Chapter Six - Bulky DNA Adducts, Tobacco Smoking, Genetic Susceptibility, and Lung Cancer Risk

https://doi.org/10.1016/bs.acc.2017.01.006Get rights and content

Abstract

The generation of bulky DNA adducts consists of conjugates formed between large reactive electrophiles and DNA-binding sites. The term “bulky DNA adducts” comes from early experiments that employed a 32P-DNA postlabeling approach. This technique has long been used to elucidate the association between adducts and carcinogen exposure in tobacco smoke studies and assess the predictive value of adducts in cancer risk. Molecular data showed increased DNA adducts in respiratory tracts of smokers vs nonsmokers. Experimental studies and meta-analysis demonstrated that the relationship between adducts and carcinogens was linear at low doses, but reached steady state at high exposure, possibly due to metabolic and DNA repair pathway saturation and increased apoptosis. Polymorphisms of metabolic and DNA repair genes can increase the effects of environmental factors and confer greater likelihood of adduct formation. Nevertheless, the central question remains as to whether bulky adducts cause human cancer. If so, lowering them would reduce cancer incidence. Pooled and meta-analysis has shown that smokers with increased adducts have increased risk of lung cancer. Adduct excess in smokers, especially in prospective longitudinal studies, supports their use as biomarkers predictive of lung cancer.

Introduction

The generation of bulky DNA adducts consists of conjugates formed between large reactive electrophiles and DNA-binding sites [1], [2]. The term “bulky DNA adducts” comes from early experiments that employed a 32P-DNA postlabeling approach for damage analysis and refers to all the relatively large aromatic and nonpolar carcinogen DNA adducts, such as those induced from polycyclic aromatic hydrocarbons (PAH) and aromatic amines [3], [4], [5], [6]. These are well-known carcinogens present in cigarette smoke and motor vehicle exhaust and fumes from industrial processes and residential heating [7], [8], [9].

Interest in the analysis of the bulky DNA adducts is derived from early experimental animal models that demonstrated that DNA damage is necessary but insufficient for cancer development [2], [10], [11]. At the beginning of the 21st century, most evidence supported the notion that exposure to environmental carcinogens [3], [5], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], including cigarette smoke [1], [3], [5], [29], [30], [31], [32], [33], [34], [35], resulted in alterations to the structural integrity of DNA, i.e., bulky DNA adducts and oxidative DNA damage [1], [12], [19], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46]. Unless repaired, DNA lesions may lead to mutations in oncogenes and tumor suppressor genes [42], [47], thereby initiating carcinogenesis [48]. As such, bulky DNA adducts are widely considered as biomarkers that reflect carcinogen exposure [1], [15], [30], [37], [49], [50], [51], [52], [53] and cancer risk [1], [29], [33], [50], [54], [55], [56], [57], [58], [59], [60].

This chapter focuses on measurement of bulky DNA adducts by 32P-postlabeling, an assay long used to assess the association between genetic damage and carcinogen exposure and the predictive value of adducts for cancer risk (Fig. 1). Included is a description of the cigarette smoke constituents responsible for the bulky DNA adduct generation. Underlying mechanisms by which tobacco smoke carcinogens are metabolically activated to reactive electrophiles capable of interacting with DNA are also discussed. The chapter subsequently focuses on the history of chemical carcinogenesis and the description of 32P-postlabeling studies as well as the influence of inherited and acquired susceptibilities, especially dietary habits and DNA polymorphisms. Finally, the dose–response relationship with lung cancer, including by pooled and meta-analysis, are reviewed.

Section snippets

DNA Adduct Detection

Over time, methods to assess DNA damage have been developed for experimental animal and human studies [1], [3], [20], [61], [62], [63], [64]. Historically, administration of labeled chemicals was the method of choice whereas the study of DNA adducts was extremely rare. Chronic carcinogen exposure was difficult to model due to the high cost of synthetic radiolabeled (3H and 14C) compounds and the complexity of procedures used to assess DNA damage. In 1981, Randerath et al.[65] developed the 32

Epidemiology

In the past century, lung cancer was extremely rare and represented < 1% of all cancer cases [82], [83]. In the late 19th century, widespread cigarette use resulted in a tremendous increase in lung cancer incidence in Western countries [84]. A 1950 study of British physicians by Doll and Hill [85] provided the first evidence linking smoking and lung cancer. Smokers died about 10 years earlier than nonsmokers. The role of tobacco smoking in cancer etiology has accumulated [84], [86] including

Chemical Carcinogenesis

In 1947, the process of carcinogenesis was studied by Berenblum and Shubik in experimental animals [94]. PAH were sequentially and topically applied to rodents, followed by repeated treatment with croton oil, causing an irreversible transformation of normal cells into tumor. These authors conclusively demonstrated increased cancer frequency in treated vs untreated animals. In 1947, Miller and Miller [95] showed for the first time the binding of chemical carcinogens in rodent liver nuclear

