351
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Gerde P. Animal models and their limitations: On the problem of high-to-low dose extrapolations following inhalation exposures. ACTA ACUST UNITED AC 2005; 57 Suppl 1:143-6. [PMID: 16092721 DOI: 10.1016/j.etp.2005.05.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Inhalation of complex mixtures such as combustion aerosols constitutes a parallel and simultaneous exposure of two distinctively different barriers to the body; the alveolar type I cells and the rest of the airway air/blood barrier, mainly the epithelium of the conducting airways. Exposure of the type I epithelium to most solutes leads to a rapid passage into the systemic circulation, and activation/deactivation of toxicants will take place mostly in the liver. Because of the huge metabolizing capacity of the liver, the dose-response of this component of an inhalation exposure is likely to be close to linear over larger exposure intervals. In contrast, exposures of the epithelium in the conducting airways lead to a slower passage, and in the case of semi-volatile solutes of high lipophilicities, a much slower passage into the systemic circulation. The result is a highly elevated concentration in the epithelium of the conducting airways during absorption, which may either lead directly to a localized toxicity, or, provide substrate for activating enzymes present in the airway mucosa. However, because of a limited capacity of the airway epithelium in this region both to dissolve sparingly soluble inhalants and to metabolize such solutes, the local dose response is likely to saturate at rather low exposure levels. One important consequence of local saturation in the epithelium of the conducting airways, is that inhalation exposures of laboratory animals conducted at elevated concentrations and limited time spans, may underestimate the risk in humans chronically exposed at relatively low concentrations. The phenomenon could be relevant in the etiology of lung cancer as well as inflammatory airway disease, where semi-volatile organic toxicants are suspected to contribute significantly.
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Affiliation(s)
- Per Gerde
- The National Institute of Environmental Health, Division of Physiology, Karolinska Institutet, Stockholm, Sweden.
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352
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Trombino S, Neri M, Puntoni R, Angelini C, Loprevite M, Cesario A, Granone P, Imperatori A, Dominioni L, Ardizzoni A, Filiberti R, Russo P. Mutations in K-ras Codon 12 Detected in Plasma DNA Are Not an Indicator of Disease in Patients with Non-Small Cell Lung Cancer. Clin Chem 2005; 51:1313-4. [PMID: 15976131 DOI: 10.1373/clinchem.2004.043976] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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353
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Bolognesi C, Martini F, Tognon M, Filiberti R, Neri M, Perrone E, Landini E, Canessa PA, Ivaldi GP, Betta P, Mutti L, Puntoni R. A Molecular Epidemiology Case Control Study on Pleural Malignant Mesothelioma. Cancer Epidemiol Biomarkers Prev 2005; 14:1741-6. [PMID: 16030111 DOI: 10.1158/1055-9965.epi-04-0903] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Pleural malignant mesothelioma is an uncommon neoplasm usually associated with asbestos exposure. The increasing incidence of malignant mesothelioma cases involving individuals with low levels of asbestos exposure suggests a complex carcinogenetic process with the involvement of other cofactors. Cytogenetic studies revealed the complexity of the genetic changes involved in this neoplasm reflecting the accumulation of genomic damage. One of the most used methodologies for assessing genomic damage is the cytokinesis-blocked micronucleus test applied in peripheral blood lymphocytes (PBL). This approach allows the detection of chromosomal alterations expressed in binucleated cells after nuclear division in vitro. This marker could provide a tool for assessing genetically determined constitutional differences in chromosomal instability. A biomonitoring study was carried out to evaluate the micronuclei frequency in PBLs of patients with pleural malignant mesothelioma with respect to lung cancer, healthy, and risk controls as a marker of cancer susceptibility in correlation with the presence of SV40. A significant increased micronuclei frequency was observed in patients with malignant mesothelioma in comparison with all the other groups, the mean micronuclei frequency was double in patients with malignant mesothelioma compared with healthy controls, risk controls, and patients with lung adenocarcinoma (median 11.4 binucleated cells with micronuclei/1,000 binucleated cells versus 6.2, 6.1, and 5.1, respectively). Our data indicate that human T lymphocyte samples carry DNA sequences coding for SV40 large T antigen at low prevalence, both in cancer cases and controls. Evidence of cytogenetic damage revealed as micronuclei frequency in mesothelioma cancer patients could be related to exogenous and endogenous cofactors besides asbestos exposure.
