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Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances and Environmental Engineering Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/lesa20
Cumulative body burdens of polycyclic aromatic hydrocarbons associated with estrogen bioactivation in pregnant women: Protein adducts as biomarkers of exposure Che Lin
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Wang , Chen-His Tsai , Hz-Han Wei , Ben-Jei Tsuang & Po-Hsiung Lin a
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, Dar-Ren Chen , Shu-Li Wang , Wei-Chung Hsieh , Wen-Fa Yu , Tzu-Wen b
Comprehensive Breast Cancer Center, Changhua Christian Hospital , Changhua , Taiwan
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Department of Environmental Engineering , National Chung Hsing University , Taichung , Taiwan c
Division of Environmental Health and Occupational Medicine, National Health Research Institutes , Miaoli , Taiwan d
Department of Laboratory Medicine, Da-Chien General Hospital , Miaoli , Taiwan Published online: 12 Feb 2014.
To cite this article: Che Lin , Dar-Ren Chen , Shu-Li Wang , Wei-Chung Hsieh , Wen-Fa Yu , Tzu-Wen Wang , Chen-His Tsai , Hz-Han Wei , Ben-Jei Tsuang & Po-Hsiung Lin (2014) Cumulative body burdens of polycyclic aromatic hydrocarbons associated with estrogen bioactivation in pregnant women: Protein adducts as biomarkers of exposure, Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances and Environmental Engineering, 49:6, 634-640, DOI: 10.1080/10934529.2014.865416 To link to this article: http://dx.doi.org/10.1080/10934529.2014.865416
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Journal of Environmental Science and Health, Part A (2014) 49, 634–640 C Taylor & Francis Group, LLC Copyright ISSN: 1093-4529 (Print); 1532-4117 (Online) DOI: 10.1080/10934529.2014.865416
Cumulative body burdens of polycyclic aromatic hydrocarbons associated with estrogen bioactivation in pregnant women: Protein adducts as biomarkers of exposure CHE LIN1,2, DAR-REN CHEN1, SHU-LI WANG3, WEI-CHUNG HSIEH4, WEN-FA YU4, TZU-WEN WANG2, CHEN-HIS TSAI2, HZ-HAN WEI2, BEN-JEI TSUANG2 and PO-HSIUNG LIN2 Downloaded by [Memorial University of Newfoundland] at 10:53 31 January 2015
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Comprehensive Breast Cancer Center, Changhua Christian Hospital, Changhua, Taiwan Department of Environmental Engineering, National Chung Hsing University, Taichung, Taiwan 3 Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Miaoli, Taiwan 4 Department of Laboratory Medicine, Da-Chien General Hospital, Miaoli, Taiwan 2
The objective of this research was to simultaneously analyze protein adducts of quinonoid metabolites of naphthalene and endogenous estrogen in serum albumin (Alb) derived from healthy pregnant women in Taiwan and to explore the correlations among them. The isomeric forms of cysteinyl adducts of naphthoquinones, including 1,2-naphthoquinone (1,2-NPQ) and 1,4-naphthoquinone (1,4-NPQ) as well as estrogen quinones, including estrogen-2,3-quinones (E2 -2,3-Q) and estrogen-3,4-quinones (E2 -3,4-Q), are characterized after adduct cleavage. Results showed that the median levels of cysteinyl adducts of 1,2-NPQ and 1,4-NPQ on serum albumin were 249-390 and 16.0–24.8 pmol g−1, respectively. Logged levels of 1,2-NPQ-Alb were correlated with logged levels of 1,4-NPQ-Alb (correlation coefficient r = 0.551, P < 0.001). Cysteinyl adducts of E2 -2,3-Q-1-S-Alb, E2 -2,3-Q-4-S-Alb, and E2 -3,4Q-2-S-Alb were detected in all subjects with median levels at 275-435, 162-288, and 197-254 pmol g−1, respectively. We also found a positive relationship between logged levels of E2 -2,3-Q-4-S-Alb and those of E2 -3,4-Q-2-S-Alb (r = 0.770, P < 0.001).We noticed that median levels of E2 -2,3-Q-derived adducts (E2 -2,3-Q-1-S-Alb plus E2 -2,3-Q-4-S-Alb) in pregnant women were greater than those of E2 -3,4-Q-2-S-Alb (∼2–3-fold). Taken together, this evidence lends further support to the theme that cumulative concentration of E2 -3,4-Q is a significant predictor of the risk of breast cancer. Furthermore, we noticed that levels of 1,2-NPQ-Alb are positively associated with levels of E2 -3,4-Q-2-S-Alb (r = 0.522, P < 0.001) and those of E2 -2,3-Q-4-S-Alb (r = 0.484, P < 0.001). Overall, this evidence suggests that environmental exposure to polycyclic aromatic hydrocarbons may modulate estrogen homeostasis and enhance the production of reactive quinone species of endogenous estrogen in humans. Keywords: Protein adducts, tissue dose, naphthalene, quinones.
Introduction Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants. PAHs are formed as a byproduct during incomplete combustion of organic material where both anthropogenic and natural sources may contribute PAHs to the environment. Recent findings in epidemiological studies point to a significant association between environmental exposure to PAHs and increased risk of developing breast cancer.[1] Carcinogenic properties
Address correspondence to Po-Hsiung Lin, Department of Environmental Engineering, National Chung Hsing University, Taichung 402, Taiwan; E-mail: [email protected]; [email protected] Received May 23, 2013.
of PAHs are primarily attributed to the bioactivation of PAHs to form diol epoxides and the subsequent generation of DNA adducts [2,3] and mutations.[4,5] Some PAHs may also have estrogenic properties that could potentially affect breast cancer risk.[6] In addition, some of the PAHs are strong inducers of aryl-hydrocarbon receptor (AhR) and are capable of binding to and activating AhR,[7] with subsequent induction of transcriptional response of genes regulated by AhR.[8] Many genes responsible for the biotransformation of estrogen to reactive quinonoid metabolites, including cytochrome P450 (CYP) 1A1 and 1B1, are target genes of the AhR.[9–16] Carcinogenicity of estrogen is predominantly mediated by the receptor-driven mitogenesis mechanism.[17] However, reactive metabolites of estrogen and the subsequent formation of DNA damage may play roles in the initiation of estrogen carcinogenesis.[18–21] CYP1A1 and CYP1B1 mediate the conversion of 17β-estradiol (E2 ) to the reactive
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Body burdens of PAHs associated with estrogen bioactivation metabolites, including 2-hydroxyestradiol (2-OH-E2 ) and 4-hydroxyestradiol (4-OH-E2 ).[22–24] Both 2-OH-E2 and 4OH-E2 may undergo a two-step oxidation process to generate the respective quinones, including estrogen-2,3-quinone (E2 -2,3-Q) and estrogen-3,4-quinone (E2 -3,4-Q).[25,26] Evidence suggests that estrogen quinones play significant roles in the initiation of estrogen carcinogenesis.[18,27,28] Both E2 2,3-Q and E2 -3,4-Q can give rise to labile DNA adducts, leading to oncogenic mutations.[29–33] However, information regarding the association between levels of estrogen and PAH quinone-derived protein adducts in human serum has not been reported. In human, serum albumin adducts appear to represent reliable biomarkers of exposure to environmental pollutants. Albumin adducts of quinonoid metabolites of naphthalene have been used as biomarkers of exposure to PAHs.[9,34] In our previous investigation, we used the Alb adducts of quinonoid metabolites of naphthalene to estimate the cumulative body burden of naphthoquinones in human subjects in Taiwan.[35] We concluded that the relatively large amounts of naphthoquinones present in human serum may point to toxicological consequences. More recently, we applied the methodology to analyze estrogen quinone-derived protein adducts in human serum Alb derived from healthy subjects and breast cancer patients in Taiwan [36] and provided evidence of cumulative body burden of E2 -3,4-Q as an important indicator of developing breast cancer. In this study, we refined the original protocol to allow simultaneous measurements of both estrogen quinone- and naphthoquinone-derived protein adducts in human serum albumin derived from healthy pregnant women (n = 41) and their respective umbilical cords (n = 41). We obtained evidence that cumulative body burdens of 1,2-NPQ is associated with the extent of bioactivation of estrogen to reactive quinone species in pregnant women. Specifically, the products of reactions between NPQ and cysteine residues of N-acetyl-L-cysteine (NAC) and those between NPQ and Alb are designed as NPQ-NAC and NPQ-Alb, respectively. For estrogen quinones, the products of reactions between estrogen quinones and NAC are designated as E2 -2,3-Q1-S-NAC, E2 -2,3-Q-4-S-NAC, and E2 -3,4-Q-2-S-NAC, respectively, and those with Alb as E2 -2,3-Q-1-S-Alb, E2 -2,3Q-4-S-Alb, and E2 -3,4-Q-2-S-Alb, respectively.
