SEARCH · PubMed Health

Results for “BPDE-DNA adduct”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed2024

Effects of particulate air pollution on BPDE-DNA adducts, telomere length, and mitochondrial DNA copy number in human exhaled breath condensate and BEAS-2B cells.

Traffic-related particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) have been linked to respiratory diseases and cancer risk in humans. Genomic damage, including benzo[a]pyrene diolepoxide (BPDE)-DNA adducts as well as alterations in telomere length (TL) and mitochondrial DNA copy number (mtDNA-CN) are associated with respiratory diseases. This study aimed to investigate the association between exposure to traffic-related particulate pollutants and genomic damage in exhaled breath condensate (EBC) in human subjects and a bronchial epithelial cell line (BEAS-2B). Among the 60 healthy recruited subjects, residents living in high-traffic-congested areas were exposed to higher concentrations of PM2.5 (1.66-fold, p < 0.01), UFPs (1.79-fold, p < 0.01), PM2.5-PAHs (1.50-fold, p < 0.01), and UFPs-PAHs (1.35-fold, p < 0.05), than those in low-traffic-congested areas. In line with increased exposure to particulate air pollution, the high-traffic-exposed group had significantly increased BPDE-DNA adducts (1.40-fold, p < 0.05), TL shortening (1.24-fold, p < 0.05), and lower mtDNA-CN (1.38-fold, p < 0.05) in EBC. The observations in the human study linking exposure to PM2.5, UFPs, PM2.5-PAHs, and UFPs-PAHs with the aforementioned biological effects were confirmed by an in vitro cell-based study, in which BEAS-2B cells were treated with diesel exhaust particulate matter (DEP) containing fine and ultrafine PM and PAHs. Increased BPDE-DNA adducts levels, shortened TL, and decreased mtDNA-CN were also found in treated BEAS-2B cells. The shortened TL and decreased mtDNA-CN were in part mediated by decreased transcript levels of hTERT, and SIRT1, which are involved in telomerase activity and mitochondrial biogenesis, respectively. These results suggest that exposure to traffic-related particulate pollutants can cause genomic instability in respiratory cells, which may increase the health risk of respiratory diseases and the development of cancer.

Humans↗

PubMed1991

[Research on adducts of benzo(a)pyrene and DNA in different cells using synchronous fluorescence spectrophotometry].

The levels of benzo(a)pyrene diolepoxide(BPDE)-DNA adducts were measured in rat and human cells by synchronous fluorescence spectrophotometry. BPDE-DNA adducts detected in human pulmonary alveolar macrophages were related to current smoking habits, in contrast to the adducts found in peripheral blood leukocytes. BP administration to rats produced BPDE-DNA adducts in both liver and lungs. Although small yet repeatable signals were also detected in lung DNA from rats treated for 3 days with tobacco smoke. None of the samples obtained from untreated animals was positive. The detection of BPDE-DNA adducts may be used in biomonitoring and experimental studies for determining of exposure to BP even when applied as a constituent of complex mixtures.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMedDate not supplied

Biomonitoring of genotoxic exposure of aluminium plant workers.

Humans are environmentally and occupationally exposed to polycyclic aromatic hydrocarbons (PAH). PAH's are a class of tumorigenic compounds which act through metabolic transformation to chemically reactive forms, epoxides, which covalently bind to DNA forming DNA adducts. To evaluate the genotoxic effects of PAH's, air and urine samples were analyzed for PAH. Blood samples were analyzed for benzo(a)pyrene-diol-epoxide-DNA (BPDE-DNA) adducts. New methods for analyzing DNA adducts in lymphocytes have been used to study the genotoxic effects of human exposure to carcinogens. BPDE-DNA adducts in lymphocytes have been used as internal dosimeters of exposure to PAH's and several studies have been conducted. We measured BPDE-DNA adducts in aluminium plant workers with immuno-assay and physico-chemical methods. PAH-DNA adducts were detectable to a lesser extent in subjects working in an aluminium plant compared to subjects working in a coke oven plant.

Air Pollutants, Occupational↗

PubMed1991

Fluorescence detection of benzo[a]pyrene--DNA adducts in human lung.

