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Carcinogenesis Advance Access originally published online on November 26, 2008
Carcinogenesis 2009 30(2):282-285; doi:10.1093/carcin/bgn264
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© The Author 2008. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org

Typical signature of DNA damage in white blood cells: a pilot study on etheno adducts in Danish mother–newborn child pairs

K. Arab1,2,*, M. Pedersen3, J. Nair2, M. Meerang2, L. E. Knudsen3 and H. Bartsch2

1 Division of Epigenomics
2 Division of Toxicology and Cancer Risk Factors (C010), German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
3 Department of Environmental Health, Institute of Public Health, University of Copenhagen, 1014 K Copenhagen, Denmark

* To whom correspondence should be addressed. Tel: +49 6221 423337; Fax: +49 6221 423359; Email: a.khelifa{at}dkfz.de


   Abstract
Top
 Abstract
Introduction
 Materials and methods
 Results
 Discussion
 Funding
 References
 
The impact of DNA damage commonly thought to be involved in chronic degenerative disease causation is particularly detrimental during fetal development. Within a multicenter study, we analyzed 77 white blood cell (WBC) samples from mother–newborn child pairs to see if imprinting of DNA damage in mother and newborn shows a similar pattern. Two adducts 1,N6-ethenodeoxyadenosine ({varepsilon}dA) and 3,N4-ethenodeoxycytidine ({varepsilon}dC) were measured by our ultrasensitive immunoaffinity 32P-post-labeling method. These miscoding etheno-DNA adducts are generated by the reaction of lipid peroxidation (LPO) end products such as 4-hydroxy-2-nonenal with DNA bases. Mean {varepsilon}dA and {varepsilon}dC levels when expressed per 109 parent nucleotides in WBC-DNA from cord blood were 138 and 354, respectively; in maternal WBC-DNA, the respective values were 317 and 916. Thus, the DNA-etheno adduct levels were reliably detectable and about two times lower in child cord blood, the difference being significant at P < 0.0004. Analysis of {varepsilon}dA and {varepsilon}dC levels in cord versus maternal blood WBC showed strong positive correlations (R2 {approx} 0.9, P < 0.00001). In conclusion, LPO-induced DNA damage arising from endogenous reactive aldehydes in WBC of both mother and newborn can be reliably assessed by {varepsilon}dA and {varepsilon}dC as biomarkers. The high correlation of etheno adduct levels in mother and child WBC suggests that a typical signature of DNA damage is induced similarly in fetus and mother. Prospective cohort studies have to reveal whether these two WBC-DNA adducts could serve as risk indicator for developing hematopoietic cancers and other disorders later in life.

Abbreviations: {varepsilon}dA, 1,N6-ethenodeoxyadenosine; {varepsilon}dC, 3,N4-ethenodeoxycytidine; LPO, lipid peroxidation; M1dG, 3-(2-deoxy-D-erythro-pentofuranosyl)pyrimido[1,2-]purin-10(3H)-one; WBC, white blood cell


   Introduction
Top
 Abstract
 Introduction
Materials and methods
 Results
 Discussion
 Funding
 References
 
Malignant childhood neoplasms account for ~2% of all cancers, but they are the second cause of death in children aged 5–14 in populations from developed parts of the world where overall mortality is low. Malignancies of the hematopoietic system are the largest subgroup of childhood cancers, accounting for 30–60% of all tumors. Among lymphatic malignancies, leukemias represent two-third of the diagnosed cases, whereby acute lymphoblastic leukemia is the largest group followed by acute myeloid leukemia and the rare chronic myeloid leukemia. Surprisingly, leukemias often occur under the age of five and the incidence decreases with age (1,2). Also, an increase of endocrinological and immunological disorders is observed, as documented by recent epidemiological surveys that reported a steeper increase of childhood disorders than it occurs in adults (3,4). The impact of DNA damage commonly thought to be involved in chronic degenerative disease causation is particularly detrimental during fetal development; it has been shown that the fetus may be 10 times more susceptible to DNA damage due to polycyclic aromatic hydrocarbon exposure in utero than the mother, resulting in a reduction of child weight and head circumference (5,6).

