Resveratrol: A Potential Protector Against Benzo[a]pyrene- Induced Lung Toxicity

<b>Background and Objective:</b> Benzo[a]pyrene (B[a]P), a major component of lipophilic pollutants then can be translated to diffluent substances. The aim of t he present article was to investigate protective activity of resveratrol against lung toxicity induced by B[a]P. Material and Methods: Male Sprague-Dawley rats were randomly assigned to 6 groups (6 animals/group): 3 negative control groups, control positive, B[a]P (20 mg kg<sup></sup><sup>1</sup> b.wt., resveratrol (50 mg kg<sup></sup><sup>1</sup> b.wt.)-B[a]P and vitamin C (1 g kg<sup></sup><sup>1</sup> b.wt.)-B[a]P groups. <b>Results:</b> The daily oral administration of the resveratrol (50 mg kg<sup></sup><sup>1</sup> b.wt.) and vitamin C (1 g kg<sup></sup><sup>1</sup> b.wt.) for 30 days to rats treated with B[a]P (20 mg kg<sup></sup><sup>1</sup> b.wt.) resulted in a significant improve plasma cholesterol, triglyceride and HDL-C as well as serum TNF-α, TBARS, IL-2,IL-6, haptoglobin, histamine, IgA, Ig E,Ig G and Ig M in B[a]P treated rats. On the other hand oral administration of resveratrol elevated the SOD, GPx and GR gene expression in lung rats treated with B[a]P. Furthermore, resveratrol and vitamin C nearly normalized these effects in lung histoarchitecture. <b>Conclusion:</b> The obtained biochemical, molecular biology and histological results of this study proved the lung protective activity of resveratrol against B[a]P induced lung toxicity in rats.

Roles for B[a]P and FICZ in subchondral bone metabolism and experimental temporomandibular joint osteoarthritis via the AhR/Cyp1a1 signaling axis

Bone loss due to smoking represents a major risk factor for fractures and bone osteoporosis. Signaling through the aryl hydrocarbon receptor (AhR) and its ligands contributes to both bone homeostasis and inflammatory diseases. It remains unclear whether the same AhR signaling axis affects the temporomandibular joint (TMJ). The aim of this study was to investigate possible mechanisms which mediate bone loss in the TMJ due to smoking. In particular, whether benzo[a]pyrene (B[a]P), a carcinogen of tobacco smoke, induces expression of the AhR target gene, Cyp1a1, in mandibular condyles. Possible functions of an endogenous ligand of FICZ, were also investigated in a TMJ-osteoarthritis (OA) mouse model. B[a]P was administered orally to wild-type and AhR-/- mice and bone metabolism was subsequently examined. TMJ-OA was induced in wild-type mice with forceful opening of the mouth. Therapeutic functions of FICZ were detected with μCT and histology. Exposure to B[a]P accelerated bone loss in the mandibular subchondral bone. This bone loss manifested with osteoclastic bone resorption and upregulated expression of Cyp1a1 in an AhR-dependent manner. In a mouse model of TMJ-OA, FICZ exhibited a dose-dependent rescue of mandibular subchondral bone loss by repressing osteoclast activity. Meanwhile, in vitro, pre-treatment with FICZ reduced RANKL-mediated osteoclastogenesis. B[a]P regulates mandibular subchondral bone metabolism via the Cyp1a1. The AhR ligand, FICZ, can prevent TMJ-OA by regulating osteoclast differentiation.

Deubiquitinase USP7-mediated MCL-1 up-regulation enhances Arsenic and Benzo(a)pyrene co-exposure-induced Cancer Stem Cell-like property and Tumorigenesis

Rationale: MCL-1 is up-regulated in cancer and a target for cancer treatment. How MCL-1 is up-regulated and whether MCL-1 up-regulation plays a role in tumorigenic process is not well-known. Arsenic and benzo(a)pyrene (BaP) are well-recognized lung carcinogens and we recently reported that arsenic and BaP co-exposure acts synergistically in inducing cancer stem cell (CSC)-like property and lung tumorigenesis. This study was performed to further investigate the underlying mechanism focusing on the role of MCL-1. Methods: The spheroid formation assay and nude mouse tumorigenesis assay were used to determine the CSC-like property and tumorigenicity of arsenic plus BaP co-exposure-transformed human bronchial epithelial BEAS-2B cells, respectively. Biochemical, pharmacological and genetic approaches were used to manipulate gene expressions, dissect signaling pathways and determine protein-protein interactions. Both loss-of-function and gain-of-function approaches were used to validate the role of MCL-1 in arsenic plus BaP co-exposure-enhanced CSC-like property and tumorigenicity. Results: Arsenic plus BaP co-exposure-transformed cells express significantly higher protein levels of MCL-1 than the passage-matched control, arsenic or BaP exposure alone-transformed cells. Knocking down MCL-1 levels in arsenic plus BaP co-exposure-transformed cells significantly reduced their apoptosis resistance, CSC-like property and tumorigenicity in mice. Mechanistic studies revealed that arsenic plus BaP co-exposure up-regulates MCL-1 protein levels by synergistically activating the PI3K/Akt/mTOR pathway to increase the level of a deubiquitinase USP7, which in turn reduces the level of MCL-1 protein ubiquitination and prevents its subsequent proteasome degradation. Conclusions: The deubiquitinase USP7-mediated MCL-1 up-regulation enhances arsenic and BaP co-exposure-induced CSC-like property and tumorigenesis, providing the first evidence demonstrating that USP7 stabilizes MCL-1 protein during the tumorigenic process.

Impacts of dietary exposure to different sized polystyrene microplastics alone and with sorbed benzo[a]pyrene on biomarkers and whole organism responses in mussels Mytilus galloprovincialis

Due to their hydrophobicity and relatively large surface area, microplastics (MPs) can act as carriers of hydrophobic pollutants in the ocean and may facilitate their transfer to organisms. This study examined effects of dietary exposure to polystyrene MPs of 0.5 and 4.5 μm alone and with sorbed benzo[a]pyrene (BaP) on mussels Mytilus galloprovincialis in order to elucidate the effects of MP size and the presence of sorbed BaP on the organism. MPs were provided daily, mixed with algae, during 26 days at equivalent mass (0.058 mg/L), corresponding to 1000 particles/mL for 4.5 μm MPs and to 7.44 × 10⁵ particles/mL for 0.5 μm MPs. Effects were determined on early cellular biomarkers in hemocytes, structure and cell type composition of digestive tubules (DTs), histopathology and whole organism responses (condition index (CI), clearance rate (CR), food absorption efficiency (AE), respiration rate (RR) and scope for growth (SFG)). BaP concentrations in mussels increased with time, in particular when sorbed to smaller MPs. Large MPs were abundant in the lumen of stomach and DTs, but were also occasionally found within epithelial cells. Effects in all treatments increased with exposure time. MPs with sorbed BaP were more toxic than MPs alone according to hemocyte viability and catalase activity and to the quantitative structure of DT epithelium. Higher toxicity of small MPs compared to larger ones was recorded for DNA damage and cell composition of DTs. At tissue level a slight increase in prevalence of inflammatory responses occurred in all exposed groups. At whole organism level a compensatory effect was observed on absorption efficiency across MP treatments at day 26, resulting in increased SFG in mussels exposed to small MPs with sorbed BaP. This could be related to an increased energy need to deal with stress observed in biomarkers. Further work is required to understand the Trojan horse effect of a variety of plastic type, size, shape combinations together with a wide variety of pollutants.

Benzo(a)pyrene facilitates dermatophagoides group 1 (Der f 1)-induced epithelial cytokine release through aryl hydrocarbon receptor in asthma

BACKGROUND

Environmental pollutants, which coexist with allergens, have been associated with the exacerbation of asthma. However, the underlying molecular mechanisms remain elusive. We sought to determine whether benzo(a)pyrene (BaP) co-exposure with dermatophagoides group 1 allergen (Der f 1) can potentiate Der f 1-induced asthma and its underlying mechanisms.

METHODS

The effect of BaP was investigated in Der f 1-induced mouse model of asthma, including airway hyper-responsiveness, allergic inflammation, and epithelial-derived cytokines. The impact of BaP on Der f 1-induced airway epithelial cell oxidative stress (ROS) and cytokine release was further analyzed. The role of aryl hydrocarbon receptor (AhR) signaling in BaP-promoted Der f 1-induced ROS, cytokine production, and allergic inflammation was also investigated.

