The precise makeup of chromatin remodeling complexes is important for determining cell type and cell function. The SWI/SNF chromatin remodeling complex is made up of multiple subunits that can be filled by mutually exclusive proteins. Inclusion or exclusion of these proteins has profound functional consequences, yet we currently understand little about the direct functional relationship between these biochemically distinct forms of remodeling complexes. Here we combine chromatin immunoprecipitation, transcriptome analysis, and transcription factor binding information from the ENCODE project to determine the functional relationship between three biochemically distinct forms of SWI/SNF. We find widespread overlap in transcriptional regulation and the genomic binding of the three ARID (AT-Rich Interacting Domain) subunits of SWI/SNF. Despite the numerous similarities in their transcriptional regulation and the co-factors bound with each ARID we identify several novel interaction modalities. Previous work has found examples of competition or subunit switching at individual loci, and we find this functional relationship is widespread, and in these cases gene expression changes following loss of one ARID depend on the function of another ARID. We also identify a previously unknown cooperative interaction between ARID1B and ARID2 in the repression of a large number of genes. Together these data help untangle the complicated combinatorial relationships between a highly heterogenous chromatin remodeling family. Overall design: We performed depletion of ARID subunits (ARID1A , n=5; ARID1B, n=3, ARID2, n=5) of SWI/SNF using siRNA or a Non-Targeting control (N=6) and performed expression analysis using polyA+ selected RNA and a strand-specific dUTP incorporation library protocol.
Genome-Wide Transcriptional Regulation Mediated by Biochemically Distinct SWI/SNF Complexes.
No sample metadata fields
View SamplesHuman neural stem and progenitor cells transformed with c-MYC, dominant-negative p53, constitutively active AKT and hTERT formed tumors in mice that recapitulated Group 3 medulloblastoma in terms of pathology and expression profile
DiSCoVERing Innovative Therapies for Rare Tumors: Combining Genetically Accurate Disease Models with In Silico Analysis to Identify Novel Therapeutic Targets.
Specimen part
View SamplesWe used microarrays to analyze gene expression changes in liver after treatment of rats with two compounds from drug development (R1, R2) to identify potential effects related to hepatotoxicity.
Gene expression-based in vivo and in vitro prediction of liver toxicity allows compound selection at an early stage of drug development.
Sex, Specimen part, Treatment
View SamplesTargeting protein kinase C (PKC) isoforms by the small molecule inhibitor enzastaurin has shown promising pre-clinical activity in a wide range of tumor cells. In this study, we further delineated its mechanism of action in multiple myeloma (MM) cells and found a novel role of b-catenin in regulating growth and survival of tumor cells. Specifically, inhibition of PKC leads to rapid accumulation of b-catenin by preventing the phosphorylation required for its proteasomal degradation. Microarray analysis and siRNA-mediated gene silencing in MM cells revealed that accumulated b-catenin activates early ER stress signaling via eIF2a, CHOP and p21, leading to immediate growth inhibition. Furthermore, accumulated b-catenin contributes to enzastaurin-induced cell death. Both sequential knock-down of b-catenin, c-Jun, and p73, as well as overexpression of b-catenin or p73 confirmed that accumulated b-catenin triggers c-Jun-dependent induction of p73, thereby conferring MM cell apoptosis. In summary, our data reveal a novel role of b-catenin in ER stress-mediated growth inhibition, and a new pro-apoptotic mechanism triggered by b-catenin upon inhibition of PKC isoforms. Moreover, we identify p73 as a potential novel therapeutic target in MM. Based on these and previous data, enzastaurin is currently under clinical investigation in a variety of hematologic malignancies including MM.
Targeting PKC: a novel role for beta-catenin in ER stress and apoptotic signaling.
No sample metadata fields
View SamplesOvarian clear cell carcinoma (OCCC) is an aggressive form of ovarian cancer with high ARID1A mutation rates. Here we present a genetically engineered mouse model of OCCC. We find that ARID1A inactivation is not sufficient for tumor formation, but requires concurrent activation of the phosphoinositide 3-kinase catalytic subunit, PIK3CA. Remarkably, the mice develop highly penetrant tumors with OCCC-like histopathology, culminating in hemorrhagic ascites and a median survival period of 7.5 weeks. Therapeutic treatment with the pan-PI3K inhibitor, BKM120, prolonged mouse survival by inhibiting tumor cell growth. Cross-species gene expression comparisons support a role for IL-6 inflammatory cytokine signaling in OCCC pathogenesis. We further show that ARID1A-PIK3CA mutations cooperate to promote tumor growth through sustained IL-6 overproduction. Our findings establish an epistatic relationship between SWI/SNF chromatin remodeling and PI3K pathway mutations in OCCC and demonstrate that these pathways converge on pro-tumorigenic cytokine signaling. We propose that ARID1A protects against inflammation-driven tumorigenesis.