Using a cytotoxicity repair assay, isolated cord blood hematopoietic stem cells (CD34+) displayed higher sensitivity to an alkylating agent (ethylnitrosourea), as compared with more differentiated cells such as CD34–, CD33+ and CD199+ (7). Also the response to genotoxins during hematopoietic differentiation of bone marrow-derived progenitors cells varied with type and time of exposure, providing a new assay to monitor adverse effects of mutagens and carcinogens in early stages of fetal development (8). Thus, it seems important to evaluate the impact of the environmental and lifestyle factors in causing DNA damage during fetal development and to investigate whether this increases the risk of developing hematopoietic cancers and other chronic degenerative diseases later in life.

Etheno adducts are well validated biomarkers for DNA damage arising from reaction of endogenous lipid peroxidation (LPO) end products such as 4-hydroxy-2-nonenal with DNA bases, to yield inter alia 1,N6-ethenodeoxyadenosine ({varepsilon}dA) and 3,N4-ethenodeoxycytidine ({varepsilon}dC). Figure 1 illustrates a proposed scheme for LPO-derived DNA adducts in white blood cell (WBC)-DNA of mother–newborn pairs. Etheno-DNA adducts occur as background levels in asymptomatic human tissue in the order of one adduct per 108 parent nucleotides. However, in subjects affected by cancer-prone inflammatory conditions, metal storage diseases and a high {omega}-6 polyunsaturated fatty acids intake, adduct levels in DNA of diseased organs or WBC can be 1 to 4 orders of magnitude higher (9–11). Recently, we could also show that atherosclerotic plaques in the aorta of cardiovascular disease patients had also high levels of these adducts (12).


Figure 1
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  		Fig. 1. Proposed scheme for LPO-derived DNA adducts in WBC-DNA of mother–newborn child pairs. A number of environmental factors can cause oxidative stress that involves the release of reactive oxygen and nitrogen species, activation of LPO and production of reactive species such as 4-hydroxyl alkenal (4-HNE), malondialdehyde (MDA). On reaction with DNA bases, 4-HNE, the major LPO by-product forms inter alia the etheno adducts {varepsilon}dA and {varepsilon}dC for which ultrasensitive detection methods have been developed. Nitric oxide overproduction can induce LPO via peroxynitrite and etheno adducts have been detected in mouse models for inflammatory diseases (30,32,33). MDA can react with guanine residues to yield the propano-DNA adduct, M1dG. If not repaired, LPO-derived miscoding DNA adducts formed in WBC and in other organs can cause mutations, which may also disrupt genes involved in epigenomic regulation. As a result, adverse health effects, such as hematopoietic malignancies, may develop during childhood.

 
Etheno-DNA adducts are thought to initiate vinyl chloride- and urethane-induced tumors (13), by their induction of various types of point mutations (14–16). Conceivably, these point mutations could also modify the binding of specific proteins involved in epigenetic processes at the position of 5-methylcytosine such as DNA-methyltransferases and the methyl-CpG-binding protein (17). Because of their probable etiological role in human chronic degenerative diseases, we measured the levels of two etheno-DNA adducts in WBC-DNA from 77 mother and newborn child pairs provided to us by a Danish biobank. Our pilot study is a part of an ongoing multicenter research project entitled ‘Newborns and Genotoxic exposure risks’ ‘acronym NewGeneris’. The overall objectives are to investigate the role of prenatal and early-life exposure to genotoxic chemicals present in food and the environment in the development of childhood cancer and immune disorders by the use of biomarker measurements in WBC samples from European mother–child cohorts. The two specific aims of this pilot study are (i) to investigate whether LPO-induced DNA damage arising from endogenous reactive aldehydes in both mother and newborn child WBC can be reliably assessed by {varepsilon}dA and {varepsilon}dC measurements and (ii) whether an induction of DNA damage in WBC occurs similarly in mother and newborn child. Further studies have to reveal whether these two WBC-DNA adducts could serve as a risk indicator for developing chronic degenerative diseases such as hematopoietic cancers later in life. Herein, we present the results of our pilot study.


   Materials and methods
Top
 Abstract
 Introduction
 Materials and methods
Results
 Discussion
 Funding
 References
 
Materials
Methanol and acetonitrile were purchased from HAYMAN (Witham, Essex, UK) with a purity of 99.85%. Proteinase K and RNAse A and RNAse T1 were purchased from Roche (Mannheim, Germany) and T4-polynucleotide kinase was purchased from Fermentas (St Leon-Rot, Germany). Desferrioxamine, micrococcal nuclease and spleen phosphodiesterase were purchased from Sigma–Aldrich (Heidelberg, Germany). All other chemicals were of the highest purity grade available from commercial suppliers.