RESULTS

Compared with Der f 1, BaP co-exposure with Der f 1 led to airway hyper-responsiveness and increased lung inflammation in mouse model of asthma. Increased expression of TSLP, IL-33, and IL-25 was also found in the airways of these mice. Moreover, BaP co-exposure with Der f 1 activated AhR signaling with increased expression of AhR and CYP1A1 and promoted airway epithelial ROS generation and TSLP and IL-33, but not IL-25, expression. Interestingly, AhR antagonist CH223191 or cells with AhR knockdown abrogated the increased expression of ROS, TSLP, and IL-33. Furthermore, ROS inhibitor N-acetyl-L-cysteine (NAC) also suppressed BaP co-exposure-induced expression of epithelial TSLP, IL-33, and IL-25. Finally, AhR antagonist CH223191 and NAC inhibited BaP co-exposure with Der f 1-induced lung inflammation.

CONCLUSIONS

Our findings suggest that BaP facilitates Der f 1-induced epithelial cytokine release through the AhR-ROS axis.

The molecular mechanism of Nrf2-Keap1 signaling pathway in the antioxidant defense response induced by BaP in the scallop Chlamys farreri

In this study, we cloned the full-length cDNA of the Kelch-like ECH-associated protein 1 (Keap1) from the scallops Chlamys farreri (C. farreri). Sequences alignment and phylogenetic analysis showed that CfKeap1 was highly specific in the scallops, and the amino acid sequence identity value is closer to that in zebrafish Keap1b and Nothobranchius furzeri Keap1b than Keap1a. The highest transcription level of CfKeap1 expression was detected in the digestive glands. The gene expressions of CfKeap1, NF-E2-related nuclear factor 2 (Nrf2), Superoxide Dismutase (SOD), Catalase (CAT) and Glutathione Peroxidase (GPx) in digestive glands were evaluated by quantitative real-time PCR (qRT-PCR) after being exposed to benzo(a)pyrene (BaP) (0.25, 1and 4 μg/L) for 15 days, which indicated that the activation of Nrf2 and Keap1 expression can be significantly induced under BaP exposure. RNA interference (RNAi) experiments were conducted to examine the expression profiles of CfKeap1, Nrf2, antioxidant genes (Cu/Zn-SOD, CAT and GPx), mitogen-activated protein kinase (MAPKs) and protein kinase C (PKC) signaling pathways key genes in digestive glands and gills when exposed to BaP. Results showed that the mRNA level of CfKeap1 was significantly decreased by 60.69% and59.485%. The changes of CfKeap1 and Nrf2 suggested that the enhancement of Keap1 expression stimulating Nrf2 degradation. Furthermore, the expression of antioxidant genes were consistent with the Nrf2 gene, which suggesting that Nrf2-Keap1 signaling pathway is required for the induction of antioxidant genes. Besides, the changes of PKC, c-Jun N-terminal kinase (JNK) and p38 genes expression suggested that PKC and MAPKs signaling pathways played a synergistic role with Nrf2-Keap1 signaling pathway in the anti-oxidative defense system of bivalve molluscs. In conclusion, these data demonstrated that Keap1 can sense nucleophilic or oxidative stress factors to regulate the Nrf2 signaling pathway together with Cul3-based E3 Ubiquitin Ligase (E3), and the Nrf2-Keap1 signaling pathway played an important role in modulating gene expression of antioxidant enzymes in bivalve mollusks.

Gestational exposure to nicotine and/or benzo[a]pyrene causes long-lasting neurobehavioral consequences

Tobacco smoke is a complex mixture that includes thousands of compounds. Previously, we have found that gestational exposure to the complex mixture of tobacco smoke extract caused long-term neurobehavioral impairments. In this study, we examined the interaction of two of the most biologically active, nicotine and benzo[a]pyrene (BaP). Developmental effects were determined in Sprague-Dawley rats prenatally exposed to low doses of BaP and nicotine (0.03 mg/kg/day of BaP and 2 mg/kg/day of nicotine) via maternal osmotic minipumps throughout gestation. Behavioral function was assessed in the offspring via a battery of tests through adolescence into adulthood. There were sex-selective effects in four of the behavioral tests. In the elevated plus maze, there was a significant interaction of BaP and sex, where BaP-treated males showed a trend for increased activity. In the novelty suppressed feeding test, there were significant sex selective effects in males such that the normal sex difference in the behavior in this test was eliminated. Male offspring with prenatal exposure to either nicotine or BaP showed significant reductions in fear response. In the Figure-8 locomotor activity test, BAP-exposed male offspring were significantly hyperactive. This also eliminated the sex difference typically seen in this test. This effect persisted into adulthood. In the attention task, males exposed to nicotine during gestation showed a significant percent hit impairment. BaP reversed this effect. No significant effects were seen with percent correct rejection. These data show that both nicotine and BaP cause persisting sex-selective behavioral effects that persist into adulthood.

Paternal exposure to benzo(a)pyrene induces genome-wide mutations in mouse offspring

Understanding the effects of environmental exposures on germline mutation rates has been a decades-long pursuit in genetics. We used next-generation sequencing and comparative genomic hybridization arrays to investigate genome-wide mutations in the offspring of male mice exposed to benzo(a)pyrene (BaP), a common environmental pollutant. We demonstrate that offspring developing from sperm exposed during the mitotic or post-mitotic phases of spermatogenesis have significantly more de novo single nucleotide variants (1.8-fold; P < 0.01) than controls. Both phases of spermatogenesis are susceptible to the induction of heritable mutations, although mutations arising from post-fertilization events are more common after post-mitotic exposure. In addition, the mutation spectra in sperm and offspring of BaP-exposed males are consistent. Finally, we report a significant increase in transmitted copy number duplications (P = 0.001) in BaP-exposed sires. Our study demonstrates that germ cell mutagen exposures induce genome-wide mutations in the offspring that may be associated with adverse health outcomes.

Response of a novel selenium-dependent glutathione peroxidase from thick shell mussel Mytilus coruscus exposed to lipopolysaccharide, copper and benzo[α]pyrene

Glutathione peroxidase (GPx) plays an important antioxidant role in cellular defense against environmental stress. In the present study, a novel selenium-dependent glutathione peroxidase termed McSeGPx firstly identified in thick shell mussel Mytilus coruscus. McSeGPx consists of 197 amino acid residues, characterized with one selenocysteine residue encoded by an opal stop codon TGA, one selenocysteine insertion sequence (SECIS) in the 3' untranslated region (UTR), two active site motifs and one signature sequence motif. McSeGPx transcripts were constitutively expressed in all examined tissues, and were significantly induced in gills and digestive glands with the stimulations of lipopolysaccharide (LPS), copper (Cu) and benzo[α]pyrene (B[α]P). Additionally, rough increases in McSeGPx activity were detected in both tissues under the challenge of LPS, Cu and B[α]P. Collectively, these results suggested that McSeGPx affiliate to selenocysteine dependent GPx (SeGPx) family and might play an important role in mediating the environmental stressors and antioxidant response in M. coruscus.

Comparative transcriptomic analysis provides insights into the response to the benzo(a)pyrene stress in aquatic firefly (Luciola leii)

Many studies have reported that behavior and bioluminescence of fireflies could be affected by changes in environment conditions. However, little is known about how the deterioration of the aquatic environment affects aquatic fireflies, particularly with respect to molecular responses following exposure to water pollutants, such as benzo(a)pyrene (BaP), which is a key indicator in environmental risk assessment because of the hazards it poses. Here, whole transcriptome sequencing and gene expression analysis were performed on freshwater fireflies (Luciola leii) exposed to BaP (concentration of 0.01 mg/L). Four transcriptomic libraries were constructed for the control and treatment groups, including two biological replicates. From the mixed pools (each pool contains 60 individuals from three time points), a total of 54,282 unigenes were assembled. Furthermore, 329,337 of Single-nucleotide Polymorphisms (SNPs) and 1324 of Simple Sequence Repeats (SSRs) were predicted using bioinformatics, which is useful for the future development of molecular markers. Subsequently, 2414 differently expressed genes (DEGs) were identified in response to BaP stress in comparison to the control, including 1350 up-regulated and 1064 down-regulated DEGs. Functional enrichment showed that these DEGs are primarily related to innate immunity; xenobiotic biodegradation and response, biomacromolecule metabolism, biosynthesis, and absorption. Eight key BaP-responsive DEGs were screened to survey the dynamic changes of expression in response to BaP stress at different time points, and to validate the RNA sequencing data using quantitative real-time PCR. The results indicate that the expression of genes encoding UGT, CYP3A, CYP9, CYP6AS5 and ADHP were induced, while those encoding UGT2B10L, PTGDS, and ALDH were reduced, to participate in response to the BaP exposure and potentially help counteract the adverse effects of BaP. This investigation provides insight into the toxicological response of fireflies to the occurrence of water deterioration.