DNA Adducts by 32P-Postlabeling

In 1986, Randerath et al.[106], demonstrated the production of bulky DNA adducts in various tissues of smokers by 32P-postlabeling. The occurrence of genotoxic events with smoking habits prompted the investigation of bulky DNA adducts in the respiratory tract of smokers [1], i.e., the main site of cigarette smoking-related cancer [8], [9]. A large number of studies (n = 25) has been performed thus far (Table 1) [31], [33], [55], [77], [80], [81], [107], [108], [109], [110], [111], [112], [113],

DNA Adduct Variability

High variability in bulky DNA adducts was found among persons exposed to similar amounts of carcinogens. Variation was associated with various parameters including gender, age, genetic susceptibilities, and dietary habit [21], [22], [32], [52], [116], [120], [137], [138], [139], [140], [141], [142], [143], [144], [145]. An earlier age of onset of smoking was reported to influence the increase and the persistence of adducts in exsmokers [117]. Polymorphisms in the 15q25 locus was linked with the

Dose–Response Relationships

Dose–response is a concept fundamental to our understanding of chemical carcinogenesis. Paracelsus, a great medieval toxicologist, told that it “is the dose that makes the poison” establishing that all the chemicals have toxic properties.

Until the development of highly sensitive methods, such as 32P-postlabeling in 1981 [65], chronic carcinogen exposure in experimental model studies has been difficult to perform due to the high cost of radiolabeled chemicals. Despite this, a number of long-term

Bulky DNA Adducts and Lung Cancer

With the exception of Cheng et al.[121], several 32P-postlabeling investigations have reported that bulky DNA adducts in peripheral blood predicted lung cancer risk. Among these were four case-controlled studies [127], [204], [205], [206] and four that employed a prospective approach [57], [203], [207], [208]. Although three (of the former) showed increased risk of lung cancer in subjects with high adduct levels, others found no association.

Using the prospective approach, a nested

Conclusion

Bulky adducts are increased in the respiratory tract of smokers with the generation of DNA damage influenced by inherited and acquired susceptibilities including vitamin intake.

Multiple genetic polymorphism may increase the effects of environmental factors and confer a greater likelihood of increased adducts. Dose–response of adducts and carcinogens, including tobacco smoke constituents, tended to be linear at low exposure, but reached a steady state at high exposure levels possibly due to

Acknowledgments

This work has received financial support from the “Istituto Toscano Tumori,” Florence, Italy; the Tuscany Region, Italy; the “Ente Cassa di Risparmio di Firenze,” Florence, Italy; the “Associazione Italiana per la Ricerca sul Cancro;” and the NIEHS Grant P42ES017198, USA.

References (211)

  • P.B. Farmer

    DNA adducts: mass spectrometry methods and future prospects

    Toxicol. Appl. Pharmacol.

    (2005)
  • H. Koc et al.

    Applications of mass spectrometry for quantitation of DNA adducts

    J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.

    (2002)
  • R.W. Giese

    Measuring DNA adducts by gas chromatography-electron capture-mass spectrometry: trace organic analysis

    Methods Enzymol.

    (1996)
  • A. Andreassen

    Comparative synchronous fluorescence spectrophotometry and 32P-postlabeling analysis of PAH-DNA adducts in human lung and the relationship to TP53 mutations

    Mutat. Res.

    (1996)
  • S.J. Culp

    Immunochemical, 32P-postlabeling, and GC/MS detection of 4-aminobiphenyl-DNA adducts in human peripheral lung in relation to metabolic activation pathways involving pulmonary N-oxidation, conjugation, and peroxidation

    Mutat. Res.

    (1997)
  • T. Soussi

    TP53 mutations in human cancer: database reassessment and prospects for the next decade

    Adv. Cancer Res.

    (2011)
  • D.H. Phillips et al.

    DNA and protein adducts in human tissues resulting from exposure to tobacco smoke

    Int. J. Cancer

    (2013)
  • E.C. Miller et al.

    Searches for ultimate chemical carcinogens and their reactions with cellular macromolecules

    Cancer

    (1981)
  • M.C. Poirier

    DNA adducts as exposure biomarkers and indicators of cancer risk

    Environ. Health Perspect.

    (1997)
  • M.C. Poirier et al.

    DNA adduct measurements and tumor incidence during chronic carcinogen exposure in animal models: implications for DNA adduct-based human cancer risk assessment

    Chem. Res. Toxicol.

    (1992)
  • M.C. Poirier et al.

    Human DNA adduct measurements: state of the art

    Environ. Health Perspect.

    (1996)
  • IARC

    Polynuclear aromatic compounds, Part 1. Chemical, environmental and experimental data

    IARC Monogr. Eval. Carcinog. Risk Chem. Hum.

    (1983)
  • IARC

    Tobacco smoke and involuntary smoking

    IARC Monogr. Eval. Carcinog. Risks Hum.