Materials and methods Chemicals and reagents N-Acetyl-L-cysteine (NAC), 1,2-NPQ (97%), 1,4-NPQ (97%), Naphthalene-d8 (99%), bovine serum albumin (BSA), human serum albumin (HSA), L-ascorbic acid (99%), Iron(II)sulfate monohydrate (99.999%), trifluoroacetic acid anhydride (TFAA), and methanesulfonic acid (MSA) were obtained from Sigma-Aldrich, Inc. (St. Louis,
635
MO, USA). TFAA, MSA, E2 , chloroform, and potassium nitrosodisulfonate were purchased from Sigma-Aldrich, Inc. E2 -2, 4, 16, 16, 17-d5 ([2H5 ]-E2 ) was from C/D/N Isotope (Pointe-Claire, Quebec, Canada). Acetone, methyl alcohol, ethyl acetate, and acetonitrile were obtained from TEDIA (Charlotte, NC, USA). All chemicals were used without further purification. Subjects The study population was described previously.[37] In brief, subjects were healthy pregnant women from the general population who were recruited in a medical center located in a suburban setting of central Taiwan. Women (n = 763) were recruited between December 2000 and November 2001. All of the participants completed questionnaires regarding maternal age, occupation, disease history, cigarette smoking, alcohol consumption, dietary habits, and baby’s stature. Of those recruited, 610 women were ultimately enrolled in the study. Among these, 430 completed the questionnaire and their placentas were collected, and 250 participants provided sufficient maternal venous blood for the chemical analyses. Samples were analyzed from placental samples (n = 41) and maternal blood (n = 41) randomly selected individuals in this group. The study protocol was reviewed by the Human Ethics Committee of the National Health Research Institutes in Taiwan. Each participant provided informed consent after receiving a detailed explanation of the study and potential consequences. Maternal venous serum was collected at weeks 28–32 of gestation. Placental samples were collected at delivery. The study population was pregnant women without any complication and with a normal birth outcome and normal body mass index. The mean ages for the subjects were 28.2 and 30.4 years for those carrying a male or female infant, respectively. None of the subjects had alcohol-drinking or cigarettesmoking habits. The body burdens of PCDD/PCDF in these participants were estimated to be 13.2 ± 5.1 pg WHOTEQ g−1 lipid. Synthesis of adducts of naphthoquinones and catechol estrogen with N-acetyl-L-cysteine Standards of 1,2-NPQ-NAC and 1,4-NPQ-NAC were synthesized by reacting naphthoquinones with NAC.[34,35] Authentic standards of E2 -2,3-Q-1-S-NAC, E2 -2,3-Q-4-SNAC, and E2 -3,4-Q-S-NAC were synthesized following the procedure of Chen et al.[36] Synthesis of isotopically-labeled protein-bound internal standards A Fenton-type hydroxyl radical-generating system [38] was employed to synthesize deuterium-labeled internal standards from [2H8 ]naphthalene.[39] For the analysis of
636 estrogenquinone-derived adducts, isotopically labeled protein bound internal standards were synthesized according to the procedure previously described by Chen et al.[36]
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Isolation of human serum Alb All serum samples were maintained at -80◦ C before protein isolation. After bringing the serum to room temperature, Alb was isolated as follows. A saturated solution of (NH4 )2 SO4 was added dropwise to the plasma until the final concentration of ammonium sulfate was 2.5 M (63% of saturation). The solution was mixed with a vortex mixer, and the immunoglobulins were removed by centrifuging for 30 min at 3000g. Alb was purified by dialysis against 4 × 4 L of 1 mM ascorbic acid at 4◦ C using Spectra-Por 2 dialysis tubing (MWCO 12000–14000). The dialyzed proteins were lyophilized, weighed, and stored under -80◦ C prior to use. Characterization and measurement of adducts All cysteinyl adducts arising from naphthoquinones and estrogen quinones were assayed by the procedure as described by Waidyanatha et al.[39] with modifications.[36] Briefly, to a 8-mL vial containing 10 mg of protein, isotopically labeled protein-bound internal standards for naphthoquinones and estrogen quinones were added. After bringing samples to complete dryness in a vacuum oven (70◦ C), we added 750 µL of TFAA and the reaction was allowed to proceed at 110◦ C for 30 min. After cooling to room temperature, 20 µL of MSA was added and the mixture was heated at 110◦ C for an additional 30 min. After cooling to room temperature, the un-reacted anhydride was removed under a gentle stream of N2 . Then, 1.5 mL of hexane was added to the residue, and the hexane layer was washed twice with 2 mL of 0.1 M Tris buffer (pH 7.4) and once with 1 mL of deionized water. After concentrating the samples to 50 µL, a 2-µl aliquot was analyzed by gas chromatograph and mass spectrometer (GC-MS). All analyses were conducted using an Agilent 6890 series GC (Santa Clara, CA, USA) coupled to an Agilent 5973N MS. A HP-5MS fused silica capillary column (30 m, 0.25-mm i.d., 0.25-µm film thickness) was used with He (99.999%) as the carrier gas at a flow rate of 1 mL/min. The MS transfer-line temperature was 250◦ C and the chemical ionization reagent gas (methane) pressure was 2.3 × 10−4torr. For characterization of adducts in the assay, our GCMS was set to scan from m/Z 50 to m/Z 750 in electron impact (EI) and negative ion chemical ionization (NCI) modes. The ion source temperature was set at 150◦ C and the injection-port temperature was 250◦ C in all cases. The GC oven temperature was held at 75◦ C for 2 min and increased at 6◦ C min−1 to 145◦ C, where it was held for 10 min. Lateeluting compounds were removed by increasing the oven temperature at 50◦ C min−1 to 260◦ C, where it was held for 5 min.
Lin et al. For quantitation of adducts, all conditions were similar to those described here for GC–NICI–MS except that the mass spectrometer was set to selected ion monitoring (SIM) mode. The following fragment ions were monitored in NICI mode for their respective TFA-derivatives: 1,2and 1,4-NPQ-S-TFA (m/Z 383); [2H5 ]1,2- and 1,4-NPQS-TFA (m/Z 388); E2 -2,3-Q-1-S-TFA, E2 -2,3-Q-4-S-TFA, and E2 -3,4-Q-S-TFA (m/Z 607); [2H3 ] E2 -2,3-Q-4-S-TFA and E2 -3,4-Q-2-S-TFA (m/Z 610); [2H4 ] E2 -2,3-Q-1-S-TFA (m/Z 611). For 1,2- and 1,4-NPQ-S-TFA, the quantitations were based on calibration against [2H5 ]1,2- and 1,4-NPQS-TFA, respectively. For E2 -2,3-Q-1-S-TFA, E2 -2,3-Q-4-STFA, and E2 -2,3-Q-2-S-TFA, the quantitations were based on calibration against [2H3 ] E2 -2,3-Q-4-S-TFA, [2H3 ] E2 3,4-Q-2-S-TFA, and [2H4 ] E2 -2,3-Q-1-S-TFA, respectively. Standard curves were prepared over a range of 0.1–500 pmol by deriving authentic standards equivalent to those of samples. Based on a signal-to-noise ratio of 3, the limit of detection of the modified MT assay corresponds to about 10 pmol g−1 for all adducts, assuming 10 mg of proteins were used for the assay. The precision, as indicated by estimated coefficients of variation, was 4% and 6% for 1,2NPQ-Alb and 1,4-NPQ-Alb (n = 10), respectively,. Statistical analysis All data are expressed as mean ± standard deviation (SD). All data were transformed to the natural logarithm and tested for normal distribution by Kolmogorov-Smirnov (K–S) for parametric analyses. Person correlation was used to evaluate the association between the levels of estrogen quinone-derived albumin adducts with those of naphthoquinones. Statistical analyses were performed using the Statistical Package for Social Science (SPSS Advanced Statistics version 18.0., Armonk, NY, USA). Two-tailed statistical significance was indicated by a P value less than 0.05.
Results Measurements of naphthoquinone-derived adducts in human serum Alb Figure 1 depicts the typical GC-NICI-MS chromatogram obtained in SIM mode after reaction of 10 mg of Alb derived from a pregnant woman. Characteristics of the study population and subjects’ levels of 1,2-NPQ-Alb or 1,4-NPQ-Alb. Cysteinyl adducts of both 1,2-NPQ and 1,4NPQ were detected in serum Alb of most of the study population. The median levels of 1,2-NPQ-Alb were 390 and 249 pmol g−1 in pregnant women (n = 41) and their corresponding umbilical cords (n = 41), respectively, whereas the median levels of 1,4-NPQ-Alb were 24.8 and 16.0 pmol g−1, respectively. We noticed that in general, the level of 1,2NPQ-Alb for each individual was much greater than that of 1,4-NPQ-Alb (∼15-fold, P < 0.001). We suspect that
Body burdens of PAHs associated with estrogen bioactivation A
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m/z 383
12000
Abundance
1,2-NPQ-S-TFA 20.34
1,4-NPQ-S-TFA
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19.75
4000
18.5
19.0
19.5
20.0
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B
30000 m/z 388 2
[ H 5 ]1,2-NPQ-S-TFA
Abundance
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0
20.31
20000
Fig. 2. Linear regression of square root of the logged levels of (1,2-NPQ-Alb) and (1,4-NPQ-Alb).
[2H 5 ]1,4-NPQ-S-TFA 19.68
10000
0 18.5
19.0 19.5 Retention time (min)
20.0
20.5
Fig. 1. GC-NICI-MS chromatogram obtained in selected ion monitoring mode following the reaction of 10 mg human serum (obtained from a pregnant woman in Taiwan) with TFAA and MSA. (a) Ions m/z 383 corresponds to TFA derivatives of 1,2NPQ and 1,4-NPQ. (b) The corresponding deuterated internal standard ions were m/z 388.
difference in their reactivity toward protein may contribute to this disparity. Additionally, linear correlation between 1,2-NPQ-Alb and 1,4-NPQ-Alb was performed using natural logarithmic transformation by simple regression analysis. Results indicated that logged levels of 1,2-NPQ-Alb correlated with logged levels of 1,4-NPQ-Alb (correlation coefficient r = 0.551, P < 0.001) (Fig. 2). Measurements of estrogen quinone-derived adducts in human serum Alb Figure 3 depicts the typical GC-NICI-MS chromatogram obtained in SIM mode after derivatization of 10 mg of Alb derived from a pregnant woman. This figure demonstrates the presence of estrogen quinone-derived cysteinyl adducts on human serum albumin after adducts cleavage from proteins. Cysteinyl adducts of E2 -2,3-Q-4-S-Alb and E2 -3,4-Q2-S-Albwere detected in serum Alb of all the study popu-
lation; whereas E2 -2,3-Q-1-S-Alb adducts were detected in only some of these subjects. The nucleophilic attack at C1or C4-position of E2 -2,3-Q generated either E2 -2,3-Q-1-SAlb or E2 -2,3-Q-4-S-Alb. We speculate that stereo hindrance may favor the formation of E2 -2,3-Q-4-S-Alb more than E2 -2,3-Q-1-S-Alb. The median levels of E2 -2,3-Q-1-S-Alb and E2 -2,3-Q-4-SAlb and E2 -3,4-Q-2-S-Alb were 275-435, 162-288, and 197254 pmol g−1 in these subjects, respectively. Similarly, when we performed linear correlation using natural logarithmic transformation by simple regression analysis, logged levels of E2 -2,3-Q-4-S-Alb highly correlated with logged levels of and E2 -3,4-Q-2-S-Alb (correlation coefficient r = 0.770, P < 0.001) (Fig. 4).