Household coal combustion, indoor air pollutants, and circulating immunologic/inflammatory markers in rural China

The study aim was to investigate whether household bituminous ("smoky") coal use and personal exposure to combustion emissions were associated with immunologic/inflammatory marker levels. A cross-sectional study of healthy never-smoking women from rural Xuanwei and Fuyuan, China was conducted, which included 80 smoky coal and 14 anthracite ("smokeless") coal users. Personal exposure to fine particulate matter (PM_2.5) and benzo[a]pyrene (BaP) was assessed using portable devices, while 67 circulating plasma immunologic/inflammatory markers were measured using multiplex bead-based assays. Multivariable linear regression models were employed to estimate associations between smoky coal versus smokeless coal use, indoor air pollutants, and immunologic/inflammatory markers. Six markers were altered among smoky coal users compared to smokeless coal, including significantly decreased interferon-inducible T-cell alpha chemoattractant (CXCL11/I-TAC), and increased serum amyloid P component (SAP). CXCL11/I-TAC was previously found to be reduced in workers exposed to high levels of diesel engine exhaust, which exhibits similar constituents as coal combustion emissions. Further, there was evidence that elevated PM_2.5 and BaP exposure was associated with significantly diminished levels of the serum amyloid A (SAA); however, the false discovery rates (FDRs) were >0.2 after accounting for multiple comparisons. Inflammatory processes may thus mediate the carcinogenic effects attributed to smoky coal emissions.

Carcinogens and DNA damage

Humans are variously and continuously exposed to a wide range of different DNA-damaging agents, some of which are classed as carcinogens. DNA damage can arise from exposure to exogenous agents, but damage from endogenous processes is probably far more prevalent. That said, epidemiological studies of migrant populations from regions of low cancer risk to high cancer risk countries point to a role for environmental and/or lifestyle factors playing a pivotal part in cancer aetiology. One might reasonably surmise from this that carcinogens found in our environment or diet are culpable. Exposure to carcinogens is associated with various forms of DNA damage such as single-stand breaks, double-strand breaks, covalently bound chemical DNA adducts, oxidative-induced lesions and DNA-DNA or DNA-protein cross-links. This review predominantly concentrates on DNA damage induced by the following carcinogens: polycyclic aromatic hydrocarbons, heterocyclic aromatic amines, mycotoxins, ultraviolet light, ionising radiation, aristolochic acid, nitrosamines and particulate matter. Additionally, we allude to some of the cancer types where there is molecular epidemiological evidence that these agents are aetiological risk factors. The complex role that carcinogens play in the pathophysiology of cancer development remains obscure, but DNA damage remains pivotal to this process.

Transcriptional responses of Acropora hyacinthus embryo under the benzo(a)pyrene stress by deep sequencing

Coral embryos are a critical and sensitive period for the early growth and development of coral. Benzo(a)pyrene (BaP) is widely distributed in the ocean and has strong toxicity, but there is little information on the toxic effects to coral embryos exposed to this widespread environmental contaminant. Thus, in this study, we utilized the Illumina Hiseq™ 4000 platform to explore the gene response of Acropora hyacinthus embryos under the BaP stress. A total of 130,042 Unigenes were obtained and analyzed, and approximately 37.67% of those matched with sequences from four different species. In total, 2606 Unigenes were up-regulated, and 3872 Unigenes were down-regulated. After Gene Ontology (GO) annotation, the results show that the "cellular process" and "metabolic process" were leading in the category of biological processes, which the "binding" and "catalytic activity" were the most abundant subcategories in molecular function. Based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, the most differentially expressed genes (DEGs) were enriched, as well as down-regulated in the pathways of oxidative phosphorylation, metabolism of xenobiotics, immune-related genes, apoptosis and human disease genes. At the same time, 388,197 of Single-nucleotide Polymorphisms (SNPs) and 6164 of Simple Sequence Repeats (SSRs) were obtained, which can be served as the richer and more valuable SSRs molecular markers in the future. The results of this study can help to better understand the toxicological mechanism of coral embryo exposed to BaP, and it is also essential for the protection and restoration of coral reef ecosystem in the future.

[Changes of cerebral cortical metabolomics in rats following benzo[a]pyrene exposure]

OBJECTIVE

To analyze the changes in endogenous small molecule metabolites after benzo[a]pyrene (B[a]P) exposure in rat cerebral cortex and explore the mechanism of B[a]P neurotoxicity.

METHODS

Five-day-old SD rats were subjected to gavage administration of 2 mg/kg B[a]P for 7 consecutive weeks. After the exposure, the rats were assessed for spatial learning ability using Morris water maze test, ultrastructural changes of the cortical neurons under electron microscope, and metabolite profiles of the cortex using GC/MS. The differential metabolites between the exposed and control rats were identified with partial least squares discriminant analysis (PLS-DA) and the metabolic pathways related with the differential metabolites were analyzed using Cytoscape software.

RESULTS

Compared with the control group, the rats exposed to B[a]P showed significantly increased escape latency (P<0.05) and decreased time spent in the target area (P<0.05). The exposed rats exhibited widened synaptic cleft, thickened endplate membrane and swollen cytoplasm compared with the control rats. Eighteen differential metabolites (VIP>1, P<0.05) in the cortex were identified between the two groups, and 9 pathways associated with B[a]P neurotoxicity were identified involving amino acid metabolism, tricarboxylic acid cycle and Vitamin B3 (niacin and nicotinamide) metabolism.

CONCLUSION

B[a]P can cause disturbance in normal metabolisms and its neurotoxicity is possibly related with disorders in amino acid metabolism, tricarboxylic acid cycle and vitamin metabolism.

Long-term exposure to urban air pollution and the relationship with life expectancy in cohort of 3.5 million people in Silesia

Air pollution is considered to be one of the most important environmental health determinants. The studies constitute an attempt to explain the role of air pollutants in the impact on the length of life of the 3.5 million people living in the cities of the Silesia province in Poland. The association between the long-term inhalation exposure to PM₁₀, benzo(a)pyrene, cadmium and lead in the period from 1989 to 2008 and length of life in the year 2014 of the inhabitants of 19 cities of the Silesia province has been estimated. The Pearson linear regression method was applied to calculate the relation between exposure to specific pollutants and length of life. In order to determine the influence of the mixture of the pollutants the multiple regression analysis was carried out. The studies have confirmed the significant correlations between the chronic exposure of Silesia province residents to PM₁₀ and benzo(a)pyrene and their length of life. The stronger correlation was demonstrated in case of the long-term exposure to the mixture of examined air pollutants. Differentiated exposure of the inhabitants of the Silesia province to air pollutants results in existing inequalities in the life expectancy of men and women among the cities.

The impact of air pollution in the Southern Bohemia Region on fetuses and newborns

Air pollution with increased concentrations of carcinogenic polycyclic aromatic hydrocarbons (c-PAHs, represented by benzo[a]pyrene, B[a]P) affect fetal development, reduce birth weights (LBW) of newborns, and increases intrauterine growth retardation (IUGR). The Southern Bohemia Region is believed to be one of the least air polluted regions in the Czech Republic. Monitoring air pollution in the city of České Budějovice from 2011-2015, PM2.5 (particulate matter <2.5 µm) decreased from 20.3 ± 14.5 µg/m3 to 14.3 ± 8.6 µg/m3, but concentrations of B[a]P did not change between the years 2007-2015: 1.5 ± 0.6 ng/m3 vs. 1.4 ± 1.4 ng/m3. Higher B[a]P concentrations the winter induce genetic damage in newborns, increase frequency of micronuclei (chromosomal aberrations), deregulate genes for immunity in umbilical cord blood, and increase incidence of IUGR and LBW in newborns.

Benzo(a)pyrene in Europe: Ambient air concentrations, population exposure and health effects

This study estimated current benzo(a)pyrene (BaP) concentration levels, population exposure and potential health impacts of exposure to ambient air BaP in Europe. These estimates were done by combining the best available information from observations and chemical transport models through the use of spatial interpolation methods. Results show large exceedances of the European target value for BaP in 2012 over large areas, particularly in central-eastern Europe. Results also show large uncertainties in the concentration estimates in regions with a few or no measurement stations. The estimation of the population exposure to BaP concentrations and its health impacts was limited to 60% of the European population, covering only the modelled areas which met the data quality requirement for modelling of BaP concentrations set by the European directive 2004/107/EC. The population exposure estimate shows that 20% of the European population is exposed to BaP background ambient concentrations above the EU target value and only 7% live in areas with concentrations under the estimated acceptable risk level of 0.12 ng m(-3). This exposure leads to an estimated 370 lung cancer incidences per year, for the 60% of the European population included in the estimation. Emissions of BaP have increased in the last decade with the increase in emissions from household combustion of biomass. At the same time, climate mitigation policies are promoting the use of biomass burning for domestic heating. The current study shows that there is a need for more BaP measurements in areas of low measurement density, particularly where high concentrations are expected, e.g. in Romania, Bulgaria, and other Balkan states. Furthermore, this study shows that the health risk posed by PAH exposure calls for better coordination between air quality and climate mitigation policies in Europe.

