Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Keywords: CANCER ; tumor ; AGENTS ; Germany ; LUNG ; RISK ; GENE ; TISSUE ; TUMORS ; RISK-FACTORS ; CARCINOGENESIS ; CONTRAST ; CELL-LINES ; fibroblasts ; SEQUENCE ; SEQUENCES ; PATTERNS ; ASSAY ; MUTATION ; risk factors ; p53 ; DATABASE ; MUTATIONS ; DNA-DAMAGE ; mutagenesis ; AGENT ; targeting ; FEATURES ; RE ; gene targeting ; HUMAN LUNG ; ADDUCT ; CODON ; p53 mutation ; BENZO〈A〉PYRENE ; DIOL EPOXIDE
    Abstract: Human p53 mutation spectra differ significantly from one cancer type to another. One possible reason is that carcinogenic risk factors differ, and these factors elicit distinct mutation patterns. There has been no mammalian assay, however, with which to generate mutation patterns in human p53 sequences experimentally, hampering interpretation of the human tumor spectra. We have designed a new mammalian cell assay using gene targeting technology that selects and scores human p53 gene sequence mutations in human-p53 knock-in (Hupki) murine embryonic fibroblasts (HUF) that have undergone immortalization. With the Hupki assay we examined here whether benzo(a)pyrene (BaP), a major tobacco smoke carcinogen could elicit p53 mutation patterns characterizing the human lung tumor p53 mutation spectrum. We found that, in contrast to unexposed HUFs or HUFs exposed to other carcinogenic agents, HUFs exposed to BaP acquire mutations that display major features of the human lung tumor p53 mutation spectrum: (a) predominance of G-to-T mutations, (h) unequivocal strand bias of the transversions, and (c) a mutation hotspot at codons 157 to 158. These data are consistent with the hypothesis that BaP has a direct role in causing smokers' lung tumor p53 mutations. The assay can be used to examine various hypotheses on the endogenous or exogenous factors responsible for the p53 mutations in human tumors arising in other tissues
    Type of Publication: Journal article published
    PubMed ID: 15805253
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    Keywords: tumor ; carcinoma ; DIAGNOSIS ; QUANTIFICATION ; EXPOSURE ; HEPATOCELLULAR-CARCINOMA ; liver ; RISK ; SITE ; GENE ; TUMORS ; PATIENT ; DNA ; INFECTION ; hepatocellular carcinoma ; PLASMA ; AGE ; MUTATION ; PROSTATE-CANCER ; ELECTROSPRAY ; mass spectrometry ; REGION ; MASS-SPECTROMETRY ; REGIONS ; RECRUITMENT ; INDIVIDUALS ; SELECTION ; QUANTITATIVE-ANALYSIS ; PREVALENCE ; MASSES ; STANDARD ; SUBSET ; P53 GENE ; targeted ; LEVEL ; AFLATOXIN EXPOSURE ; INTERVAL ; CODON ; analysis ; HEPATITIS-B ; GENDER ; MASS ; PARTICIPANTS ; AFLATOXIN B-1 ; CELL-FREE DNA ; CODON-249 MUTATIONS ; GAMBIA ; HEPATOCELLULAR-CARCINOMA PATIENTS ; WEST-AFRICA ; hepatitis B
    Abstract: A mutation in codon 249 of the TP53 gene (249(Ser)), related to aflatoxin B(1) exposure, has previously been associated with hepatocellular carcinoma risk. Using a novel internal standard plasmid, plasma concentrations of 249(Ser)-mutated DNA were quantified by electrospray ionization mass spectrometry in 89 hepatocellular carcinoma cases, 42 cirrhotic patients, and 131 nonliver diseased control subjects, all from highly aflatoxin-exposed regions of The Gambia. The hepatocellular carcinoma cases had higher median plasma concentrations of 249(Ser) (2,800 copies/mL; interquartile range: 500-11,000) compared with either cirrhotic (500 copies/mL; interquartile range: 500-2,600) or control subjects (500 copies/mL; interquartile range: 500-2,000; P 〈 0.05). About half (52%) of the hepatocellular carcinoma cases had 〉2,500 copies of 249(Ser)/mL plasma, corresponding to the prevalence of this mutation in liver tumors in The Gambia. In comparison, only 15% of control group and 26% of cirrhotic participants exceeded this level (P 〈 0.05). Further subset analysis revealed a statistically significant, quantitative relation between diagnosis of hepatocellular carcinoma and levels of 249(Ser) detected at 2,501 to 10,000 copies/mL plasma (odds ratio, 3.8; 95% confidence interval, 1.3-10.9) and at 〉10,000 copies/mL plasma (odds ratio, 62; 95% confidence interval, 4.7-820) when compared with control subjects and after adjusting for age, gender, recruitment site, hepatitis B and C serologic status, and total DNA concentration. Levels of 〉10,000 copies of 249(Ser)/mL plasma were also significantly associated with the diagnosis of hepatocellular carcinoma (odds ratio, 15; 95% confidence interval, 1.6-140) when compared with cirrhotic patients. Potential applications for the quantification of 249(Ser) DNA in plasma include estimation of long-term, cumulative aflatoxin exposure and selection of appropriate high-risk individuals for targeted intervention.
