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GSE5127
Mus musculus
18 Downloadable Samples
Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Two-year rodent bioassays play a central role in evaluating both the carcinogenic potential of a chemical and generating quantitative information on the dose-response behavior for chemical risk assessments. The bioassays involved are expensive and time-consuming, requiring nearly lifetime exposures (two years) in mice and rats and costing $2 to $4 million per chemical. Since there are approximately 80,000 chemicals registered for commercial use in the United States and 2,000 more are added each year, applying animal bioassays to all chemicals of concern is clearly impossible. To efficiently and economically identify carcinogens prior to widespread use and human exposure, alternatives to the two-year rodent bioassay must be developed. In this study, animals were exposed for 13 weeks to two chemicals that were positive for lung tumors in the two-year rodent bioassay, two chemicals that were negative for tumors, and two vehicle controls. Gene expression analysis was performed on the lungs of the animals to assess the potential for identifying gene expression biomarkers that can predict tumor formation in a two-year bioassay following a 13 week exposure.
Publication Title
A comparison of transcriptomic and metabonomic technologies for identifying biomarkers predictive of two-year rodent cancer bioassays.
Sample Metadata Fields
Sex, Age, Subject
View Samples- Mus musculus
- 18 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Two-year rodent bioassays play a central role in evaluating both the carcinogenic potential of a chemical and generating quantitative information on the dose-response behavior for chemical risk assessments. The bioassays involved are expensive and time-consuming, requiring nearly lifetime exposures (two years) in mice and rats and costing $2 to $4 million per chemical. Since there are approximately 80,000 chemicals registered for commercial use in the United States and 2,000 more are added each year, applying animal bioassays to all chemicals of concern is clearly impossible. To efficiently and economically identify carcinogens prior to widespread use and human exposure, alternatives to the two-year rodent bioassay must be developed. In this study, animals were exposed for 13 weeks to two chemicals that were positive for liver tumors in the two-year rodent bioassay, two chemicals that were negative for liver tumors, and two vehicle controls. Gene expression analysis was performed on the livers of the animals to assess the potential for identifying gene expression biomarkers that can predict tumor formation in a two-year bioassay following a 13 week exposure.
Publication Title
A comparison of transcriptomic and metabonomic technologies for identifying biomarkers predictive of two-year rodent cancer bioassays.
Sample Metadata Fields
Sex, Age, Subject
View Samples- Homo sapiens
- 42 Downloadable Samples
- Affymetrix Human Genome U133A 2.0 Array (hgu133a2)
Description
Although HSF1 is known to play an important role in regulating the cellular response to proteotoxic stressors, little is known about the structure and function of the HSF1 signaling network under both stressed and unstressed conditions. In this study, we used a combination of chromatin immunoprecipitation (ChIP) microarray analysis and time course gene expression microarray analysis with and without siRNA-mediated inhibition of HSF1 comprehensively identify genes directly and indirectly regulated by HSF1 and examine the structure of the extended HSF1 signaling network. Correlation between promoter binding and gene expression was not significant for all genes bound by HSF1 suggesting that HSF1 binding per se is not sufficient for expression. However, the correlation with promoter binding was significant for genes identified as HSF1-regulated following siRNA knockdown allowing the identification of direct transcriptional targets of HSF1. Among promoters bound by HSF1 following heat shock, a gene ontology (GO) analysis showed significant enrichment only in categories related to protein folding. In contrast, analysis of the extended HSF1 signaling network showed enrichment in a variety of categories related to protein folding, anti-apoptosis, RNA splicing, ubiquitination and others, highlighting a complex transcriptional program directly and indirectly regulated by HSF1.
Publication Title
Genome-wide analysis of human HSF1 signaling reveals a transcriptional program linked to cellular adaptation and survival.
Sample Metadata Fields
No sample metadata fields
View Samples- Arabidopsis thaliana
- 6 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
Effect of geminivirus Cabbage leaf curl virus on Arabidopsis Col-0 at 12 days post-inoculation during short day conditions.
Publication Title
Global analysis of Arabidopsis gene expression uncovers a complex array of changes impacting pathogen response and cell cycle during geminivirus infection.
Sample Metadata Fields
No sample metadata fields
View Samples- Pan troglodytes, Homo sapiens
- 355 Downloadable Samples
- Affymetrix Human Genome U133A Array (hgu133a)
Description
Lymphoblastoid cell lines (LCLs), originally collected as renewable sources of DNA, are now being used as a model system to study genotype-phenotype relationships in human cells. These cell lines have been used to search for genetic variants that are associated with drug response as well as with more basic cellular traits such as RNA levels. In setting out to extend such studies by searching for genetic variants contributing to drug response, we observed that phenotypes in LCLs were, in our lab and others, significantly affected by experimental confounders (i.e. in vitro growth rate, metabolic state, and relative levels of the Epstein-Barr virus used to transform the cells). As we did not find any SNPs associated with genome-wide significance to drug response, we evaluated whether incorporating RNA expression levels (and eQTLs) in the analysis could increase power to detect such effects. As previously shown, cis-acting eQTLs were detectable for a sizeable fraction of RNAs and baseline levels of many RNAs predicted response to several drugs. However, we found only limited evidence that SNPs influenced drug response through their effect on expression of RNA. Efforts to use LCLs to map genes underlying cellular traits will require great care to control experimental confounders, unbiased methods for integrating and interpreting such multi-dimensional data, and much larger sample sizes than have been applied to date.