Poly(ADP-Ribose) Glycohydrolase (PARG) Silencing Suppresses Benzo(a)pyrene Induced Cell Transformation

Benzo(a)pyrene (BaP) is a ubiquitously distributed environmental pollutant and known carcinogen, which can induce malignant transformation in rodent and human cells. Poly(ADP-ribose) glycohydrolase (PARG), the primary enzyme that catalyzes the degradation of poly(ADP-ribose) (PAR), has been known to play an important role in regulating DNA damage repair and maintaining genomic stability. Although PARG has been shown to be a downstream effector of BaP, the role of PARG in BaP induced carcinogenesis remains unclear. In this study, we used the PARG-deficient human bronchial epithelial cell line (shPARG) as a model to examine how PARG contributed to the carcinogenesis induced by chronic BaP exposure under various concentrations (0, 10, 20 and 40 μM). Our results showed that PARG silencing dramatically reduced DNA damages, chromosome abnormalities, and micronuclei formations in the PARG-deficient human bronchial epithelial cells compared to the control cells (16HBE cells). Meanwhile, the wound healing assay showed that PARG silencing significantly inhibited BaP-induced cell migration. Furthermore, silencing of PARG significantly reduced the volume and weight of tumors in Balb/c nude mice injected with BaP induced transformed human bronchial epithelial cells. This was the first study that reported evidences to support an oncogenic role of PARG in BaP induced carcinogenesis, which provided a new perspective for our understanding in BaP exposure induced cancer.

Insight into the transgenerational effect of benzo[a]pyrene on bone formation in a teleost fish (Oryzias latipes)

Recent cross-generational studies in teleost fish have raised the awareness that high levels of benzo[a]pyrene (BaP) could affect skeletal integrity in the directly exposed F0 and their F1-F2. However, no further details were provided about the causes for abnormalities on the molecular and cellular level and the persistence of such sub-organismal impairments at the transgenerational scale (beyond F2). Adult Oryzias latipes were exposed to 1μg/L BaP for 21days. The F1-F3 were examined for skeletal deformities, histopathological alterations of vertebral bodies and differential expression of key genes of bone metabolism. Significant increase of dorsal-ventral vertebral compression was evident in ancestrally exposed larvae. Histopathological analysis revealed abnormal loss of notochord sheath, a lack of notochord epithelial integrity, reduced bone tissue and decreased osteoblast abundance. A significant downregulation of ATF4 and/or osterix and a high biological variability of COL10, coupled with a significant deregulation of SOX9a/b in the F1-F3 suggest that ancestral BaP exposure most likely perturbed chordoblasts, chondroblast and osteoblast differentiation, resulting in defective notochord sheath repair and rendering the vertebral column more vulnerable to compression. The present findings provide novel molecular and cellular insights into BaP-induced transgenerational bone impairment in the unexposed F3. From the ecological risk assessment perspective, BaP needs to be regarded as a transgenerational skeletal toxicant, which exerts a far-reaching impact on fish survival and fitness. Given that basic mechanisms of cartilage/bone formation are conserved between medaka and mammals, the results may also shed light on the potential transgenerational effect of BaP on the genesis of skeletal diseases in humans.

[Cohort study of effects on lung function of coke oven workers exposured to coke oven emissions]

OBJECTIVE

Through comparative study on pulmonary function damage of coke oven workers exposed to coke oven emissions with the same group before and after five years, and further explore the relationship between the coke oven emissions and injury in pulmonary function of coke oven worker.

METHODS

Select a coking plant in Shanxi 165 coke oven workers (exposed group) and 52 auxiliary workers (control group) for the study, using a uniform questionnaire to collect workers' personal information. Fixed workplace air samples collected periodically. Air samples of benzo (a) pyrene concentrations was measured by high pressure liquid chromatograph. Pulmonary function of research object was measured by portable spirometer respectively in 2009 and 2013, and comparative analysis on it.

RESULTS

The concentration of B(a)P was no significant difference in the same area between 5 years in 2009-2013. Compared with 2009, 2013 control workers lung function index and the abnormal rate had no significant difference (P > 0.05). But FVC%, FEV1.0%, MVV%, VC% and FEF25% of exposed workers in 2013 was significantly lower than in 2009, FVC%, FEV1.0%, VC% and FEF25% pulmonary dysfunction rate in 2013 was also significantly higher than in 2009, difference was statistically significant (P < 0.05). Workers emerging pulmonary function abnormalities mainly distributed in furnace roof and side. furnace roof group FVC%, FEV1.0%, VC% additional abnormal number (rate) was significantly higher than furnace floor and the control group (P < 0.05), and furnace side groop was significantly higher than the control group, the difference was statistically significant (P < 0.05). Multivariate Logistic regression analysis showed that after 5 years FVC%, FEV1% and VC% of abnormal lung function emerging adjusted OR of furnace roof workers were 7.939, 5.966 and 4.956. For abnormal of FVC%, FEV1%, VC% and MVV%, the contacting coke seniority is a risk factor. There is a positive interaction between contacting coke seniority and furnace roof (P < 0.05).

CONCLUSION

Coke oven workers lung function damage associated with exposureing to coke oven emissions, coke oven emissions exposure level and exposure time are the main factors of coke oven workers in lung function damage, there is a positive interaction between the two factors.

The protective effect of astragaloside IV against benzo[a]pyrene induced endothelial progenitor cell dysfunction

AIMS

Benzo[a]pyrene (BaP), a prominent component of tobacco, has been revealed to induce damage to endothelial progenitor cells (EPCs). Astragaloside IV (AS-IV) is widely used for the treatment of cardiovascular diseases in China. In this study, we evaluated the effects of AS-IV on the function of human EPCs after BaP exposure and explored the underlying mechanism.

MATERIALS AND METHODS

Human umbilical cord blood mononuclear cells were isolated using density gradient centrifugation. Cells of the 4th passage were randomly divided into 6 groups. EPCs of experimental groups were pre-treated with different concentrations (2, 10 and 50 μg/mL) of AS-IV for 2h before exposure to BaP (20 μM) for 24h. The proliferation, migration, and adhesion of the treated EPCs were evaluated using a cell counting kit-8, Transwell assay and adhesion assay respectively. Interleukin-1β, tumor necrosis factor-α, malondialdehyde and SOD contents in the supernatant were evaluated. The expression of RAGE protein was measured by Western blotting.

KEY FINDINGS

The results demonstrated that AS-IV pre-treatment significantly improved BaP-induced dysfunction of EPCs in terms of proliferation, migration and adhesion. Furthermore, AS-IV reduced the production of reactive oxygen species, malondialdehyde, interleukin-1β and tumor necrosis factor-α of the BaP-treated EPCs. Finally AS-IV pre-treated EPCs showed an increased SOD activity and decreased RAGE protein expression.

SIGNIFICANCE

AS-IV is able to prevent BaP-mediated EPC dysfunction by at least inhibiting oxidative stress through the RAGE pathway.

Characterization of Somatic Mutations in Air Pollution-Related Lung Cancer

Air pollution has been classified as Group 1 carcinogenic to humans, but the underlying tumorigenesis remains unclear. In Xuanwei City of Yunnan Province, the lung cancer incidence is among the highest in China attributed to severe air pollution generated by combustion of smoky coal, providing a unique opportunity to dissect lung carcinogenesis of air pollution. Here we analyzed the somatic mutations of 164 non-small cell lung cancers (NSCLCs) from Xuanwei and control regions (CR) where smoky coal was not used. Whole genome sequencing revealed a mean of 289 somatic exonic mutations per tumor and the frequent C:G → A:T nucleotide substitutions in Xuanwei NSCLCs. Exome sequencing of 2010 genes showed that Xuanwei and CR NSCLCs had a mean of 68 and 22 mutated genes per tumor, respectively (p < 0.0001). We found 167 genes (including TP53, RYR2, KRAS, CACNA1E) which had significantly higher mutation frequencies in Xuanwei than CR patients, and mutations in most genes in Xuanwei NSCLCs differed from those in CR cases. The mutation rates of 70 genes (e.g., RYR2, MYH3, GPR144, CACNA1E) were associated with patients' lifetime benzo(a)pyrene exposure. This study uncovers the mutation spectrum of air pollution-related lung cancers, and provides evidence for pollution exposure-genomic mutation relationship at a large scale.

Benzo(a)pyrene-induced cytochrome p4501A expression of four freshwater fishes (Oryzias latipes, Danio rerio, Cyprinus carpio, and Zacco platypus)

Oryzias latipes, Danio rerio, Cyprinus carpio, and Zacco platypus are useful indicator species for CYP1A biomarker studies; however, comparative studies have not been performed. To compare susceptibility, dose- and time-dependent CYP1A induction at the mRNA and protein levels in response to benzo(a)pyrene (BaP) exposure was analyzed. At the mRNA level, a statistically significant difference was found among the four species; however, such was not observed at the protein level. C. carpio showed the highest CYP1A induction level and the steepest slope in the dose-response curve. To assess susceptibility, the difference in CYP1A mRNA induction among species must be considered, and C. carpio was the most sensitive species of the four evaluated in terms of CYP1A expression.

