Expression of the SS18/SYT-SSX fusion protein is believed to underlie the pathogenesis of synovial sarcoma (SS). Recent evidence suggests that deregulation of the Wnt pathway may play an important role in SS but the mechanisms whereby SS18-SSX might affect Wnt signaling remain to be elucidated. Here, we show that SS18/SSX tightly regulates the elevated expression of the key Wnt target AXIN2 in primary SS. SS18-SSX is shown to interact with TCF/LEF, TLE and HDAC but not -catenin in vivo and to induce Wnt target gene expression by forming a complex containing promoter-bound TCF/LEF and HDAC but lacking -catenin. Our observations provide a tumor-specific mechanistic basis for Wnt target gene induction in SS that can occur in the absence of Wnt ligand stimulation.
The fusion protein SS18-SSX1 employs core Wnt pathway transcription factors to induce a partial Wnt signature in synovial sarcoma.
Cell line
View SamplesOverexpression of the Polycomb group protein Enhancer of Zeste Homolog 2 (EZH2) occurs in diverse malignancies, including prostate cancer, breast cancer, and glioblastoma multiforme (GBM) (1). Based on its ability to modulate transcription of key genes implicated in cell cycle control, DNA repair and cell differentiation, EZH2 is believed to play a crucial role in tissue-specific stem cell maintenance and tumor development. Here we show that targeted pharmacologic disruption of EZH2 by the S-adenosylhomocysteine hydrolase inhibitor 3-Deazaneplanocin A (DZNep), or its specific down-regulation by shRNA, strongly impairs GBM cancer stem cell self-renewal in vitro and tumor-initiating capacity in vivo. Using genome-wide expression analysis of DZNep-treated GBM cancer stem cells, we found the expression of c-myc, recently reported to be essential for GBM cancer stem cells, to be strongly repressed upon EZH2 depletion. Specific shRNA-mediated down-regulation of EZH2 in combination with chromatin immunoprecipitation (ChIP) experiments revealed that c-myc is a direct target of EZH2 in GBM cancer stem cells. Taken together, our observations provide evidence that direct transcriptional regulation of c-myc by EZH2 may constitute a novel mechanism underlying GBM cancer stem cell maintenance and suggest that EZH2 may be a valuable new therapeutic target for GBM management.
EZH2 is essential for glioblastoma cancer stem cell maintenance.
Specimen part, Treatment
View SamplesCancer stem cells (CSCs) display plasticity and self-renewal properties reminiscent of normal tissue stem cells, but the events responsible for their emergence remain obscure. We recently identified CSCs in Ewing sarcoma family tumors (ESFTs) and showed that they retain mesenchymal stem cell (MSC) plasticity. In the present study, we addressed the mechanisms that underlie ESFT CSC development. We show that the EWS-FLI-1 fusion gene, associated with 85%-90% of ESFTs and believed to initiate their pathogenesis, induces expression of the embryonic stem cell (ESC) genes OCT4, SOX2, and NANOG in human pediatric MSCs (hpMSCs) but not in their adult counterparts. Moreover, under appropriate culture conditions, hpMSCs expressing EWS-FLI-1 generate a cell subpopulation displaying ESFT CSC features in vitro. We further demonstrate that induction of the ESFT CSC phenotype is the result of the combined effect of EWS-FLI-1 on its target gene expression and repression of microRNA-145 (miRNA145) promoter activity. Finally, we provide evidence that EWS-FLI-1 and miRNA-145 function in a mutually repressive feedback loop and identify their common target gene, SOX2, in addition to miRNA145 itself, as key players in ESFT cell differentiation and tumorigenicity. Our observations provide insight for the first time into the mechanisms whereby a single oncogene can reprogram primary cells to display a CSC phenotype.
EWS-FLI-1 modulates miRNA145 and SOX2 expression to initiate mesenchymal stem cell reprogramming toward Ewing sarcoma cancer stem cells.
Specimen part
View SamplesHere we present a strategy to adapt hESCs to high-throughput screening (HTS) conditions, resulting in an assay suitable for the discovery of small molecules that drive hESC self-renewal or differentiation. Use of this new assay has led to the identification of several currently marketed drugs and natural compounds promoting short-term hESC maintenance and compounds directing early lineage choice. Global gene expression analysis upon drug treatment reveals overlapping and novel pathways correlated to hESC self-renewal and differentiation. Our results demonstrate feasibility of hESC-based HTS and enhance the available repertoire of chemical compounds for manipulating hESC fate.
High-throughput screening assay for the identification of compounds regulating self-renewal and differentiation in human embryonic stem cells.
No sample metadata fields
View SamplesTranscriptomic studies revealed that hundreds of mRNAs show differential expression in the brains of sleeping versus awake rats, mice, flies, and sparrows. Although these results have offered clues regarding the molecular consequences of sleep and sleep loss, their functional significance thus far has been limited. This is because the previous studies pooled transcripts from all brain cells, including neurons and glia.
Transcriptome profiling of sleeping, waking, and sleep deprived adult heterozygous Aldh1L1 - eGFP-L10a mice.
Disease
View SamplesEscherichia coli exhibits diauxic growth in sugar mixtures due to CRP-mediated catabolite repression and inducer exclusion related to phosphotransferase system enzyme activity. Replacement of the native crp gene with a catabolite repression mutant (referred to as crp*) alleviates diauxic effects in E. coli and enables co-utilization of glucose and other sugars. While previous studies have examined the effects of expressing CRP* mutants on the expression of specific catabolic genes, little is known about the global transcriptional effects of CRP* expression.
Transcriptional effects of CRP* expression in Escherichia coli.
No sample metadata fields
View SamplesHD11 cells were stimulated with 1 ug/ml endotoxin from ST-798 for 1, 2, 4 and 8 hours
Unique genome-wide transcriptome profiles of chicken macrophages exposed to Salmonella-derived endotoxin.
Cell line, Time
View SamplesPurpose: Next-generation sequencing (NGS) has revolutionized systems-based analysis of cellular pathways. The goals of this study was to obtain the trasncriptome of DGCR8_KO mESCs to compare it with the transcriptome of WT mESCs (deposit separately). Overall design: mRNA profiles of DGCR8_KO mouse embryonic stem cells were generated by deep sequencing, in duplicate, using Illumina HiSeq2000.
Noncanonical function of DGCR8 controls mESC exit from pluripotency.
Specimen part, Cell line, Subject
View SamplesTranscriptomic studies revealed that hundreds of mRNAs show differential expression in the brains of sleeping versus awake rats, mice, flies, and sparrows. Although these results have offered clues regarding the molecular consequences of sleep and sleep loss, their functional significance thus far has been limited. This is because the previous studies pooled transcripts from all brain cells, including neurons and glia.
Effects of sleep and wake on oligodendrocytes and their precursors.
Specimen part
View SamplesWe sequenced mRNA from subcuteneous adipose tissue of 36 pigs (12 Low, 12 Mean and 12 High) to investigate expression profiling of obesity (porcine model) Overall design: Examination of mRNA levels in different obese states in a porcine model for human obesity
An integrative systems genetics approach reveals potential causal genes and pathways related to obesity.
Sex, Specimen part, Subject
View Samples