Discussion Incidence of breast cancer has increased dramatically in Taiwanese women over the past decade.[40] Environmental and occupational exposure to PAHs and other toxic substances may be responsible for the increased risk of developing breast cancer.[1,41] It is likely that induction of genes responsible for activation of estrogen to its reactive quinones by AhR agonists, including PAHs, may contribute to the initiation of estrogen carcinogenesis. The urinary excretion of mono- and di-hydroxylated PAH metabolites are classically measured for the determination of PAH exposure in epidemiological studies.[7,8] In addition, albumin adducts of a quinonoid metabolite of naphthalene, 1,2NPQ, have been used as biomarkers of occupational and environmental exposure to PAHs where increased levels of
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Lin et al.
Fig. 4. Linear regression of square root of the logged levels of (E2 -2,3-Q-4-Alb) and (E2 -3,4-Q-2-Alb).
Fig. 3. GC-NICI-MS chromatogram obtained in selected ion monitoring mode following the reaction of 10 mg human serum (obtained from a pregnant woman in Taiwan) with TFAA and MSA. (a) Ions m/z 607 corresponds to TFA derivatives of E2 2,3-Q and E2 -3,4-EQ. (b) The corresponding deuterated internal standard ions were m/z 610 for [2H4 ] E2 -2,3-Q-4-S-TFA, and (c) 611 for [2H3 ]E2 -2,3-EQ-1-S-TFA.
naphthoquinone-derived albumin adducts were detected in coke oven workers when compared to their respective controls.[9] To measure both estrogen quinone- and naphthoquinone-derived protein adducts in human serum albumin and to explore the association between them, we conducted the current investigation to simultaneously analyze both adducts in serum albumin derived from healthy pregnant women in Taiwan. Logged levels of 1,2-NPQ correlated with logged levels of 1,4-NPQ (r = 0.551, P < 0.001) (Fig. 2). This finding is agreeable with that reported by our previous investigation in healthy blood donors for the correlation between 1,2-NPQ-Alb and 1,4-NPQ-Alb (r = 0.643, P < 0.001). The median levels of 1,4-NPQ-Alb were estimated to be between 16–25 (range 10–70) pmol g−1 Alb in the study population. We noticed that this observation is slightly lower than that reported in female blood donors where the median levels of 1,4-NPQ-Alb were estimated to be 38.9 (range 22–172) pmol g−1.[35] By contrast, the median levels of 1,2-NPQ-Alb detected in this study population (249–390 pmol g−1 Alb; range 121–859 pmol g−1 Alb) were comparable with those reported in female blood donors (203 pmol g−1 Alb; range 128–1352 pmol g−1 Alb). The mechanism underlying the differences in the disposition of naphthalene between female blood donors and pregnant women is not clear. The fact that a wide range of variables may influence the expression of P450 enzymes, including estrogen homeostasis, may attribute to this disparity.[42] Many factors may affect the generation of estrogen quinones in humans, including environmental issues and genetic predisposition.[43–45] To gauge the burden of estrogen quinones in human serum, we measured the levels of estrogen quinone-derived adducts in serum Alb in
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correlation between adduct levels of 1,2-NPQ-Alb and estrogen quinone-derived adducts in pregnant women was performed using natural logarithmic transformation by simple regression analysis. Results showed that logged levels of 1,2-NPQ-Alb highly correlate with logged levels of E2 -2,3-Q-4-S-Alb (r = 0.484, P < 0.001) and and E2 -3,4Q-2-S-Alb (r = 0.522, P < 0.001) (Figs. 5a and 5b). This finding provides direct evidence of positive correlation of cumulative body burdens of PAHs and activation of estrogen in healthy pregnant women. Overall, we conclude that environmental exposure to PAHs may modulate estrogen homeostasis and enhance the production of reactive quinone species of endogenous estrogen (∼1.7-fold) in human. The methodology developed in this study may be applied to epidemiological studies to serve as biomarkers of PAH exposure and estrogen homeostasis.
Funding This work was supported by the National Science Council, Taiwan, through Grants NSC98-2314-B-371-004-MY2 and NSC99-2314-B-005-001-MY3.
References
Fig. 5. (a) Linear regression of square root of the logged levels of (1,2-NPQ-Alb) and (E2 -3,4-Q-2-Alb). (b) Linear regression of square root of the logged levels of (1,2-NPQ-Alb) and (E2 -2,3-Q4-Alb).
the study population. Results from our analyses indicated that E2 -2,3-Q-1-S-Alb, E2 -2,3-Q-4-S-Alb, and E2 -3,4-Q-2S-Alb were detected in most of the participants. As expected, logged levels of E2 -2,3-Q-4-S-Alb highly correlated with logged levels of E2 -3,4-Q-2-S-Alb with correlation coefficient (r) at 0.770 (P < 0.001) (Fig. 4). Furthermore, we noticed that median levels of E2 -2,3-Q-derived adducts (E2 2,3-Q-1-S-Alb plus E2 -2,3-Q-4-S-Alb) in pregnant women were greater than those of E2 -3,4-Q-2-S-Alb (∼2–3-fold). This observation is comparable with our previous investigation where levels of E2 -2,3-Q-derived adducts in serum of healthy female blood donors were much greater than those of E2 -3,4-Q-2-S-Alb (∼5-fold).[36] To examine the degree of association between PAH exposure and cumulative body burden of estrogen quinones,
[1] Bonner, M.R.; Han, D.; Nie, J.; Rogerson, P.; Vena, J.E.; Muti, P.; Trevisan, M.; Edge, S.B.; Freudenheim, J.L. Breast cancer risk and exposure in early life to polycyclic aromatic hydrocarbons using total suspended particulates as a proxy measure. Cancer Epidemiol. Biomark. Prev. 2005, 14(1), 53–60. [2] Devanesan, P.D.; RamaKrishna, N.V.; Todorovic, R.; Rogan, E.G.; Cavalieri, E.L.; Jeong, H.; Jankowiak, R.; Small, G.J. Identification and quantitation of benzo[a]pyrene-DNA adducts formed by rat liver microsomes in vitro. Chem. Res. Toxicol. 1992, 5(2), 302–309. [3] Marshall, C.J.; Vousden, K.H.; Phillips, D.H. Activation of c-Haras-1 proto-oncogene by in vitro modification with a chemical carcinogen, benzo(a)pyrene diol-epoxide. Nature 1984, 310(5978), 586–589. [4] Rodenhuis, S. Ras and human tumors. Semin. Cancer Biol. 1992, 3(4), 241–247. [5] van der Schroeff, J.G.; Evers, L.M.; Boot, A.J.; Bos, J.L. Ras oncogene mutations in basal cell carcinomas and squamous cell carcinomas of human skin. J. Invest. Dermatol. 1990, 94(4), 423–425. [6] Santodonato, J. Review of the estrogenic and antiestrogenic activity of polycyclic aromatic hydrocarbons: relationship to carcinogenicity. Chemosphere 1997, 34(4), 835–848. [7] Buratti, M.; Campo, L.; Fustinoni, S.; Cirla, P.E.; Martinotti, I.; Cavallo, D.; Foa, V. Urinary hydroxylated metabolites of polycyclic aromatic hydrocarbons as biomarkers of exposure in asphalt workers. Biomarkers 2007, 12(3), 221–239. [8] Seidel, A.; Spickenheuer, A.; Straif, K.; Rihs, H.P.; Marczynski, B.; Scherenberg, M.; Dettbarn, G.; Angerer, J.; Wilhelm, M.; Bruning, T.; Jacob, J.; Pesch, B. New biomarkers of occupational exposure to polycyclic aromatic hydrocarbons. J. Toxicol. Environ. Health A 2008, 71(11–12), 734–745. [9] Waidyanatha, S.; Zheng, Y.; Serdar, B.; Rappaport, S.M. Albumin adducts of naphthalene metabolites as biomarkers of exposure to polycyclic aromatic hydrocarbons. Cancer Epidemiol. Biomark. Prev. 2004, 13(1), 117–124. [10] Preuss, R.; Angerer, J.; Drexler, H. Naphthalene—An environmental and occupational toxicant. Int. Arch. Occup. Environ. Health 2003, 76(8), 556–576.