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Affiliation(s)
- Claudia Bolognesi
- Environmental Carcinogenesis Unit, National Cancer Research Institute, L. go Rosanna Benzsi, 10 Genoa, Italy 16132.
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354
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Meiring JJ, Borm PJA, Bagate K, Semmler M, Seitz J, Takenaka S, Kreyling WG. The influence of hydrogen peroxide and histamine on lung permeability and translocation of iridium nanoparticles in the isolated perfused rat lung. Part Fibre Toxicol 2005; 2:3. [PMID: 15982423 PMCID: PMC1180470 DOI: 10.1186/1743-8977-2-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Accepted: 06/27/2005] [Indexed: 11/25/2022] Open
Abstract
Background Translocation of ultrafine particles (UFP) into the blood that returns from the lungs to the heart has been forwarded as a mechanism for particle-induced cardiovascular effects. The objective of this study was to evaluate the role of the endothelial barrier in the translocation of inhaled UFP from the lung into circulation. Methods The isolated perfused rat lung (IPRL) was used under negative pressure ventilation, and radioactive iridium particles (18 nm, CMD, 192Ir-UFP) were inhaled during 60 minutes to achieve a lung burden of 100 – 200 μg. Particle inhalation was done under following treatments: i) control perfusion, ii) histamine (1 μM in perfusate, iii) luminal histamine instillation (1 mM), and iv) luminal instillation of H2O2. Particle translocation to the perfusate was assessed by the radioactivity of 192Ir isotope. Lung permeability by the use of Tc99m-labeled diethylene triamine pentaacetic acid (DTPA). In addition to light microscopic morphological evaluation of fixed lungs, alkaline phosphatase (AKP) and angiotensin converting enzyme (ACE) in perfusate were measured to assess epithelial and endothelial integrity. Results Particle distribution in the lung was homogenous and similar to in vivo conditions. No translocation of Ir particles at negative pressure inhalation was detected in control IPL, but lungs pretreated with histamine (1 μM) in the perfusate or with luminal H2O2 (0.5 mM) showed small amounts of radioactivity (2–3 % dose) in the single pass perfusate starting at 60 min of perfusion. Although the kinetics of particle translocation were different from permeability for 99mTc-DTPA, the pretreatments (H2O2, vascular histamine) caused similar changes in the translocation of particles and soluble mediator. Increased translocation through epithelium and endothelium with a lag time of one hour occurred in the absence of epithelial and endothelial damage. Conclusion Permeability of the lung barrier to UFP or nanoparticles is controlled both at the epithelial and endothelial level. Conditions that affect this barrier function such as inflammation may affect translocation of NP.