Study subjects and WBC sample collection
Written invitations to participate in a Danish biobank for studies on fetal versus adult’s susceptibility to environmental and dietary exposures were sent to ~200 pregnant women who had planned a ‘caesarian section’ at the Danish National Hospital located in the central area of Copenhagen city. Prior to participation, further information was exchanged about the conditions of participation by phone and during an information meeting at the hospital. The inclusion criteria comprised: (i) no health complications and no smoking; (ii) age >18 years; (iii) no private commercial banking of cord blood; (iv) signing of written informed consent; (v) capacity to understand the informed consent and (vi) willingness to complete the questionnaires in Danish.

The biomonitoring study was approved by the Ethical Committee of The Capital Region of Denmark (Reference No. J.Nr. H-KF-01-327603 Tillaeg) and The Danish Data Protection Agency (Reference No. J.Nr. 2007-41-0415).

Maternal blood (~50 ml) was collected 1–2 h before the planned cesarean section. Umbilical cord blood (~80 ml) was collected from the placenta immediately after delivery. The blood samples were collected in 10 ml Li/Na-heparin vacutainer tubes (Venoject®, Terumo Europe, Leuven, Belgium). Within 1–2 h, the buffy coats were separated by centrifugation (650g x 10 min at room temperature) and stored in Eppendorf tubes at –20°C.

DNA isolation and etheno adducts analysis
The isolation of genomic DNA from buffy coats was achieved using the blood and cell culture Midi kit (Qiagen, Hilden, Germany) according to the manufacturer’s protocol, except with the modification of the digestion buffer; hereby, 5 mM of desferrioxamine was added, the NaCl concentration in the elution buffer was 1.4 M, the pH was adjusted to 7.4 and then the buffer was heated at 50°C. {varepsilon}dA and {varepsilon}dC were analyzed in DNA by the immunoaffinity 32P-post-labeling method (18). In brief, ~20 µg of DNA was hydrolyzed to nucleotide 3'-monophosphates using micrococcal nuclease and spleen phosphodiesterase. Normal nucleotides were quantitated by high-performance liquid chromatography and the adducts were enriched on immunoaffinity columns prepared with the monoclonal antibodies EM-A-1 ({varepsilon}dA) and EM-C-1 ({varepsilon}dC) (Antibodies were provided by Dr Manfred Rajewsky, Institute of Cell Biology, University of Essen, Essen, Germany.)

Adducts and the internal standard deoxyuridine 3'-monophosphate were labeled with [{gamma}-32P]-adenosine triphosphate (>5000 Ci/mM) and T4-polynucleotide kinase. The etheno adducts were separated on polyethyleneimine–thin-layer chromatography plates using two-directional chromatography [D1 = 1 M acetic acid (pH 3.5), D2 = saturated ammonium sulfate (pH 3.5)]. After autoradiography, the radioactivity was measured in a liquid scintillation counter and results were expressed per amount of deoxycytidine or deoxyadenosine.

The absolute adduct levels were quantified using standards, and the relative adduct levels (expressed per 109 parent nucleotides) were calculated. Our method has a detection limit of five adducts per 1010 parent nucleotides that permits reliable adduct measurements in small amounts of WBC-DNA.

3-(2-Deoxy-D-erythro-pentofuranosyl)pyrimido[1,2-]purin-10(3H)-one (M1dG), a DNA adduct arising from the reaction of 2-deoxyguanosine with the LPO product, malondialdehyde, or from the DNA peroxidation product base propenal, was measured by our high-performance liquid chromatography method described earlier (19). M1dG levels are expressed per 107 2-deoxyguanosine.

Statistical analysis
Data analysis was done with StatView 5.0 program (SAS Institute, Cary, NC), Mann–Whitney U-test was used for the comparison between mother and child adduct levels. Spearman’s rank test was used for correlations between variables.