Downloaded by [Memorial University of Newfoundland] at 10:53 31 January 2015
640 [11] Toxicology and Carcinogenesis Studies of Naphthalene (CAS No. 91-20-3) in B6C3F1 Mice (Inhalation Studies). Natl. Toxicol. Prog. Tech. Rep. Ser. 1992, 410, 1–172. [12] Yang, Y.; Sharma, R.; Cheng, J.Z.; Saini, M.K.; Ansari, N.H.; Andley, U.P.; Awasthi, S.; Awasthi, Y.C. Protection of HLE B-3 cells against hydrogen peroxide- and naphthalene-induced lipid peroxidation and apoptosis by transfection with hGSTA1 and hGSTA2. Invest. Ophthalmol. Vis. Sci. 2002, 43(2), 434–445. [13] Bagchi, D.; Bagchi, M.; Balmoori, J.; Vuchetich, P.J.; Stohs, S.J. Induction of oxidative stress and DNA damage by chronic administration of naphthalene to rats. Res. Commun. Mol. Pathol. Pharmacol. 1998, 101(3), 249–257. [14] Bagchi, M.; Balmoori, J.; Ye, X.; Bagchi, D.; Ray, S.D.; Stohs, S.J. Protective effect of melatonin on naphthalene-induced oxidative stress and DNA damage in cultured macrophage J774A.1 cells. Mol. Cell Biochem. 2001, 221(1–2), 49–55. [15] Schreiner, C.A. Genetic toxicity of naphthalene: A review. J. Toxicol. Environ. Health B Crit Rev. 2003, 6(2), 161–183. [16] Toxicology and carcinogenesis studies of naphthalene (cas no. 9120-3) in F344/N rats (inhalation studies). Natl. Toxicol. Prog. Tech. Rep. Ser. 2000, 500, 1–173. [17] Feigelson, H.S.; Henderson, B.E. Estrogens and breast cancer. Carcinogenesis 1996, 17(11), 2279–2284. [18] Bolton, J.L.; Thatcher, G.R. Potential mechanisms of estrogen quinone carcinogenesis. Chem. Res. Toxicol. 2008, 21(1), 93–101. [19] Cavalieri, E.; Frenkel, K.; Liehr, J.G.; Rogan, E.; Roy, D. Estrogens as endogenous genotoxic agents–DNA adducts and mutations. J. Natl. Cancer Inst. Monogr. 2000, 27, 75–93. [20] Lavigne, J.A.; Goodman, J.E.; Fonong, T.; Odwin, S.; He, P.; Roberts, D.W.; Yager, J.D. The effects of catechol-Omethyltransferase inhibition on estrogen metabolite and oxidative DNA damage levels in estradiol-treated MCF-7 cells. Cancer Res. 2001, 61(20), 7488–7494. [21] Yager, J.D. Endogenous estrogens as carcinogens through metabolic activation. J. Natl. Cancer Inst. Monogr. 2000, 27, 67–73. [22] Hayes, C.L.; Spink, D.C.; Spink, B.C.; Cao, J.Q.; Walker, N.J.; Sutter, T.R. 17 beta-estradiol hydroxylation catalyzed by human cytochrome P450 1B1. Proc. Natl. Acad. Sci. USA 1996, 93(18), 9776–9781. [23] Martucci, C.P.; Fishman, J. P450 enzymes of estrogen metabolism. Pharmacol. Ther. 1993, 57(2–3), 237–257. [24] Spink, D.C.; Spink, B.C.; Cao, J.Q.; Gierthy, J.F.; Hayes, C.L.; Li, Y.; Sutter, T.R. Induction of cytochrome P450 1B1 and catechol estrogen metabolism in ACHN human renal adenocarcinoma cells. J. Ster. Biochem. Mol. Biol. 1997, 62(2–3), 223–232. [25] Butterworth, M.; Lau, S.S.; Monks, T.J. 17 beta-estradiol metabolism by hamster hepatic microsomes: comparison of catechol estrogen O-methylation with catechol estrogen oxidation and glutathione conjugation. Chem. Res. Toxicol. 1996, 9(4), 793–799. [26] Cao, K.; Stack, D.E.; Ramanathan, R.; Gross, M.L.; Rogan, E.G.; Cavalieri, E.L. Synthesis and structure elucidation of estrogen quinones conjugated with cysteine, N-acetylcysteine, and glutathione. Chem. Res. Toxicol. 1998, 11(8), 909–916. [27] Yager, J.D.; Davidson, N.E. Estrogen carcinogenesis in breast cancer. N. Engl. J. Med. 2006, 354(3), 270–282. [28] Parl, F.F.; Dawling, S.; Roodi, N.; Crooke, P.S. Estrogen metabolism and breast cancer: a risk model. Ann. NY Acad. Sci. 2009, 1155, 68–75. [29] Convert, O.; Van Aerden, C.; Debrauwer, L.; Rathahao, E.; Molines, H.; Fournier, F.; Tabet, J.C.; Paris, A. Reactions of estradiol-2,3quinone with deoxyribonucleosides: possible insights in the reactivity of estrogen quinones with DNA. Chem. Res. Toxicol. 2002, 15(5), 754–764. [30] Cavalieri, E.L.; Stack, D.E.; Devanesan, P.D.; Todorovic, R.; Dwivedy, I.; Higginbotham, S.; Johansson, S.L.; Patil, K.D.; Gross,
Lin et al.
[31]
[32]
[33]
[34]
[35]
[36]
[37]
[38]
[39]
[40]
[41] [42]
[43]
[44]
[45]
M.L.; Gooden, J.K.; Ramanathan, R.; Cerny, R.L.; Rogan, E.G. Molecular origin of cancer: catechol estrogen-3,4-quinones as endogenous tumor initiators, Proc. Natl. Acad. Sci. USA 1997, 94(20), 10937–10942. Cavalieri, E.L.; Devanesan, P.; Bosland, M.C.; Badawi, A.F.; Rogan, E.G. Catechol estrogen metabolites and conjugates in different regions of the prostate of Noble rats treated with 4-hydroxyestradiol: implications for estrogen-induced initiation of prostate cancer. Carcinogenesis 2002, 23(2), 329–333. Zahid, M.; Kohli, E.; Saeed, M.; Rogan, E.; Cavalieri, E. The greater reactivity of estradiol-3,4-quinone vs estradiol-2,3-quinone with DNA in the formation of depurinating adducts: implications for tumor-initiating activity. Chem. Res. Toxicol. 2006, 19(1), 164–172. Lin, P.H.; Nakamura, J.; Yamaguchi, S.; Asakura, S.; Swenberg, J.A. Aldehydic DNA lesions induced by catechol estrogens in calf thymus DNA. Carcinogenesis 2003, 24(6), 1133–1141. Waidyanatha, S.; Rappaport, S.M. Hemoglobin and albumin adducts of naphthalene-1,2-oxide, 1,2-naphthoquinone and 1,4naphthoquinone in Swiss Webster mice. Chem. Biol. Interact. 2008, 172(2), 105–114. Lin, P.H.; Chen, D.R.; Wang, T.W.; Lin, C.H.; Chuang, M.C. Investigation of the cumulative tissue doses of naphthoquinones in human serum using protein adducts as biomarker of exposure. Chem. Biol. Interact. 2009, 181(1), 107–114. Chen, D.R.; Chen, S.T.; Wang, T.W.; Tsai, C.H.; Wei, H.H.; Chen, G.J.; Yang, T.C.; Lin, C.; Lin, P.H. Characterization of estrogen quinone-derived protein adducts and their identification in human serum albumin derived from breast cancer patients and healthy controls. Toxicol. Lett. 2011, 202(3), 244–252. Wang, S.L.; Chang, Y.C.; Chao, H.R.; Li, C.M.; Li, L.A.; Lin, L.Y.; Papke, O. Body burdens of polychlorinated dibenzo-pdioxins, dibenzofurans, and biphenyls and their relations to estrogen metabolism in pregnant women. Environ. Health Perspect. 2006, 114(5), 740–745. Halliwell, B.; Gutteridge, J.M. The importance of free radicals and catalytic metal ions in human diseases. Mol. Aspects Med. 1985, 8(2), 89–193. Waidyanatha, S.; Troester, M.A.; Lindstrom, A.B.; Rappaport, S.M. Measurement of hemoglobin and albumin adducts of naphthalene1,2-oxide, 1,2-naphthoquinone and 1,4-naphthoquinone after administration of naphthalene to F344 rats. Chem. Biol. Interact. 2002, 141(3), 189–210. Huang, C.S.; Lin, C.H.; Lu, Y.S.; Shen, C.Y. Unique features of breast cancer in Asian women—breast cancer in Taiwan as an example. J. Ster. Biochem. Mol. Biol. 2010, 118(4–5), 300– 303. Boffetta, P.; Nyberg, F. Contribution of environmental factors to cancer risk. Br. Med. Bull. 2003, 68, 71–94. Ishii, T.; Nishimura, K.; Nishimura, M. Administration of xenobiotics with anti-estrogenic effects results in mRNA induction of adult male-specific cytochrome P450 isozymes in the livers of adult female rats. J. Pharmacol. Sci. 2006, 101(3), 250–255. Shin, A.; Kang, D.; Choi, J.Y.; Lee, K.M.; Park, S.K.; Noh, D.Y.; Ahn, S.H.; Yoo, K.Y. Cytochrome P450 1A1 (CYP1A1) polymorphisms and breast cancer risk in Korean women. Exp. Mol. Med. 2007, 39(3), 361–366. Okobia, M.N.; Bunker, C.H.; Garte, S.J.; Zmuda, J.M.; Ezeome, E.R.; Anyanwu, S.N.; Uche, E.E.; Osime, U.; Ojukwu, J.; Kuller, L.H.; Ferrell, R.E.; Taioli, E. Cytochrome P450 1B1 Val432Leu polymorphism and breast cancer risk in Nigerian women: A case control study. Infect. Agent Cancer 4 Suppl. 2009, 1, S12. Brody, J.G.; Moysich, K.B.; Humblet, O.; Attfield, K.R.; Beehler, G.P.; Rudel, R.A. Environmental pollutants and breast cancer: Epidemiologic studies. Cancer 2007, 109(12 Suppl), 2667– 2711.
Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances and Environmental Engineering Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/lesa20
Cumulative body burdens of polycyclic aromatic hydrocarbons associated with estrogen bioactivation in pregnant women: Protein adducts as biomarkers of exposure Che Lin
a b
b
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c
d
b
b
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Wang , Chen-His Tsai , Hz-Han Wei , Ben-Jei Tsuang & Po-Hsiung Lin a
Click for updates
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, Dar-Ren Chen , Shu-Li Wang , Wei-Chung Hsieh , Wen-Fa Yu , Tzu-Wen b
Comprehensive Breast Cancer Center, Changhua Christian Hospital , Changhua , Taiwan
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Department of Environmental Engineering , National Chung Hsing University , Taichung , Taiwan c
Division of Environmental Health and Occupational Medicine, National Health Research Institutes , Miaoli , Taiwan d
Department of Laboratory Medicine, Da-Chien General Hospital , Miaoli , Taiwan Published online: 12 Feb 2014.
To cite this article: Che Lin , Dar-Ren Chen , Shu-Li Wang , Wei-Chung Hsieh , Wen-Fa Yu , Tzu-Wen Wang , Chen-His Tsai , Hz-Han Wei , Ben-Jei Tsuang & Po-Hsiung Lin (2014) Cumulative body burdens of polycyclic aromatic hydrocarbons associated with estrogen bioactivation in pregnant women: Protein adducts as biomarkers of exposure, Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances and Environmental Engineering, 49:6, 634-640, DOI: 10.1080/10934529.2014.865416 To link to this article: http://dx.doi.org/10.1080/10934529.2014.865416
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Journal of Environmental Science and Health, Part A (2014) 49, 634–640 C Taylor & Francis Group, LLC Copyright ISSN: 1093-4529 (Print); 1532-4117 (Online) DOI: 10.1080/10934529.2014.865416
Cumulative body burdens of polycyclic aromatic hydrocarbons associated with estrogen bioactivation in pregnant women: Protein adducts as biomarkers of exposure CHE LIN1,2, DAR-REN CHEN1, SHU-LI WANG3, WEI-CHUNG HSIEH4, WEN-FA YU4, TZU-WEN WANG2, CHEN-HIS TSAI2, HZ-HAN WEI2, BEN-JEI TSUANG2 and PO-HSIUNG LIN2 Downloaded by [Memorial University of Newfoundland] at 10:53 31 January 2015
1
Comprehensive Breast Cancer Center, Changhua Christian Hospital, Changhua, Taiwan Department of Environmental Engineering, National Chung Hsing University, Taichung, Taiwan 3 Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Miaoli, Taiwan 4 Department of Laboratory Medicine, Da-Chien General Hospital, Miaoli, Taiwan 2
The objective of this research was to simultaneously analyze protein adducts of quinonoid metabolites of naphthalene and endogenous estrogen in serum albumin (Alb) derived from healthy pregnant women in Taiwan and to explore the correlations among them. The isomeric forms of cysteinyl adducts of naphthoquinones, including 1,2-naphthoquinone (1,2-NPQ) and 1,4-naphthoquinone (1,4-NPQ) as well as estrogen quinones, including estrogen-2,3-quinones (E2 -2,3-Q) and estrogen-3,4-quinones (E2 -3,4-Q), are characterized after adduct cleavage. Results showed that the median levels of cysteinyl adducts of 1,2-NPQ and 1,4-NPQ on serum albumin were 249-390 and 16.0–24.8 pmol g−1, respectively. Logged levels of 1,2-NPQ-Alb were correlated with logged levels of 1,4-NPQ-Alb (correlation coefficient r = 0.551, P < 0.001). Cysteinyl adducts of E2 -2,3-Q-1-S-Alb, E2 -2,3-Q-4-S-Alb, and E2 -3,4Q-2-S-Alb were detected in all subjects with median levels at 275-435, 162-288, and 197-254 pmol g−1, respectively. We also found a positive relationship between logged levels of E2 -2,3-Q-4-S-Alb and those of E2 -3,4-Q-2-S-Alb (r = 0.770, P < 0.001).We noticed that median levels of E2 -2,3-Q-derived adducts (E2 -2,3-Q-1-S-Alb plus E2 -2,3-Q-4-S-Alb) in pregnant women were greater than those of E2 -3,4-Q-2-S-Alb (∼2–3-fold). Taken together, this evidence lends further support to the theme that cumulative concentration of E2 -3,4-Q is a significant predictor of the risk of breast cancer. Furthermore, we noticed that levels of 1,2-NPQ-Alb are positively associated with levels of E2 -3,4-Q-2-S-Alb (r = 0.522, P < 0.001) and those of E2 -2,3-Q-4-S-Alb (r = 0.484, P < 0.001). Overall, this evidence suggests that environmental exposure to polycyclic aromatic hydrocarbons may modulate estrogen homeostasis and enhance the production of reactive quinone species of endogenous estrogen in humans. Keywords: Protein adducts, tissue dose, naphthalene, quinones.
Introduction Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants. PAHs are formed as a byproduct during incomplete combustion of organic material where both anthropogenic and natural sources may contribute PAHs to the environment. Recent findings in epidemiological studies point to a significant association between environmental exposure to PAHs and increased risk of developing breast cancer.[1] Carcinogenic properties
Address correspondence to Po-Hsiung Lin, Department of Environmental Engineering, National Chung Hsing University, Taichung 402, Taiwan; E-mail: [email protected]; [email protected] Received May 23, 2013.
of PAHs are primarily attributed to the bioactivation of PAHs to form diol epoxides and the subsequent generation of DNA adducts [2,3] and mutations.[4,5] Some PAHs may also have estrogenic properties that could potentially affect breast cancer risk.[6] In addition, some of the PAHs are strong inducers of aryl-hydrocarbon receptor (AhR) and are capable of binding to and activating AhR,[7] with subsequent induction of transcriptional response of genes regulated by AhR.[8] Many genes responsible for the biotransformation of estrogen to reactive quinonoid metabolites, including cytochrome P450 (CYP) 1A1 and 1B1, are target genes of the AhR.[9–16] Carcinogenicity of estrogen is predominantly mediated by the receptor-driven mitogenesis mechanism.[17] However, reactive metabolites of estrogen and the subsequent formation of DNA damage may play roles in the initiation of estrogen carcinogenesis.[18–21] CYP1A1 and CYP1B1 mediate the conversion of 17β-estradiol (E2 ) to the reactive
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Body burdens of PAHs associated with estrogen bioactivation metabolites, including 2-hydroxyestradiol (2-OH-E2 ) and 4-hydroxyestradiol (4-OH-E2 ).[22–24] Both 2-OH-E2 and 4OH-E2 may undergo a two-step oxidation process to generate the respective quinones, including estrogen-2,3-quinone (E2 -2,3-Q) and estrogen-3,4-quinone (E2 -3,4-Q).[25,26] Evidence suggests that estrogen quinones play significant roles in the initiation of estrogen carcinogenesis.[18,27,28] Both E2 2,3-Q and E2 -3,4-Q can give rise to labile DNA adducts, leading to oncogenic mutations.[29–33] However, information regarding the association between levels of estrogen and PAH quinone-derived protein adducts in human serum has not been reported. In human, serum albumin adducts appear to represent reliable biomarkers of exposure to environmental pollutants. Albumin adducts of quinonoid metabolites of naphthalene have been used as biomarkers of exposure to PAHs.[9,34] In our previous investigation, we used the Alb adducts of quinonoid metabolites of naphthalene to estimate the cumulative body burden of naphthoquinones in human subjects in Taiwan.[35] We concluded that the relatively large amounts of naphthoquinones present in human serum may point to toxicological consequences. More recently, we applied the methodology to analyze estrogen quinone-derived protein adducts in human serum Alb derived from healthy subjects and breast cancer patients in Taiwan [36] and provided evidence of cumulative body burden of E2 -3,4-Q as an important indicator of developing breast cancer. In this study, we refined the original protocol to allow simultaneous measurements of both estrogen quinone- and naphthoquinone-derived protein adducts in human serum albumin derived from healthy pregnant women (n = 41) and their respective umbilical cords (n = 41). We obtained evidence that cumulative body burdens of 1,2-NPQ is associated with the extent of bioactivation of estrogen to reactive quinone species in pregnant women. Specifically, the products of reactions between NPQ and cysteine residues of N-acetyl-L-cysteine (NAC) and those between NPQ and Alb are designed as NPQ-NAC and NPQ-Alb, respectively. For estrogen quinones, the products of reactions between estrogen quinones and NAC are designated as E2 -2,3-Q1-S-NAC, E2 -2,3-Q-4-S-NAC, and E2 -3,4-Q-2-S-NAC, respectively, and those with Alb as E2 -2,3-Q-1-S-Alb, E2 -2,3Q-4-S-Alb, and E2 -3,4-Q-2-S-Alb, respectively.