Improved techniques are described for the specific identification of benzo[a]pyrene-diolepoxide (BPDE)--DNA adducts in human tissues. Immunoaffinity chromatography, synchronous fluorescence spectroscopy and second-derivative synchronous fluorescence spectroscopy have previously been used to detect BPDE-DNA adducts in human placenta. Here we report how these methods, together with HPLC and the generation of complete fluorescence excitation--emission matrices, have been used to identify unequivocally BPDE-DNA adducts in samples of human lung. BPDE nucleotide adducts were isolated with immunoaffinity chromatography columns bearing antibodies raised against the (+/-)anti-7,8-diol-9,10-epoxide-deoxyguanosine adduct of benzo[a]pyrene. These adducts were hydrolyzed to tetrahydrotetrols and the hydrolysis products subjected to HPLC. The major product isolated by HPLC, benzo[a]-pyrene-7,10/8,9-tetrahydrotetrol, was determined by fluorescence spectroscopy. Using this method, levels of BPDE-DNA adducts in the range of 1-40 in 10(8) nucleotides were measured in 6 out of 25 samples, with a lower detection limit of one adduct in 10(8) nucleotides. The data may also indicate that adduct levels show regional variation in different parts of the same lung.

Adolescent↗

PubMed1992

Detection of benzo[a]pyrene-diol-epoxide-DNA adducts in white blood cells of psoriatic patients treated with coal tar.

An enzyme-linked immunosorbent assay (ELISA) was used to detect BPDE-DNA adducts in white blood cells of 23 psoriatic patients undergoing clinical coal tar therapy. Ten of these patients were reanalyzed 2-5 months after the end of the coal tar treatments. The results show that the mean adduct level during the treatment period was 0.26 +/- 0.16 fmole BPDE/micrograms DNA (7.7 +/- 4.9 adducts/10(8) nucleotides), while 2-5 months later the mean adduct level had decreased significantly (P less than 0.005) to 0.11 +/- 0.08 fmole BPDE/micrograms DNA (3.3 +/- 2.4 adducts/10(8) nucleotides). No relationship could be ascertained between the level of exposure and the amount of BPDE-DNA adducts. In addition, no difference in the level of DNA adducts was found between smoking and non-smoking patients.

Adult↗

PubMed1992

Oxygen radical-dependent epoxidation of (7S,8S)-dihydroxy-7,8-dihydrobenzo[a]pyrene in mouse skin in vivo. Stimulation by phorbol esters and inhibition by antiinflammatory steroids.

(7S,8S)--Dihydroxy--7,8--dihydrobenzo[a]pyrene ((+)-BP-7,8-diol) is epoxidized to (7S,8R)-dihydroxy-(9S,10R)-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene ((+)-syn-BPDE) by cytochrome P-450 isoenzymes and to (7S,8R)-dihydroxy-(9R,10S)-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene ((-)-anti-BPDE) by peroxyl free radicals. 32P postlabeling analysis of the diastereomeric BPDE-DNA adducts was used to investigate the pathways of (+)-BP-7,8-diol oxidation in mouse skin in vivo. The pattern of deoxynucleoside 3',5'-bisphosphate adducts in epidermal scrapings from female CD-1 mice indicated that cytochrome P-450 was the major oxidant. Similar results were obtained when the tumor-promoting phorbol ester tetradecanoylphorbolacetate (TPA) was coadministered with (+)-BP-7,8-diol. However, when animals were pretreated with TPA 24 h before coadministration of TPA and (+)-BP-7,8-diol, the pattern of BPDE-DNA adducts indicated that peroxyl radicals made a major contribution to (+)-BP-7,8-diol epoxidation. Peroxyl radical-dependent epoxidation was maximal when the time between the two TPA administrations was 24-72 h. No increase in (-)-anti-BPDE-DNA was observed when the non-tumor-promoting phorbol ester 4-O-methyl-TPA was substituted for TPA. The calcium ionophore A23187 stimulated peroxyl radical generation when substituted for the first, but not the second, TPA treatment. The antiinflammatory steroid fluocinolone acetonide inhibited (-)-anti-BPDE-DNA adduct formation when coadministered with the first but not the second TPA treatment. These findings demonstrate the existence of two independent pathways of metabolic activation of (+)-BP-7,8-diol in mouse epidermis, one dependent on cytochrome P-450 and the other dependent on peroxyl free radicals. The results also suggest that repetitive topical administration of tumor-promoting phorbol esters remodels epidermal metabolism leading to a significant increase in free radical generation.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed1991

Benzo[a]pyrene-globin adducts detected by synchronous fluorescence spectrophotometry: method development and relation to lung DNA adducts in mice.

