Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA117057 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Chromatin modifications are increasingly recognized as a key mechanism in cancer. The histone methyl-transferase Enhancer of Zeste, Drosophila, Homolog 2 (EZH2) is the enzymatic subunit of the polycomb PRC2 complex and methylates histone H3K27, thereby, mediating gene silencing. Down-regulation of EZH2 by RNA interference in ET suppressed oncogenic transformation, tumor development and metastasis in a respective mouse model. Further microarray analysis of EZH2 knock down, or functionally linked HDAC-inhibitor treatment revealed an undifferentiated reversible phenotype in ET maintained by EZH2. EZH2 suppression resulted in a generalized loss of H3K27me3 as well as an increase in H3 acetylation levels. In addition, ChIP-Chip assays for H3K27me3 identified genes that had specifically lost H3K27me3 upon EZH2 silencing. These findings suggested that stemness features are preserved via epigenetic mechanisms. Taken together, the genetic EWS-Fli1 translocation is intimately linked to global and gene specific epigenetic alterations in ET biology. EZH2 mediates neuroectodermal and endothelial embryonal tumor stem cell growth and metastasic spread induced by a translocation derived chimeric transcription factor. Keywords: PNET, Ewing Tumor Epigenetic regulation A673 transiently transfected with siRNA-EZH2 and siRNA-scrambled were harvested and Chromatin-IPs of H3K27me3 or H3 followed by microarray hybridisation were carried out. For detailed procedures see Burdach et al. Epigenetic Maintenance of Stemness and Malignancy in Peripheral Neuroectodermal Tumors by EZH2.
2010-05-18 | E-GEOD-15890 | biostudies-arrayexpress
Project description:Ewing Tumors (ET) are highly malignant tumors, localized in bone or soft tissue and are molecularly defined by ews/ets translocations. We identified histone methyl-transferase Enhancer of Zeste, Drosophila, Homolog 2 (EZH2) to be increased in ET. EZH2âs suppressive activity maintains stemness in normal and malignant cells. Here we found EZH2 to be upregulated by the pathognomonic fusion oncogene EWS-FLI1 in ET and mesenchymal stem cells. Downregulation of EZH2 by RNA interference in ET suppressed oncogenic transformation by inhibiting clonogenicity in vitro. Similarly, tumor development and metastasis in immunodeficient Rag2-/-γC-/- mice was suppressed. EZH2-mediated gene silencing was shown to be dependent on histone deacetylase (HDAC) activity. Subsequent microarray analysis of EZH2 knock down, HDAC-inhibitor treatment and confirmation in independent assays revealed an undifferentiated phenotype maintained by EZH2 in ET. Downregulation of EZH2 decreased histone H3 lysine 27 trimethylation (H3K27me3) at target loci. EZH2 regulated stemness genes such as nerve growth factor receptor (NGFR) as well as genes involved in neuroectodermal differentiation (EMP1, EPHB2, GFAP, GAP43). These data suggest that EZH2 might play a central role in Ewing Tumor pathology shaping the oncogenicity and stem cell phenotype of this tumor presumably by epigenetic regulation. Experiment Overall Design: A673 cells were treated for 24 hours either with 100 nM Trichostatin A (TSA) or 0.01% DMSO. In siRNA experiments with ezh2 specific siRNA A673 cells were resuspended in medium containing 5 nM siRNA and transfection reagent and incubated for 48 hours. RNA from cells under such treatment was isolated with Trizol and subjected to microarray analysis onto human U133A microarray following the Affymetrix protocol.
2008-10-26 | E-GEOD-12692 | biostudies-arrayexpress
Project description:Ewing Tumors (ET) are highly malignant tumors, localized in bone or soft tissue and are molecularly defined by ews/ets translocations. We identified histone methyl-transferase Enhancer of Zeste, Drosophila, Homolog 2 (EZH2) to be increased in ET. EZH2’s suppressive activity maintains stemness in normal and malignant cells. Here we found EZH2 to be upregulated by the pathognomonic fusion oncogene EWS-FLI1 in ET and mesenchymal stem cells. Downregulation of EZH2 by RNA interference in ET suppressed oncogenic transformation by inhibiting clonogenicity in vitro. Similarly, tumor development and metastasis in immunodeficient Rag2-/-γC-/- mice was suppressed. EZH2-mediated gene silencing was shown to be dependent on histone deacetylase (HDAC) activity. Subsequent microarray analysis of EZH2 knock down, HDAC-inhibitor treatment and confirmation in independent assays revealed an undifferentiated phenotype maintained by EZH2 in ET. Downregulation of EZH2 decreased histone H3 lysine 27 trimethylation (H3K27me3) at target loci. EZH2 regulated stemness genes such as nerve growth factor receptor (NGFR) as well as genes involved in neuroectodermal differentiation (EMP1, EPHB2, GFAP, GAP43). These data suggest that EZH2 might play a central role in Ewing Tumor pathology shaping the oncogenicity and stem cell phenotype of this tumor presumably by epigenetic regulation.
