Comparison of hepatocarcinogen-induced gene expression profiles in conventional primary rat hepatocytes with in vivo rat liver
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ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE36524 | GEO | 2012/04/24
SECONDARY ACCESSION(S): PRJNA153479
REPOSITORIES: GEO
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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:Hepatocellular carcinoma (HCC) is an important cause of morbidity and mortality worldwide. Although the risk factors of human HCC are well known, the molecular characterization of this disease is complex, and treatment options in general remain poor. The use of rodent models to study human cancer has been extensively pursued both through genetically engineered rodents and rodent models used in carcinogenicity and toxicology studies. In particular, the B6C3F1 mouse used in the National Toxicology Program (NTP) 2-year bioassay has been used to evaluate the carcinogenic effects of environmental and occupational chemicals, and other compounds. The high incidence of spontaneous HCC in the B6C3F1 mouse has challenged its use as a model for chemically induced HCC in terms of relevance to the human disease. Using global gene expression profiling, we identify the dysregulation of several mediators similarly altered in human HCC, including re-expression of fetal oncogenes, upregulation of protooncogenes, downregulation of tumor suppressor genes, and abnormal expression of cell cycle mediators, growth factors, apoptosis regulators, and angiogenesis and extracellular matrix remodeling factors. Although important differences in etiology and pathogenesis remain between human and mouse HCC, there are important similarities in global gene expression and the types of signaling networks dysregulated in mouse and human HCC. These data provide further relevance for the use of this model in hazard identification of compounds with potential human carcinogenicity risk, and may help in better understanding mechanisms of tumorigenesis due to chemical exposure in the NTP 2-year carcinogenicity bioassay.
2011-06-07 | GSE26538 | GEO
Project description:Hepatocellular carcinoma (HCC) is an important cause of morbidity and mortality worldwide. Although the risk factors of human HCC are well known, the molecular characterization of this disease is complex, and treatment options in general remain poor. The use of rodent models to study human cancer has been extensively pursued both through genetically engineered rodents and rodent models used in carcinogenicity and toxicology studies. In particular, the B6C3F1 mouse used in the National Toxicology Program (NTP) 2-year bioassay has been used to evaluate the carcinogenic effects of environmental and occupational chemicals, and other compounds. The high incidence of spontaneous HCC in the B6C3F1 mouse has challenged its use as a model for chemically induced HCC in terms of relevance to the human disease. Using global gene expression profiling, we identify the dysregulation of several mediators similarly altered in human HCC, including re-expression of fetal oncogenes, upregulation of protooncogenes, downregulation of tumor suppressor genes, and abnormal expression of cell cycle mediators, growth factors, apoptosis regulators, and angiogenesis and extracellular matrix remodeling factors. Although important differences in etiology and pathogenesis remain between human and mouse HCC, there are important similarities in global gene expression and the types of signaling networks dysregulated in mouse and human HCC. These data provide further relevance for the use of this model in hazard identification of compounds with potential human carcinogenicity risk, and may help in better understanding mechanisms of tumorigenesis due to chemical exposure in the NTP 2-year carcinogenicity bioassay. Six spontaneous hepatocellular carcinomas and six normal livers (as controls) from 2-year-old B6C3F1 mice.
2011-06-06 | E-GEOD-26538 | biostudies-arrayexpress
Project description:Background: Information on the carcinogenic potential of chemicals is only availably for High Production Volume products. There is however, a pressing need for alternative methods allowing for the chronic toxicity of substances, including carcinogenicity, to be detected earlier and more reliably. Here we applied advanced genomics to a cellular transformation assay to identify gene signatures useful for the prediction of risk for carcinogenicity. Methods: Genome wide gene expression analysis and qRT-PCR were applied to untransformed and transformed Balb/c 3T3 cells that exposed to 2, 4-diaminotoluene (DAT), benzo(a)pyrene (BaP), 2-Acetylaminoflourene (AAF) and 3-methycholanthrene (MCA) for 24h and 120h, at different concentrations, respectively. Furthermore, various bioinformatics tools were used to identify gene signatures predicting for the carcinogenic risk. Results: Bioinformatics analysis revealed distinct datasets for the individual chemicals tested while the number of significantly regulated genes increased with ascending treatment concentration of the cell cultures. Filtering of the data revealed a common gene signature that comprised of 13 genes whose regulation in cancer tissue has already been established. Strikingly, this gene signature was already identified prior to cell transformation therefore confirming the predictive power of this gene signature in identifying carcinogenic risks of chemicals. Comparison of fold changes determined by microarray analysis and qRT-PCR were in good agreement. Conclusion: Our data describes selective and commonly regulated carcinogenic pathways observed in an easy to use in vitro carcinogenicity assay. Here we defined a set of genes which can serve as a simply assay to predict the risk for carcinogenicity by use of an alternative in vitro testing strategy.
