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GSE24810
Homo sapiens
47 Downloadable Samples
Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Cellular senescence is a program of irreversible cell cycle arrest that normal cells undergo in response to progressive shortening of telomeres, changes in telomeric structure, oncogene activation or oxidative stress. The underlying signalling pathways, potentially of major clinicopathological relevance, are unknown. A major stumbling block to studying senescence has been the absence of suitable model systems because of the asynchrony of this process in heterogeneous cell populations. To simplify this process many investigators study oncogene-induced senescence due to expression of activated oncogenes where senescence occurs prematurely without telomere attrition and can be induced acutely in a variety of cell types. We have taken a different approach by making use of the finding that reconstitution of telomerase activity by introduction of the catalytic subunit of human telomerase alone is incapable of immortalising all human somatic cells, but inactivation of the p16-pRB and p53-p21 pathways are required in addition. The ability of SV40 large T antigen to inactivate the p16-pRB and p53-p21 pathways has enabled us to use a thermolabile mutant of LT antigen, in conjunction with hTERT, to develop conditionally immortalised human (HMF3A) fibroblasts that are immortal but undergo an irreversible growth arrest when the thermolabile LT antigen is inactivated leading to activation of pRB and p53. When these cells cease dividing, senescence-associated- b-galactosidase activity is induced and the growth-arrested cells have morphological features and express genes in common with senescent cells. Since these cells growth arrest in a synchronous manner they are an excellent starting point for dissecting the pathways that underlie cellular senescence and act downstream of p16-pRB and p53-p21 pathways. We have combined genome-wide expression profiling with genetic complementation to undertake identification of genes that are differentially expressed when these conditionally immortalised human fibroblasts undergo senescence upon activation of the p16-pRB and p53-p21 tumour suppressor pathways.
Publication Title
Activation of nuclear factor-kappa B signalling promotes cellular senescence.
Sample Metadata Fields
Cell line, Treatment
View Samples- Arabidopsis thaliana
- 12 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
Pseudomonas fluorescens strain SS101 (Pf.SS101) promotes growth of Arabidopsis thaliana, enhances greening and lateral root formation, and induces systemic resistance (ISR) against the bacterial pathogen Pseudomonas syringae pv. tomato (Pst). Here, targeted and untargeted approaches were adopted to identify bacterial determinants and underlying mechanisms involved in plant growth promotion and ISR by Pf.SS101. Based on targeted analyses, no evidence was found for volatiles, lipopeptides and siderophores in plant growth promotion by Pf.SS101. Untargeted, genome-wide analyses of 7,488 random transposon mutants of Pf.SS101 led to the identification of 21 mutants defective in both plant growth promotion and ISR. Many of these mutants, however, were auxotrophic and impaired in root colonization. Genetic analysis of three mutants followed by site-directed mutagenesis, genetic complementation and plant bioassays revealed the involvement of the phosphogluconate dehydratase gene edd, the response regulator gene colR and the adenylsulfate reductase gene cysH in both plant growth promotion and ISR. Subsequent comparative plant transcriptomics analyses strongly suggest that modulation of sulfur assimilation, auxin biosynthesis and transport, steroid biosynthesis and carbohydrate metabolism in Arabidopsis are key mechanisms linked to growth promotion and ISR by Pf.SS101.
Publication Title
Genome-wide analysis of bacterial determinants of plant growth promotion and induced systemic resistance by Pseudomonas fluorescens.
Sample Metadata Fields
Specimen part, Treatment
View Samples- Homo sapiens
- 437 Downloadable Samples
- Affymetrix HT HG-U133+ PM Array Plate (hthgu133pluspm)
Description
Purpose: Severe late normal tissue damage limits radiotherapy treatment regimens. This study aims to validate -H2AX foci decay ratios and induced expression levels of DNA double strand break (DSB) repair genes, found in a retrospective study, as possible predictors for late radiation toxicity. Methods and Materials: Prospectively, decay ratios (initial/residual -H2AX foci numbers) and genome-wide expression profiles were examined in ex vivo irradiated lymphocytes of 198 prostate cancer patients. All patients were followed 2 years after radiotherapy, clinical characteristics were assembled and toxicity was recorded using the Common Terminology Criteria (CTCAE) v4.0. Results: No clinical factors were correlated with late radiation toxicity. Analysis of -H2AX foci uncovered a negative correlation between the foci decay ratio and toxicity grade. Significantly smaller decay ratios were found in grade3 compared to grade 0 patients (p=0.02), indicating less efficient DNA-DSB repair in radio-sensitive patients. Moreover, utilizing a foci decay ratio threshold determined in our previous retrospective study correctly classified 23 of the 28 grade3 patients (sensitivity, 82%) and 9 of the 14 grade 0 patients (specificity, 64%). Grade of toxicity also correlated with a reduced induction of the homologous recombination (HR) repair gene-set. The difference in average fold induction of the HR gene-set was most pronounced between grade 0 and grade3 patients (p=0.008). Conclusions: Reduced responsiveness of HR repair genes to irradiation and inefficient DSB repair correlate with an increased risk of late radiation toxicity. Using a decay ratio classifier, we could correctly classify 82% of the patients with grade3 toxicity. Additional studies are required to further optimize and validate the foci decay assay and to assess its predictive value for late radiation toxicity in patients prostate cancer
Publication Title
Prostate Cancer Patients with Late Radiation Toxicity Exhibit Reduced Expression of Genes Involved in DNA Double-Strand Break Repair and Homologous Recombination.