2008-10-01 | GSE12692 | GEO
Project description:Gene expression analysis of primitive neuroectodermal tumors
| PRJNA121773 | ENA
Project description:Chromatin modifications are increasingly recognized as a key mechanism in cancer. The histone methyl-transferase Enhancer of Zeste, Drosophila, Homolog 2 (EZH2) is the enzymatic subunit of the polycomb PRC2 complex and methylates histone H3K27, thereby, mediating gene silencing. Down-regulation of EZH2 by RNA interference in ET suppressed oncogenic transformation, tumor development and metastasis in a respective mouse model. Further microarray analysis of EZH2 knock down, or functionally linked HDAC-inhibitor treatment revealed an undifferentiated reversible phenotype in ET maintained by EZH2. EZH2 suppression resulted in a generalized loss of H3K27me3 as well as an increase in H3 acetylation levels. In addition, ChIP-Chip assays for H3K27me3 identified genes that had specifically lost H3K27me3 upon EZH2 silencing. These findings suggested that stemness features are preserved via epigenetic mechanisms. Taken together, the genetic EWS-Fli1 translocation is intimately linked to global and gene specific epigenetic alterations in ET biology. EZH2 mediates neuroectodermal and endothelial embryonal tumor stem cell growth and metastasic spread induced by a translocation derived chimeric transcription factor. Keywords: PNET, Ewing Tumor Epigenetic regulation
2009-06-02 | GSE15890 | GEO
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
| S-EPMC2531291 | biostudies-literature
Project description:RNA extracted at 240min. Samples are rRNA depleted. Expression measurement of Homo sapiens genes.
2019-07-31 | GSE114179 | GEO
Project description:Array-CGH screening of supratentorial primitive neuroectodermal tumors (stPNETs)
| PRJNA101999 | ENA
Project description:As the evolution of miRNA genes has been found to be one of the important factors in formation of the modern type of man, we performed a comparative analysis of the evolution of miRNA genes in two archaic hominines, Homo sapiens neanderthalensis and Homo sapiens denisova, and elucidated the expression of their target mRNAs in bain.A comparative analysis of the genomes of primates, including species in the genus Homo, identified a group of miRNA genes having fixed substitutions with important implications for the evolution of Homo sapiens neanderthalensis and Homo sapiens denisova. The mRNAs targeted by miRNAs with mutations specific for Homo sapiens denisova exhibited enhanced expression during postnatal brain development in modern humans. By contrast, the expression of mRNAs targeted by miRNAs bearing variations specific for Homo sapiens neanderthalensis was shown to be enhanced in prenatal brain development.Our results highlight the importance of changes in miRNA gene sequences in the course of Homo sapiens denisova and Homo sapiens neanderthalensis evolution. The genetic alterations of miRNAs regulating the spatiotemporal expression of multiple genes in the prenatal and postnatal brain may contribute to the progressive evolution of brain function, which is consistent with the observations of fine technical and typological properties of tools and decorative items reported from archaeological Denisovan sites. The data also suggest that differential spatial-temporal regulation of gene products promoted by the subspecies-specific mutations in the miRNA genes might have occurred in the brains of Homo sapiens denisova and Homo sapiens neanderthalensis, potentially contributing to the cultural differences between these two archaic hominines.
| S-EPMC4686780 | biostudies-literature
Project description:BACKGROUND: The polycomb group protein Ezh2 is an epigenetic repressor of transcription originally found to prevent untimely differentiation of pluripotent embryonic stem cells. We previously demonstrated that Ezh2 is also expressed in multipotent neural stem cells (NSCs). We showed that Ezh2 expression is downregulated during NSC differentiation into astrocytes or neurons. However, high levels of Ezh2 remained present in differentiating oligodendrocytes until myelinating. This study aimed to elucidate the target genes of Ezh2 in NSCs and in premyelinating oligodendrocytes (pOLs). METHODOLOGY/PRINCIPAL FINDINGS: We performed chromatin immunoprecipitation followed by high-throughput sequencing to detect the target genes of Ezh2 in NSCs and pOLs. We found 1532 target genes of Ezh2 in NSCs. During NSC differentiation, the occupancy of these genes by Ezh2 was alleviated. However, when the NSCs differentiated into oligodendrocytes, 393 of these genes remained targets of Ezh2. Analysis of the target genes indicated that the repressive activity of Ezh2 in NSCs concerns genes involved in stem cell maintenance, in cell cycle control and in preventing neural differentiation. Among the genes in pOLs that were still repressed by Ezh2 were most prominently those associated with neuronal and astrocytic committed cell lineages. Suppression of Ezh2 activity in NSCs caused loss of stem cell characteristics, blocked their proliferation and ultimately induced apoptosis. Suppression of Ezh2 activity in pOLs resulted in derangement of the oligodendrocytic phenotype, due to re-expression of neuronal and astrocytic genes, and ultimately in apoptosis. CONCLUSIONS/SIGNIFICANCE: Our data indicate that the epigenetic repressor Ezh2 in NSCs is crucial for proliferative activity and maintenance of neural stemness. During differentiation towards oligodendrocytes, Ezh2 repression continues particularly to suppress other neural fate choices. Ezh2 is completely downregulated during differentiation towards neurons and astrocytes allowing transcription of these differentiation programs. The specific fate choice towards astrocytes or neurons is apparently controlled by epigenetic regulators other than Ezh2. Examination of Ezh2 target sites in 2 different primary cells types
2012-07-30 | E-GEOD-31655 | biostudies-arrayexpress