2010-10-02 | GSE22180 | GEO
Project description:To provide insights into the mode of action for Ni3S2 lung carcinogenicity by examining gene expression changes in target cells after inhalation exposure. Gene expression changes were determined in micro-dissected lung broncho-alveolar cells from Fischer F344 rats following inhalation of Ni3S2 at 0.0, 0.04, 0.08, 0.15, and 0.60 mg/m3 (0.03, 0.06, 0.11, and 0.44 mg Ni/m3) for one and four weeks (6 hours per day, 5 days per week). Results: Broncho-alveolar lavage fluid evaluation and lung histopathology provided evidence of inflammation only at the two highest concentrations, which were similar to those tested in the 2-year bioassay. The number of statistically significant up- and down-regulated genes decreased markedly from one to four weeks of exposure, suggesting adaptation. Cell signal pathway enrichment at both time-points primarily reflected responses to toxicity, including inflammatory and proliferative signaling. While proliferative signaling was up-regulated at both time points, some inflammatory signaling reversed from down-regulation at 1 week to up-regulation at 4 weeks. Conclusions: These results support a mode of action for Ni3S2 carcinogenicity driven by chronic toxicity, inflammation and proliferation, leading to mis-replication, rather than by direct genotoxicity. Benchmark dose (BMD) analysis identified the lowest pathway transcriptional BMD exposure concentration as 0.026 mg Ni/m3, for apoptosis/survival signaling. When conducted on the basis of lung Ni concentration the lowest pathway BMD was 0.64 µg Ni/g lung, for immune/inflammatory signaling. Implications: These highly conservative BMDs could be used to derive a point of departure in a nonlinear risk assessment for Ni3S2 toxicity and carcinogenicity.
2014-07-19 | GSE59593 | GEO
Project description:Analysis of gene expression level in a mouse tumorigenic phthalate, DEHP vs non-tumorigenic DNOP. The hypothesis tested in the present study was to identify early key event thresholds related to tumor outcomes in a two-year carcinogenicity bioassay. Our results highlight marked differences in the toxicity profiles of structurally similar phthalates and demonstrate quantitative relationships between early bioindicators and later tumor outcomes.
2013-12-20 | GSE53523 | GEO
Project description:Aristolochic acid (AA) is an active component of herbal drugs derived from the Aristolochia species that have been used for medicinal purposes since antiquity. However, AA is genotoxic and induces tumors in animals and humans. AA induces mutations and tumors in the kidney but solely mutations in the liver. To evaluate whether miRNAs could indicate AA’s tissue-specific carcinogenicity and mutagenicity, we first conducted microarray analysis of miRNA expression in kidneys and livers of rats treated with a carcinogenic dose of AA. Then, miR-21, a biomarker for carcinogenicity, and miR-34a, a biomarker for mutagenicity, the two miRNAs whose expressions were most altered, were evaluated for their expression in the kidney (the AA’s mutagenic and carcinogenic target tissue), liver (the AA’s mutagenic target tissue), and testis, the non-target tissue where neither tumors nor mutation induction was found in previous studies and in this study. Genomic analysis of miRNA expression for kidney and liver samples showed that miRNA expression was globally changed by the treatment. Nineteen miRNAs were significantly dysregulated by the treatment in the kidney. Most of these miRNAs are related to carcinogenesis. Only one miRNA, miR-34a, was differentially expressed in the liver. Expression of miR-21 was induced in the kidney by AA treatment in a dose-dependent manner while no changes occurred in the liver or testis, indicating that the kidney is the carcinogenic target. miR-34a was dose-dependently up-regulated in the kidneys and livers of rats treated with AA, but not in the testis, suggesting that the kidney and liver are mutagenic target tissues, but the testis is not. Our results demonstrate that miRNA profiles can reflect the AA’s carcinogenicity in a tissue-specific manner while specific miRNAs can signify the target tissues for carcinogenicity or mutagenicity of AA.