Single cell gel electrophoresis (SCGE) and Pig-a mutation assay in vivo-tools for genotoxicity testing from a regulatory perspective: a study of benzo[a]pyrene in Ogg1(-/-) mice

The OECD has developed test guidelines (TG) to identify agents with genotoxic effects. The in vivo alkaline single cell gel electrophoresis (SCGE) assay is currently being prepared to become such a TG. The performance of a combined SCGE/Pig-a gene mutation study was evaluated with the prototypical genotoxicant benzo[a]pyrene (BaP) at an exposure level known to induce germ cell mutation. We aimed to better understand (i) the strengths and weaknesses of the two methods applied in blood and their potential to predict germ cell mutagenicity, and (ii) the involvement of reactive oxygen species (ROS) following in vivo BaP-exposure. To explore the involvement of ROS on BaP genotoxicity, we utilised a mouse model deficient in a DNA glycosylase. Specifically, C57BL/6 mice (Ogg1(+/+) and Ogg1(-/-)) were treated for three consecutive days with 50 mg BaP/kg/day. DNA damage in nucleated blood cells was measured four hours after the last treatment with the SCGE assay, with and without formamidopyrimidine DNA glycosylase (Fpg). Pig-a mutant phenotype blood erythrocytes were analysed two and four weeks after treatment. BaP-induced DNA lesions were not significantly increased in either version of the SCGE assay. The phenotypic mutation frequencies for immature and mature erythrocytes were significantly increased after two weeks. These effects were not affected by genotype, suggesting oxidative damage may have a minor role in BaP genotoxicity, at least in the acute exposure situation studied here. While both assays are promising tools for risk assessment, these results highlight the necessity of understanding the limitations regarding each assay's ability to detect chemicals' genotoxic potential.

Use of physiologically-based pharmacokinetic modeling to simulate the profiles of 3-hydroxybenzo(a)pyrene in workers exposed to polycyclic aromatic hydrocarbons

Biomathematical modeling has become an important tool to assess xenobiotic exposure in humans. In the present study, we have used a human physiologically-based pharmacokinetic (PBPK) model and an simple compartmental toxicokinetic model of benzo(a)pyrene (BaP) kinetics and its 3-hydroxybenzo(a)pyrene (3-OHBaP) metabolite to reproduce the time-course of this biomarker of exposure in the urine of industrially exposed workers and in turn predict the most plausible exposure scenarios. The models were constructed from in vivo experimental data in rats and then extrapolated from animals to humans after assessing and adjusting the most sensitive model parameters as well as species specific physiological parameters. Repeated urinary voids from workers exposed to polycyclic aromatic hydrocarbons (PAHs) have been collected over the course of a typical workweek and during subsequent days off work; urinary concentrations of 3-OHBaP were then determined. Based on the information obtained for each worker (BaP air concentration, daily shift hours, tasks, protective equipment), the time courses of 3-OHBaP in the urine of the different workers have been simulated using the PBPK and toxicokinetic models, considering the various possible exposure routes, oral, dermal and inhalation. Both models were equally able to closely reproduce the observed time course of 3-OHBaP in the urine of workers and predicted similar exposure scenarios. Simulations of various scenarios suggest that the workers under study were exposed mainly by the dermal route. Comparison of measured air concentration levels of BaP with simulated values needed to obtain a good approximation of observed time course further pointed out that inhalation was not the main route of exposure for most of the studied workers. Both kinetic models appear as a useful tool to interpret biomonitoring data of PAH exposure on the basis of 3-OHBaP levels.

LncRNA-DQ786227-mediated cell malignant transformation induced by benzo(a)pyrene

It has recently been found that the new class of transcripts, long non-coding RNAs (lncRNAs), are pervasively transcribed in the genome. LncRNAs are a large family of non-coding RNAs and regulate many protein-coding genes. Growing evidence indicates that lncRNAs may play an important functional role in cancer biology. Emerging data have shown that lncRNAs are closely related to the occurrence and development of lung cancer. However, the function and mechanism of lncRNAs in lung cancer remain elusive. Here, we investigated the role of a novel lncRNA in transformed human bronchial epithelial cells induced by benzo(a)pyrene. After establishing the transformed cell model using the BEAS-2B cell line in vitro, we found that expression of lncRNA-DQ786227 was high and changed during the transformation of BEAS-2B cells. Silencing of lncRNA-DQ786227 expression in malignant transformed BEAS-2B cells led to inhibition of cell proliferation and colony formation, and increased apoptosis. LncRNA-DQ786227 dramatically promoted the ability of BEAS-2B-T cells to form colonies in vitro and develop tumors in nude mice. These findings revealed that lncRNA-DQ786227 acts as an oncogene in malignantly transformed BEAS-2B cells induced by benzo(a)pyrene. The identification of lncRNA could provide new insight into the molecular mechanisms of chemical carcinogenesis.

Antibodies against benzo[a]pyrene in immunized mouse and in lung cancer patients

AIM

To evaluate the production of antibodies against benzo[a]pyrene (BP) (Ab1) and corresponding antiidiotypic antibodies (Ab2) in mice after immunization with BP-protein conjugate and in lung cancer patients.

MATERIALS AND METHODS

The Ab1 and Ab2 levels were measured by non-competitive ELISA in blood serum of 10 mice immunized with BP-protein conjugate, and in blood serum of 288 healthy persons and 165 lung cancer patients.

RESULTS

The Ab1 level of was 2-fold higher than Ab2 level in blood serum of BP-immunized mice. In lung cancer patients the Ab1 level was almost 3 times higher and the Ab2 level was by 30% higher than these indexes in healthy individuals. The Ab1/Ab2 ratio was 2 in BP-immunized mice and healthy individuals and 1 in lung cancer patients.

CONCLUSION

Our data have shown that the Ab1/Ab2 ratio in lung cancer patients differ from that in healthy individuals and is close to the Ab1/Ab2 ratio in BP-immunized mouse.

Fuzzy logic and adaptive neuro-fuzzy inference system for characterization of contaminant exposure through selected biomarkers in African catfish

This study represents a first attempt at applying a fuzzy inference system (FIS) and an adaptive neuro-fuzzy inference system (ANFIS) to the field of aquatic biomonitoring for classification of the dosage and time of benzo[a]pyrene (BaP) injection through selected biomarkers in African catfish (Clarias gariepinus). Fish were injected either intramuscularly (i.m.) or intraperitoneally (i.p.) with BaP. Hepatic glutathione S-transferase (GST) activities, relative visceral fat weights (LSI), and four biliary fluorescent aromatic compounds (FACs) concentrations were used as the inputs in the modeling study. Contradictory rules in FIS and ANFIS models appeared after conversion of bioassay results into human language (rule-based system). A "data trimming" approach was proposed to eliminate the conflicts prior to fuzzification. However, the model produced was relevant only to relatively low exposures to BaP, especially through the i.m. route of exposure. Furthermore, sensitivity analysis was unable to raise the classification rate to an acceptable level. In conclusion, FIS and ANFIS models have limited applications in the field of fish biomarker studies.

The effect of occupational exposure to benzo[a]pyrene on neurobehavioral function in coke oven workers

BACKGROUND

Coke oven workers are regularly exposed to polycyclic aromatic hydrocarbons (PAHs). Benzo[a]pyrene (B[a]P), known as an indicator species for PAH contamination, is a neurobehavioral toxicant. The purpose of the study was to evaluate the relationship between B[a]P exposure, a B[a]P-related urinary metabolite and neurobehavioral function among coke oven workers.

METHODS

Coke oven workers and oxygen factory workers participated in this study. B[a]P exposure was monitored by air sampling pump, and urinary 1-hydroxypyrene (1-OHP) level was detected with high performance liquid chromatography (HPLC). A questionnaire and the neurobehavioral core test battery (NCTB) were administered to all subjects.

RESULTS

B[a]P-exposed workers were found to have higher urinary 1-OHP levels and worse NCTB performances on eight items than control workers. B[a]P concentrations were higher in the coke oven plant than that in the controls' workplace. The performances on simple reaction time, correct pursuit aiming, and error pursuit aiming decreased with increasing airborne B[a]P in coke oven workers. There were significant correlations between urinary 1-OHP level and six items of the NCTB.

CONCLUSIONS

Occupational exposure to B[a]P is associated with neurobehavioral function impairment in coke oven workers.