Publication Title
Genetic analysis of human traits in vitro: drug response and gene expression in lymphoblastoid cell lines.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 191 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
The process for evaluating chemical safety is inefficient, costly, and animal intensive. There is growing consensus that the current process of safety testing needs to be significantly altered to improve efficiency and reduce the number of untested chemicals. In this study, the use of short-term gene expression profiles was evaluated for predicting the increased incidence of mouse lung tumors. Animals were exposed to a total of 26 diverse chemicals with matched vehicle controls over a period of three years. Upon completion, significant batch-related effects were observed. Adjustment for batch effects significantly improved the ability to predict increased lung tumor incidence. For the best statistical model, the estimated predictive accuracy under honest five-fold cross-validation was 79.3% with a sensitivity and specificity of 71.4 and 86.3%, respectively. A learning curve analysis demonstrated that gains in model performance reached a plateau at 25 chemicals, indicating that the size of the current data set was sufficient to provide a robust classifier. The classification results showed a small subset of chemicals contributed disproportionately to the misclassification rate. For these chemicals, the misclassification was more closely associated with genotoxicity status than efficacy in the original bioassay. Statistical models were also used to predict dose-response increases in tumor incidence for methylene chloride and naphthalene. The average posterior probabilities for the top models matched the results from the bioassay for methylene chloride. For naphthalene, the average posterior probabilities for the top models over-predicted the tumor response, but the variability in predictions were significantly higher. The study provides both a set of gene expression biomarkers for predicting chemically-induced mouse lung tumors as well as a broad assessment of important experimental and analysis criteria for developing microarray-based predictors of safety-related endpoints.
Publication Title
Use of short-term transcriptional profiles to assess the long-term cancer-related safety of environmental and industrial chemicals.
Sample Metadata Fields
Sex, Age, Specimen part, Disease, Subject
View Samples- Homo sapiens
- 141 Downloadable Samples
- Illumina HumanHT-12 V3.0 expression beadchip
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
Maternal influences on the transmission of leukocyte gene expression profiles in population samples from Brisbane, Australia.
Sample Metadata Fields
Sex, Age, Specimen part
View Samples- Homo sapiens
- 72 Downloadable Samples
- Illumina HumanHT-12 V3.0 expression beadchip
Description
This is a companion study to (GSE21342). Peripheral blood leukocyte samples were obtained with consent from 100 red cross blood donors sampled cross-sectionally across the city of Brisbane, Australia. After correction for RNA integrity values, individuals fall into major profiles of expression variation suggesting environmental and cultural influences on immune gene expression.
Publication Title
Maternal influences on the transmission of leukocyte gene expression profiles in population samples from Brisbane, Australia.
Sample Metadata Fields
Sex, Age
View Samples- Homo sapiens
- 41 Downloadable Samples
- Illumina HumanHT-12 V3.0 expression beadchip
Description
This study contrasts the expression profiles of peripheral blood leukocytes from third trimester pregnant mothers, with cord blood leukocytes from their newborn children. It is a companion to (GSE21311). After normalization for RNA integrity, major principal components of the variation were found to distinguish individuals. Transmission of gene expression profiles from mother to child was documented, along with differences between gestational diabetic, obese, and normal weight mothers and their children.
Publication Title
Maternal influences on the transmission of leukocyte gene expression profiles in population samples from Brisbane, Australia.
Sample Metadata Fields
Specimen part
View Samples- Homo sapiens
- 36 Downloadable Samples
- Affymetrix Human Genome U133A Array (hgu133a)
Description
We have previously identified a family of novel androgen receptor (AR) ligands that, upon binding, enable AR to adopt structures distinct from that observed in the presence of canonical agonists. In this report, we describe the use of these compounds to establish a relationship between AR structure and biological activity with a view to defining a rational approach with which to identify useful Selective Androgen Receptor Modulators (SARMs). As one of the approaches, we used a DNA microarray analysis to demonstrate that differently conformed receptors facilitate distinct patterns of gene expression in LNCaP cells. Interestingly, we observed a complete overlap in the identity of genes expressed following treatment with mechanistically distinct AR ligands. However, it was differences in the kinetics of gene regulation that distinguished these compounds. Follow-up studies, in cell-based assays of AR action, confirmed the importance of these alterations in gene expression. Together these studies demonstrate an important link between AR structure, gene expression and biological outcome.
Publication Title
Linking ligand-induced alterations in androgen receptor structure to differential gene expression: a first step in the rational design of selective androgen receptor modulators.
Sample Metadata Fields
No sample metadata fields
View Samples