Coexistent ARID1A-PIK3CA mutations promote ovarian clear-cell tumorigenesis through pro-tumorigenic inflammatory cytokine signalling.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Genome-wide profiles of CtBP link metabolism with genome stability and epithelial reprogramming in breast cancer.
Specimen part, Cell line, Treatment
View SamplesCtBP is a global co-repressor by serving as transcriptional factor in multiple pathways. CtBP functioned as transcriptional factor by recruiting other cofactors such as G9a, HDAC1 and PcG proteins. CtBP is found to be over enriched in several type of tumor samples. To dipict the role of CtBP in globally regulating gene expression, we applied gene microarray technology to find out what subgroups of genes are mainly affected.
Genome-wide profiles of CtBP link metabolism with genome stability and epithelial reprogramming in breast cancer.
Cell line, Treatment
View SamplesMicroglia are tissue macrophages of the central nervous system (CNS) that control tissue homeostasis, and as such they are crucially important for organ integrity. Microglia dysregulation is thought to be causal for a group of neuropsychiatric, neurodegenerative and neuroinflammatory diseases, called microgliopathies. However, how the intracellular stimulation machinery in microglia is controlled is poorly understood. By using expression studies, we identified the ubiquitin-specific protease (Usp) 18 in white matter microglia that essentially contributes to microglial quiescence under homeostatic conditions. We further found that microglial Usp18 negatively regulated the activation of STAT1 and concomitant induction of interferon-induced genes thereby disabling the termination of IFN signalling. Unexpectedly, the Usp18-mediated feedback loop was independent from the catalytic domain of the protease but instead required the interacting region of Ifnar2. Additionally, the absence of Ifnar1 completely rescued microglial activation indicating a tonic IFN signal mediated by receptor interactions under non-diseased conditions. Finally, conditional depletion of Usp18 only in myeloid cells significantly enhanced the disease burden in a mouse model of CNS autoimmunity, increased axonal and myelin damage and determined the spatial distributions of CNS lesions that shared the same STAT1 signature as myeloid cells found in active multiple sclerosis (MS) lesions. These results identify Usp18 as novel negative regulator of microglia activation, demonstrate a protective role of the IFNAR pathway for microglia and establish Usp18 as potential therapeutic target for the treatment of MS.
USP18 lack in microglia causes destructive interferonopathy of the mouse brain.
Specimen part
View SamplesMicroglia are tissue macrophages of the central nervous system (CNS) that control tissue homeostasis, and as such they are crucially important for organ integrity. Microglia dysregulation is thought to be causal for a group of neuropsychiatric, neurodegenerative and neuroinflammatory diseases, called microgliopathies. However, how the intracellular stimulation machinery in microglia is controlled is poorly understood. By using expression studies, we identified the ubiquitin-specific protease (Usp) 18 in white matter microglia that essentially contributes to microglial quiescence under homeostatic conditions. We further found that microglial Usp18 negatively regulated the activation of STAT1 and concomitant induction of interferon-induced genes thereby disabling the termination of IFN signalling. Unexpectedly, the Usp18-mediated feedback loop was independent from the catalytic domain of the protease but instead required the interacting region of Ifnar2. Additionally, the absence of Ifnar1 completely rescued microglial activation indicating a tonic IFN signal mediated by receptor interactions under non-diseased conditions. Finally, conditional depletion of Usp18 only in myeloid cells significantly enhanced the disease burden in a mouse model of CNS autoimmunity, increased axonal and myelin damage and determined the spatial distributions of CNS lesions that shared the same STAT1 signature as myeloid cells found in active multiple sclerosis (MS) lesions. These results identify Usp18 as novel negative regulator of microglia activation, demonstrate a protective role of the IFNAR pathway for microglia and establish Usp18 as potential therapeutic target for the treatment of MS.
USP18 lack in microglia causes destructive interferonopathy of the mouse brain.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
USP18 lack in microglia causes destructive interferonopathy of the mouse brain.
Specimen part
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