ABSTRACT: The final goal of this study is to develop a short term and highly accurate prediction method of carcinogenicity based on gene expression profile of rats administrated by carcinogens. We conducted 3 days-, 14 days- and 28 days-repeated dose experiments in male F344 rats with 47 carcinogens and 26 non-carcinogens, and the gene expression profiles in liver were investigated by custom glass microarrays. Supplementary file "73 Compounds for training" indicates 47 carcinogens and 26 non-carcinogens. Supplementary file "15 Compounds for test" lists the other compounds which are for test. Two-condition experiment, control vs. chemical treated rat liver. Biological replicates: 4 control, 4 treated, control samples were pooled. One replicate per array.
Project description:The final goal of this study is to develop a short term and highly accurate prediction method of carcinogenicity based on gene expression profile of rats administrated by carcinogens. We conducted 3 days-, 14 days- and 28 days-repeated dose experiments in male F344 rats with 47 carcinogens and 26 non-carcinogens, and the gene expression profiles in liver were investigated by custom glass microarrays. Supplementary file "73 Compounds for training" indicates 47 carcinogens and 26 non-carcinogens. Supplementary file "15 Compounds for test" lists the other compounds which are for test. Two-condition experiment, control vs. chemical treated rat liver. Biological replicates: 4 control, 4 treated, control samples were pooled. One replicate per array.
Project description:The final goal of this study is to develop a short term and highly accurate prediction method of carcinogenicity based on gene expression profiles of rats subjected to carcinogen exposure. We conducted 3 day-, 14 day- and 28 day-repeated dose experiments in male F344 rats with 47 carcinogens and 26 non-carcinogens, and the gene expression profiles in liver were investigated by custom glass microarrays. Supplementary file "73 Compounds for training" indicates 47 carcinogens and 26 non-carcinogens. Supplementary file "15 Compounds for test" lists the other compounds which are for test. Two-condition experiment, control vs. chemical treated rat liver. Biological replicates: 4 control, 4 treated, control samples were pooled. One replicate per array.
Project description:The rodent carcinogenicity test requires extremely long test term and large examination cost. Therefore, now we need to develop a short term and low cost screening method. We already developed a chemical carcinogenicity short term screening method CARCINOscreenM-BM-.. This study was performed to validate this screening method. We conducted 28 days-repeated dose experiments in male F344 rats with 4 carcinogens and 2 non-carcinogens, and the gene expression profiles in liver were measureed by custom oligo microarrays. Two-condition experiment, control vs. chemical treated rat liver. Biological replicates: 4 control, 4 treated, control samples were pooled. One replicate per array. Compound treatments: 4 carcinogens: Hexachloroethane, 1,2,3-Trichloropropane, 1-Amino-2-methylanthraquinone, 3-(4-Chlorophenyl)-1,1-dimethylurea 2 non-carcinogens: 1,2-Dichlorobenzene and Tetracycline hydrochloride
Project description:This SuperSeries is composed of the following subset Series: GSE16340: Rat liver. Control vs. Chemical treated, 3 days GSE16394: Rat liver. Control vs. Chemical treated, 28 days GSE16743: Rat liver: Control vs. Chemical treated, 14 days Refer to individual Series
Project description:The need for an efficient carcinogenicity test prompted this study, in which we used a microarray-based genomics approach, with a short-term in vivo model, in combination with insights from statistical and mechanistic analyses. We performed additional experiments to support the significance of the microarray results. Carcinogens were evaluated based on differences in the mechanisms involved in the response to genotoxic (GTX) carcinogens and non-genotoxic (NGTX) carcinogens. Microarray data were analyzed for 2 time points after treatment with the following 6 carcinogens. The analysis was performed using t-tests to compare the fold changes, and we selected differentially expressed genes (DEGs) and evaluated the reasons for differential expression in terms of cellular pathways and processes. We mapped the DEG-related pathways to analyze cellular processes, and we were able to uncover significant mechanisms that involve critical cellular components, such as CDKN1A (p21) and BAX. In addition, a comparison of the data from two time points showed that the repeated administration model was more effective than a single administration for carcinogen research. The classification analysis of selected DEGs was performed by setting microarray data of 4 carcinogens as test sets; these test sets were evaluated as classifiers. Microarray results were further supported using the Comet and micronucleus assays. It was found that gene expression profiling using microarrays, followed by pathway analysis, was effective in increasing the understanding of the characteristics of different carcinogens, and the efficiency of these methods was exemplified by the short-term (3 day) nature of the animal experiments. The following 10 hepatocarcinogens were used: 2-acetylaminofluorene (53-96-3), diethylnitrosamine (55-18-5), 4-dimethylamino-3'-methyl azobenzene (55-80-1), clofibrate (637-07-0), 1,4-dioxane (123-91-1), DL-ethionine (67-21-0), 1,3-dichloro-2'-propanol (96-23-1), urethane (51-79-6), sodium nitrite (7632-00-0), and methyleugenol (93-15-2). Forty-one data were obtained for the training compounds in this study. We treated rats with one of three compounds or a control for each GTX and NGTX experimental group and measured 2 time points for each group. All experimental procedures were repeated three times. We excluded 1 file that was found to be a failure. Each ‘.CEL’ file obtained as a raw data file was standardized using the RMA (Robust Multi-array Average) algorithm.
