GRN163L is a potent and specifictelomeraseinhibitor and in clinical trials for cancer treatment. To identify the biomarker that might predict response to telomease based therapy, gene expression analysis of the cancer cell lines after treatiment with telomerase inhibitor Imetelstat (GRN163L) was performed.
Interleukin 8 is a biomarker of telomerase inhibition in cancer cells.
Cell line
View SamplesWe used microarrays to measure the expression levels of genes in irradiated immortalized B cells, lymphoblastoid cells, from members of Centre d'Etude du Polymorphisme Humain (CEPH) Utah pedigrees. Data were collected for cells at baseline and 2 hours and 6 hours after exposure to 10 Gy of ionizing radiation (IR).
Genetic variation in radiation-induced cell death.
Specimen part, Treatment
View Samplesgene expression database and algorithm to define cell expression modules
Identifying gene expression modules that define human cell fates.
Specimen part
View SamplesIdentifying the effect of the co-regulator Hic-5 (TGFB1I1) and TGFB on the transcriptional profile of WPMY human prostate fibroblast cells with view to further elucidating the broader biological role of Hic-5 and TGFB on fibroblast.
VDR activity is differentially affected by Hic-5 in prostate cancer and stromal cells.
Specimen part, Cell line, Treatment
View SamplesWe show that mesenchymal CSC-like cells express an embryonic stem cell signature that is mutant p53 dependent Overall design: Examination of three p53 mutant mesenchymal stem cells and ten derived CSC-like cell lines and 2 derived p53 mutant KO clones compared to control clones
A Mutant p53-Dependent Embryonic Stem Cell Gene Signature Is Associated with Augmented Tumorigenesis of Stem Cells.
Specimen part, Cell line, Subject
View SamplesDuplication of chromosomal arm 20q occurs in prostate, cervical, colon, gastric, bladder, melanoma, pancreas and breast cancer, suggesting that 20q amplification may play a key causal role in tumorigenesis. According to an alternative view, chromosomal instabilities are mainly a common side effect of cancer progression. To test whether a specific genomic aberration might serve as a cancer initiating event, we established an in vitro system that models the evolutionary process of early stages of prostate tumor formation; normal prostate cells were immortalized and cultured for 650 days till several transformation hallmarks were observed. Gene expression patterns were measured and chromosomal aberrations were monitored by spectral karyotype analysis at different times. Several chromosomal aberrations, in particular duplication of chromosomal arm 20q, occurred early in the process and were fixed in the cell populations, while other aberrations became extinct shortly after their appearance. A wide range of bioinformatic tools, applied to our data and to data from several cancer databases, revealed that spontaneous 20q amplification can promote cancer initiation. Our computational model suggests that deregulation of some key pathways, such as MAPK, p53, cell cycle regulation and Polycomb group factors, in addition to activation of several genes like Myc, AML, B-Catenin and the ETS family transcription factors, are key steps in cancer development driven by 20q amplification. Finally we identified 13 cancer initiating genes, located on 20q13, which were significantly overexpressed in many tumors, with expression levels correlated with tumor grade and outcome; these probably play key roles in inducing malignancy via20q amplification.
Amplification of the 20q chromosomal arm occurs early in tumorigenic transformation and may initiate cancer.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
MicroRNAs are essential for differentiation of the retinal pigmented epithelium and maturation of adjacent photoreceptors.
Specimen part, Treatment
View SamplesDysfunction of the retinal pigmented epithelium (RPE) results in degeneration of photoreceptors and vision loss and is correlated with common blinding disorders in humans. Although many protein-coding genes are known to be expressed in RPEs and important for their development and maintenance, virtually nothing is known about the in vivo roles of non-protein coding transcripts in RPEs. The expression patterns of microRNAs (miRNAs) have been analyzed in a variety of ocular tissues, and few were implicated to play role in RPE based on studies in cell lines. Herein, through RPE specific conditional mutagenesis of Dicer1 or DGCR8, the importance of miRNA for RPE differentiation was uncovered. Interestingly, miRNAs were found to be dispensable for maintaining the RPE fate and survival, and yet they are essential for acquisition of important RPE properties such as the expression of genes involved in the visual cycle pathway, pigmentation and cell adhesion. Importantly miRNAs of the RPE were found to be required for maturation of the adjacent photoreceptors, specifically for the morphogenesis of the outer segments. The profiles of miRNA and mRNA altered in the Dicer1 deficient RPE point to a key role of miR-204 in regulation of RPE differentiation program in vivo and uncovers the importance of additional novel RPE miRNAs. The study exposes the combined regulatory activity of miRNAs of the RPE, which is required for RPE differentiation and for the development of the adjacent neuroretina.