   Results
Top
 Abstract
 Introduction
 Materials and methods
 Results
Discussion
 Funding
 References
 
The Danish biobank has been collecting blood samples from birth cohorts and provided paired blood samples from healthy pregnant women and the child umbilical cord blood after cesarean section during December 2006 to December 2007. Analysis of the etheno adducts {varepsilon}dA and {varepsilon}dC in 77 paired WBC-DNA samples was done by our ultrasensitive and specific method, with a slight modification; for DNA extraction, 5 mM of desferrioxamine was added to the digestion buffer so as to avoid any artifactual reactive oxygen species formation resulting from redox reactions.

The correlation between {varepsilon}dA versus {varepsilon}dC levels in WBC-DNA was examined as they are assumed to be formed by the same pathway and initially in a 1:1 molar ratio (13). Our results showed strong positive associations (r = 0.65 for {varepsilon}dA and r = 0.66 for {varepsilon}dC) in both newborn and mother WBC-DNA. Figure 2 shows a dot plot of {varepsilon}dA and {varepsilon}dC levels in 77 newborn and maternal WBC-DNA samples revealing up to 500-fold interindividual variation. Mean etheno adduct levels (expressed per 109 parent nucleotides ± standard error) in newborn were 138 ± 439 for {varepsilon}dA and 354 ± 885 for {varepsilon}dC, respectively. In maternal WBC-DNA, the respective values were 317 ± 1017 ({varepsilon}dA) and 916 ± 3669 ({varepsilon}dC). The mean {varepsilon}dA and {varepsilon}dC levels in newborn WBC-DNA were 2.2 (P < 0.0003) and 2.6 (P < 0.004) times lower than those in the mother, respectively (Mann–Whitney U-test). In both newborn and maternal DNA, the level of {varepsilon}dC was twice as high as {varepsilon}dA. Etheno adduct levels in newborn versus mother DNA showed strongly positive correlations (Figures 3 and 4); the coefficients were R2 = 0.86 (P < 0.0001) for {varepsilon}dA and R2 = 0.78 (P < 0.0001) for {varepsilon}dC. Analysis of the correlation by non-parametric Spearman test yielded: r = 0.79 ({varepsilon}dA) and r = 0.67 ({varepsilon}dC).


Figure 2
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  		Fig. 2. Dot plot on a log scale of {varepsilon}dA and {varepsilon}dC levels in 77 WBC-DNA samples from mothers and newborn child pairs. Means ± SDs in newborn DNA were 138 ± 439 ({varepsilon}dA) and 354 ± 885 ({varepsilon}dC); in maternal DNA, the respective values were 317 ± 1017 ({varepsilon}dA) and 916 ± 3669 ({varepsilon}dC). The P-values (Mann–Whitney U-test, two tailed) for the difference of levels in maternal versus newborn WBC-DNA were P < 0.0003 for {varepsilon}dA and P < 0.004 for {varepsilon}dC.

 


Figure 3
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  		Fig. 3. Scatter diagram of {varepsilon}dA levels in 77 paired maternal and newborn WBC-DNA samples. A significant correlation was observed: R2 = 0.86 with P-value < 0.00001 (Spearman’s rank test, two tailed). Linear regression was calculated from the combined maternal and newborn WBC values.

 


Figure 4
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  		Fig. 4. Scatter diagram of {varepsilon}dC levels in 77 paired maternal and newborn WBC-DNA samples. A significant correlation was observed: R2 = 0.78 with P-value < 0.00001 (Spearman’s rank test, two tailed). Linear regression was calculated from all maternal and newborn WBC values combined.

 
Analysis of the same 77 WBC-DNA pairs for M1dG levels (expressed per 107 2-deoxyguanosine) by our high-performance liquid chromatography method described earlier (19) revealed no significant difference in means: 2.3 ± 2.2 in newborn versus 3.2 ± 4.0 in maternal WBC-DNA (data not shown). Correlation analysis with Spearman test for M1dG levels in newborn cord blood versus maternal WBC-DNA showed a weak interrelation of (r = 0.36, P = 0.03). Additionally, no correlation was found between etheno adduct and M1dG levels in mother and child WBC samples.


