The NF-B pathway is a critical regulator of the immune system and has been implicated in cellular transformation and tumorigenesis. NF-B response is regulated by the activation state of the IB kinase (IKK) complex and triggered by a wide spectrum of stimuli. We previously reported that NF-B is downstream of Notch1 in T cell acute lymphoblastic leukaemia (T-ALL), however both the mechanisms involving Notch1-induced NF-B activation and the potential importance of NF-B in the maintenance of the disease are unknown. Here we visualize Notch-induced NF-B activation using both human T-ALL cell lines and animal models of this type of leukemia. We show that it is not Notch1 itself but Hes1, a canonical Notch target, the responsible for sustaining IKK activation in T-ALL. Hes1 exerts its effects by a direct transcriptional repression of the deubiquitinating enzyme CYLD, a well-characterized IKK inhibitor. Consistently, CYLD expression is significantly reduced in primary T-ALL leukemias. Finally, we demonstrate that IKK complex inhibition is a promising option for the targeted therapy of T-ALL as suppression of IKK function affected both the survival of human T-ALL cells in vitro and the maintenance of the disease in vivo.
The Notch/Hes1 pathway sustains NF-κB activation through CYLD repression in T cell leukemia.
Specimen part, Cell line
View SamplesAlterations of chromatin modifiers are frequent in cancer but their functional consequences remain often unclear. Focusing on the Polycomb protein EZH2 that deposits H3K27me3 mark, we showed that its high expression in solid tumors is a consequence, and not a cause, of tumorigenesis. In mouse and human models, EZH2 is dispensable for prostate cancer development and restrains breast tumorigenesis. High EZH2 expression in tumors results from a tight coupling to proliferation to ensure H3K27me3 homeostasis. However, this process is malfunctioning in breast cancer. Low EZH2 expression relative to proliferation and mutations in Polycomb genes are actually of poor prognosis and occur in metastases. We show that while altered EZH2 activity consistently modulates a subset of its target genes, it promotes a wider transcriptional instability. Importantly, transcriptional changes consequent to EZH2 loss are predominantly irreversible. Our study provides an unexpected understanding of EZH2's contribution to solid tumors with important therapeutic implications.
Impaired PRC2 activity promotes transcriptional instability and favors breast tumorigenesis.
Specimen part
View SamplesPolycomb Repressive Complex 2 (PRC2) plays a key role in controlling transcriptional repression. It is thought to act at the level of the chromatin, where its enzymatic subunits Ezh1 and Ezh2 catalyse the di/tri-methylation of histone H3 on its lysine 27 (H3K27me3).
Impaired PRC2 activity promotes transcriptional instability and favors breast tumorigenesis.
Specimen part
View SamplesThe edr1 mutant of Arabidopsis thaliana displays enhanced resistance to the powdery mildew Golovinomyces cichoracearum, resulting in cell death and an absence of visible disease symptoms. To better characterize and understand the defense response of edr1, a time course of early signaling responses was performed after inoculation with powdery mildew and compared to the responses of wild-type Col-0. These time points represent early stages in the infection process, before any signs of susceptibility or resistance are visible.
Negative regulation of defence signalling pathways by the EDR1 protein kinase.
No sample metadata fields
View SamplesA great number of studies have investigated changes induced by morphine exposure in gene expression using several experimental models. In this study, we examined gene expression changes during chronic exposure to morphine during maturation and differentiation of zebrafish CNS.
Whole-genome expression profile in zebrafish embryos after chronic exposure to morphine: identification of new genes associated with neuronal function and mu opioid receptor expression.