MicroRNAs are essential for differentiation of the retinal pigmented epithelium and maturation of adjacent photoreceptors.
Specimen part, Treatment
View SamplesIn sickle cell disease, ischemia-reperfusion injury and intravascular hemolysis produce endothelial dysfunction and vasculopathy characterized by reduced nitric oxide (NO) and arginine bioavailability. Recent functional studies of platelets in patients with sickle cell disease reveal a basally activated state, suggesting that pathological platelet activation may contribute to sickle cell disease vasculopathy. Studies were therefore undertaken to examine transcriptional signaling pathways in platelets that may be dysregulated in sickle cell disease. We demonstrate and validate here the feasibility of comparative platelet transcriptome studies on clinical samples from single donors, by the application of RNA amplification followed by microarray-based analysis of 54,000 probe sets. Data mining an existing microarray database, we identified 220 highly abundant genes in platelets and a subset of 72 relatively platelet-specific genes, defined by more than 10-fold increased expression compared to the median of other cell types in the database with amplified transcripts. The highly abundant platelet transcripts found in the current study included 82% or 70% of platelet abundant genes identified in two previous gene expression studies on non-amplified mRNA from pooled or apheresis samples, respectively. On comparing the platelet gene expression profiles in 18 patients with sickle cell disease in steady state to 12 African American controls, at a 3-fold cut-off and 5% false discovery rate, we identified ~100 differentially expressed genes, including multiple genes involved in arginine metabolism and redox homeostasis. Further characterization of these pathways using real time PCR and biochemical assays revealed increased arginase II expression and activity and decreased platelet polyamine levels. These studies suggest a potential pathogenic role for platelet arginase and altered arginine and polyamine metabolism in sickle cell disease and provide a novel framework for the study of disease-specific platelet biology.
Amplified expression profiling of platelet transcriptome reveals changes in arginine metabolic pathways in patients with sickle cell disease.
Specimen part
View SamplesAlternative mRNA splicing is a major mechanism for gene regulation and transcriptome diversity. Despite the extent of the phenomenon, the regulation and specificity of the splicing machinery are only partially understood. Adenosine-to-inosine (A-to-I) RNA editing of pre-mRNA by ADAR enzymes has been linked to splicing regulation in several cases. Here we used bioinformatics approaches, RNA-seq and exon-specific microarray of ADAR knockdown cells to globally examine how ADAR and its A-to-I RNA editing activity influence alternative mRNA splicing. Although A-to-I RNA editing only rarely targets canonical splicing acceptor, donor, and branch sites, it was found to affect splicing regulatory elements (SREs) within exons. Cassette exons were found to be significantly enriched with A-to-I RNA editing sites compared with constitutive exons. RNA-seq and exon-specific microarray revealed that ADAR knockdown in hepatocarcinoma and myelogenous leukemia cell lines leads to global changes in gene expression, with hundreds of genes changing their splicing patterns in both cell lines. This global change in splicing pattern cannot be explained by putative editing sites alone. Genes showing significant changes in their splicing pattern are frequently involved in RNA processing and splicing activity. Analysis of recently published RNA-seq data from glioblastoma cell lines showed similar results. Our global analysis reveals that ADAR plays a major role in splicing regulation. Although direct editing of the splicing motifs does occur, we suggest it is not likely to be the primary mechanism for ADAR-mediated regulation of alternative splicing. Rather, this regulation is achieved by modulating trans-acting factors involved in the splicing machinery. Overall design: HepG2 and K562 cell lines were stably transfected with plasmids containing siRNA designed to specifically knock down ADAR expression (ADAR KD). This in order to examine how ADAR affects alternative splicing globally.
Global regulation of alternative splicing by adenosine deaminase acting on RNA (ADAR).
Cell line, Subject
View Samples