   Discussion
Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
Funding
 References
 
The observation of increased development of some etiologically ill-defined diseases during childhood, such as leukemia and immunological disorders, led to the hypothesis that maternal exposure during pregnancy to exogenous and endogenous genotoxins could predispose the fetus to higher disease risk later in life. We therefore investigated the impact of DNA-reactive LPO by-products such as 4-hydroxy-2-nonenal and their role in inducing DNA damage in WBC of mother–newborn child pairs. As markers, we used the etheno adducts {varepsilon}dA and {varepsilon}dC, for which we have developed highly sensitive and specific detection methods involving immunopurification and 32P-post-labeling thin-layer chromatography, which can detect a physiological background of etheno adducts occuring in normal cells (20). Previous studies have established that etheno adducts are stable, biologically relevant markers for oxidative stress-induced LPO [(21) and (M.Meerang, J.Nair, P.Sirankapracha, C.Thephinlap, S.Srichairatanakool, K.Arab, R.Kalpravidh, J.Vadolas, S.Fucharoen and H.Bartsch, submitted for publication)]. {varepsilon}dA and {varepsilon}dC were found elevated in many cancer-prone organs in patients and experimental animals when oxidative stress was induced by chronic inflammatory processes or metal storage diseases (9,22,23). In our study on 77 paired WBC-DNA samples, we found that {varepsilon}dA and {varepsilon}dC levels were 2.2–2.6 times lower in newborns, revealing a protective effect by the placenta, as postulated in previous environmental exposure studies (5,6,24,25). However, some other biomarker studies failed to detect any oxidative stress-related DNA damage in newborns, even when the mothers were smokers (26,27). The presence of {varepsilon}dA in placental DNA was reported although the mass spectrometric method lacked sensitivity (28). As found previously in other human tissues, also in our study, the amount of {varepsilon}dC was two times higher than that of {varepsilon}dA in WBC-DNA of both newborn and mother. This finding is in keeping with in vitro results whereby, {varepsilon}dA was shown to be more rapidly removed from DNA than {varepsilon}dC by DNA repair. Interestingly, interaction of {varepsilon}dC with the alkyl-N-purine-DNA glycosylase that repairs {varepsilon}dA inhibits and blocks excision repair of {varepsilon}dC, providing evidence for a higher genotoxicity of {varepsilon}dC in human cells (29). More recently, in a mouse model for inflammatory bowel disease, it was shown that etheno adducts were highly increased during inflammatory processes (30). If such DNA lesions are not repaired in colon tissue, they may program damaged cells to progress to a neoplastic phenotype. Indeed, earlier we found a 2- to 20-fold increase of {varepsilon}dA and {varepsilon}dC in colon DNA of Crohn’s disease patients and a 4-fold increase of {varepsilon}dC but not of {varepsilon}dA in ulcerative colitis patients, both prone to develop colon cancer (31). Furthermore, in an NO-overproducing and inflammatory mouse models, etheno–base adducts dominated among other measured DNA lesions such as 8-oxo-dG and M1dG, providing additional proof for the stability and validity of etheno adducts as DNA damage markers (32,33).

In conclusion, our data confirm for the first time that (i) LPO-induced DNA damage occurs in WBC of both mother and newborn; (ii) this damage can be reliably quantified by {varepsilon}dA and {varepsilon}dC measurements and was shown to be about two times lower in newborns and (iii) the strongly positive and highly significant correlations of adduct levels in WBC-DNA from mother versus newborn and the constant ratio of {varepsilon}dA:{varepsilon}dC in both groups suggests that a specific signature of DNA damage occurs similarly in WBC of both mother and newborn and possibly also in other solid tissues. Further studies are warranted to verify whether these etheno adducts in WBC-DNA from cord blood could serve as a predictive marker for developing chronic degenerative diseases such as hematopoietic cancers later in life. Attention should be focused on outliers with extremely high adduct levels that were also found in this study.


   Funding
Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 Funding
References
 
European Union Integrated Project NewGeneris, 6th Framework Programme, Priority 5: Food Quality and Safety (FOOD-CT-2005-016320); European Union-supported Newgeneris network fellowship program (K.A.).


   Acknowledgments
 
We thank all Danish volunteers who participated in this study, Dr Clarissa Gerhäuser and Susanna Fuladdjusch for careful reading the manuscript, Dr Jos Kleinjans (Department of Health Risk Analysis and Toxicology, University of Maastricht) who is the co-ordinator of NewGeneris network and Dr Dan Segerbäck (Department of Biosciences and Nutrition, Karolinska Institute, Stockholm, Sweden) who is the principal investigator, as well as all other NewGeneris Network members. NewGeneris is the acronym of the project ‘Newborns and Genotoxic exposure risks’ http://www.newgeneris.org. This article is dedicated to J.N. who died prematurely in August 2007.