A simple synchronous fluorescence spectrophotometry (SFS) to detect benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE)-globin adducts is described. SFS for BPDE-DNA, which measures detached benzo[a]pyrene (B[a]P)-tetrols after acid hydrolysis of DNA, was applied for BPDE-globin adducts in B[a]P-treated C57BL/6 (B6) mice. Unlike DNA samples, globin is not measurable as such after acid hydrolysis because proteins give a background in SFS. Furthermore, proteinase incubation before acid hydrolysis of globin gave too much background even after purification to be useful in this assay. Of several purification procedures tried after acid hydrolysis (protein precipitation, elution through Sep-Pak C18, filtration, ether extraction of tetrols), the lowest background fluorescence was obtained with ether extractions of B[a] moieties. Ether phases were evaporated to dryness and the remainder dissolved in distilled water (1 ml), which was measured by SFS. Compared to DNA, somewhat milder hydrolysis conditions were optimal for globin samples (0.05 M HCl, 1.5 h, + 90 degrees C). Globin samples from B[a]P-treated mice gave a peak at the same wavelength (345 nm excitation) as the hydrolysis products of BPDE-DNA adducts, indicating B[a]P-tetrols and triols in the sample. Less than half of B[a]P measured in globin was from covalently bound BPDE. In mice injected i.p. with 1-160 mg/kg of B[a]P there was a dose-dependent increase in the amount of BPDE adducts in globin and a positive correlation with lung and liver DNA. Globin adducts were a more sensitive indicator of B[a]P exposure than DNA adducts because more globin can be used for the assay. Although both covalently and non-covalently bound BPDE in globin are detected by SFS, this method is the simplest described so far, reproducible and theoretically sensitive enough for human biomonitoring.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed1992

Polycyclic aromatic hydrocarbon--DNA adducts in white blood cells from lung cancer patients: no correlation with adduct levels in lung.

Smokers of cigarettes are exposed to a number of carcinogens, including polycyclic aromatic hydrocarbons (PAHs), and are at a high risk for lung cancer. PAHs exert their carcinogenic activity after metabolic activation to reactive intermediates that can damage DNA through adduct formation. Measuring DNA adducts in peripheral white blood cells (WBC) could serve as a means of monitoring human exposure to genotoxic agents and subsequently risk assessment. In this study, DNA from WBC obtained from 39 lung cancer patients was examined for PAH-DNA adducts both in an ELISA using a polyclonal antibody against benzo[a]pyrene 7,8-diol-9,10-epoxide (BPDE)-DNA and the 32P-post-labeling technique. The ELISA results showed BPDE-DNA antigenicity in WBC DNA from 12/38 (32%) patients and adduct levels ranged from 1.5 to greater than 150 adducts in 10(8) nucleotides. The autoradiographs of chromatograms of 32P-post-labeled digests of WBC DNA from the 38 patients showed a variety of adduct spots; relative adduct labeling (RAL) values ranged from 0.3 to 407 adducts in 10(8) nucleotides. In 18 of the 38 (47%) persons an adduct spot was detected that co-chromatographed with the major BPDE-DNA adduct (BPDE-dG); RAL values ranged from 0.03 to 382 adducts in 10(8) nucleotides. Correlations were not significant between the adduct levels in WBC and smoking habits, age or sex. From 20 patients of the same group lung tissue was collected at surgery and examined for PAH-DNA adducts by ELISA and 32P-post-labeling assay. No significant correlation was found between DNA adduct levels in blood and lung. This finding stresses the limitations of the use of WBC as a surrogate for adduct levels in the target organ.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed1992

Coal tar therapy does not influence in vitro benzo[a]pyrene metabolism and DNA adduct formation in peripheral blood lymphocytes of psoriatic patients.

