Expression Characteristics of Genes Hypermethylated and Downregulated in Rat Liver Specific to Non-genotoxic Hepatocarcinogens
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ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE123408 | GEO | 2019/05/09
REPOSITORIES: GEO
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Project description:This 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. Among 52 genes, Ldlrad4, Proc, Cdh17, and Nfia were confirmed to show promoter-region hypermethylation by methylation-specific quantitative PCR analysis on day 28. The transcript levels of these 4 genes decreased by real-time reverse transcription-PCR analysis in the livers of rats treated with nongenotoxic hepatocarcinogens for up to 90 days compared with untreated controls and genotoxic hepatocarcinogens. Immunohistochemically, LDLRAD4 and PROC showed decreased immunoreactivity, forming negative foci, in glutathione S-transferase placental form (GST-P)+ foci, and incidences of LDLRAD4- and PROC- foci in GST-P+ foci induced by treatment with nongenotoxic hepatocarcinogens for 84 or 90 days were increased compared with those with genotoxic hepatocarcinogens. In contrast, CDH17 and NFIA responded to hepatocarcinogens without any relation to the genotoxic potential of carcinogens. All 4 genes did not respond to renal carcinogens after treatment for 28 days. Considering that Ldlrad4 is a negative regulator of transforming growth factor-β signaling, Proc participating in p21WAF1/CIP1 upregulation by activation, Cdh17 inducing cell cycle arrest by gene knockdown, and Nfia playing a role in a tumor-suppressor, all these genes may be potential in vivo epigenetic markers of nongenotoxic hepatocarcinogens from the early stages of treatment in terms of gene expression changes. LDLRAD4 and PROC may have a role in the development of preneoplastic lesions produced by nongenotoxic hepatocarcinogens.
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Project description:Expression Characteristics of Genes Hypermethylated and Downregulated in Rat Liver Specific to Non-genotoxic Hepatocarcinogens
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Project description:The effect of Tlr4P712H mutation (rendering TLR4 non-functional), or gut-sterilization by antbiotics, on the induction of tumorgenesis by CCl4 and diethylnitrosamine (DEN) was characterized. Affymetrix Mouse 430 2.0 gene expression measurements were used to characterize the transcriptomic basis of the effects of the above treatments and genotypes on tumorgenesis. Gene expression of mouse livers of A. Normal liver from WT C3H/HeOuJ mice, B. HCC from WT C3H/HeOuJ mice treated with CCl4 and DEN, C.HCC from TLR4-mutant C3H/HeJ mice (Tlr4P712H) treated with CCl4 and DEN and D.HCC from WT C3H/HeOuJ mice treated with antibiotics (a combination of ampicillin (1 g/l), neomycin [1 g/l], metronidazole[1 g/l] and vancomycin [500 mg/l] in drinking water) and CCl4 and DEN were characterized.
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Project description:Liver fibrosis resulting from chronic liver damage constitutes a major health care bur-den worldwide; however, no antifibrogenic agents are currently available. Our previ-ous study reported that the small molecule NPLC0393 extracted from the herb Gyno-stemma pentaphyllum exerts efficient antifibrotic effects both in vivo and in vitro. In this study, a TMT-based quantitative proteomic study using a carbon tetrachloride (CCl4)-induced mouse model of liver fibrosis was performed to identify the potential target of NPLC0393. Combining this study with protein-protein interaction network analysis of differentially expressed proteins between the CCl4 model and NPLC0393 treatment groups, we focused on the function of NDRG2 involved in cell differentia-tion. In vitro studies showed that NPLC0393 prevented the TGF-β1 stimula-tion-induced decrease in the NDRG2 level in hepatic stellate cells (HSCs). Functional studies indicated that NDRG2 can inhibit the activation of HSCs by preventing the phosphorylation of ERK and JNK. Furthermore, knockdown of NDRG2 abolished the ability of NPLC0393 to inhibit HSC activation. In conclusion, these results pro-vide information on the mechanism underlying the antifibrotic effect of NPLC0393 and shed new light on the potential therapeutic function of the TGF-β1/NDRG2/MAPK signaling axis in liver fibrosis.
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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.
2007-06-22 | E-GEOD-8251 | biostudies-arrayexpress
Project description:IntroductionVarious challenges have been overcome with regard to applying 'omics technologies for chemical risk assessments. Previously we published results detailing targeted mRNA sequencing (RNA-Seq) on a next generation sequencer using intact RNA derived from freshly frozen rat liver tissues. We successfully discriminated genotoxic hepatocarcinogens (GTHCs) from non-genotoxic hepatocarcinogens (NGTHCs) using 11 selected marker genes. Based on this, we next attempted to use formalin-fixed paraffin-embedded (FFPE) pathology specimens for RNA-Seq analyses.FindingsIn this study we performed FFPE RNA-Seq to compare a typical GTHC, 2-acetylaminofluorene (AAF) to genotoxicity equivocal p-cresidine (CRE). CRE is used as a synthetic chemical intermediate, and this compound is classified as an IARC 2B carcinogen and is mutagenic in S. typhimurium, which is non-genotoxic to rat livers as assessed by single strand DNA damage analysis. RNA-Seq was used to examine liver FFPE samples obtained from groups of five 10-week-old male F344 rats that were fed with chemicals (AAF: 0.025% and CRE: 1% in food) for 4 weeks or from controls that were fed a basal diet. We extracted RNAs from FFPE samples and RNA-Seq was performed on a MiniSeq (Illumina) using the TruSeq custom RNA panel. AAF induced remarkable differences in the expression of eight genes (Aen, Bax, Btg2, Ccng1, Gdf15, Mbd1, Phlda3 and Tubb4b) from that in the control group, while CRE only induced expression changes in Gdf15, as shown using Tukey's test. Gene expression profiles for nine genes (Aen, Bax, Btg2, Ccng1, Cdkn1a, Gdf15, Mbd1, Phlda3, and Plk2) differed.between samples treated with AAF and CRE. Finally, principal component analysis (PCA) of 12 genes (Aen, Bax, Btg2, Ccnf, Ccng1, Cdkn1a, Gdf15, Lrp1, Mbd1, Phlda3, Plk2, and Tubb4b) using our previous Open TG-GATE data plus FFPE-AAF and FFPE-CRE successfully differentiated FFPE-AAF, as GTHC, from FFPE-CRE, as NGHTC.ConclusionOur results suggest that FFPE RNA-Seq and PCA are useful for evaluating typical rat GTHCs and NGTHCs.
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