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Affiliation(s)
- James J Meiring
- Particle Research Core, Institute für Umweltmedizinische Forschung (IUF) an der Heinrich-Heine Universität gGmbH, Auf'm Hennekamp 50 D-40225 Düsseldorf, Germany
| | - Paul JA Borm
- Particle Research Core, Institute für Umweltmedizinische Forschung (IUF) an der Heinrich-Heine Universität gGmbH, Auf'm Hennekamp 50 D-40225 Düsseldorf, Germany
- Centre of Expertise in Life Sciences (CEL), Zuyd University, PO Box 550, 6400 AN HEERLEN, The Netherlands
| | - Karim Bagate
- Particle Research Core, Institute für Umweltmedizinische Forschung (IUF) an der Heinrich-Heine Universität gGmbH, Auf'm Hennekamp 50 D-40225 Düsseldorf, Germany
| | - Manuela Semmler
- GSF Forschungszentrum für Umwelt und Gesundheit, Ingolstädter Landstr. 1, Institute for Inhalation Biology & Focus Network Aerosols and Health, D-85746 Neuherberg / München, Germany
| | - Jürgen Seitz
- GSF Forschungszentrum für Umwelt und Gesundheit, Ingolstädter Landstr. 1, Institute for Inhalation Biology & Focus Network Aerosols and Health, D-85746 Neuherberg / München, Germany
| | - Shinji Takenaka
- GSF Forschungszentrum für Umwelt und Gesundheit, Ingolstädter Landstr. 1, Institute for Inhalation Biology & Focus Network Aerosols and Health, D-85746 Neuherberg / München, Germany
| | - Wolfgang G Kreyling
- GSF Forschungszentrum für Umwelt und Gesundheit, Ingolstädter Landstr. 1, Institute for Inhalation Biology & Focus Network Aerosols and Health, D-85746 Neuherberg / München, Germany
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355
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Arlt VM, Stiborova M, Henderson CJ, Osborne MR, Bieler CA, Frei E, Martinek V, Sopko B, Wolf CR, Schmeiser HH, Phillips DH. Environmental pollutant and potent mutagen 3-nitrobenzanthrone forms DNA adducts after reduction by NAD(P)H:quinone oxidoreductase and conjugation by acetyltransferases and sulfotransferases in human hepatic cytosols. Cancer Res 2005; 65:2644-52. [PMID: 15805261 DOI: 10.1158/0008-5472.can-04-3544] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
3-Nitrobenzanthrone (3-nitro-7H-benz[de]anthracen-7-one, 3-NBA) is a potent mutagen and suspected human carcinogen identified in diesel exhaust and air pollution. We compared the ability of human hepatic cytosolic samples to catalyze DNA adduct formation by 3-NBA. Using the (32)P-postlabeling method, we found that 12/12 hepatic cytosols activated 3-NBA to form multiple DNA adducts similar to those formed in vivo in rodents. By comparing 3-NBA-DNA adduct formation in the presence of cofactors of NAD(P)H:quinone oxidoreductase (NQO1) and xanthine oxidase, most of the reductive activation of 3-NBA in human hepatic cytosols was attributed to NQO1. Inhibition of adduct formation by dicoumarol, an NQO1 inhibitor, supported this finding and was confirmed with human recombinant NQO1. When cofactors of N,O-acetyltransferases (NAT) and sulfotransferases (SULT) were added to cytosolic samples, 3-NBA-DNA adduct formation increased 10- to 35-fold. Using human recombinant NQO1 and NATs or SULTs, we found that mainly NAT2, followed by SULT1A2, NAT1, and, to a lesser extent, SULT1A1 activate 3-NBA. We also evaluated the role of hepatic NADPH:cytochrome P450 oxidoreductase (POR) in the activation of 3-NBA in vivo by treating hepatic POR-null mice and wild-type littermates i.p. with 0.2 or 2 mg/kg body weight of 3-NBA. No difference in DNA binding was found in any tissue examined (liver, lung, kidney, bladder, and colon) between null and wild-type mice, indicating that 3-NBA is predominantly activated by cytosolic nitroreductases rather than microsomal POR. Collectively, these results show the role of human hepatic NQO1 to reduce 3-NBA to species being further activated by NATs and SULTs.
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Affiliation(s)
- Volker M Arlt
- Section of Molecular Carcinogenesis, Institute of Cancer Research, Sutton, Surrey, United Kingdom.