Sample Metadata Fields
Specimen part, Subject
View Samples- Homo sapiens
- 71 Downloadable Samples
- Affymetrix HT HG-U133+ PM Array Plate (hthgu133pluspm)
Description
Colorectal cancer (CRC) is a heterogeneous disease classified into four consensus molecular subtype (CMSs) with distinct biological and clinical features. This study aims to understand the value of patient-derived xenografts (PDXs) in relation to these CMSs. A total of 42 primary tumors, recurrences and metastases were used to develop PDXs. Detailed genetic analyses were performed on PDXs and corresponding patient tumors to determine relationship and PDX heterogeneity. Out of 42 tumors 22 (52%) showed successfully PDX engraftment, which was biased towards metastases and CMS1 and CMS4 tumors. Importantly, gene expression analysis revealed a clinical relevant association between an engraftment gene signature and prognosis for stage II patients. Moreover, this gene signature revealed an association between Src pathway activation and positive engraftment. Src pathway activity co-aligned with CMS4 and the levels of fibronectin in tumors and was confirmed by pSrc immunohistochemistry. From this analysis we further deduced that decreased cell cycle activity is a prognostic factor for successful engraftment and related to patient prognosis. However, this is not a general phenomenon, but subtype specific as decreased cell cycle activity was highly prognostic for recurrence-free survival within CMS2 but not in CMS1 and CMS4, while it showed an inverse correlation in CMS3. These data illustrate that CRC PDX establishment is biased toward CMS1 and CMS4, which impacts translation of results derived from pre-clinical studies using PDXs. Moreover, our analysis reveals subtype-specific features, pSrc in CMS4 and low Ki67 in CMS2, which provide novel avenues for therapy and diagnosis.
Publication Title
Capturing colorectal cancer inter-tumor heterogeneity in patient-derived xenograft (PDX) models.
Sample Metadata Fields
Sex, Age, Specimen part, Disease, Disease stage
View Samples- Homo sapiens
- 1 Downloadable Sample
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Primary colon CSC cultures were transduced with a Wnt responsive construct (TOP-GFP) and were single cell cloned. 10% highest and lowest TOP-GFP cell fractions were FACS sorted and arrayed.
Publication Title
Wnt activity defines colon cancer stem cells and is regulated by the microenvironment.
Sample Metadata Fields
Specimen part
View Samples- Homo sapiens
- 36 Downloadable Samples
- Affymetrix HT HG-U133+ PM Array Plate (hthgu133pluspm)
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
TGFβ signaling directs serrated adenomas to the mesenchymal colorectal cancer subtype.
Sample Metadata Fields
Specimen part, Treatment
View Samples- Homo sapiens
- 20 Downloadable Samples
- Affymetrix HT HG-U133+ PM Array Plate (hthgu133pluspm)
Description
The aim of this study was to determine the effects of TGF at the premalignant stage of CRC development.
Publication Title
TGFβ signaling directs serrated adenomas to the mesenchymal colorectal cancer subtype.
Sample Metadata Fields
Specimen part, Treatment
View Samples- Homo sapiens
- 18 Downloadable Samples
Illumina HiSeq 2500
Description
The spatial organization of chromosomes influences many nuclear processes including gene expression. The cohesin complex shapes the 3D genome by looping together CTCF sites along chromosomes. We show here that chromatin loop size can be increased, and that the duration with which cohesin embraces DNA determines the degree to which loops are enlarged. Cohesin's DNA release factor WAPL restricts the degree of this loop extension and also prevents looping between incorrectly oriented CTCF sites. We reveal that the SCC2/SCC4 complex promotes the extension of chromatin loops and the formation of topologically associated domains (TADs). Our data support the model that cohesin structures chromosomes through the processive enlargement of loops and that TADs reflect polyclonal collections of loops in the making. Finally, we find that whereas cohesin promotes chromosomal looping, it rather limits nuclear compartmentalization. We conclude that the balanced activity of SCC2/SCC4 and WAPL enables cohesin to correctly structure chromosomes. Overall design: RNAseq was performed in control, ?WAPL 3.3, ?WAPL 1.14, ?SCC4 and ?WAPL/?SCC4 cells in triplicate.
Publication Title
The Cohesin Release Factor WAPL Restricts Chromatin Loop Extension.
Sample Metadata Fields
Cell line, Subject
View Samples- Homo sapiens
- 16 Downloadable Samples
- Affymetrix HT HG-U133+ PM Array Plate (hthgu133pluspm)
Description
Colorectal cancer can be divided into four consensus molecular subtypes, which might associate with distinct precursor lesions. The aim of this study was to determine the subtype affiliation of two types of colorectal adenomas: tubular adenomas (TAs) and sessile serrated adenomas (SSAs) and to determine the activity of TGF signaling and the role of this cytokine in subtype affiliation.
Publication Title
TGFβ signaling directs serrated adenomas to the mesenchymal colorectal cancer subtype.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 12 Downloadable Samples
- Illumina MouseWG-6 v2.0 expression beadchip
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
CFTR is a tumor suppressor gene in murine and human intestinal cancer.
Sample Metadata Fields
Age, Specimen part
View Samples