This SuperSeries is composed of the SubSeries listed below.
Genome-wide analysis in human colorectal cancer cells reveals ischemia-mediated expression of motility genes via DNA hypomethylation.
Cell line, Treatment
View SamplesDNA hypomethylation is an important epigenetic modification found to occur in many different cancer types, leading to the upregulation of previously silenced genes and loss of genomic stability. We previously demonstrated that hypoxia and hypoglycaemia (ischemia), two common micro-environmental changes in solid tumors, decrease DNA methylation through the downregulation of DNMTs in human colorectal cancer cells. Here, we utilized a genome-wide cross-platform approach to identify genes hypomethylated and upregulated by ischemia. Following exposure to hypoxia or hypoglycaemia, methylated DNA from human colorectal cancer cells (HCT116) was immunoprecipitated and analysed with an Affymetrix promoter array. Additionally, RNA was isolated and analysed in parallel with an Affymetrix expression array. Ingenuity pathway analysis software revealed that a significant proportion of the genes hypomethylated and upregulated were involved in cellular movement, including PLAUR and CYR61. A Matrigel invasion assay revealed that indeed HCT116 cells grown in hypoxic or hypoglycaemic conditions have increased mobility capabilities. Confirmation of upregulated expression of cellular movement genes was performed with qPCR. The correlation between ischemia and metastasis is well established in cancer progression, but the molecular mechanisms responsible for this common observation have not been clearly identified. Our novel results suggest that hypoxia and hypoglycaemia may be driving changes in DNA methylation through downregulation of DNMTs. This is the first report to our knowledge that provides an explanation for the increased metastatic potential seen in ischemic cells; i.e. that ischemia could be driving DNA hypomethylation and increasing expression of cellular movement genes.
Genome-wide analysis in human colorectal cancer cells reveals ischemia-mediated expression of motility genes via DNA hypomethylation.
Cell line, Treatment
View SamplesIn mammals, expansion of adipose tissue mass induces accumulation of adipose tissue macrophages (ATMs). We isolated CD11c- (FB) and CD11c+ (FBC) perigonadal ATMs from SVCs of lean (C57BL/6J Lep +/+) and obese leptin-deficient (C57BL/6J Lep ob/ob) mice.
Obesity activates a program of lysosomal-dependent lipid metabolism in adipose tissue macrophages independently of classic activation.
Specimen part
View SamplesThe microarray analysis was designed to test the effects of HES5.3 siRNAs, Atoh7 siRNAs and nt siRNAs on gene expression in embryonic chick retina.
A positive feedback loop between ATOH7 and a Notch effector regulates cell-cycle progression and neurogenesis in the retina.
Age, Specimen part
View SamplesThe goal of the study was to understand how integrin beta1 expressed in epithelial cells directs developmental angiogenesis. Integrin beta1 was deleted specifically in the pituitary glands of embryonic mice. RNA was isolated from knockout and WT control pituitaries dissected at e12.5, one day prior to the initiation of developmental angiogenesis. Overall design: RNA from the e12.5 pituitaries of 3 WT and 2 KO littermate embryos was profiled.
Epithelial cell integrin β1 is required for developmental angiogenesis in the pituitary gland.
Specimen part, Subject
View SamplesSubstantial evidence supports the hypothesis that enhancers are critical regulators of cell type determination, orchestrating both positive and negative transcriptional programs; however, the basic mechanisms by which enhancers orchestrate interactions with cognate promoters during activation and repression events remain incompletely understood. Here we report the required actions of the LIM domain binding protein, LDB1/CLIM2/NLI, interacting with the enhancer binding protein, ASCL1, to mediate looping to target gene promoters and target gene regulation in corticotrope cells. LDB1-mediated enhancer:promoter looping appears to be required for both activation and repression of these target target gene promoter genes. While LDB1-dependend activated genes are regulated at the level of transcriptional initiation, the LDB1-dependent repressed transcription units appear to be regulated primarily at the level of promoter pausing, with LDB1 regulating recruitment of MTA2, a component of the NuRD complex, on these negative enhancers, required for the repressive enhancer function. These results indicate that LDB1-dependent looping events can deliver repressive cargo to cognate promoters to mediate promoter pausing events in a pituitary cell type. Overall design: Global Run On (GRO) assay followed by high throughput sequencing (GRO-seq)
Enhancer-bound LDB1 regulates a corticotrope promoter-pausing repression program.
No sample metadata fields
View SamplesWe addressed the clinical significance and mechanisms behind in vitro cellular responses to ionising radiation (IR)-induced DNA double strand breaks in 74 paediatric ALL patients. We found an apoptosis-resistant response in 36% of patients and an apoptosis-sensitive response in the remaining 64% of leukaemias. Global gene expression profiling of 11 apoptosis-resistant and 11 apoptosis-sensitive ALLs revealed abnormal up-regulation of multiple pro-survival pathways in response to IR in apoptosis-resistant leukaemias and differential post-transcriptional activation of the PI3-Akt pathway was observed in representative resistant cases. It is possible that abnormal pro-survival responses to DNA damage provide one of the mechanisms of primary resistance in ALL .
Stratification of pediatric ALL by in vitro cellular responses to DNA double-strand breaks provides insight into the molecular mechanisms underlying clinical response.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Characterization of a novel OTX2-driven stem cell program in Group 3 and Group 4 medulloblastoma.
Cell line
View SamplesMedulloblastoma (MB) is the most common malignant primary pediatric brain cancer. Among the most aggressive subtypes, Group 3 and Group 4 originate from stem/progenitor cells, frequently metastasize, and often display the worst prognosis, yet, as the names imply, we know the least about the molecular mechanisms driving their progression. Here, we show that the transcription factor orthodenticle homeobox 2 (OTX2) promotes self-renewal while inhibiting differentiation in vitro and increases tumor-initiating capacity from MB stem cell populations in vivo. Characterization of the OTX2 regulatory network revealed a novel relationship between OTX2 and genes associated with multiple axon guidance signaling pathways in Group 3 and Group 4 MB stem/progenitor cells. In particular, OTX2 levels were negatively correlated with semaphorin (SEMA) signaling, as expression of 9 SEMA pathway genes is upregulated following OTX2 knockdown with some being potential direct OTX2 targets. Importantly, this negative correlation between OTX2 and SEMA pathway genes was also observed in patient samples, with lower expression of SEMA4D associated with poor outcome in Group 3 and 4 tumors. Functional studies using established and newly derived MB cell lines demonstrated that increased levels of SEMA pathway genes are associated with decreased self-renewal and growth, and that RHO signaling, known to mediate the effects of SEMA genes, is contributing to the OTX2 KD phenotype. Our study provides critical mechanistic insight into the networks controlled by OTX2 in self-renewing MB cells and reveals novel roles for axon guidance genes and their downstream effectors as putative tumor suppressors and therapeutic targets in Group 3 and Group 4 MB.
Characterization of a novel OTX2-driven stem cell program in Group 3 and Group 4 medulloblastoma.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Medulloblastoma subgroups remain stable across primary and metastatic compartments.
Sex, Age, Specimen part, Subject
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