2013-11-10 | GSE50946 | GEO
Project description:To provide insights into the mode of action for Ni3S2 lung carcinogenicity by examining gene expression changes in target cells after inhalation exposure. Gene expression changes were determined in micro-dissected lung broncho-alveolar cells from Fischer F344 rats following inhalation of Ni3S2 at 0.0, 0.04, 0.08, 0.15, and 0.60 mg/m3 (0.03, 0.06, 0.11, and 0.44 mg Ni/m3) for one and four weeks (6 hours per day, 5 days per week). Results: Broncho-alveolar lavage fluid evaluation and lung histopathology provided evidence of inflammation only at the two highest concentrations, which were similar to those tested in the 2-year bioassay. The number of statistically significant up- and down-regulated genes decreased markedly from one to four weeks of exposure, suggesting adaptation. Cell signal pathway enrichment at both time-points primarily reflected responses to toxicity, including inflammatory and proliferative signaling. While proliferative signaling was up-regulated at both time points, some inflammatory signaling reversed from down-regulation at 1 week to up-regulation at 4 weeks. Conclusions: These results support a mode of action for Ni3S2 carcinogenicity driven by chronic toxicity, inflammation and proliferation, leading to mis-replication, rather than by direct genotoxicity. Benchmark dose (BMD) analysis identified the lowest pathway transcriptional BMD exposure concentration as 0.026 mg Ni/m3, for apoptosis/survival signaling. When conducted on the basis of lung Ni concentration the lowest pathway BMD was 0.64 M-BM-5g Ni/g lung, for immune/inflammatory signaling. Implications: These highly conservative BMDs could be used to derive a point of departure in a nonlinear risk assessment for Ni3S2 toxicity and carcinogenicity. Gene expression changes were determined in micro-dissected lung broncho-alveolar cells from Fischer F344 rats following inhalation of Ni3S2 at 0.0, 0.04, 0.08, 0.15, and 0.60 mg/m3 (0.03, 0.06, 0.11, and 0.44 mg Ni/m3) for one and four weeks (6 hours per day, 5 days per week).
2014-07-19 | E-GEOD-59593 | biostudies-arrayexpress
Project description:The primary goal of toxicology and safety testing is to identify agents that have the potential to cause adverse effects in humans. Unfortunately, many of these tests have not changed significantly in the past 30 years and most are inefficient, costly, and rely heavily on the use of animals. The rodent cancer bioassay is one of these safety tests and was originally established as a screen to identify potential carcinogens that would be further analyzed in human epidemiological studies. Today, the rodent cancer bioassay has evolved into the primary means to determine the carcinogenic potential of a chemical and generate quantitative information on dose-response behavior in chemical risk assessments. Due to the resource-intensive nature of these studies, each bioassay costs $2 to $4 million and takes over three years to complete. Over the past 30 years, only 1,468 chemicals have been tested in a rodent cancer bioassay. By comparison, approximately 9,000 chemicals are used by industry in quantities greater than 10,000 lbs and nearly 90,000 chemicals have been inventoried by the U.S. Environmental Protection Agency as part of the Toxic Substances Control Act. Given the disparity between the number of chemicals tested in a rodent cancer bioassay and the number of chemicals used by industry, a more efficient and economical system of identifying chemical carcinogens needs to be developed. Keywords: toxicology, chemical carcinogenesis, lung
2007-02-14 | GSE6116 | GEO
Project description:A large number of drugs and compounds produced by the chemical and agrochemical industry score as non-genotoxic carcinogens (NGC) in rodent models. It is unclear whether these compounds are also carcinogens for humans. The most extensively investigated compounds have been the anti-convulsive drugs, phenobarbital (PB) and phenytoin. Liver tumours induced by PB are dependent upon the activation of the constitutive androstane receptor (CAR). However, marked species differences in CAR activation by exogenous chemicals exist with some being much more potent activators of human CAR e.g. 6-(4-chlorophenyl)imidazo[2,1-b][1,3]thiazole-5-carbaldehyde-O-(3,4-dichlorobenzyl)oxime (CITCO). We have compared CITCO-induced tumour formation in the livers of mice in which human CAR has been replaced its murine counterpart. Our findings reveal that CITCO-dependent liver tumours are only formed in mice expressing human CAR and not in wild-type animals. In addition, contrary to one of the proposed mechanisms of NGC carcinogenicity, we show that CITCO did not induce a hyperplastic response in the liver of the humanised mice. These data raise some key questions about the mechanism of action of NGCs and identifies limitations of current rodent carcinogenicity test systems in relation to risk assessment
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