Human lymphocytes (HL) from healthy subjects and psoriatic patients were treated in vitro for 24 h with 4 microM [3H]benzo[a]pyrene (B[a]P) and 2 microM (-)-B[a]P-7,8-dihydrodiol in order to verify if the coal tar (CT) used in the therapy of psoriasis, which is characterized by a high content of polycyclic aromatic hydrocarbons (PAH), influences the formation of B[a]P-DNA adducts and the metabolism of B[a]P. Significant amounts of syn-BPDE-dGuo adducts were detected in all the examined HL samples, but no significant difference in the amounts of total BPDE-DNA adducts or of specific anti- and syn-BPDE-dGuo adducts was observed between healthy subjects and psoriatic patients, or between psoriatic patients before and after CT treatment. Moreover, the CT treatment of psoriatic patients did not influence the enantiomeric composition of B[a]P-7,8-dihydrodiols present in the HL culture medium, among which the (-)-7R,8R form was found to predominate (greater than 98%) in all the HL samples. The existence in HL of a specific metabolic pathway of B[a]P leading to the formation of (-)-syn-BPDE and the corresponding tetrols, through the epoxidation of the (-)-7R,8R enantiomer of B[a]P-7,8-dihydrodiol, was confirmed by determining the tetrols derived from the syn- and anti-stereoisomers of BPDE, released in HL culture medium after treatment for 24 h with 2 microM (-)-B[a]P-7,8-dihydrodiol. Although B[a]P-7,10/8,9 and B[a]P-7/8,9,10 tetrols, derived from (+)-anti-BPDE, were the predominant isomers, significant amounts of B[a]P-7,9/8,10 and B[a]P-7,9,10/8 tetrols, derived from the hydrolysis of (-)-syn-BPDE, were also detected. The mean ratio of anti/syn tetrols in healthy subjects was significantly lower than in psoriatic patients, but no difference in that ratio was found in psoriatic patients before and after CT treatment.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed1992

Carcinogen-DNA adducts in human alveolar macrophages.

The occurrence of 7 beta,8 alpha-dihydroxy-(9 alpha,10 alpha)-epoxy-7,8,9,10- tetrahydrobenzo(a)pyrene (BPDE-)-DNA adducts was investigated by synchronous fluorescence spectrophotometry in human pulmonary alveolar macrophages (PAM) collected by bronchoalveolar lavage. In preliminary assays BPDE-DNA adducts were consistently detected in PAM of smokers, whereas samples from nonsmokers did not exhibit specific peaks.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed1992

Assessment of PAH-exposure among coke oven workers.

Coke oven workers are exposed to high concentrations of polycyclic aromatic hydrocarbons. Only recently have methods been developed to try to assess the individual, biologically significant exposure. The only coke oven plant in Finland started to function in 1987, in Raahe, enabling the implementation of a cohort study among the workers to determine the usefulness of some currently available biomonitoring methods, e.g. methods of measuring PAH-DNA adducts. Urine and blood samples were taken several times from a sample of workers starting from before they worked at the plant. A questionnaire (smoking, diet, former and current occupations) was filled in by the workers at every sampling, and air samples (personal and stationary) were collected at the same time. The mean values of both benzo(a)pyrene diolepoxide (BPDE)-DNA adducts were measured by synchronous fluorescence spectrophotometry (SFS) and the antibodies to these adducts increased somewhat after the work at the plant started. However, all the adduct values were low, and no differences between the smokers and non-smokers at any time point were detected. Battery workers had slightly increased means of BPDE-DNA adducts compared to non-battery workers. Also, coke oven workers had slightly higher adduct values than age, sex and smoking matched controls.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed1992

Differences and similarities in the repair of two benzo[a]pyrene diol epoxide isomers induced DNA adducts by uvrA, uvrB, and uvrC gene products.

