Expression Characteristics of Genes Hypermethylated and Downregulated in Rat Liver Specific to Non-genotoxic Hepatocarcinogens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA508720 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:The present study examined hypermethylated and downregulated genes specific to carbon tetrachloride (CCl4) by Methyl-Seq analysis combined with expression microarray analysis in the liver of rats treated with CCl4 or N-nitrosodiethylamine (DEN) for 28 days, by excluding those with DEN.
2019-05-09 | GSE123408 | GEO
Project description:Liver tumors in rodents are frequently induced by non-genotoxic carcinogens. These hepatocarcinogens generally activate hepatic nuclear receptors (e.g., CAR and PXR), resulting in a cascade of signals causing modifications in the expression of genes responsible for several processes involved in carcinogenesis. Evaluation of the carcinogenic potential of chemicals is a regulatory requirement but is time-consuming and expensive. Consequently, several short-term in vivo and in vitro approaches, using molecular tools, have been proposed as predictive models for non-genotoxic hepatocarcinogens. The objective of our study was to discriminate between chemicals that are either non-genotoxic hepatocarcinogens or merely hepatotoxicants and also between CAR and PXR modulators on the basis of their gene expression profiles. Thus, we treated rats for seven days with the hepatoxicants, diclofenac and diazepam, or with several CAR and PXR modulators, which were mainly hepatocarcinogens. Different hepatic gene expression profiles were obtained not only between the hepatotoxicants and the non-genotoxic hepatocarcinogens but also between the CAR activators phenobarbital, phenytoin and 1,1-bis-(4-chlorophenyl)-2,2-dichloroethene which were grouped together, and the two PXR activators pregnenolone 16α-carbonitrile and clotrimazole. Diethylstilbestrol had an expression profile that was quite distinct from the other PXR activators, suggesting that this compound is certainly not a classic PXR modulator. Moreover, some differences were observed between phenytoin (not considered as a hepatocarcinogen), and the other two CAR activators. Our data therefore indicate that discrimination is possible between hepatocarcinogens and hepatotoxicants, between CAR and PXR modulators and also between compounds within the same class of modulators using a short-term transcriptomic approach.
2013-07-31 | GSE39350 | GEO
Project description:Liver tumors in rodents are frequently induced by non-genotoxic carcinogens. These hepatocarcinogens generally activate hepatic nuclear receptors (e.g., CAR and PXR), resulting in a cascade of signals causing modifications in the expression of genes responsible for several processes involved in carcinogenesis. Evaluation of the carcinogenic potential of chemicals is a regulatory requirement but is time-consuming and expensive. Consequently, several short-term in vivo and in vitro approaches, using molecular tools, have been proposed as predictive models for non-genotoxic hepatocarcinogens. The objective of our study was to discriminate between chemicals that are either non-genotoxic hepatocarcinogens or merely hepatotoxicants and also between CAR and PXR modulators on the basis of their gene expression profiles. Thus, we treated rats for seven days with the hepatoxicants, diclofenac and diazepam, or with several CAR and PXR modulators, which were mainly hepatocarcinogens. Different hepatic gene expression profiles were obtained not only between the hepatotoxicants and the non-genotoxic hepatocarcinogens but also between the CAR activators phenobarbital, phenytoin and 1,1-bis-(4-chlorophenyl)-2,2-dichloroethene which were grouped together, and the two PXR activators pregnenolone 16α-carbonitrile and clotrimazole. Diethylstilbestrol had an expression profile that was quite distinct from the other PXR activators, suggesting that this compound is certainly not a classic PXR modulator. Moreover, some differences were observed between phenytoin (not considered as a hepatocarcinogen), and the other two CAR activators. Our data therefore indicate that discrimination is possible between hepatocarcinogens and hepatotoxicants, between CAR and PXR modulators and also between compounds within the same class of modulators using a short-term transcriptomic approach. CAR or PXR inducers were administered in suspension to rats (7 weeks old at start of treatment) by oral gavage at a daily dose for 7 consecutive days. Treatment-related changes in gene expression were determined in the liver using whole genome oligonucleotide microarrays.
2013-07-31 | E-GEOD-39350 | biostudies-arrayexpress
Project description:In order to screen candidate genes that discriminate genotoxic hepatocarcinogens from nongenotoxic ones, we compared gene expression in the liver of mice treated with 6 genotoxic hepatocarcinogens or 5 nongenotoxic hepatocarcinogens.
2011-10-27 | GSE33248 | GEO
Project description:Several studies have successfully detected hepatocarcinogenicity in rats based on gene expression data. Here, we constructed a model for detecting non-genotoxic (NGTX) hepatocarcinogens and predicted their MOAs in rats. Piperonyl butoxide (PBO) and Dammar resin (DAM) are NGTX hepatocarcinogens. Gene expression data in the liver treated by PBO and DAM was used for validation of constructed model.
