DNA damage activates a complex signaling network in cells that blocks cell cycle progression, recruits factors involved in DNA repair, and/or triggers programs that control senescence or programmed cell death. Alterations in chromatin structure are known to be important for the initiation and propagation of the DNA damage response, although the molecular details are unclear. We investigated the role of chromatin structure in the DNA damage response by monitoring multiple timedependent checkpoint signaling and response events with a high-content multiplex image-based RNAi screen of chromatin modifying and interacting genes. We discovered that Brd4, a double bromodomain-containing protein, functions as an endogenous inhibitor of DNA damage signaling by binding to acetylated histones at sites of open chromatin and altering chromatin accessibility. Loss of Brd4 or disruption of acetyl-lysine binding results in an increase in both the number and size of radiation-induced !H2AX nuclear foci while overexpression of a Brd4 splice isoform completely suppresses !H2AX formation, despite equivalent double strand break formation. Brd4 knock-down cells displayed altered chromatin structure, prolonged cell cycle checkpoint arrest and enhanced survival after irradiation, while overexpression of Brd4 isoform B results in enhanced radiationinduced lethality. Brd4 is the target of the t(15;19) chromosomal translocation in a rare form of cancer, NUT Midline Carcinoma. Acetyl lysine-bromodomain interactions of the Brd4-NUT fusion protein suppresses !H2AX foci in discrete nuclear compartments, rendering cells more radiosensitive, mimicking overexpression of Brd4 isoform B. NUT Midline Carcinoma is sensitive to radiotherapy, however tumor material from this rare cancer is scarce. We therefore investigated Brd4 expression in another human cancer commonly treated with radiotherapy, glioblastoma multiforme, and found that expression of Brd4 isoform B correlated specifically with treatment response to radiotherapy. These data implicate Brd4 as an endogenous insulator of DNA damage signaling through recognition of epigenetic modifications in chromatin and suggest that expression of the Brd4 in human cancer can modulate the clinical response to DNA-damaging cancer therapy.
The bromodomain protein Brd4 insulates chromatin from DNA damage signalling.
Cell line
View SamplesBackground: Substantial progress has been made in the identification of sequence elements that control mRNA splicing and the genetic variants in these elements that alter mRNA splicing (referred to as splicing quantitative trait loci -- sQTLs). Genetic variants that affect mRNA splicing in trans are harder to identify because their effects can be more subtle and diffuse, and the variants are not co-located with their targets. We carried out a transcriptome-wide analysis of the effects of a mutation in a ubiquitous splicing factor that causes retinitis pigmentosa (RP) on mRNA splicing, using exon microarrays.
A mutation in a splicing factor that causes retinitis pigmentosa has a transcriptome-wide effect on mRNA splicing.
Specimen part
View SamplesIn order to understand if early epigenetic mechanisms instruct the long-term behaviour of neural stem cells (NSCs) and their progeny, we examined the protein Uhrf1 as it is highly expressed in NSCs of the developing brain and rapidly downregulated upon differentiation. Conditional deletion of Uhrf1 in the developing cerebral cortex resulted in rather normal proliferation and neurogenesis but severe postnatal neurodegeneration. During development, deletion of Uhrf1 resulted in global DNA hypomethylation with a strong activation of the IAP family of endogenous retroviral elements, accompanied by an increase in hydroxy methyl cytosine. Downregulation of Tet enzymes rescued the IAP activation in Uhrf1 cKO cells, suggesting an antagonistic interplay between Uhrf1 and Tet on IAP regulation. As IAP upregulation persists into postnatal stages in the conditional Uhrf1 KO mice, our data show the lack of means to repress IAPs in differentiating neurons that normally never express Uhrf1. The high load of viral proteins and other transcriptional dysregulation ultimately lead to extensive postnatal neurodegeneration. Taken together, these data show that early developmental NSC factors can have long-term effects in neuronal differentiation and survival. Moreover, it highlights how specific the consequences of widespread changes in DNA methylation are for certain classes of retroviral elements. Overall design: Transcriptome analysis in control vs. Uhrf1-deficient brain
Loss of Uhrf1 in neural stem cells leads to activation of retroviral elements and delayed neurodegeneration.