We have determined the role of the uvrA, uvrB, and uvrC genes in Escherichia coli cells in repairing DNA damage induced by three benzo[a]pyrene diol epoxide isomers. Using the phi X174 RF DNA-E. coli transfection system, we have found that BPDE-I or BPDE-II modified phi X174 RF DNA has much lower transfectivity in uvrA, uvrB, and uvrC mutant cells compared to wild type cells. In contrast, BPDE-III modification of phi X174 RF DNA causes much less difference in transfectivity between wild type and uvr- mutant cells. Moreover, BPDE-I and -II-DNA adducts are much more genotoxic than are BPDE-III-DNA adducts. Using purified UVRA, UVRB, and UVRC proteins, we have found that these three gene products, working together, incise both BPDE-I- and BPDE-III-DNA adducts quantitatively and, more importantly, at the same rate. In general, UVRABC nuclease incises on both the 5' (six to seven nucleotides) and 3' (four nucleotides) sides of BPDE-DNA adducts with similar efficiency with few exceptions. Quantitation of the UVRABC incision bands indicates that both of these BPDE isomers have different sequence selectivities in DNA binding. These results suggest that although UVR proteins can efficiently repair both BPDE-I- and BPDE-III-DNA adducts, in vivo the uvr system is the major excision mechanism for repairing BPDE-I-DNA adducts but may play a lesser role in repairing BPDE-III-DNA adducts. It is possible the low lethality of BPDE-III-DNA adducts is due to less complete blockage of DNA replication.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphatases↗

PubMed1990

Polycyclic aromatic hydrocarbon-DNA adducts in lung tissue from lung cancer patients.

In an attempt to probe for polycyclic aromatic hydrocarbon (PAH)-DNA adducts in human subjects resulting from smoking (or other chronic environmental exposure), lung tissue and lung tumours were obtained from patients hospitalized for lung cancer. DNA was isolated from the tissue samples and examined both in an ELISA using a polyclonal antibody against (+/-)trans-7,8-dihydroxy-anti-9,10-epoxy-7,8,9,10- tetrahydrobenzo[a]pyrene (BPDE)-DNA as well as by the nuclease P1-mediated modification of the 32P-post-labelling technique. The ELISA results showed BPDE-DNA antigenicity in lung DNA from 6 out of 21 patients, and adduct levels ranged from 2 to 134 adducts per 10(8) nucleotides. For all 21 patients, the autoradiographs of chromatograms of 32P-postlabelled digests of DNA from non-tumorous lung tissue showed a strong diagonal radioactive zone (DRZ). This DRZ was generally absent in tumorous tissue. DNA samples that were positive in the ELISA contained a dominant spot within the DRZ that co-chromatographed with the major BPDE-DNA adduct (BPDE-dG). The quantities of the BPDE-dG spots ranged from 2.1 to 42 adducts in 10(9) nucleotides. These values were lower than the levels found in the ELISA but correlated well with the ELISA results (Kendall W = 0.97; P = 0.00). The levels of the DRZ adducts ranged from 1.9 to 34 adducts in 10(8) nucleotides. Correlations between smoking and DNA adduct levels were poor because of the small number of current smokers (n = 13). However, smokers of filter cigarettes had significantly lower DNA adduct levels compared with smokers of cigarettes without a filter (P = 0.02 by Fischer's exact test).

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed1991

Benzo[a]pyrene diolepoxide-DNA adducts in alveolar macrophages of smokers.

The presence of benzo[a]pyrene diolepoxide (BPDE)-DNA adducts was investigated by synchronous fluorescence spectrophotometry in cells recovered by bronchoalveolar lavage from 39 individuals. Pulmonary alveolar macrophages constituted, on average, 90% of these cells. No adduct was detected in samples from non-smokers or ex-smokers, whereas 84.6% of samples from current smokers exhibited typical fluorescence peaks. The samples from four subjects who had stopped smoking during the last 6 months were also positive. A considerable variability was observed in the intensity of signals, which in positive samples was significantly correlated with the number of cigarettes currently smoked but not with the cumulative total of cigarettes smoked during a lifetime. In any case, part of the recorded quantitative variations could not be ascribed to the daily number of cigarettes but probably depended on interindividual variability in smoking habits or in toxicokinetics and metabolism. On the whole, detection of BPDE-DNA adducts in alveolar macrophages, compared to other surrogate cell populations, appears to represent a sensitive and specific biomonitoring tool, assessing the internal dose of inhaled benzo[a]pyrene in the proximity of target cells of the respiratory tract. Exploitation of this end-point in molecular epidemiology and cancer prevention studies warrants further investigation.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed1991

Immunocytochemical visualization of DNA adducts in mouse tissues and human white blood cells following treatment with benzo[a]pyrene or its diol epoxide. A quantitative approach.