[The role of mutation of gene cyp1A1 and benzapilene in cytogenetic changes of urinary tract epitheliocytes in oil industry workers employed in the oil fields of the North of West Siberia]

The examination of 477 oil industry workers and office personnel (control) employed in the oil fields of the North of Tomsk and Tyumen regions has detected increased number of epithelyocytes with micronuclei and an elevated urine level ofbenzapilene in workers employed in oil production. Especially pronounced changes of the above parameters were observed in men with mutant alleles Val of CYP1A1 gene. An enhanced mutation process in oil production workers may be due to a resultant action of different factors on human genome. Involved may be both mutagens and factors of comutagenic nature. The results obtained in this study suggest a conclusion about urgent need of introduction of new scientifically validated criteria of selection of personnel for oil production in the North of the West Siberia. Health examination of the applicants must include genotyping.

Comparison of standard methods for assessing dietary intake of benzo[a]pyrene

BACKGROUND

Inconsistent presence and strength of associations between dietary benzo[a]pyrene (BaP) exposure and cancers may be due to differences in exposure assessment methods. Thus, we determined correlations of usual meat and BaP intake among three methods: food frequency questionnaires (FFQ), diet diaries, and a biomarker.

METHODS

Thirty-six nonsmokers were recruited in Baltimore, MD during 2004-2005. Meat and BaP intake estimated from baseline and follow-up FFQs combined with a BaP residue database (FFQ-RD), mean meat and BaP intake estimated from three diet diaries coupled with the residue database (Diary-RD), and mean of three urinary 1-hydroxypyrene glucuronide (1-OHPG) measurements were compared using Spearman correlations. Collections spanned approximately nine months.

RESULTS

BaP intakes from meat from the baseline [median = 6.4, interquartile range (IQR) = 13.9 ng/d] and follow-up FFQ-RD (median = 7.3, IQR = 35.7 ng/d) were higher than the Diary-RD (median = 1.1, IQR = 7.4 ng/d). Mean 1-OHPG concentration was weakly correlated with mean meat intake (r = 0.33, P = 0.05) and BaP intake from meat (r = 0.27, P = 0.11) from the Diary-RD. Mean BaP intake estimated from the Diary-RD was positively correlated with the follow-up (r = 0.35, P = 0.04) but not baseline (r = 0.20, P = 0.24) FFQ; the converse was true for meat intake.

CONCLUSIONS

Diary-RD estimates were supported by biomarker measurements, but considerable unexplained variability remained. Limited correlation among the dietary BaP exposure assessment methods could be due to differences in timeframes covered by the assessments, interpersonal variability in metabolism, deficiencies in the residue database, or nondietary exposures to BaP.

IMPACT

Limited correlation in estimated BaP intake among standard methods may contribute to inconsistent epidemiology of BaP and cancer.

[Role of poly (ADP-ribose) polymerase 1 on DNA methylation variation induced by B(a)P in human bronchial epithelial cell]

OBJECTIVE

To investigate DNA methylation variation in human cells induces by B(a)P, and to explore the role of PARP1 during this process.

METHODS

The changes of DNA methylation of 16HBE and its PARP1-deficient cells exposed to B(a)P (1.0, 2.0, 5.0, 10.0, 15.0, 30.0 µmol/L) were investigated by immunofluorescence and high performance capillary electrophoresis, and simultaneously, the expression level of PARP 1 and DNMT 1 were monitored dynamically.

RESULTS

The percentage of methylated DNA of overall genome (mCpG%) in 16HBE and 16HBE-shPARP1 cells were separately (4.04 ± 0.08)% and (9.69 ± 0.50)%. After being treated by 5-DAC for 72 hours, mCpG% decreased to (3.15 ± 0.14)% and (6.07 ± 0.54)%. After both being exposed to B(a)P for 72 hours, the mCpG% in 16HBE group (ascending rank) were separately (5.10 ± 0.13), (4.25 ± 0.10), (3.91 ± 0.10), (4.23 ± 0.27), (3.70 ± 0.15), (3.08 ± 0.07); while the figures in 16HBE-shPARP1 group (ascending rank) were respectively (10.63 ± 0.60), (13.08 ± 0.68), (9.75 ± 0.55), (7.32 ± 0.67), (6.90 ± 0.49) and (6.27 ± 0.21). The difference of the results was statistically significant (F values were 61.67 and 60.91, P < 0.01). For 16HBE group, expression of PARP 1 and DNMT 1 were 141.0%, 158.0%, 167.0%, 239.0%, 149.0%, 82.9% and 108.0%, 117.0%, 125.0%, 162.0%, 275.0%, 233.0% comparing with the control group, whose difference also has statistical significance (t values were 11.45, 17.32, 32.24, 33.44, 20.21 and 9.87, P < 0.01). For 16HBE-shPARP1 group, expression of PARP 1 and DNMT 1 were 169.0%, 217.0%, 259.0%, 323.0%, 321.0%, 256.0% and 86.0%, 135.0%, 151.0%, 180.0%, 229.0%, 186.0% comparing with the control group, with statistical significance (t values were 9.06, 15.92, 22.68, 26.23, 37.19 and 21.15, P < 0.01). When the dose of B(a)P reached 5.0 µmol/L, the mRNA expression of DNMT 1 in 16HBE group (ascending rank) were 125.0%, 162.0%, 275.0%, 233.0% times of it in control group, with statistical significance (t values were 12.74, 24.92, 55.11, 59.07, P < 0.01); while the dose of B(a)P reached 2.0 µmol/L, the mRNA expression of DNMT 1 in 16HBE-shPARP1 group were 135.0%, 151.0%, 180.0%, 229.0%, 186.0% of the results in control group, and the differences were statistically significant (t values were 23.82, 40.17, 32.69, 74.85, 46.76, P < 0.01).

CONCLUSION

The hypomethylation of 16HBE cells induced by B(a)P might be one important molecular phenomenon in its malignant transformation process. It suggests that PARP1 could regulate DNA methylation by inhibiting the enzyme activity of DNMT1, and this effect could be alleviated by PARP1-deficiency.

Dietary benzo[a]pyrene, alcohol drinking, and risk of breast cancer: a case-control study in Uruguay

In order to determine to the effect of benzo[a]pyrene (BaP) on breast cancer risk we conducted a case-control study in the time period 1996-2004. The study included 1,098 participants (460 cases and 638 controls). All the patients were drawn from the four major hospitals in Montevideo, Uruguay. Statistical analysis was performed using unconditional multiple logistic regression and the models included age, residence, urban/rural status, education, monthly income, body mass index, menopausal status, age at menarche, parity, smoking index, alcohol drinking, mate consumption, total energy, total vegetables and fruits, and BaP intake. The highest vs. the lowest quartile of BaP intake (OR 2.0, 95% CI 1.2-3.3) was significantly associated with breast cancer risk. Alcohol drinking was also directly associated with breast cancer risk (OR 1.63, 95% CI 1.19-2.23) and the joint effect of BaP and alcohol drinking showed an elevated risk of the disease (OR 3.32, 95% CI 2.17-5.06). The present study suggests that elevated consumption of BaP could play an important role in the etiology of breast cancer. This effect is enhanced by the intake of alcohol.

Oral health risks of tobacco use and effects of cessation

The purpose of this paper is to review the epidemiologic evidence for the effects of tobacco use and tobacco use cessation on a variety of oral diseases and conditions. Exposures considered include cigarette and bidi smoking, pipe and cigar smoking, and smokeless tobacco use. Oral diseases and disorders considered include oral cancer and precancer, periodontal disease, caries and tooth loss, gingival recession and other benign mucosal disorders as well as implant failure. Particular attention is given to the impact of tobacco use cessation on oral health outcomes. We conclude that robust epidemiologic evidence exists for adverse oral health effects of tobacco smoking and other types of tobacco use. In addition, there is compelling evidence to support significant benefits of tobacco use cessation with regard to various oral health outcomes. Substantial oral health benefits can be expected from abstention and successful smoking cessation in a variety of populations across all ages.

[Relationship between CYP1A1 gene polymorphisms and urinary 1-hydroxypyrene levels in coke oven workers]

OBJECTIVE

To study the associations of CYP1A1 gene polymorphisms with levels of urinary 1-hydroxypyrene among coke oven workers.

METHODS

223 male workers from a coke plant (76, 82 and 65 workers in oven top group, oven-side group and oven-bottom group respectively) and 119 controls without occupational polycyclic aromatic hydrocarbons exposure were selected. The MspI gene polymorphism in CYP1A1 3' flanking region and the genotypes at I462V site in exon 7 of CYP1A1 were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele specific amplification (ASA).