Specimen part, Cell line, Subject
View SamplesIn order to understand if early epigenetic mechanisms instruct the long-term behaviour of neural stem cells (NSCs) and their progeny, we examined the protein Uhrf1 as it is highly expressed in NSCs of the developing brain and rapidly downregulated upon differentiation. Conditional deletion of Uhrf1 in the developing cerebral cortex resulted in rather normal proliferation and neurogenesis but severe postnatal neurodegeneration. During development, deletion of Uhrf1 resulted in global DNA hypomethylation with a strong activation of the IAP family of endogenous retroviral elements, accompanied by an increase in hydroxy methyl cytosine. Downregulation of Tet enzymes rescued the IAP activation in Uhrf1 cKO cells, suggesting an antagonistic interplay between Uhrf1 and Tet on IAP regulation. As IAP upregulation persists into postnatal stages in the conditional Uhrf1 KO mice, our data show the lack of means to repress IAPs in differentiating neurons that normally never express Uhrf1. The high load of viral proteins and other transcriptional dysregulation ultimately lead to extensive postnatal neurodegeneration. Taken together, these data show that early developmental NSC factors can have long-term effects in neuronal differentiation and survival. Moreover, it highlights how specific the consequences of widespread changes in DNA methylation are for certain classes of retroviral elements. Overall design: Transcriptome analysis in control vs. Uhrf1-deficient brain
Loss of Uhrf1 in neural stem cells leads to activation of retroviral elements and delayed neurodegeneration.
Specimen part, Cell line, Subject
View SamplesGBM samples were clusered using gene expression of AKT pathway genes to reveal at least 5 GBM AKT subtypes, having distinct DNA copy number alterations, enrichment in oncogenes and tumor suppressor genes and patterns of expression for PI3K/AKT/mTOR signaling components.
AKT pathway genes define 5 prognostic subgroups in glioblastoma.
Sex, Age
View SamplesThe aim of this study was to identify differentially-expressed genes in CCR4hi/CXCR3- and CCR4lo CXCR3+ CCR6+ human Th17 cell subsets
Pro-inflammatory human Th17 cells selectively express P-glycoprotein and are refractory to glucocorticoids.
No sample metadata fields
View SamplesThe aim of this study was to characterize the transcriptional signature of MDR1+ human memory T cells isolated from clinically inflamed gut tissue, and compare it to local MDR1- memory T cells
Pro-inflammatory human Th17 cells selectively express P-glycoprotein and are refractory to glucocorticoids.
Specimen part
View SamplesThe aim of this study was to identify differential gene expression resulting from the inhibition of RORgt in human CD4+ T cells.
Pharmacologic inhibition of RORγt regulates Th17 signature gene expression and suppresses cutaneous inflammation in vivo.
Specimen part, Treatment
View SamplesDespite education and aggressive treatment, breast cancer (BC) remains a clinical problem. BC cells (BCCs) can migrate early to metastatic sites where they may exist in cellular dormancy for decades. Presently, there are no consensus markers for cancer stem cells (CSCs) that are involved in tumor initiation and progression, and drug resistance. The current designation of CSCs might comprise similar tumor initiating cells, but at different developmental phase. In order to understand these differences, we developed a working hierarchy of BCCs. We initiated the studies in which three BCC subsets were selected based on the relative expressions of the stem cell-linked genes, Octamer4A (Oct4A). The sorted BCCs were subjected to array analyses using Affymetrix gene chip. Hierarchical clustering indicated distinct gene expression among the three subsets. Differential gene expressions of membrane proteins validated three novel genes, TMEM-98, GPR64 and FAT4. These three genes, in combination of known markers for CSCs, CD44, CD24, aldehyde dehydrogenase 1 (ALDH1) and Oct4A, were used to stratify BCCs led to a working hierarchy of BCCs. The validity of the hierarchical BCCs was applied to blood samples from patients, during relapse, and before and after treatment. These studies resulted in the patients grouped with distinct BCCs in the circulation. The relevance of the latter findings are discussed with regards to prediction of treatment response and time of BC relapse. The findings require a larger cohort of patients in a prospective multi-center study. The stratification could be important to understand treatment response, strategies for alternative approaches, and an understanding of the interaction between particular BCC subsets and the tissue microenvironment.
Evaluation of a developmental hierarchy for breast cancer cells to assess risk-based patient selection for targeted treatment.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Consensus molecular subtypes of colorectal cancer are recapitulated in in vitro and in vivo models.
Specimen part, Disease, Disease stage, Cell line, Subject
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