The formation and stability of benzo[a]pyrene DNA adducts were studied in tissues of BALB/c mice exposed to benzo[a]pyrene (B[a]P). The DNA adducts were visualized with an immunocytochemical peroxidase staining technique using an antiserum specific for the major B[a]P-derived adduct in DNA [(+/-)trans-7,8-dihydroxy-anti-9,10-epoxy-7,8,9,10- tetrahydrobenzo[a]pyrene (BPDE-N2-dG)]. The nuclear staining density was measured by microdensitometry. When mice were treated with an increasing dose of B[a]P the nuclear staining increased in the tissues studied (lung, heart and kidney). A linear relationship was found between the immunocytochemical nuclear staining signal and the actual DNA adduct level in the lung as measured by 32P-postlabeling. Maximum adduct formation was found 5 days after a single i.p. injection of B[a]P. Adduct levels decreased gradually after 7 days, but even after 61 days a slight specific staining was still present, suggesting that not all adducts had disappeared at that time. As judged from the disappearance of [3H]thymidine from prelabeled DNA the loss of adducts from the lung was not a result of DNA repair but one of cell turnover. In human white blood cells B[a]P-derived adducts could be detected after in vitro incubation with the reactive metabolite of B[a]P (BPDE). Dose-response studies demonstrated a positive relationship between BPDE-DNA adduct formation, the immunocytochemical staining signal and the BPDE concentration in the culture medium.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed1992

Identification and quantitative detection of isomeric benzo[a]pyrene diolepoxide--DNA adducts by low-temperature conventional fluorescence methods.

The pyrene-like fluorescence of adducts derived from the covalent binding of (+/-)-trans-7,8-dihydroxy-anti-9,10-epoxy-7,8,9, 10-tetrahydrobenzo[a]pyrene [+/-]-anti-BPDE] to DNA increases in intensity by factors of 20 or more as the temperature is lowered from ambient to approximately 100 K. This effect is primarily associated with the strong quenching of the pyrene-like fluorescence of BPDE-deoxyguanosyl adducts at room temperature, and the suppression of the electron-transfer quenching mechanism at 100 K. In contrast, the fluorescence of BPDE-deoxyadenosyl adducts is not quenched at ambient temperatures, and the fluorescence yields of (+/-)-anti-BPDE-poly(dA-dT).(dA-dT) adducts increases by only a factor of 2 in this same temperature range. Utilizing an internal fluorescein fluorescence standard to correct for differences in light scattering and variations in instrumental factors, a fluorescence method is described for quantitatively determining the levels of benzo[a]pyrene diolepoxide derivatives covalently bound to cellular DNA at 100 K. The method is illustrated with (+/-)-reverse-BPDE [(+/-)-trans-9,10-dihydroxy-anti-7, 8-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene]. Adduct levels as low as 10 pmol in a 400 microliters sample volume can be detected and identified from their excitation and fluorescence emission spectra using a conventional and commercially available fluorometer. In the case of modified DNA extracted from BPDE-treated Chinese hamster ovary cells or from mouse skin (approximately 1 BPDE residue/20,000 bases), such an analysis requires only 100 micrograms of DNA. Conformationally different adducts derived from the binding of the isomeric (+/-)-anti-BPDE, (+/-)-reverse-BPDE or (+/-)-syn-BPDE to cellular DNA can be distinguished by their low-temperature fluorescence excitation spectra. Specifically, the quasi-intercalated site I BPDE adducts (believed to be associated with cis-addition stereochemistry) can be distinguished from site II adducts situated at external BPDE binding sites (trans-addition stereochemistry). These results suggest that the fates of these conformationally different BPDE-DNA adducts, e.g. due to enzymatic repair, can be monitored as a function of time in DNA extracted from intact, functioning cells.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed1990

Serological characterization of polycyclic aromatic hydrocarbon diolepoxide-DNA adducts using monoclonal antibodies.