Treatment
View SamplesHuntington’s disease (HD) is an autosomal dominant neurodegenerative disease whose predominant neuropathological signature is the selective loss of medium spiny neurons in the striatum. Despite this selective neuropathology, the mutant protein (huntingtin) is found in virtually every cell so far studied, and, consequently, phenotypes are observed in a wide range of organ systems both inside and outside the central nervous system. We, and others, have suggested that peripheral dysfunction could contribute to the rate of progression of striatal phenotypes of HD. To test this hypothesis, we lowered levels of huntingtin by treating mice with antisense oligonucleotides (ASOs) targeting the murine Huntingtin gene. To study the relationship between peripheral huntingtin levels and striatal HD phenotypes, we utilized a knock-in model of the human HD mutation (the B6.HttQ111/+ mouse). We treated mice with ASOs from 2-10 months of age, a time period over which significant HD-relevant signs progressively develop in the brains of HttQ111/+ mice. Peripheral treatment with ASOs led to persistent reduction of huntingtin protein in peripheral organs, including liver (64% knockdown), brown adipose (66% knockdown), and white adipose tissues (71% knockdown). This reduction was not associated with alterations in the severity of HD-relevant signs in the striatum of HttQ111/+ mice at the end of the study, including transcriptional dysregulation, the accumulation of neuronal intranuclear inclusions, and behavioral changes such as subtle hypoactivity and reduced exploratory drive. These results suggest that the amount of peripheral reduction achieved in the current study does not significantly impact the progression of HD-relevant signs in the central nervous system. Overall design: HttQ111/+ and Htt+/+ mice were given weekly intraperitoneal injections of Htt ASO, control ASO, or saline from 2 to 10 months of age. Striatal mRNA was sequenced from and N of 5-6 per arm (N=35 total).
Peripheral huntingtin silencing does not ameliorate central signs of disease in the B6.HttQ111/+ mouse model of Huntington's disease.
Sex, Cell line, Treatment, Subject
View SamplesAging signatures developed from a longitudinal study design are dominated by reduced transcription of genes involved in protein synthesis Aging is a multifactorial process where the impact of singular components still remains unclear. Furthermore, previous studies were focused on measuring specific traits such as DNA -methylation and used categorical group-wise designs, unable to capture intra-individual signature changes. Here we have developed a new method for a longitudinal, age-related analysis combining the merits of a pair-wise design with the statistical power of gene set enrichment analysis. We present an integrated analysis, including transcriptional changes and genome-wide epigenetic changes in DNA- methylation, H3K4- and H3K27- histone methylation in promoter regions. We tested our method on a rare collection of paired skin fibroblast samples from male middle age to old age transitions and obtained functional, age-related clusters. By using a set of only ten individuals, we could demonstrate a high overlap of functional terms to previously established tissue-independent age signatures including extracellular matrix, apoptosis and oxidative stress. Importantly, we identify protein translation-related processes as the main cluster of age-driven, specific down regulation. Overall design: Evaluation of transcriptional changes in matched sample pairs of primary skin fibroblasts from middle and old age.
Longitudinal epigenetic and gene expression profiles analyzed by three-component analysis reveal down-regulation of genes involved in protein translation in human aging.
No sample metadata fields
View SamplesWe used a RAG2-GFP reporter mouse to show that RAG+ B lineage cells can be found in the small intestinal lamina proria in normally-housed mice at weaning age. We used microarry expression analysis to compare the RAG2+ population in the gut to the RAG2+ B lineage population in the bone marrow.
Microbial colonization influences early B-lineage development in the gut lamina propria.
Specimen part
View SamplesPooling of microarray datasets seems to be a reasonable approach to increase sample size when a heterogeneous disease like breast cancer is concerned. Different methods for the adaption of datasets have been used in the literature. We have analyzed influences of these strategies using a pool of 3,030 Affymetrix U133A microarrays from breast cancer samples. We present data on the resulting concordance with biochemical assays of well known parameters and highlight critical pitfalls. We further propose a method for the inference of cutoff values directly from the data without prior knowledge of the true result. The cutoffs derived by this method displayed high specificity and sensitivity. Markers with a bimodal distribution like ER, PgR, and HER2 discriminate different biological subtypes of disease with distinct clinical courses. In contrast, markers displaying a continuous distribution like proliferation markers as Ki67 rather describe the composition of the mixture of cells in the tumor.
Data-driven derivation of cutoffs from a pool of 3,030 Affymetrix arrays to stratify distinct clinical types of breast cancer.
Sex, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
MYBL2 is a sub-haploinsufficient tumor suppressor gene in myeloid malignancy.
Specimen part, Disease, Disease stage
View Samples