    (2004)
  • IARC

    Tobacco smoking

    IARC Monogr. Eval. Carcinog. Risk Chem. Hum.

    (1986)
  • C.C. Harris

    Chemical and physical carcinogenesis: advances and perspectives for the 1990s

    Cancer Res.

    (1991)
  • F. Merlo

    Genotoxic damage in subjects exposed to automobile exhaust: preliminary results

    Epidemiol. Prev.

    (1995)
  • F. Merlo

    Airborne levels of polycyclic aromatic hydrocarbons: 32P-postlabeling DNA adducts and micronuclei in white blood cells from traffic police workers and urban residents

    J. Environ. Pathol. Toxicol. Oncol.

    (1997)
  • M. Peluso

    (32)P-postlabeling detection of DNA adducts in peripheral white blood cells of greenhouse floriculturists from western Liguria, Italy

    Cancer Epidemiol. Biomarkers Prev.

    (1996)
  • M. Peluso

    32P Postlabelling analysis of urinary mutagens from smokers of black tobacco implicates 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) as a major DNA-damaging agent

    Carcinogenesis

    (1991)
  • M. Peluso

    32P-postlabelling analysis of DNA adducted with urinary mutagens from smokers of black tobacco

    Carcinogenesis

    (1990)
  • M. Peluso

    Analysis of 13 (32)P-DNA postlabeling studies on occupational cohorts exposed to air pollution

    Am. J. Epidemiol.

    (2001)
  • M. Peluso

    Malondialdehyde-deoxyguanosine and bulky DNA adducts in schoolchildren resident in the proximity of the Sarroch industrial estate on Sardinia Island, Italy

    Mutagenesis

    (2013)
  • S. Balbo et al.

    DNA adductomics

    Chem. Res. Toxicol.

    (2014)
  • F.P. Perera

    Molecular cancer epidemiology: a new tool in cancer prevention

    J. Natl. Cancer Inst.

    (1987)
  • F.P. Perera

    Molecular epidemiology: on the path to prevention?

    J. Natl. Cancer Inst.

    (2000)
  • F.P. Perera

    Carcinogen-DNA adducts and gene mutation in foundry workers with low-level exposure to polycyclic aromatic hydrocarbons

    Carcinogenesis

    (1994)
  • F.P. Perera

    A pilot project in molecular cancer epidemiology: determination of benzo[a]pyrene–DNA adducts in animal and human tissues by immunoassays

    Carcinogenesis

    (1982)
  • P.A. Schulte

    Molecular epidemiology: linking molecular scale insights to population impacts

    IARC Sci. Publ.

    (2011)
  • M.T. Smith

    Future perspectives on molecular epidemiology

    IARC Sci. Publ.

    (2011)
  • M. Peluso

    Comparison of DNA adduct levels in nasal mucosa, lymphocytes and bronchial mucosa of cigarette smokers and interaction with metabolic gene polymorphisms

    Carcinogenesis

    (2004)
  • M. Peluso

    Bulky DNA adducts, 4-aminobiphenyl-haemoglobin adducts and diet in the European Prospective Investigation into Cancer and Nutrition (EPIC) prospective study

    Br. J. Nutr.

    (2008)
  • M. Peluso

    Detection of DNA adducts in human nasal mucosa tissue by 32P-postlabeling analysis

    Carcinogenesis

    (1997)
  • M. Peluso

    White blood cell DNA adducts, smoking, and NAT2 and GSTM1 genotypes in bladder cancer: a case-control study

    Cancer Epidemiol. Biomarkers Prev.

    (1998)
  • A. Izzotti

    Duration of exposure to environmental carcinogens affects DNA-adduct level in human lymphocytes

    Biomarkers

    (2010)
  • M. Peluso

    Aromatic DNA adducts and number of lung cancer risk alleles in Map-Ta-Phut Industrial Estate workers and nearby residents

    Mutagenesis

    (2013)
  • M. Peluso

    Malondialdehyde-deoxyguanosine adducts among workers of a Thai industrial estate and nearby residents

    Environ. Health Perspect.

    (2010)
  • M.E. Peluso

    Oxidatively damaged DNA in the nasal epithelium of workers occupationally exposed to silica dust in Tuscany region, Italy

    Mutagenesis

    (2015)
  • M.E. Peluso

    Aberrant methylation of hypermethylated-in-cancer-1 and exocyclic DNA adducts in tobacco smokers

    Toxicol. Sci.

    (2014)
  • M.E.M. Peluso

    Exocyclic DNA adducts in sheep with skeletal fluorosis resident in the proximity of the Portoscuso-Portovesme industrial estate on Sardinia Island, Italy

    Toxicol. Res.

    (2015)
  • B. Brancato

    8-Oxo-7,8-dihydro-2′-deoxyguanosine and other lesions along the coding strand of the exon 5 of the tumour suppressor gene P53 in a breast cancer case-control study

    DNA Res.

    (2016)
  • Cited by (0)

    View full text