    Type of Publication: Journal article published
    PubMed ID: 16365016
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    Keywords: ACAD, analysis, animal, animals, CELL, CELLS, CENTRAL-NERVOUS-SYSTEM, DISTINCT, EXPRESSION, fibrobla
    Abstract: Current methods to analyze gene expression measure steady-state levels of mRNA. To specifically analyze mRNA transcription, we have developed a technique that can be applied in vivo in intact cells and animals. Our method makes use of the cellular pyrimidine salvage pathway and is based on affinity-chromatographic isolation of thiolated mRNA. When combined with data on mRNA steady-state levels, this method is able to assess the relative contributions of mRNA synthesis and degradation/stabilization. It overcomes limitations associated with currently available methods such as mechanistic intervention that disrupts cellular physiology, or the inability to apply the techniques in vivo. Our method was first tested in serum response of cultured fibroblast cells and then applied to the study of renal ischemia reperfusion injury, demonstrating its applicability for whole organs in vivo. Combined with data on mRNA steady-state levels, this method provided a detailed analysis of regulatory mechanisms of mRNA expression and the relative contributions of RNA synthesis and turnover within distinct pathways, and identification of genes expressed at low abundance at the transcriptional level
    Type of Publication: Journal article published
    PubMed ID: 17405863
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    Keywords: SPECTRA ; CANCER ; CELLS ; CELL ; IN-VIVO ; LUNG ; LUNG-CANCER ; EXPOSURE ; RISK ; GENE ; DNA ; DOMAIN ; DIESEL EXHAUST ; DNA ADDUCT FORMATION ; ENVIRONMENTAL CONTAMINANT 3-NITROBENZANTHRONE ; BINDING ; CELL-LINES ; fibroblasts ; MOUSE ; ASSAY ; MUTATION ; genetics ; p53 ; HUMAN ACETYLTRANSFERASES ; MUTATIONS ; KNOCK-IN MICE ; mutagenesis ; cell lines ; P53 MUTATIONS ; aristolochic acid ; HUMAN CANCER ; intratracheal instillation ; P-32-POSTLABELING ANALYSIS ; CULTURES ; MUTAGENIC SPECIFICITY
    Abstract: 3-Nitrobenzanthrone (3-NBA) is a potent mutagen and a suspected human carcinogen present in particulate matter of diesel exhaust and ambient air pollution. Employing an assay with human p53 knock-in (Hupki) murine embryonic fibroblasts (HUFs), we examined p53 mutations induced by 3-NBA and its active metabolite, N-hydroxy-3-aminobenzanthrone (N-OH-3-ABA). Twenty-nine immortalized cultures (cell lines) from 89 HUF primary cultures exposed at passage 1 for 5 days to 2 mu M 3-NBA harboured 22 different mutations in the human DNA-binding domain sequence of the Hupki p53 tumour suppressor gene. The most frequently observed mutation was GC to TA transversion (46%), corroborating previous mutation studies with 3-NBA, and consistent with the presence of persistent 3-NBA-guanosine adducts found in DNA of exposed rodents. Six of the transversions found solely in 3-NBA-treated HUFs have not been detected thus far in untreated HUFs, but have been found repeatedly in human lung tumours. P-32-post-labelling adduct analysis of DNA from HUF cells treated with 2 mu M 3-NBA for 5 days showed a pattern similar to that found in vivo, indicating the metabolic competence of HUF cells to metabolize 3-NBA to electrophilic intermediates. Total DNA binding was 160 +/- 56 per 10(7) normal nucleotides with N-2-guanosine being the major adduct. In contrast, identical treatment with N-OH-3-ABA resulted in a 100-fold lower level of specific DNA adducts and no carcinogen-specific mutation pattern in the Hupki assay. This indicates that the level of DNA adduct formation by the mutagen is critical to obtain specific mutation spectra in the assay. Our results are consistent with previous experiments in Muta Mouse and are compatible with the possibility that diesel exhaust exposure contributes to mutation load in humans and to lung cancer risk
    Type of Publication: Journal article published
    PubMed ID: 18765419
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0027-5107
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...