Materials and methods Chemicals and reagents N-Acetyl-L-cysteine (NAC), 1,2-NPQ (97%), 1,4-NPQ (97%), Naphthalene-d8 (99%), bovine serum albumin (BSA), human serum albumin (HSA), L-ascorbic acid (99%), Iron(II)sulfate monohydrate (99.999%), trifluoroacetic acid anhydride (TFAA), and methanesulfonic acid (MSA) were obtained from Sigma-Aldrich, Inc. (St. Louis,
635
MO, USA). TFAA, MSA, E2 , chloroform, and potassium nitrosodisulfonate were purchased from Sigma-Aldrich, Inc. E2 -2, 4, 16, 16, 17-d5 ([2H5 ]-E2 ) was from C/D/N Isotope (Pointe-Claire, Quebec, Canada). Acetone, methyl alcohol, ethyl acetate, and acetonitrile were obtained from TEDIA (Charlotte, NC, USA). All chemicals were used without further purification. Subjects The study population was described previously.[37] In brief, subjects were healthy pregnant women from the general population who were recruited in a medical center located in a suburban setting of central Taiwan. Women (n = 763) were recruited between December 2000 and November 2001. All of the participants completed questionnaires regarding maternal age, occupation, disease history, cigarette smoking, alcohol consumption, dietary habits, and baby’s stature. Of those recruited, 610 women were ultimately enrolled in the study. Among these, 430 completed the questionnaire and their placentas were collected, and 250 participants provided sufficient maternal venous blood for the chemical analyses. Samples were analyzed from placental samples (n = 41) and maternal blood (n = 41) randomly selected individuals in this group. The study protocol was reviewed by the Human Ethics Committee of the National Health Research Institutes in Taiwan. Each participant provided informed consent after receiving a detailed explanation of the study and potential consequences. Maternal venous serum was collected at weeks 28–32 of gestation. Placental samples were collected at delivery. The study population was pregnant women without any complication and with a normal birth outcome and normal body mass index. The mean ages for the subjects were 28.2 and 30.4 years for those carrying a male or female infant, respectively. None of the subjects had alcohol-drinking or cigarettesmoking habits. The body burdens of PCDD/PCDF in these participants were estimated to be 13.2 ± 5.1 pg WHOTEQ g−1 lipid. Synthesis of adducts of naphthoquinones and catechol estrogen with N-acetyl-L-cysteine Standards of 1,2-NPQ-NAC and 1,4-NPQ-NAC were synthesized by reacting naphthoquinones with NAC.[34,35] Authentic standards of E2 -2,3-Q-1-S-NAC, E2 -2,3-Q-4-SNAC, and E2 -3,4-Q-S-NAC were synthesized following the procedure of Chen et al.[36] Synthesis of isotopically-labeled protein-bound internal standards A Fenton-type hydroxyl radical-generating system [38] was employed to synthesize deuterium-labeled internal standards from [2H8 ]naphthalene.[39] For the analysis of
636 estrogenquinone-derived adducts, isotopically labeled protein bound internal standards were synthesized according to the procedure previously described by Chen et al.[36]
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Isolation of human serum Alb All serum samples were maintained at -80◦ C before protein isolation. After bringing the serum to room temperature, Alb was isolated as follows. A saturated solution of (NH4 )2 SO4 was added dropwise to the plasma until the final concentration of ammonium sulfate was 2.5 M (63% of saturation). The solution was mixed with a vortex mixer, and the immunoglobulins were removed by centrifuging for 30 min at 3000g. Alb was purified by dialysis against 4 × 4 L of 1 mM ascorbic acid at 4◦ C using Spectra-Por 2 dialysis tubing (MWCO 12000–14000). The dialyzed proteins were lyophilized, weighed, and stored under -80◦ C prior to use. Characterization and measurement of adducts All cysteinyl adducts arising from naphthoquinones and estrogen quinones were assayed by the procedure as described by Waidyanatha et al.[39] with modifications.[36] Briefly, to a 8-mL vial containing 10 mg of protein, isotopically labeled protein-bound internal standards for naphthoquinones and estrogen quinones were added. After bringing samples to complete dryness in a vacuum oven (70◦ C), we added 750 µL of TFAA and the reaction was allowed to proceed at 110◦ C for 30 min. After cooling to room temperature, 20 µL of MSA was added and the mixture was heated at 110◦ C for an additional 30 min. After cooling to room temperature, the un-reacted anhydride was removed under a gentle stream of N2 . Then, 1.5 mL of hexane was added to the residue, and the hexane layer was washed twice with 2 mL of 0.1 M Tris buffer (pH 7.4) and once with 1 mL of deionized water. After concentrating the samples to 50 µL, a 2-µl aliquot was analyzed by gas chromatograph and mass spectrometer (GC-MS). All analyses were conducted using an Agilent 6890 series GC (Santa Clara, CA, USA) coupled to an Agilent 5973N MS. A HP-5MS fused silica capillary column (30 m, 0.25-mm i.d., 0.25-µm film thickness) was used with He (99.999%) as the carrier gas at a flow rate of 1 mL/min. The MS transfer-line temperature was 250◦ C and the chemical ionization reagent gas (methane) pressure was 2.3 × 10−4torr. For characterization of adducts in the assay, our GCMS was set to scan from m/Z 50 to m/Z 750 in electron impact (EI) and negative ion chemical ionization (NCI) modes. The ion source temperature was set at 150◦ C and the injection-port temperature was 250◦ C in all cases. The GC oven temperature was held at 75◦ C for 2 min and increased at 6◦ C min−1 to 145◦ C, where it was held for 10 min. Lateeluting compounds were removed by increasing the oven temperature at 50◦ C min−1 to 260◦ C, where it was held for 5 min.
Lin et al. For quantitation of adducts, all conditions were similar to those described here for GC–NICI–MS except that the mass spectrometer was set to selected ion monitoring (SIM) mode. The following fragment ions were monitored in NICI mode for their respective TFA-derivatives: 1,2and 1,4-NPQ-S-TFA (m/Z 383); [2H5 ]1,2- and 1,4-NPQS-TFA (m/Z 388); E2 -2,3-Q-1-S-TFA, E2 -2,3-Q-4-S-TFA, and E2 -3,4-Q-S-TFA (m/Z 607); [2H3 ] E2 -2,3-Q-4-S-TFA and E2 -3,4-Q-2-S-TFA (m/Z 610); [2H4 ] E2 -2,3-Q-1-S-TFA (m/Z 611). For 1,2- and 1,4-NPQ-S-TFA, the quantitations were based on calibration against [2H5 ]1,2- and 1,4-NPQS-TFA, respectively. For E2 -2,3-Q-1-S-TFA, E2 -2,3-Q-4-STFA, and E2 -2,3-Q-2-S-TFA, the quantitations were based on calibration against [2H3 ] E2 -2,3-Q-4-S-TFA, [2H3 ] E2 3,4-Q-2-S-TFA, and [2H4 ] E2 -2,3-Q-1-S-TFA, respectively. Standard curves were prepared over a range of 0.1–500 pmol by deriving authentic standards equivalent to those of samples. Based on a signal-to-noise ratio of 3, the limit of detection of the modified MT assay corresponds to about 10 pmol g−1 for all adducts, assuming 10 mg of proteins were used for the assay. The precision, as indicated by estimated coefficients of variation, was 4% and 6% for 1,2NPQ-Alb and 1,4-NPQ-Alb (n = 10), respectively,. Statistical analysis All data are expressed as mean ± standard deviation (SD). All data were transformed to the natural logarithm and tested for normal distribution by Kolmogorov-Smirnov (K–S) for parametric analyses. Person correlation was used to evaluate the association between the levels of estrogen quinone-derived albumin adducts with those of naphthoquinones. Statistical analyses were performed using the Statistical Package for Social Science (SPSS Advanced Statistics version 18.0., Armonk, NY, USA). Two-tailed statistical significance was indicated by a P value less than 0.05.
Results Measurements of naphthoquinone-derived adducts in human serum Alb Figure 1 depicts the typical GC-NICI-MS chromatogram obtained in SIM mode after reaction of 10 mg of Alb derived from a pregnant woman. Characteristics of the study population and subjects’ levels of 1,2-NPQ-Alb or 1,4-NPQ-Alb. Cysteinyl adducts of both 1,2-NPQ and 1,4NPQ were detected in serum Alb of most of the study population. The median levels of 1,2-NPQ-Alb were 390 and 249 pmol g−1 in pregnant women (n = 41) and their corresponding umbilical cords (n = 41), respectively, whereas the median levels of 1,4-NPQ-Alb were 24.8 and 16.0 pmol g−1, respectively. We noticed that in general, the level of 1,2NPQ-Alb for each individual was much greater than that of 1,4-NPQ-Alb (∼15-fold, P < 0.001). We suspect that
Body burdens of PAHs associated with estrogen bioactivation A
637
m/z 383
12000
Abundance
1,2-NPQ-S-TFA 20.34
1,4-NPQ-S-TFA
8000
19.75
4000
18.5
19.0
19.5
20.0
20.5
Retention time (min)
B
30000 m/z 388 2
[ H 5 ]1,2-NPQ-S-TFA
Abundance
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0
20.31
20000
Fig. 2. Linear regression of square root of the logged levels of (1,2-NPQ-Alb) and (1,4-NPQ-Alb).
[2H 5 ]1,4-NPQ-S-TFA 19.68
10000
0 18.5
19.0 19.5 Retention time (min)
20.0
20.5
Fig. 1. GC-NICI-MS chromatogram obtained in selected ion monitoring mode following the reaction of 10 mg human serum (obtained from a pregnant woman in Taiwan) with TFAA and MSA. (a) Ions m/z 383 corresponds to TFA derivatives of 1,2NPQ and 1,4-NPQ. (b) The corresponding deuterated internal standard ions were m/z 388.
difference in their reactivity toward protein may contribute to this disparity. Additionally, linear correlation between 1,2-NPQ-Alb and 1,4-NPQ-Alb was performed using natural logarithmic transformation by simple regression analysis. Results indicated that logged levels of 1,2-NPQ-Alb correlated with logged levels of 1,4-NPQ-Alb (correlation coefficient r = 0.551, P < 0.001) (Fig. 2). Measurements of estrogen quinone-derived adducts in human serum Alb Figure 3 depicts the typical GC-NICI-MS chromatogram obtained in SIM mode after derivatization of 10 mg of Alb derived from a pregnant woman. This figure demonstrates the presence of estrogen quinone-derived cysteinyl adducts on human serum albumin after adducts cleavage from proteins. Cysteinyl adducts of E2 -2,3-Q-4-S-Alb and E2 -3,4-Q2-S-Albwere detected in serum Alb of all the study popu-
lation; whereas E2 -2,3-Q-1-S-Alb adducts were detected in only some of these subjects. The nucleophilic attack at C1or C4-position of E2 -2,3-Q generated either E2 -2,3-Q-1-SAlb or E2 -2,3-Q-4-S-Alb. We speculate that stereo hindrance may favor the formation of E2 -2,3-Q-4-S-Alb more than E2 -2,3-Q-1-S-Alb. The median levels of E2 -2,3-Q-1-S-Alb and E2 -2,3-Q-4-SAlb and E2 -3,4-Q-2-S-Alb were 275-435, 162-288, and 197254 pmol g−1 in these subjects, respectively. Similarly, when we performed linear correlation using natural logarithmic transformation by simple regression analysis, logged levels of E2 -2,3-Q-4-S-Alb highly correlated with logged levels of and E2 -3,4-Q-2-S-Alb (correlation coefficient r = 0.770, P < 0.001) (Fig. 4).