2015-07-29 | GSE71413 | GEO
Project description:In order to screen candidate genes that discriminate genotoxic hepatocarcinogens from nongenotoxic ones, we compared gene expression in the liver of mice treated with 6 genotoxic hepatocarcinogens or 5 nongenotoxic hepatocarcinogens. 6 genotoxic and 2 non-genotoxic hepatocarcinogens with expression time of 4h, 20h, 14 days, and 28 days
2011-10-26 | E-GEOD-33248 | biostudies-arrayexpress
Project description:In vitro toxicogenomics signatures to predict mode of action can facilitate chemical screening. We recently demonstrated the use of the TGx-28.65 genomic biomarker (representing: toxicogenomics (TGx), developed using a 28 chemical training set, and comprising 65 genes) in classifying agents as genotoxic (DNA damaging) and non-genotoxic in human lymphoblastoid TK6 cells. Because TK6 cells do not possess cytochrome P450 activity, we confirmed accurate classification in cells co-exposed to 1% 5,6 benzoflavone/phenobarbital-induced rat liver S9 for metabolic activation. However, chemicals may require different types of S9 for activation. Here we conducted experiments in TK6 cells exposed to chemicals in the presence of 2% or 10% Aroclor-induced, or 5% ethanol-induced rat liver S9 to expand TGx-28.65 biomarker application. Gene expression profiles were produced 3-4 hr following a 4 hr co-exposure of TK cells to test chemicals (seven genotoxic and two non-genotoxic, three concentrations, and concurrent solvent controls) and S9. Relative survival and micronucleus frequency was assessed by flow cytometry in cells 20 hr after the exposure. We found that genotoxicity/non-genotoxicity could be accurately predicted for the test compounds using the different S9s. One technical replicate of cells co-treated with dexamethasone and 10% Aroclor-induced S9 was falsely predicted as genotoxic, suggesting caution in using high concentrations of S9. TGx-28.65 correctly classified low concentrations of genotoxic chemicals (those not causing cytotoxicity or micronuclei) as genotoxic, demonstrating that it is a sensitive biomarker of genotoxicity. Overall, the work confirms that different S9s can be used in TK6 cells without impairing predictivity using the TGx-28.65 biomarker.
2016-08-25 | GSE74216 | GEO
Project description:At present, substantial efforts are focused on the development of in vitro assays coupled with M-bM-^@M-^]omicsM-bM-^@M-^] technologies for the identification of carcinogenic substances as an alternative to the classical 2-year rodent carcinogenicity bioassay. A prerequisite for the eventual regulatory acceptance of such assays, however, is the in vivo relevance of the observed in vitro findings. In the current study, hepatocarcinogen-induced gene expression profiles generated after exposure of conventional cultures of primary rat hepatocytes to three non-genotoxic carcinogens (methapyrilene hydrochloride, piperonyl butoxide and Wy-14643), three genotoxic carcinogens (aflatoxin B1, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and 2-nitrofluorene), and two non-carcinogens (nifedipine and clonidine) are compared with previously obtained in vivo data after oral administration for up to 14 days of the same hepatocarcinogens to rats.
2012-04-23 | E-GEOD-36524 | biostudies-arrayexpress
Project description:When applied in toxicological studies, the recently developed gene expression profiling techniques using microarrays, which brought forth the new field of toxicogenomics, facilitate the interpretation of a toxic compound?s mechanism of action. In this study, we investigated whether genotoxic carcinogens at doses known to induce liver tumors in the 2-year rat bioassay deregulate a common set of genes in a short-term in vivo study and, if so, whether these deregulated genes represent defined biological pathways. Rats were dosed with the four genotoxic hepatocarcinogens Dimethylnitrosamine [CAS:62-75-9;CHEBI:21778] (4 mg/kg/day), 2-nitrofluorene [CAS:607-57-8;CHEBI:1224] (44 mg/kg/day), Aflatoxin B1 [CAS:1162-65-8;CHEBI:2504] (0.24 mg/kg/day), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone [CAS:64091-91-4;CHEBI:32692] (NNK, 20 mg/kg/day). After treatment for up to 14 days, the expression profiles of the livers were analyzed on Affymetrix RG_U34A microarrays. Among the significantly upregulated genes were a set of target genes of the tumor suppressor protein p53, indicating a DNA damage response. Such a response was expected and, therefore, confirmed the validity of our approach. In addition, the gene expression changes suggest a specific detoxification response, the activation of proliferative and survival signaling pathways, and some cell structural changes. These responses were strong throughout the 14 day time course for 2-nitrofluorene and aflatoxin B1; in the case of dimethylnitrosamine and NNK, the effects were weakly detectable at day 1 and then increased with time. For dimethylnitrosamine and aflatoxin B1, which caused observable inflammation in vivo, we found a corresponding upregulation of inflammatory genes at the same time points. Thus, by the toxicogenomic analysis of short-term in vivo studies, we identified genes and pathways commonly deregulated by genotoxic carcinogens, which may be indicative for the early events in tumorigenesis and, thus, predictive of later tumor development.
2005-05-15 | E-TOXM-16 | biostudies-arrayexpress