We report that decreased expression and activity of AhR exacerbates murine neovascular age-related macular degeneration, and increases cell migration and tube formation. The mechanism involves increased expression of pro-angiogenic mediators and altered matrix degradation. The results of our study suggest that the AhR signaling pathway may be important in multiple AMD related pathways. Overall design: Gene expression analysis in the retinal pigment epithelium (RPE)-choroid tissue from AhR knockout mice contrasted against wild-type age-matched controls.
Aryl hydrocarbon receptor knock-out exacerbates choroidal neovascularization via multiple pathogenic pathways.
No sample metadata fields
View SamplesBackground & Aims: Ursodeoxycholic acid (UDCA) attenuates chemical and colitis-induced colon carcinogenesis in animal models. We investigated its mechanism of action on normal intestinal cells, in which carcinogenesis- or inflammation-related alterations do not interfere with the result. Methods: Alterations of gene expression were identified in Affymetrix arrays in isolated colon epithelium of mice fed with a diet containing 0.4% UDCA and were confirmed in the normal rat intestinal cell line IEC-6 by RT-PCR. The effect of the insulin receptor substrate 1 (Irs-1) expression and of ERK phosphorylation on proliferation was investigated in vitro by flow cytometry, western blotting, siRNA-mediated gene suppression or by pharmacological inhibition of the kinase activity. The ERK1-effect on Irs-1 transcription was tested in a reporter system. Results: UDCA-treatment in vivo suppressed potential pro-proliferatory genes including Irs-1 and reduced cell proliferation by more than 30%. In vitro it neutralised the proliferatory signals of IGF-1 and EGF and slowed down the cell cycle. Irs-1 transcription was suppressed due to high ERK1 activation. Both Irs-1 suppression and the persistent high ERK activation inhibited proliferation. Conversely, the decrease of phosphorylation of ERK1 (but not ERK2) or of its expression partially abrogated the inhibitory effects of UDCA. Conclusions: UDCA inhibits proliferation of intestinal epithelial cells by acting upon IGF-1 and EGF pathways and targeting ERK1 and, consequently, Irs-1. The inhibition of these pathways adds a new dimension to the physiological and therapeutic action of UDCA and, since both pathways are activated in inflammation and cancer, suggests new applications of UDCA in chemoprevention and chemotherapy.
UDCA slows down intestinal cell proliferation by inducing high and sustained ERK phosphorylation.
Specimen part, Cell line
View SamplesmicroRNAs play crucial roles in the early development of an organism. However the regulation of transcription through the action of microRNAs during the initial embyonic development has not been studied.
miR-34 is maternally inherited in Drosophila melanogaster and Danio rerio.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Identification of nuclear-enriched miRNAs during mouse granulopoiesis.
Specimen part
View SamplesDifferentiation of hemopoietic stem cells into granulocytes is characterized by distinct changes in the transcriptome.
Identification of nuclear-enriched miRNAs during mouse granulopoiesis.
Specimen part
View SamplesUBL5 is an atypical ubiquitin-like protein, whose function in metazoans remains largely unexplored. We show that UBL5 is required for sister chromatid cohesion maintenance in human cells. UBL5 primarily associates with spliceosomal proteins, and UBL5 depletion decreases pre-mRNA splicing efficiency, leading to globally enhanced intron retention. Defective sister chromatid cohesion is a general consequence of dysfunctional pre-mRNA splicing, resulting from the selective downregulation of the cohesion protection factor Sororin. As the UBL5 yeast orthologue, Hub1, also promotes spliceosome functions, our results show that UBL5 plays an evolutionary conserved role in pre-mRNA splicing, the integrity of which is essential for the fidelity of chromosome segregation. Overall design: Total RNA was extracted from HeLa cells treated with control (CTRL), UBL5 (#57, #58, or #82), or SART1 siRNAs for 48 h and processed for RNA-Seq analysis
UBL5 is essential for pre-mRNA splicing and sister chromatid cohesion in human cells.