Conflict of Interest Statement: None declared.


   References
Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 Funding
 References
 

  1. Zeller JL, et al. JAMA patient page. Acute lymphoblastic leukemia. JAMA (2007) 297:1278.[Free Full Text]
  2. Hijiya N, et al. Cumulative incidence of secondary neoplasms as a first event after childhood acute lymphoblastic leukemia. JAMA (2007) 297:1207–1215.[Abstract/Free Full Text]
  3. Lannero E, et al. Exposure to environmental tobacco smoke and sensitisation in children. Thorax (2008) 63:172–176.[Abstract/Free Full Text]
  4. Duramad P, et al. Early environmental exposures and intracellular Th1/Th2 cytokine profiles in 24-month-old children living in an agricultural area. Environ. Health Perspect. (2006) 114:1916–1922.[Web of Science][Medline]
  5. Perera F, et al. DNA damage from polycyclic aromatic hydrocarbons measured by benzo[a]pyrene-DNA adducts in mothers and newborns from Northern Manhattan, the World Trade Center Area, Poland, and China. Cancer Epidemiol. Biomarkers Prev. (2005) 14:709–714.[Abstract/Free Full Text]
  6. Perera FP, et al. Relationships among polycyclic aromatic hydrocarbon-DNA adducts, proximity to the World Trade Center, and effects on fetal growth. Environ. Health Perspect. (2005) 113:1062–1067.[Web of Science][Medline]
  7. Buschfort-Papewalis C, et al. Down-regulation of DNA repair in human CD34(+) progenitor cells corresponds to increased drug sensitivity and apoptotic response. Blood (2002) 100:845–853.[Abstract/Free Full Text]
  8. Shuga J, et al. In vitro erythropoiesis from bone marrow-derived progenitors provides a physiological assay for toxic and mutagenic compounds. Proc. Natl Acad. Sci. USA (2007) 104:8737–8742.[Abstract/Free Full Text]
  9. Meerang M, et al. Increased urinary 1,N6-ethenodeoxyadenosine and 3,N4-ethenodeoxycytidine excretion in thalassemia patients: markers for lipid peroxidation-induced DNA damage. Free Radic. Biol. Med. (2008) 44:1863–1868.[CrossRef][Web of Science][Medline]
  10. Schmid K, et al. Increased levels of promutagenic etheno-DNA adducts in colonic polyps of FAP patients. Int. J. Cancer (2000) 87:1–4.[CrossRef][Web of Science][Medline]
  11. Marrogi AJ, et al. Oxidative stress and p53 mutations in the carcinogenesis of iron overload-associated hepatocellular carcinoma. J. Natl Cancer Inst. (2001) 93:1652–1655.[Free Full Text]
  12. Nair J, et al. Lipid peroxidation-derived etheno-DNA adducts in human atherosclerotic lesions. Mutat. Res. (2007) 621:95–105.[Web of Science][Medline]
  13. Nair J, et al. 1,N6-ethenodeoxyadenosine and 3,N4-ethenodeoxycytine in liver DNA from humans and untreated rodents detected by immunoaffinity/32P-postlabeling. Carcinogenesis (1995) 16:613–617.[Abstract/Free Full Text]
  14. Pandya GA, et al. 1,N6-ethenodeoxyadenosine, a DNA adduct highly mutagenic in mammalian cells. Biochemistry (1996) 35:11487–11492.[CrossRef][Web of Science][Medline]
  15. Palejwala VA, et al. Quantitative multiplex sequence analysis of mutational hot spots. Frequency and specificity of mutations induced by a site-specific ethenocytosine in M13 viral DNA. Biochemistry (1993) 32:4105–4111.[CrossRef][Web of Science][Medline]
  16. Moriya M, et al. Mutagenic potency of exocyclic DNA adducts: marked differences between Escherichia coli and simian kidney cells. Proc. Natl Acad. Sci. USA (1994) 91:11899–11903.[Abstract/Free Full Text]
  17. Singer MJ, et al. DNA methylation associated with repeat-induced point mutation in Neurospora crassa. Mol. Cell. Biol. (1995) 15:5586–5597.[Abstract/Free Full Text]