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356
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Jeyabal PVS, Syed MB, Venkataraman M, Sambandham JK, Sakthisekaran D. Apigenin inhibits oxidative stress-induced macromolecular damage inN-nitrosodiethylamine (NDEA)-induced hepatocellular carcinogenesis in Wistar albino rats. Mol Carcinog 2005; 44:11-20. [PMID: 15924350 DOI: 10.1002/mc.20115] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Apigenin (4',5,7-trihydroxyflavone), a flavone subclass of flavonoid widely distributed in many herbs, fruits, and vegetables is a substantial component of the human diet and has been shown to possess a variety of biological activities including tumor growth inhibition and chemoprevention. Recent studies in several biological systems have shown that apigenin induces tumor growth inhibition, cell cycle arrest, and apoptosis. Free radical-induced degradation of polyunsaturated fatty acid results in electrophilic products and causes severe oxidative stress. Oxidative stress induced by free radicals, nonoxidizing species, electrophiles, and associated DNA damages have been frequently coupled with carcinogenesis. In the present study, the protective role of apigenin was examined against the oxidative stress caused by N-nitrosodiethylamine (NDEA) and phenobarbital (PB) in Wistar albino rats. Oxidative stress was measured in terms of lipid peroxidation (LPO) and protein carbonyl formation. Oxidative stress-induced DNA damage was measured by single cell gel electrophoresis (comet assay). Apigenin exhibited its antioxidant defense against NDEA-induced oxidative stress. We have observed minimal levels of LPO and DNA damage in apigenin-treated hepatoma bearing animals. Based on the results, we suggest that apigenin may be developed as a promising chemotherapeutic agent against the development of chemical carcinogenesis.
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357
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Albrecht C, Borm PJA, Unfried K. Signal transduction pathways relevant for neoplastic effects of fibrous and non-fibrous particles. Mutat Res 2004; 553:23-35. [PMID: 15288530 DOI: 10.1016/j.mrfmmm.2004.06.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2004] [Accepted: 04/30/2004] [Indexed: 01/06/2023]
Abstract
Apart from their genotoxic effects, both fibrous and non-fibrous particles are known to induce signalling pathways involved in the development of malignant lung diseases. Different direct effects of particles as well as indirect cellular effects are believed to induce changes in apoptosis or proliferation in target cells. Signalling events, e.g. the induction of mitogen-activated protein kinase (MAPK) cascades resulting in the activation of the transcription factor AP-1, as well as the induction of the transcription factor NFkappaB which mainly mediates the expression of pro-inflammatory genes are discussed. There is some insight into the molecular mechanisms eliciting these pathways. Therefore, this review aims to give an overview on signalling pathways as well as initial events including effects of reactive oxygen and nitrogen species, membrane receptors and particle uptake.
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Affiliation(s)
- Catrin Albrecht
- Institut für umweltmedizinische Forschung, Particle Research, Auf'm Hennekamp 50, 40225 Düsseldorf, Germany
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358
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Borm PJA, Schins RPF, Albrecht C. Inhaled particles and lung cancer, part B: paradigms and risk assessment. Int J Cancer 2004; 110:3-14. [PMID: 15054863 DOI: 10.1002/ijc.20064] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Poorly soluble particles of low toxicity (PSP), such as CB, TiO(2) and coal mine dust, have been demonstrated to cause lung cancer in rodents, being most pronounced in rats. Adequate epidemiologic studies do not clearly indicate increased lung cancer rates in humans exposed to such particles. This has caused controversial positions in regulatory decisions on PSP on different levels. The present review discusses the current paradigms in rodent particle carcinogenicity, i.e., (i) role of particle overload and of persistent inflammation and (ii) fibrosis as an intermediate step in particle-induced lung cancer with regard to human risk assessment. Fibrosis, which is usually considered a precursor of lung cancer in humans, was not related to lung tumors in an animal study using 6 different particles, each at 3 dosages. Lung tumors after both inhalation and intratracheal instillation of PSP are related to particle surface dose, which forwards hazard assessment at surface-based nonoverload concentrations and a standard setting using surface as an exposure metric. The scarce data available on humans do not support the overload concept but suggest a role for persistent lung inflammation. Differences in antioxidant protection between different rodent species correlate with susceptibility to PSP-induced carcinogenicity and support the need for detailed studies on antioxidant response in humans. Apart from such bridging studies, further focus is also needed on surface chemistry and modifications in relation to their adverse biologic effects.
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Affiliation(s)
- Paul J A Borm
- Particle Research, Institut für Umweltmedizinische Forschung, Heinrich-Heine-University Düsseldorf, Auf'm Hennekamp 50, D-40225 Düsseldorf, Germany.
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