Polycyclic aromatic hydrocarbons (PAHs) are a group of structurally related compounds that are present in the environment in complex mixtures as common pollutants. These compounds have been studied extensively because of their carcinogenic and toxic properties to humans. We reported previously that humans exposed to certain PAHs produce antibodies that bind to different PAH diolepoxide-DNA (PAH-DNA) adducts. The ability to detect and measure antibodies to PAH-DNA adducts in human blood samples could prove useful as a biological dosimeter for identifying persons that have been exposed to high levels of PAHs, i.e. persons who may be at high cancer risk. In our initial studies we found that it was common for persons who were exposed to PAH to produce antibodies against PAH-DNA adducts. However, we were unable to identify the actual chemical types of PAH-DNA adducts that were recognized by the serum antibodies because many serum samples contained antibody activity to more than one adduct. These data indicate that different PAH-DNA adducts may be serologically similar or that humans actually produce immune responses against more than a single PAH-DNA adduct. We have used monoclonal antibody technology to determine the extent to which different PAH-DNA adducts share serologically recognized epitopes. Monoclonal antibodies were produced against two different PAH-DNA adducts, benzo[a]pyrene diolepoxide-DNA (BPDE-DNA) and benz[a]anthracene diolepoxide-DNA (BADE-DNA). The binding of these antibodies to five PAH-DNA adduct preparations and to soluble PAHs was assessed. We found that most monoclonal antibodies bound to more than a single type of PAH-DNA adduct, documenting the serological relatedness of different PAH-DNA adducts. However, two monoclonal antibodies were produced that bound only to BPDE-DNA. Soluble non-metabolized PAHs and PAH tetraols were not recognized by these antibodies, thus demonstrating their specificity for PAH-DNA adducts and not the PAHs alone. Monoclonal antibodies produced against BADE-DNA also bound to chrysene diolepoxide-DNA but not to BPDE-DNA or to two other PAH-DNA adducts. These data demonstrate that significant serological cross-reactivity exists between different PAH-DNA adducts and support our contention that human antibodies to PAH-DNA can often bind to more than a single type of PAH-DNA adduct. However, our ability to produce monoclonal antibodies with restricted specificity suggest that the production of highly monoclonal antibody reagents for use in assays designed to measure PAH-DNA adducts in biological samples is feasible.

Animals↗

PubMed1990

Molecular mechanics and antibody binding in the structural analysis of polycyclic aromatic hydrocarbon-diol-epoxide--DNA adducts.

Analysis of polycyclic aromatic hydrocarbon (PAH)-DNA adducts using monoclonal antibodies raised against DNA that had been modified with (+-)-r-7-,t-8-dihydroxy-t-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene in an enzyme-linked immunosorbent assay, as well as analysis using human serum antibodies and antibodies raised in laboratory animals, have suggested the presence on these adducts of both common and unique immunological epitopes. The molecular mechanics studies reported here establish a model for the analysis of PAH-DNA adducts through the identification of energetically favored binding conformations and they further reveal structural alterations in DNA due to the presence of carcinogen adducts. The data explain the antibody reactivity patterns by defining different molecular presenting surfaces that are available for antibody binding. The preferred orientation of the aromatic portions of the adducts, which align either 3' or 5' in the minor groove, were found to be correlated with antibody reactivity patterns. Examination of the topographical characteristics of the adducts facilitated correlation of adduct-antibody recognition and adduct presenting surface. Significant differences were found between benzo[a]pyrene-diol-epoxide (BPDE)-DNA adducts, which align 5' in the minor groove, and benz[a]anthracene-diol-epoxide (BADE)-DNA and dibenz[a,c]anthracene-diol-epoxide-DNA adducts, which align 3' within the minor groove. Chrysene-diol-epoxide-DNA adducts were found to have only a weak preference for 5' alignment and therefore share topographical characteristics with both BPDE-DNA and BADE-DNA adducts.

Animals↗