RESULTS

The urinary 1-hydroxypyrene of coke oven workers in oven-top, oven-side and oven-bottom (3.77+/-0.64, 3.57+/-0.49, 3.26+/-0.80 micromol/mol Cr) were significantly higher than controls (2.80+/-1.02 micromol/mol Cr) (P<0.01). The urinary 1-hydroxypyrene was not significantly different among MspI genotypes in CYP1A1 3' flanking region (P>0.05). In oven-top group and oven-side group, the subjects with Val/Val genotype in exon 7 of CYP1A1 had significantly higher urinary 1-hydroxypyrene levels than those with Ile/Val or Ile/Ile genotype, and urinary 1-hydroxypyrene of Ile-Val genotype were also significantly higher than Ile/Ile genotype (P<0.01). Multivariate logistic regression analysis showed that the coke oven workers (OR in oven top group, oven-side group and oven-bottom group was 24.926, 4.226 and 6.729 respectively) and subjects with m2/m2 genotype in CYP1A1 3' flanking region (OR=4.031) or with Val/Val or Ile/Val genotype in exon 7 of CYP1A1 (OR were 5.524 and 3.811) had elevated urinary 1-hydroxypyrene (greater than 95 percentile of control group, 3.876 micromol/mol Cr).

CONCLUSION

BAP concentration of work environment contributes to the elevated urinary 1-hydroxypyrene levels, and the exposed BAP levels were regulated by the CYP1A1 MspI and I462V genotypes. Genetic polymorphism of CYP1A1 gene could be a susceptible biomarker in coke oven workers which was involved in the individual susceptibility on metabolism of PAHs.

[Ambient air benzo(a)pyrene and its role in the formation of cancer morbidity in Tashkent]

The ambient air benz(a)pyrene concentration was found to be greatly variable in Tashkent in 1985 to 2005. A high correlation was established between the ambient air content of benz(a)pyrene and the rate of primary malignancy morbidity. The findings show it necessary to monitor the level of benz(a)pyrene in the ambient air of Tashkent.

[Relationship between heat shock protein 72 and DNA genetic damage in peripheral blood lymphocytes of coke oven workers]

OBJECTIVE

To investigate the relationship between heat shock protein 72 (Hsp72) and DNA genetic damage in peripheral blood lymphocytes of coke oven workers and the role of Hsp72 in protection of cells from genetic damage induced by coke oven emissions.

METHODS

Two hundred and sixty-seven coke oven workers and thirty controls without occupational PAHs exposure were investigated. Benzo[a]pyrene concentrations in the ambient air individually collected were assayed by high performance liquid chromatography (HPLC). Western Blot was used to measure Hsp72 levels and Comet assay was used to evaluate DNA damage degree. Personal information was collected by questionnaire.

RESULTS

The Hsp72 level (G+/-S(G)) and olive comet tail moment (G+/-S(G) of peripheral blood lymphocytes in high-exposure workers (1.24 +/- 0.42 and 4.49 +/- 1.24) were significantly higher than those in low-exposure workers (1.01 +/- 0.35 and 2.99 +/- 1.10, P < 0.05) and control (0.85 +/- 0.34 and 2.40 +/- 1.00, P < 0.05) respectively. The Hsp72 median level of all subjects was used as the limit to divide subjects into high Hsp72 level group and low Hsp72 level group. The rate with high Hsp72 level was 36.7%, 43.1% and 58.3% in control, low exposure and high exposure workers respectively and had a rising tendency following exposure level (P = 0.003). In high Hsp72 level group Hsp72 level in high exposure workers was significantly higher than that in control (P < 0.05), and there was a rising tendency along with the increase of exposed levels. But the olive comet tail moment had no significant difference among three exposed groups (P > 0.05). In low Hsp72 level group there no difference among three exposed groups about Hsp72 levels. The olive comet tail moment in high exposure workers was significantly higher than that in low exposure workers and control (P < 0.01) and high exposure workers in Hsp72 positive group and there was a rising tendency along with the increase of exposed levels. Hsp72 levels had strong negative correlation with the olive comet tail moment (r = -0.503, P < 0.01) in high exposure workers.

CONCLUSION

The coke oven emissions can induce hsp72 expression. Hsp72 play a role of protecting cells from DNA damage induced by coke oven emissions.

Dietary mutagen exposure and risk of pancreatic cancer

To investigate the association between dietary exposure to food mutagens and risk of pancreatic cancer, we conducted a hospital-based case-control study at the University of Texas M. D. Anderson Cancer Center during June 2002 to May 2006. A total of 626 cases and 530 noncancer controls were frequency matched for race, sex and age (+/-5 years). Dietary exposure information was collected via personal interview using a meat preparation questionnaire. A significantly greater portion of the cases than controls showed a preference to well-done pork, bacon, grilled chicken, and pan-fried chicken, but not to hamburger and steak. Cases had a higher daily intake of food mutagens and mutagenicity activity (revertants per gram of daily meat intake) than controls did. The daily intakes of 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx) and benzo(a)pyrene (BaP), as well as the mutagenic activity, were significant predictors for pancreatic cancer (P = 0.008, 0.031, and 0.029, respectively) with adjustment of other confounders. A significant trend of elevated cancer risk with increasing DiMeIQx intake was observed in quintile analysis (P(trend) = 0.024). A higher intake of dietary mutagens (those in the two top quintiles) was associated with a 2-fold increased risk of pancreatic cancer among those without a family history of cancer but not among those with a family history of cancer. A possible synergistic effect of dietary mutagen exposure and smoking was observed among individuals with the highest level of exposure (top 10%) to PhIP and BaP, P(interaction) = 0.09 and 0.099, respectively. These data support the hypothesis that dietary mutagen exposure alone and in interaction with other factors contribute to the development of pancreatic cancer.

The influence of experimental desynchronosis on the morphofunctional characteristics of mouse immune system

The aim of this study is to investigate the influence of experimental desynchronosis on the immune system and estimate benzo[a]pyrene (BP) influence on the immune reactivity of mice under the condition of desyncronosis (DS) in comparison with intact organisms. Mice (CBA X C57BL)F1 were kept under constant light during two weeks and natural alternation of darkness and light (control group). Animals of the two groups received benzo[a]pyrene solution in olive oil. The existence of diurnal variation of cell populations of lymphoid organs and blood, humoral immune response to SRBC were revealed. Changes of diurnal dynamics of these parameters and decrease of humoral immune response to SRBC have been observed in animals kept under constant light in comparison with animals kept under standard light conditions. It is likely to indicate the development of internal DS. BP influenced the cellular composition and immune response of intact and DS animals in a different way. So, the changes of light regime lead to development of the internal DS of immune system that influenced its functional capacity and sensitivity to damaging effect of chemical ecological factor.

Diagnostic relevance of the determination of lymphocyte subpopulations in environmental medicine

Earlier hopes that determination of lymphocyte subpopulations might become a strong diagnostic tool in environmental medicine have not been fulfilled in recent years. Analysis of the scientific literature rather shows that there are only few examples for environmental exposures causing reproducible shifts of lymphocyte subpopulations. Moreover, current knowledge suggests that "environmental diseases" are not associated with characteristic changes of subpopulation patterns. If lymphocyte subpopulations are analyzed, each diagnostic step, including indication, sample handling, analytic procedure and data-interpretation, should adhere to good quality criteria. Taking all together, the determination of lymphocyte subpopulations in the context of environmental medicine comes under category IV of the criteria of the Commission for Methods and Quality Assurance in Environmental Medicine of the German federal health authority (Robert Koch-Institute; RKI): "A procedure cannot be recommended because there is not sufficient information to justify it" (here: no solid trends in epidemiological examinations), "and because theoretical considerations speak against an application" (here: high physiological variability and missing exposure or substance specificity).

Higher urine 1-hydroxy pyrene glucuronide (1-OHPG) is associated with tobacco smoke exposure and drinking maté in healthy subjects from Rio Grande do Sul, Brazil

Background

The highest rates of esophageal squamous cell carcinoma (ESCC) in Brazil occur in Rio Grande do Sul, the most southern state, which has incidence rates of 20.4/100,000/year for men and 6.5/100,000/year for women. Exposure to carcinogenic polycyclic aromatic hydrocarbons (PAHs) through tobacco smoke and other sources may increase the risk of ESCC. The aims of the current study were to investigate the degree and sources of PAH exposure of the inhabitants of this region of southern Brazil.

Methods

Two hundred healthy adults (half smokers, half non smokers, half male and half female) were recruited, given a standardized questionnaire, and asked to provide a urine sample for measurement of 1-hydroxypyrene glucuronide (1-OHPG), a PAH metabolite). Urine 1-OHPG concentrations were measured using immunoaffinity chromatography and synchronous fluorescence spectroscopy and urine cotinine was measured using a dipstick test. We examined factors associated with 1-OHPG concentration using Wilcoxon tests and multiple linear regression.

Results

Urine 1-hydroxypyrene glucuronide (1-OHPG) was successfully measured on 199 subjects. The median (interquartile range) of urine 1-OHPG in the 199 participants was 2.09 pmol/mL (0.51, 5.84). Tobacco smoke exposure and maté drinking were statistically significantly associated with higher urine 1-OHPG concentrations in the multivariate linear regression model.