Discussion Incidence of breast cancer has increased dramatically in Taiwanese women over the past decade.[40] Environmental and occupational exposure to PAHs and other toxic substances may be responsible for the increased risk of developing breast cancer.[1,41] It is likely that induction of genes responsible for activation of estrogen to its reactive quinones by AhR agonists, including PAHs, may contribute to the initiation of estrogen carcinogenesis. The urinary excretion of mono- and di-hydroxylated PAH metabolites are classically measured for the determination of PAH exposure in epidemiological studies.[7,8] In addition, albumin adducts of a quinonoid metabolite of naphthalene, 1,2NPQ, have been used as biomarkers of occupational and environmental exposure to PAHs where increased levels of
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Lin et al.
Fig. 4. Linear regression of square root of the logged levels of (E2 -2,3-Q-4-Alb) and (E2 -3,4-Q-2-Alb).
Fig. 3. GC-NICI-MS chromatogram obtained in selected ion monitoring mode following the reaction of 10 mg human serum (obtained from a pregnant woman in Taiwan) with TFAA and MSA. (a) Ions m/z 607 corresponds to TFA derivatives of E2 2,3-Q and E2 -3,4-EQ. (b) The corresponding deuterated internal standard ions were m/z 610 for [2H4 ] E2 -2,3-Q-4-S-TFA, and (c) 611 for [2H3 ]E2 -2,3-EQ-1-S-TFA.
naphthoquinone-derived albumin adducts were detected in coke oven workers when compared to their respective controls.[9] To measure both estrogen quinone- and naphthoquinone-derived protein adducts in human serum albumin and to explore the association between them, we conducted the current investigation to simultaneously analyze both adducts in serum albumin derived from healthy pregnant women in Taiwan. Logged levels of 1,2-NPQ correlated with logged levels of 1,4-NPQ (r = 0.551, P < 0.001) (Fig. 2). This finding is agreeable with that reported by our previous investigation in healthy blood donors for the correlation between 1,2-NPQ-Alb and 1,4-NPQ-Alb (r = 0.643, P < 0.001). The median levels of 1,4-NPQ-Alb were estimated to be between 16–25 (range 10–70) pmol g−1 Alb in the study population. We noticed that this observation is slightly lower than that reported in female blood donors where the median levels of 1,4-NPQ-Alb were estimated to be 38.9 (range 22–172) pmol g−1.[35] By contrast, the median levels of 1,2-NPQ-Alb detected in this study population (249–390 pmol g−1 Alb; range 121–859 pmol g−1 Alb) were comparable with those reported in female blood donors (203 pmol g−1 Alb; range 128–1352 pmol g−1 Alb). The mechanism underlying the differences in the disposition of naphthalene between female blood donors and pregnant women is not clear. The fact that a wide range of variables may influence the expression of P450 enzymes, including estrogen homeostasis, may attribute to this disparity.[42] Many factors may affect the generation of estrogen quinones in humans, including environmental issues and genetic predisposition.[43–45] To gauge the burden of estrogen quinones in human serum, we measured the levels of estrogen quinone-derived adducts in serum Alb in
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correlation between adduct levels of 1,2-NPQ-Alb and estrogen quinone-derived adducts in pregnant women was performed using natural logarithmic transformation by simple regression analysis. Results showed that logged levels of 1,2-NPQ-Alb highly correlate with logged levels of E2 -2,3-Q-4-S-Alb (r = 0.484, P < 0.001) and and E2 -3,4Q-2-S-Alb (r = 0.522, P < 0.001) (Figs. 5a and 5b). This finding provides direct evidence of positive correlation of cumulative body burdens of PAHs and activation of estrogen in healthy pregnant women. Overall, we conclude that environmental exposure to PAHs may modulate estrogen homeostasis and enhance the production of reactive quinone species of endogenous estrogen (∼1.7-fold) in human. The methodology developed in this study may be applied to epidemiological studies to serve as biomarkers of PAH exposure and estrogen homeostasis.
Funding This work was supported by the National Science Council, Taiwan, through Grants NSC98-2314-B-371-004-MY2 and NSC99-2314-B-005-001-MY3.
References
Fig. 5. (a) Linear regression of square root of the logged levels of (1,2-NPQ-Alb) and (E2 -3,4-Q-2-Alb). (b) Linear regression of square root of the logged levels of (1,2-NPQ-Alb) and (E2 -2,3-Q4-Alb).
the study population. Results from our analyses indicated that E2 -2,3-Q-1-S-Alb, E2 -2,3-Q-4-S-Alb, and E2 -3,4-Q-2S-Alb were detected in most of the participants. As expected, logged levels of E2 -2,3-Q-4-S-Alb highly correlated with logged levels of E2 -3,4-Q-2-S-Alb with correlation coefficient (r) at 0.770 (P < 0.001) (Fig. 4). Furthermore, we noticed that median levels of E2 -2,3-Q-derived adducts (E2 2,3-Q-1-S-Alb plus E2 -2,3-Q-4-S-Alb) in pregnant women were greater than those of E2 -3,4-Q-2-S-Alb (∼2–3-fold). This observation is comparable with our previous investigation where levels of E2 -2,3-Q-derived adducts in serum of healthy female blood donors were much greater than those of E2 -3,4-Q-2-S-Alb (∼5-fold).[36] To examine the degree of association between PAH exposure and cumulative body burden of estrogen quinones,
[1] Bonner, M.R.; Han, D.; Nie, J.; Rogerson, P.; Vena, J.E.; Muti, P.; Trevisan, M.; Edge, S.B.; Freudenheim, J.L. Breast cancer risk and exposure in early life to polycyclic aromatic hydrocarbons using total suspended particulates as a proxy measure. Cancer Epidemiol. Biomark. Prev. 2005, 14(1), 53–60. [2] Devanesan, P.D.; RamaKrishna, N.V.; Todorovic, R.; Rogan, E.G.; Cavalieri, E.L.; Jeong, H.; Jankowiak, R.; Small, G.J. Identification and quantitation of benzo[a]pyrene-DNA adducts formed by rat liver microsomes in vitro. Chem. Res. Toxicol. 1992, 5(2), 302–309. [3] Marshall, C.J.; Vousden, K.H.; Phillips, D.H. Activation of c-Haras-1 proto-oncogene by in vitro modification with a chemical carcinogen, benzo(a)pyrene diol-epoxide. Nature 1984, 310(5978), 586–589. [4] Rodenhuis, S. Ras and human tumors. Semin. Cancer Biol. 1992, 3(4), 241–247. [5] van der Schroeff, J.G.; Evers, L.M.; Boot, A.J.; Bos, J.L. Ras oncogene mutations in basal cell carcinomas and squamous cell carcinomas of human skin. J. Invest. Dermatol. 1990, 94(4), 423–425. [6] Santodonato, J. Review of the estrogenic and antiestrogenic activity of polycyclic aromatic hydrocarbons: relationship to carcinogenicity. Chemosphere 1997, 34(4), 835–848. [7] Buratti, M.; Campo, L.; Fustinoni, S.; Cirla, P.E.; Martinotti, I.; Cavallo, D.; Foa, V. Urinary hydroxylated metabolites of polycyclic aromatic hydrocarbons as biomarkers of exposure in asphalt workers. Biomarkers 2007, 12(3), 221–239. [8] Seidel, A.; Spickenheuer, A.; Straif, K.; Rihs, H.P.; Marczynski, B.; Scherenberg, M.; Dettbarn, G.; Angerer, J.; Wilhelm, M.; Bruning, T.; Jacob, J.; Pesch, B. New biomarkers of occupational exposure to polycyclic aromatic hydrocarbons. J. Toxicol. Environ. Health A 2008, 71(11–12), 734–745. [9] Waidyanatha, S.; Zheng, Y.; Serdar, B.; Rappaport, S.M. Albumin adducts of naphthalene metabolites as biomarkers of exposure to polycyclic aromatic hydrocarbons. Cancer Epidemiol. Biomark. Prev. 2004, 13(1), 117–124. [10] Preuss, R.; Angerer, J.; Drexler, H. Naphthalene—An environmental and occupational toxicant. Int. Arch. Occup. Environ. Health 2003, 76(8), 556–576.
