicly available databases of human tumor transcriptomes. We shortlisted novel invasion promoting candidates and tested the role of four genes from the list C11orf68, G0S2, SHISA2 and TMEM156 in invasiveness using siRNA depletion. Importantly these genes are upregulated in human cancer specimens as determined by immunostaining of human normal and cancer breast, liver and prostate tissue arrays. Since these genes are activated in cancer they constitute a group of targets for specific pharmacological inhibitors of cancer invasiveness.
A common promoter hypomethylation signature in invasive breast, liver and prostate cancer cell lines reveals novel targets involved in cancer invasiveness.
Sex, Disease, Disease stage, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Role of DNA methylation in the nucleus accumbens in incubation of cocaine craving.
Sex, Specimen part
View SamplesGene expression profiling of nucleus Accumbens of rats that self administered cocaine and were subjected to 1 or 30 withdrawal days with or without extinction tests.
Role of DNA methylation in the nucleus accumbens in incubation of cocaine craving.
Sex, Specimen part
View SamplesGrowth factors (GFs) suppression by steroid hormones recurs in embryology and is co-opted in pathology. While studying mammary cell migration, which is stimulated by GFs and antagonized by glucocorticoids (GCs), we found that GCs inhibit positive feedback loops activated by GFs and stimulate the reciprocal negative loops. Although no alterations in DNA methylation accompany the transcriptional events instigated by either stimulus, forced demethylation of distal regions broadened the repertoire of inducible genes. Our data indicate that the crosstalk involve transcription factors like p53 and NF-kB, along with reduced pausing (and traveling) of RNA polymerase II (RNAPII) at the promoters (and bodies) of GF-inducible genes. In addition, while GFs hyper-acetylated chromatin at unmethylated promoters and enhancers of genes involved in motility, GCs hypo-acetylated the corresponding regions. In conclusion, stably unmethylated genomic regions that encode feedback regulatory modules and differentially recruit RNAPII and acetylases/deacetylases underlie suppression of growth factor signaling by glucocorticoids. Overall design: RNA-Seq – EGF treatemnt for 60 min of WT and DNMT1a and DNMT3b double-knockout HCT116 cells
Epigenetic mechanisms underlie the crosstalk between growth factors and a steroid hormone.
Treatment, Subject
View SamplesUncontrolled Transforming growth factor-beta (TGF) signaling promotes aggressive metastatic properties in late-stage breast cancers. However, how TGF-mediated cues are directed to induce late-stage tumorigenic events is poorly understood, particularly given that TGF has clear tumor suppressing activity in other contexts. Here we demonstrate that the transcriptional regulators TAZ and YAP (TAZ/YAP), key effectors of the Hippo pathway, are necessary to promote and maintain TGF-induced tumorigenic phenotypes in breast cancer cells. Interactions between TAZ/YAP, TGF-activated SMAD2/3, and TEAD transcription factors reveal convergent roles for these factors in the nucleus. Genome-wide expression analyses indicate that TAZ/YAP, TEADs and TGF-induced signals coordinate a specific pro-tumorigenic transcriptional program. Importantly, genes cooperatively regulated by TAZ/YAP, TEAD, and TGF, such as the novel targets NEGR1 and UCA1, are necessary for maintaining tumorigenic activity in metastatic breast cancer cells. Nuclear TAZ/YAP also cooperate with TGF signaling to promote phenotypic and transcriptional changes in non-tumorigenic cells to overcome TGF repressive effects. Our work thus identifies crosstalk between nuclear TAZ/YAP and TGF signaling in breast cancer cells, revealing novel insight into late-stage disease-driving mechanisms.
The transcriptional regulators TAZ and YAP direct transforming growth factor β-induced tumorigenic phenotypes in breast cancer cells.
Cell line, Treatment
View SamplesOur study identified long term salt stress treatment to induce symptoms similar to developmental senescence. In order to identify possible crosstalk components shared between developmental and salt-triggered senescence.
Salt stress and senescence: identification of cross-talk regulatory components.
Age, Specimen part, Treatment
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