Conclusion

Tobacco smoke and maté both contribute to high levels of benzo[a]pyrene exposure in the people of southern Brazil. This high PAH exposure may contribute to the high rates of ESCC observed in this population. The increased urine 1-OHPG concentrations associated with maté suggest that contaminants, not just thermal injury, may help explain the increased risk of ESCC previously reported for maté consumption.

A prospective study of meat and meat mutagens and prostate cancer risk

High-temperature cooked meat contains heterocyclic amines, including 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), and polycyclic aromatic hydrocarbons, such as benzo(a)pyrene (BaP). In rodents, a high intake of PhIP induces prostate tumors. We prospectively investigated the association between meat and meat mutagens, specifically PhIP, and prostate cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Diet was assessed using a 137-item food frequency questionnaire and a detailed meat-cooking questionnaire linked to a database for BaP and the heterocyclic amines 2-amino-3,8-dimethylimidazo[4,5-b]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx), and PhIP. During follow-up, we ascertained a total of 1,338 prostate cancer cases among 29,361 men; of these, 868 were incident cases (diagnosed after the first year of follow-up) and 520 were advanced cases (stage III or IV or a Gleason score of > or =7). Total, red, or white meat intake was not associated with prostate cancer risk. More than 10 g/d of very well done meat, compared with no consumption, was associated with a 1.4-fold increased risk of prostate cancer [95% confidence interval (95% CI), 1.05-1.92] and a 1.7-fold increased risk (95% CI, 1.19-2.40) of incident disease. Although there was no association with MeIQx and DiMeIQx, the highest quintile of PhIP was associated with a 1.2-fold increased risk of prostate cancer (95% CI, 1.01-1.48) and a 1.3-fold increased risk of incident disease (95% CI, 1.01-1.61). In conclusion, very well done meat was positively associated with prostate cancer risk. In addition, this study lends epidemiologic support to the animal studies, which have implicated PhIP as a prostate carcinogen.

Dietary Intake of Heterocyclic Amines and Benzo(a)Pyrene: Associations with Pancreatic Cancer

OBJECTIVE

Heterocyclic amines (HCA) and polycyclic aromatic hydrocarbons, formed in temperature- and time-dependent manners during the cooking of meat, are mutagens and carcinogens. We sought to assess the association between dietary intake of HCA and benzo(a)pyrene [B(a)P] and exocrine pancreatic cancer in a population-based case-control study.

METHODS

Subjects (193 cases and 674 controls) provided information on their usual meat intake and preparation method, e.g., stewed, fried, or grilled/barbecued, etc. Meat doneness preferences were measured using photographs that showed internal doneness and external brownness. We used a meat-derived HCA, B(a)P, and mutagen database with a questionnaire to estimate intake of PhIP, DiMeIQx, MeIQx, B(a)P, and mutagenic activity (revertants/g of daily meat intake). Data were analyzed with unconditional logistic regression.

RESULTS

In analyses adjusted for age, sex, smoking, education, race, and diabetes, the odds ratio and 95% confidence interval for the highest compared with the lowest quintile were as follows: PhIP, 1.8 (1.0-3.1); DiMeIQx, 2.0 (1.2-3.5); MeIQx, 1.5 (0.9-2.7); B(a)P, 2.2 (1.2-4.0); and mutagenic activity, 2.4 (1.3-4.3).

CONCLUSIONS

HCAs and B(a)P from well-done barbecued and pan-fried meats may be associated with increased risk for pancreatic cancer.

Dietary benzo[a]pyrene intake and risk of colorectal adenoma

We carried out a clinic-based case-control study specifically designed to address the hypothesis that dietary intake of polycyclic aromatic hydrocarbons (PAH) is associated with colorectal adenoma risk. We developed a food frequency questionnaire with detailed questions on meat-cooking methods and doneness levels and a benzo[a]pyrene (BaP) database (as a surrogate for total carcinogenic PAHs) based on the collection and analysis of a wide range of food samples. We estimated BaP intake derived from meat and from all foods to test its relationship with risk of colorectal adenomas. The median (10th and 90th percentiles) BaP intake in controls was 5 ng/d (0.2 and 66 ng/d) estimated from meat and 73 ng/d (35 and 140 ng/d) from all foods. In cases, median BaP intake was 17 ng/d (0.5 and 101 ng/d) from meat and 76 ng/d (44 and 163 ng/d) from all foods. Multivariate analysis was carried out on 146 cases and 228 controls. The odds ratios (95% confidence interval) for dietary BaP from meat with the first quintile as the reference group were 1.19 (0.51-2.80) for the second quintile, 1.71 (0.76-3.83) for the third quintile, 2.16 (0.96-4.86) for the fourth quintile, and 2.82 (1.24-6.43) for the fifth quintile (Ptrend=0.01). Increased risk of colorectal adenomas was more strongly associated with BaP intake estimated from all foods: 2.61 (1.08-6.29) for the second quintile, 4.21 (1.79-9.91) for the third quintile, 2.45 (0.98-6.12) for the fourth quintile, and 5.60 (2.20-14.20) for the fifth quintile (Ptrend=0.002). This study provides evidence that dietary BaP plays a role in colorectal adenoma etiology.

[Microbiological degradation of benz(a)pyrene in soil]

Several microbial clones that could grow on the benz(a)pyrene medium were identified from the soils contaminated with petroleum products. It was shown that benz(a)pyrene could be degraded by the obtained cultures that selectively utilized the carcinogenic molecules of benz(a)pyrene in the presence of other sources of carbohydrate. The authors give recommendations on the biodestruction of benz(a)pyrene and other polycyclic aromatic hydrocarbons under natural conditions in order to improve the oncoecological situation.

Analysis of resveratrol as a lung cancer chemopreventive agent in A/J mice exposed to benzo[a]pyrene

Resveratrol inhibits PAH bioactivation through reduced expression of the CYP1A1 and CYP1B1 genes in human bronchial epithelial cells. Ad libitum access to a diet containing resveratrol showed no effect on benzo[a]pyrene-induced lung tumorigenesis in A/J mice. Also, resveratrol did not change CYP1A1 and CYP1B1 gene expression or benzo[a]pyrene protein adduct levels in the lung tissue. The lack of chemopreventive activity may have been caused by insufficient concentrations or nonreactive forms of resveratrol in the lungs.

[Environmental carcinogens and p53 gene mutation]

P53 gene is the most prominent tumor suppressor gene in human cancer among those genes that have been found till now. It not only acts as a tumor suppressor gene, but also participates in many cellular functions: cell cycle control, DNA damage and repair, gene transcription and cell apoptosis. The studies on the etiology of cancer show that 60-90% of human cancer are caused by the carcinogens in ambient environment. In the carcinogenic process, environmental carcinogens or pre-carcinogens can cause the changes in p53 gene and protein, the mutation spectra of p53 gene varies with the different carcinogens and cancer type. In these years, many studies on p53 suppressor gene were reported. This article reviews some of the major carcinogens in ambient environment which can affect the p53 gene and protein, and the carcinogenic effects of them.

Modulation of Carcinogen Metabolism and DNA Interaction by Calcium Glucarate in Mouse Skin

Almost all the polycyclic aromatic hydrocarbons (PAHs) require metabolic activation to exert their carcinogenic activity. Environmental carcinogen [(3)H] benzo[a]pyrene (BP) is carcinogenic only after its metabolic transformation to a reactive intermediate, which can then bind to cellular macromolecules. Inhibition of dimethylbenz anthracene- (DMBA-) DNA binding generally accompanied inhibition of tumor initiation as most inhibitors of initiation interfere with the metabolic activation of the initiator. The importance of carcinogen-DNA interaction and the enzymes involved in the metabolism of carcinogenic polycyclic hydrocarbons has led to a search for inhibitors that would be useful in modifying the cancer-causing effects of the PAHs. We tested the effect of calcium glucarate (Cag), a naturally occurring nontoxic compound, on carcinogen metabolism and DNA interaction. Cag inhibited [(3)H] BP binding to both calf thymus DNA in vitro and to epidermal DNA in vivo. Application of Cag to mouse skin caused a dose-dependent inhibition of [(3)H] BP binding to epidermal DNA. To establish the relevance of the in vivo results to the in vitro situation, we followed the in vitro effect of Cag on [(3)H] BP binding to calf thymus DNA and observed that Cag inhibited the [(3)H] BP binding to calf thymus DNA in the presence of microsomes prepared from animals treated with DMBA. We also studied related events like DNA synthesis and carcinogen metabolism. For assessing the DNA synthesis, thymidine kinase was used as marker. Cag caused a dose-dependent inhibition of DMBA-induced thymidine kinase activity. At the same time, Cag caused a marked inhibition of DMBA-induced aryl hydrocarbon hydroxylase (AHH) activity, an enzyme responsible for the metabolism of PAHs like BP, both in vivo and in vitro. Our study indicates that Cag exerted its antitumor effect possibly by inhibiting the carcinogen-DNA binding, which appears to be due to reduced DNA synthesis and AHH activity.