Downloaded by [Memorial University of Newfoundland] at 10:53 31 January 2015
640 [11] Toxicology and Carcinogenesis Studies of Naphthalene (CAS No. 91-20-3) in B6C3F1 Mice (Inhalation Studies). Natl. Toxicol. Prog. Tech. Rep. Ser. 1992, 410, 1–172. [12] Yang, Y.; Sharma, R.; Cheng, J.Z.; Saini, M.K.; Ansari, N.H.; Andley, U.P.; Awasthi, S.; Awasthi, Y.C. Protection of HLE B-3 cells against hydrogen peroxide- and naphthalene-induced lipid peroxidation and apoptosis by transfection with hGSTA1 and hGSTA2. Invest. Ophthalmol. Vis. Sci. 2002, 43(2), 434–445. [13] Bagchi, D.; Bagchi, M.; Balmoori, J.; Vuchetich, P.J.; Stohs, S.J. Induction of oxidative stress and DNA damage by chronic administration of naphthalene to rats. Res. Commun. Mol. Pathol. Pharmacol. 1998, 101(3), 249–257. [14] Bagchi, M.; Balmoori, J.; Ye, X.; Bagchi, D.; Ray, S.D.; Stohs, S.J. Protective effect of melatonin on naphthalene-induced oxidative stress and DNA damage in cultured macrophage J774A.1 cells. Mol. Cell Biochem. 2001, 221(1–2), 49–55. [15] Schreiner, C.A. Genetic toxicity of naphthalene: A review. J. Toxicol. Environ. Health B Crit Rev. 2003, 6(2), 161–183. [16] Toxicology and carcinogenesis studies of naphthalene (cas no. 9120-3) in F344/N rats (inhalation studies). Natl. Toxicol. Prog. Tech. Rep. Ser. 2000, 500, 1–173. [17] Feigelson, H.S.; Henderson, B.E. Estrogens and breast cancer. Carcinogenesis 1996, 17(11), 2279–2284. [18] Bolton, J.L.; Thatcher, G.R. Potential mechanisms of estrogen quinone carcinogenesis. Chem. Res. Toxicol. 2008, 21(1), 93–101. [19] Cavalieri, E.; Frenkel, K.; Liehr, J.G.; Rogan, E.; Roy, D. Estrogens as endogenous genotoxic agents–DNA adducts and mutations. J. Natl. Cancer Inst. Monogr. 2000, 27, 75–93. [20] Lavigne, J.A.; Goodman, J.E.; Fonong, T.; Odwin, S.; He, P.; Roberts, D.W.; Yager, J.D. The effects of catechol-Omethyltransferase inhibition on estrogen metabolite and oxidative DNA damage levels in estradiol-treated MCF-7 cells. Cancer Res. 2001, 61(20), 7488–7494. [21] Yager, J.D. Endogenous estrogens as carcinogens through metabolic activation. J. Natl. Cancer Inst. Monogr. 2000, 27, 67–73. [22] Hayes, C.L.; Spink, D.C.; Spink, B.C.; Cao, J.Q.; Walker, N.J.; Sutter, T.R. 17 beta-estradiol hydroxylation catalyzed by human cytochrome P450 1B1. Proc. Natl. Acad. Sci. USA 1996, 93(18), 9776–9781. [23] Martucci, C.P.; Fishman, J. P450 enzymes of estrogen metabolism. Pharmacol. Ther. 1993, 57(2–3), 237–257. [24] Spink, D.C.; Spink, B.C.; Cao, J.Q.; Gierthy, J.F.; Hayes, C.L.; Li, Y.; Sutter, T.R. Induction of cytochrome P450 1B1 and catechol estrogen metabolism in ACHN human renal adenocarcinoma cells. J. Ster. Biochem. Mol. Biol. 1997, 62(2–3), 223–232. [25] Butterworth, M.; Lau, S.S.; Monks, T.J. 17 beta-estradiol metabolism by hamster hepatic microsomes: comparison of catechol estrogen O-methylation with catechol estrogen oxidation and glutathione conjugation. Chem. Res. Toxicol. 1996, 9(4), 793–799. [26] Cao, K.; Stack, D.E.; Ramanathan, R.; Gross, M.L.; Rogan, E.G.; Cavalieri, E.L. Synthesis and structure elucidation of estrogen quinones conjugated with cysteine, N-acetylcysteine, and glutathione. Chem. Res. Toxicol. 1998, 11(8), 909–916. [27] Yager, J.D.; Davidson, N.E. Estrogen carcinogenesis in breast cancer. N. Engl. J. Med. 2006, 354(3), 270–282. [28] Parl, F.F.; Dawling, S.; Roodi, N.; Crooke, P.S. Estrogen metabolism and breast cancer: a risk model. Ann. NY Acad. Sci. 2009, 1155, 68–75. [29] Convert, O.; Van Aerden, C.; Debrauwer, L.; Rathahao, E.; Molines, H.; Fournier, F.; Tabet, J.C.; Paris, A. Reactions of estradiol-2,3quinone with deoxyribonucleosides: possible insights in the reactivity of estrogen quinones with DNA. Chem. Res. Toxicol. 2002, 15(5), 754–764. [30] Cavalieri, E.L.; Stack, D.E.; Devanesan, P.D.; Todorovic, R.; Dwivedy, I.; Higginbotham, S.; Johansson, S.L.; Patil, K.D.; Gross,
Lin et al.
[31]
[32]
[33]
[34]
[35]
[36]
[37]
[38]
[39]
[40]
[41] [42]
[43]
[44]
[45]
M.L.; Gooden, J.K.; Ramanathan, R.; Cerny, R.L.; Rogan, E.G. Molecular origin of cancer: catechol estrogen-3,4-quinones as endogenous tumor initiators, Proc. Natl. Acad. Sci. USA 1997, 94(20), 10937–10942. Cavalieri, E.L.; Devanesan, P.; Bosland, M.C.; Badawi, A.F.; Rogan, E.G. Catechol estrogen metabolites and conjugates in different regions of the prostate of Noble rats treated with 4-hydroxyestradiol: implications for estrogen-induced initiation of prostate cancer. Carcinogenesis 2002, 23(2), 329–333. Zahid, M.; Kohli, E.; Saeed, M.; Rogan, E.; Cavalieri, E. The greater reactivity of estradiol-3,4-quinone vs estradiol-2,3-quinone with DNA in the formation of depurinating adducts: implications for tumor-initiating activity. Chem. Res. Toxicol. 2006, 19(1), 164–172. Lin, P.H.; Nakamura, J.; Yamaguchi, S.; Asakura, S.; Swenberg, J.A. Aldehydic DNA lesions induced by catechol estrogens in calf thymus DNA. Carcinogenesis 2003, 24(6), 1133–1141. Waidyanatha, S.; Rappaport, S.M. Hemoglobin and albumin adducts of naphthalene-1,2-oxide, 1,2-naphthoquinone and 1,4naphthoquinone in Swiss Webster mice. Chem. Biol. Interact. 2008, 172(2), 105–114. Lin, P.H.; Chen, D.R.; Wang, T.W.; Lin, C.H.; Chuang, M.C. Investigation of the cumulative tissue doses of naphthoquinones in human serum using protein adducts as biomarker of exposure. Chem. Biol. Interact. 2009, 181(1), 107–114. Chen, D.R.; Chen, S.T.; Wang, T.W.; Tsai, C.H.; Wei, H.H.; Chen, G.J.; Yang, T.C.; Lin, C.; Lin, P.H. Characterization of estrogen quinone-derived protein adducts and their identification in human serum albumin derived from breast cancer patients and healthy controls. Toxicol. Lett. 2011, 202(3), 244–252. Wang, S.L.; Chang, Y.C.; Chao, H.R.; Li, C.M.; Li, L.A.; Lin, L.Y.; Papke, O. Body burdens of polychlorinated dibenzo-pdioxins, dibenzofurans, and biphenyls and their relations to estrogen metabolism in pregnant women. Environ. Health Perspect. 2006, 114(5), 740–745. Halliwell, B.; Gutteridge, J.M. The importance of free radicals and catalytic metal ions in human diseases. Mol. Aspects Med. 1985, 8(2), 89–193. Waidyanatha, S.; Troester, M.A.; Lindstrom, A.B.; Rappaport, S.M. Measurement of hemoglobin and albumin adducts of naphthalene1,2-oxide, 1,2-naphthoquinone and 1,4-naphthoquinone after administration of naphthalene to F344 rats. Chem. Biol. Interact. 2002, 141(3), 189–210. Huang, C.S.; Lin, C.H.; Lu, Y.S.; Shen, C.Y. Unique features of breast cancer in Asian women—breast cancer in Taiwan as an example. J. Ster. Biochem. Mol. Biol. 2010, 118(4–5), 300– 303. Boffetta, P.; Nyberg, F. Contribution of environmental factors to cancer risk. Br. Med. Bull. 2003, 68, 71–94. Ishii, T.; Nishimura, K.; Nishimura, M. Administration of xenobiotics with anti-estrogenic effects results in mRNA induction of adult male-specific cytochrome P450 isozymes in the livers of adult female rats. J. Pharmacol. Sci. 2006, 101(3), 250–255. Shin, A.; Kang, D.; Choi, J.Y.; Lee, K.M.; Park, S.K.; Noh, D.Y.; Ahn, S.H.; Yoo, K.Y. Cytochrome P450 1A1 (CYP1A1) polymorphisms and breast cancer risk in Korean women. Exp. Mol. Med. 2007, 39(3), 361–366. Okobia, M.N.; Bunker, C.H.; Garte, S.J.; Zmuda, J.M.; Ezeome, E.R.; Anyanwu, S.N.; Uche, E.E.; Osime, U.; Ojukwu, J.; Kuller, L.H.; Ferrell, R.E.; Taioli, E. Cytochrome P450 1B1 Val432Leu polymorphism and breast cancer risk in Nigerian women: A case control study. Infect. Agent Cancer 4 Suppl. 2009, 1, S12. Brody, J.G.; Moysich, K.B.; Humblet, O.; Attfield, K.R.; Beehler, G.P.; Rudel, R.A. Environmental pollutants and breast cancer: Epidemiologic studies. Cancer 2007, 109(12 Suppl), 2667– 2711.
