Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

MAQC-II Project: NIEHS data set

ABSTRACT: The NIEHS data set (endpoint C) was provided by the National Institute of Environmental Health Sciences (NIEHS) of the National Institutes of Health (Research Triangle Park, NC, USA). The study objective was to use microarray gene expression data acquired from the liver of rats exposed to hepatotoxicants to build classifiers for prediction of liver necrosis. The gene expression compendium data set was collected from 418 rats exposed to one of eight compounds (1,2-dichlorobenzene, 1,4-dichlorobenzene, bromobenzene, monocrotaline, N-nitrosomorpholine, thioacetamide, galactosamine, and diquat dibromide). All eight compounds were studied using standardized procedures, i.e. a common array platform (Affymetrix Rat 230 2.0 microarray), experimental procedures and data retrieving and analysis processes. For each compound, four to six male, 12 week old F344 rats were exposed to a low dose, mid dose(s) and a high dose of the toxicant and sacrificed at 6, 24 and 48 hrs later. At necropsy, liver was harvested for RNA extraction, histopathology, and clinical chemistry assessments.

ORGANISM(S): Rattus norvegicus

SUBMITTER: Leming Shi

PROVIDER: E-GEOD-24363 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Effect of training-sample size and classification difficulty on the accuracy of genomic predictors.

Popovici Vlad V Chen Weijie W Gallas Brandon G BG Hatzis Christos C Shi Weiwei W Samuelson Frank W FW Nikolsky Yuri Y Tsyganova Marina M Ishkin Alex A Nikolskaya Tatiana T Hess Kenneth R KR Valero Vicente V Booser Daniel D Delorenzi Mauro M Hortobagyi Gabriel N GN Shi Leming L Symmans W Fraser WF Pusztai Lajos L

Breast cancer research : BCR 20100111 1

<h4>Introduction</h4>As part of the MicroArray Quality Control (MAQC)-II project, this analysis examines how the choice of univariate feature-selection methods and classification algorithms may influence the performance of genomic predictors under varying degrees of prediction difficulty represented by three clinically relevant endpoints.<h4>Methods</h4>We used gene-expression data from 230 breast cancers (grouped into training and independent validation sets), and we examined 40 predictors (fiv ...[more]

PMID: 20064235

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Project description:Wild-type and AHR-KO rats harboring a 29-bp deletion mutation in exon 2 of the AHR gene were used in this study. Wild-type and AHR-KO rats were generated from heterozygous breeding stocks generated on a Sprague-Dawley outbred background and maintained at the Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina Persistent activation of the aryl hydrocarbon receptor (AHR) is believed to play a key role in the mode-of-action for TCDD induced rat liver tumorigenesis. It has been hypothesized that the cellular responses of hepatocytes to AHR activation may differ across regions of the liver lobule and that zone-specific effects of AHR agonists may play a role in the pathogenesis of rat liver tumorigenesis. Dose-dependent changes in gene expression were observed in both populations of hepatocytes collected from WT rats which were consistent with activation of AHR signaling. No significant or dose-dependent changes in gene expression were observed in samples from AHR-KO rats. In addition, evidence of inflammatory signaling pathway activation was observed only in centrilobular hepatocytes. Evidence of cell adhesion pathway enrichment was observed only in periportial hepatocytes. Benchmark dose analysis demonstrated that dose-dependent changes in gene expression occurred at lower doses in centrilobular as compared to periportal hepatocytes. These results indicate zone-specific differences in the sensitivity and response of hepatocytes to persistent AHR activation. AHR-KO and WT rats (n = 10 rats/dose/genotype) were dosed by oral gavage (4-5 doses / week, 19 total doses) with varying concentrations of TCDD in corn oil (0, 3, 22, 100, 300, 1000 ng/kg/day). Cryopreserved liver slices collected at necropsy were thawed, cryosectioned (12 Âµm thickness), fixed with ethanol and âquick-stainedâ with hematoxylin. Centrilobular and periportal hepatocytes were collected using laser capture microdissection. Total RNA was extracted, amplified and labeled using low-yield techniques and global transcriptomic profiles were obtained using Affymetrix Gene-Titan peg arrays.

Dataset Information

MAQC-II Project: NIEHS data set

Publications

Effect of training-sample size and classification difficulty on the accuracy of genomic predictors.

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