Project description:There is no accurate and well-validated short-term test for non-genotoxic carcinogens, necessitating an expensive two year rodent bioassay before a risk assessment can begin. We have developed a short-term in vivo rat assay that predicts whether non-genotoxic chemicals are likely to induce hepatic tumors based on transcript profiles in the liver. Using a large independent test set, assay accuracy was found to be superior to existing pathological and genomic markers. Comparison of the test chemical's signature profile to reference carcinogens of known mechanism can also identify a potential mode(s) of action, allowing an early assessment of human cancer risk. Guidelines for commercial use: http://www.iconixbiosciences.com/guidelineCommUse.pdf Keywords: dose response, time course, compound treatment Treatment of male Sprague-Dawley rats with 147 non-genotoxic compounds at various doses and durations, in biological triplicate, along with vehicle-matched control animals. Liver samples were assayed for gene expression. Hepatocarcinogenic and non-carcinogenic compounds were included. A classifier for carcinogenicity was built on a training set of 25 carcinogens and 75 noncarcinogens (randomly selected compounds, maximum tolerated dose, 5 day timepoints), and tested on the remaining 47 compounds at various timepoints. A total of 990 samples were hybridized to single-channel CodeLink RU1 arrays. Biological triplicates were combined with matched control samples to calculate log ratios.
Project description:Quorum sensing system (QS) is a global regulator that regulates gene expression in response to cell density and other environmental factors. Two QS genes have been identified in Brucella, one of which (vjbR) is involved in Brucella intracellular survival and virulence. But the regulation mechanism of Brucella intracellular survival by the vjbR remains unknown.To characterize the regulation roles of vjbR, the in vitro vjbR induction conditions simulating intracellular environments were firstly defined, and then, transcriptome of the vjbR mutant is compared to that of the wild type strain. The vjbR gene was highly activated under acidified nutrition limitation condition. Comparative transcriptome analysis showed that a total of 126 genes were greatly differentially expressed in the vjbR mutant. 2 wild type samples and 2 vjbR mutant samples were analyzed.
Project description:The prediction of possible carcinogenicity of chemicals for humans represents an ongoing challenge. Chronic rodent bioassays predict human cancer risk at only limited reliability while simultaneously being expensive and long-lasting. In order to seek for alternatives, in the present study, the ability of a transcriptomics-based primary mouse hepatocyte model to classify carcinogens by their modes of action was evaluated. As it is obvious that exposure will induce a cascade of gene expression modifications, in particular, the influence of exposure time in vitro on discriminating genotoxic (GTX) carcinogens from non-genotoxic (NGTX) carcinogens class prediction was investigated. Primary mouse hepatocytes from male C57Bl6 mice were treated for 12, 24, 36 and 48 h with two GTX and two NGTX carcinogens. For the purpose of validation, two additional GTX compounds were studied after incubation periods of 24 and 48 h. Immunostaining of ?H2AX foci was applied to phenotypically verify DNA damage. Whole genome gene expression modifications were analyzed by means of Affymetrix mouse genome 430 2.0 microarrays. Datasets were normalized using RMA and differentially expressed genes were selected for assessing class prediction. The ?H2AX assay confirmed significant induction of DNA damage after treatment with GTX compounds, whereas NGTX compounds showed no activity beyond background levels. Discrimination of GTX and NGTX carcinogens by Prediction Analysis of Microarray (PAM) was validated and resulted in a perfect classification. The present study shows that gene expression profiling in primary mouse hepatocytes is promising for discriminating between GTX and NGTX compounds and that this classification improves with increasing treatment period.
Project description:To prospectively identify new oncogenes implicated in lung Squamous Cell Carcinoma pathogenesis, we investigated chromosome 3 aberrations in advanced tumours using arrayCGH. These aberrations are indeed among the most frequent aberrations in lung SCC and correlate with SCC patient's poor prognosis. We precisely map regions of recurrent losses at 3p and gains at 3q25-qter in a series of lung SCC. We moreover uncover 3q26.3-q27 high level amplifications in 20% of tumours. Keywords: ArrayCGH, Lung Squamous Cell Carcinoma, 3q26.3, SOX2 Profiling of 26 advanced (stage III) lung SCC. Replicates : each tumor sample is hybridized together with a normal dna sample to one microarray. Each microarray contain 3 replicates per BAC clone.
Project description:We conducted a large-scale gene expression screen using the 3,200 cDNA probe microarray developed specifically for Ursus americanus to detect expression differences in liver and skeletal muscle that occur during winter hibernation in comparison to animals sampled during summer. The expression of 12 genes, including RNA binding protein motif 3 (Rbm3), that are mostly involved in protein biosynthesis, was induced during hibernation in both liver and muscle. The Gene Ontology and Gene Set Enrichment analysis consistently showed a highly significant enrichment of the protein biosynthesis category by over-expressed genes in both liver and skeletal muscle during hibernation. Coordinated induction in transcriptional level of genes involved in protein biosynthesis is a distinctive feature of the transcriptome in hibernating black bears. This finding implies induction of translation and suggests an adaptive mechanism that contributes to a unique ability to reduce muscle atrophy over prolonged periods of immobility during hibernation. Comparing expression profiles in bears to small mammalian hibernators shows a general trend during hibernation of transcriptional changes that include induction of genes involved in lipid metabolism and carbohydrate synthesis as well as depression of genes involved in the urea cycle and detoxification function in liver. Black bears sampled during winter hibernation were compared with the animals sampled during summer. Two tissue types, liver and muscle, were hybridized on a custom 3,200-gene nylon membrane microarray platform with three replicates for each gene (9.600 spots in total). Six hibernating and five summer active bears were studied in experiments with liver tissue, five hibernating and five summer active animals were tested with muscle tissue.