No sample metadata fields
View SamplesIncreased ploidy is common in tumors but treatments for tumors with excess chromosome sets are not available. Here, we characterize high-ploidy breast cancers and identify potential anticancer compounds selective for the high-ploidy state. Among 354 human breast cancers, 10% have mean chromosome copy number exceeding 3, and this is most common in triple negative and HER2-positive types. Women with high-ploidy breast cancers have higher risk of recurrence and death in two patient cohorts, demonstrating that it represents an important group for improved treatment. Because high-ploidy cancers are aneuploid, rather than triploid or tetraploid, we devised a two-step screen to identify selective compounds. The screen was designed to assure both external validity on diverse karyotypic backgrounds and specificity for high-ploidy cell types. This screen identified novel therapies specific to high-ploidy cells. First, we discovered 8-azaguanine, an antimetabolite that is activated by hypoxanthine phosphoribosyltransferase (HPRT), suggesting an elevated gene-dosage of HPRT in high-ploidy tumors can control sensitivity to this drug. Second, we discovered a novel compound, 2,3-Diphenylbenzo[g]quinoxaline-5,10-dione (DPBQ). DPBQ activates p53 and triggers apoptosis in a polyploid-specific manner, but does not inhibit topoisomerase or bind DNA. Mechanistic analysis demonstrates that DPBQ elicits a hypoxia gene signature and its effect is replicated, in part, by enhancing oxidative stress. Structure-function analysis defines the core benzo[g]quinoxaline-5,10 dione as being necessary for the polyploid-specific effects of DPBQ. We conclude that polyploid breast cancers represent a high-risk subgroup and that DPBQ provides a functional core to develop polyploid-selective therapy.
Identification of Selective Lead Compounds for Treatment of High-Ploidy Breast Cancer.
Cell line
View SamplesThe basic helix-loop-helix (bHLH) transcription factor hairy and enhancer of split (Hes3) is a member of the Hes/Hey gene family that regulates developmental processes in progenitor cells from various tissues. We demonstrated the Hes3 expression in mouse pancreatic tissue, suggesting it may have a role in modulating beta-cell function. We employed a transfection approach to address specific functions of Hes3. Hes3 RNA interference opposed the growth of the mouse insulinoma cell line Min6. Western blotting and PCR approaches specifically showed that Hes3 RNA interference opposes the expression of Pdx1 and insulin. Likewise, Hes3 knock down reduced evoked insulin release from Min6 cells.
Hes3 is expressed in the adult pancreatic islet and regulates gene expression, cell growth, and insulin release.
Specimen part
View SamplesRNA-seq analysis of BJ cells overexpressing RasV12 and escaping senescence Overall design: Immortalized BJ-hTERT cells expressing an oncogenic version of Ras under the control of a doxycyclin-inducible promoter were grown for 60 days in the presence of Dox to induce oncogene-induced senescence (OIS). Three individual clones escaping senescence were isolated and were analyzed by RNA-seq.
Overexpression of Claspin and Timeless protects cancer cells from replication stress in a checkpoint-independent manner.
Specimen part, Subject
View SamplesWe combine a genome-scale RNAi screen in mouse epiblast stem cells (EpiSCs) with genetic interaction, protein localization and “protein-level dependency” studies – a systematic technique that uncovers post-transcriptional regulation – to delineate the network of factors that control the expression of Oct4, a key regulator of pluripotency. Our data signify that there are similarities, but also fundamental differences in Oct4 regulation in EpiSCs vs. embryonic stem cells (ESCs). Through multiparametric data analyses we predict that Tox4 is associating with the Paf1C complex, which maintains cell identity in both cell types and validate that this protein-protein interaction exists in ESCs and EpiSCs. We also identify numerous knockdowns that increase Oct4 expression in EpiSCs, indicating that, in stark contrast to ESCs, Oct4 is under active repressive control in EpiSCs. These studies provide a framework for better understanding pluripotency and for dissecting the molecular events that govern the transition from the pre-implantation to the post-implantation state. Overall design: RNA-seq of Tox4 knockdown in mouse EpiSCs
Systems Analyses Reveal Shared and Diverse Attributes of Oct4 Regulation in Pluripotent Cells.
No sample metadata fields
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