  18. Hollstein M, et al. Detection of DNA base damage by 32P-postlabelling: TLC separation of 5'-deoxynucleoside monophosphates. IARC Sci. Publ. (1986) 70:437–448.[Medline]
  19. Sun X, et al. A modified immuno-enriched 32P-postlabeling method for analyzing the malondialdehyde-deoxyguanosine adduct, 3-(2-deoxy-beta-D-erythro-pentofuranosyl)- pyrimido[1,2-alpha]purin-10(3H)one in human tissue samples. Chem. Res. Toxicol. (2004) 17:268–272.[CrossRef][Web of Science][Medline]
  20. Guichard Y, et al. Immunoaffinity clean-up combined with 32P-postlabelling analysis of 1,N6-ethenoadenine and 3,N4-ethenocytosine in DNA. IARC Sci. Publ. (1993) 124:263–269.[Medline]
  21. Nair U, et al. Lipid peroxidation-induced DNA damage in cancer-prone inflammatory diseases: a review of published adduct types and levels in humans. Free Radic. Biol. Med. (2007) 43:1109–1120.[CrossRef][Web of Science][Medline]
  22. Dechakhamphu S, et al. High excretion of etheno adducts in liver fluke-infected patients: protection by praziquantel against DNA damage. Cancer Epidemiol. Biomarkers Prev. (2008) 17:1658–1664.[Abstract/Free Full Text]
  23. Yang Y, et al. Immunohistochemical detection of 1,N(6)-ethenodeoxyadenosine, a promutagenic DNA adduct, in liver of rats exposed to vinyl chloride or an iron overload. Carcinogenesis (2000) 21:777–781.[Abstract/Free Full Text]
  24. Vanderlelie J, et al. Antioxidant gene expression in preeclamptic placentae: a preliminary investigation. Placenta (2008) 29:519–522.[CrossRef][Web of Science][Medline]
  25. Ejima K, et al. Localization of thioredoxin reductase and thioredoxin in normal human placenta and their protective effect against oxidative stress. Placenta (1999) 20:95–101.[CrossRef][Web of Science][Medline]
  26. Daube H, et al. DNA adducts in human placenta in relation to tobacco smoke exposure and plasma antioxidant status. J. Cancer Res. Clin. Oncol. (1997) 123:141–151.[Web of Science][Medline]
  27. Whyatt RM, et al. Polycyclic aromatic hydrocarbon-DNA adducts in human placenta and modulation by CYP1A1 induction and genotype. Carcinogenesis (1998) 19:1389–1392.[Abstract/Free Full Text]
  28. Chen HJ, et al. Detection and quantification of 1,N(6)-ethenoadenine in human placental DNA by mass spectrometry. Chem. Res. Toxicol. (1999) 12:1119–1126.[CrossRef][Web of Science][Medline]
  29. Gros L, et al. Hijacking of the human alkyl-N-purine-DNA glycosylase by 3,N4-ethenocytosine, a lipid peroxidation-induced DNA adduct. J. Biol. Chem. (2004) 279:17723–17730.[Abstract/Free Full Text]
  30. Meira LB, et al. DNA damage induced by chronic inflammation contributes to colon carcinogenesis in mice. J. Clin. Invest. (2008) 118:2516–2525.[Web of Science][Medline]
  31. Nair J, et al. Increased etheno-DNA adducts in affected tissues of patients suffering from Crohn's disease, ulcerative colitis, and chronic pancreatitis. Antioxid. Redox Signal. (2006) 8:1003–1010.[CrossRef][Web of Science][Medline]
  32. Pang B, et al. Lipid peroxidation dominates the chemistry of DNA adduct formation in a mouse model of inflammation. Carcinogenesis (2007) 28:1807–1813.[Abstract/Free Full Text]
  33. Nair J, et al. Etheno adducts in spleen DNA of SJL mice stimulated to overproduce nitric oxide. Carcinogenesis (1998) 19:2081–2084.[Abstract/Free Full Text]
Received September 19, 2008; revised November 13, 2008; accepted November 18, 2008.


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