Effects of airborne particles on the expression status of markers of cellular toxic stress and on the release of eicosanoids, linked with inflammation and oxidative damage, remain poorly characterized. Therefore, we proposed a set of various methodological approaches in order to address complexity of PM0.5-induced toxicity. For this purpose, we used a well-characterized model of A549 pulmonary epithelial cells exposed to a non-cytotoxic concentration of ambient aerosol particle fraction PM0.5 for 24 h. Electron microscopy confirmed accumulation of PM0.5 within A549 cells, yet, autophagy was not induced. Expression profiles of various cellular stress response genes that have been previously shown to be involved in early stress responses, namely unfolded protein response, DNA damage response, and in aryl hydrocarbon receptor (AhR) and p53 signaling, were analyzed. This analysis revealed induction of GREM1, EGR1, CYP1A1, CDK1A, PUMA, NOXA and GDF15 and suppression of SOX9 in response to PM0.5 exposure. Analysis of eicosanoids showed no oxidative damage and only a weak anti-inflammatory response. In conclusion, this study helps to identify novel gene markers, GREM1, EGR1, GDF15 and SOX9, that may represent a valuable tool for routine testing of PM0.5-induced in vitro toxicity in lung epithelial cells.

• MeSH
• aerosoly MeSH
• buňky A549 MeSH
• epitelové buňky metabolismus   patologie   MeSH
• látky znečišťující vzduch toxicita   MeSH
• lidé MeSH
• pevné částice toxicita   MeSH
• plíce metabolismus   patologie   MeSH
• regulace genové exprese účinky léků   MeSH
• signální transdukce účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Industrial particulate matter (PM) air pollution exposing nearby residential areas forms several European air pollution hot-spots. One of these hot-spot is the residential district of Ostrava Radvanice-Bartovice with frequent exceedances for PM and benzo[a]pyrene B[a]P, a carcinogenic polycyclic aromatic hydrocarbon (PAH) of MW > 228 amu. Such PAHs are highly bonded to the ultrafine particles (UFPs), the smallest PM size fraction, which deposits most efficiently in the alveolar region of human lungs. Airborne measurements identified UFP point sources in the adjacent metallurgical complex and mapped limited horizontal and vertical dispersion of industrial plumes enriched with UFPs (3.2 × 10(5)cm(-3)). The plumes, episodes of simultaneous peaks of UFPs (1.4 × 10(5)cm(-3)), SO2 (88.2 ppb), and CO (11.3 ppm), were recorded on the ground downwind in the residential district when wind speeds >1 ms(-1). In the plumes, UFPs were mostly 19-44 nm in diameter, enriched with PAHs/B[a]P up to 43.8/3.5 mg·g(-1). Electron microscopy showed that these plume UFPs were mostly agglomerates of spherules of 30-50 nm in diameter. These source impact measurements, that combine airborne and ground-level measurements, are applicable to clearly identify specific industrial air pollution sources and provide information to assess their possible impact to human health in similar hot-spots worldwide.

• MeSH
• hutnictví MeSH
• látky znečišťující vzduch * MeSH
• lidé MeSH
• pevné částice * MeSH
• vítr MeSH
• znečištění ovzduší MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Many of the toxic and carcinogenic effects of urban air pollution have been linked to polycyclic aromatic hydrocarbons (PAHs) adsorbed to airborne particulate matter (PM). The carcinogenic properties of PAHs in complex organic mixtures derived from PM have been chiefly attributed to their mutagenicity. Nevertheless, PAHs are also potent activators of the aryl hydrocarbon receptor (AhR), which may contribute to their nongenotoxic effects, including tumor promotion. As the genotoxicity of carcinogenic PAHs in complex mixtures derived from urban PM is often inhibited by other mixture constituents, the AhR-mediated activity of urban PM extracts might significantly contribute to the carcinogenic activity of such mixtures. In the present study, we used an organic extract of the urban dust standard reference material, SRM1649a, as a model mixture to study a range of toxic effects related to DNA damage and AhR activation. Both the organic extract and its neutral aromatic fraction formed a low number of DNA adducts per nucleotide in the liver epithelial WB-F344 cells model, without inducing DNA damage response, such as tumor suppressor p53 activation and apoptosis. In contrast, we found that this extract, as well as its neutral and polar fractions, were potent inducers of a range of AhR-mediated responses, including induction of the AhR-mediated transcription, such as cytochrome P450 1A1/1B1 expression, and the AhR-dependent cell proliferation. Importantly, these toxic events occurred at doses one order of magnitude lower than DNA damage. The AhR-mediated activity of the neutral fraction was linked to PAHs and their derivatives, as polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls were only minor contributors to the overall AhR-mediated activity. Taken together, our data suggest that more attention should be paid to the AhR-dependent nongenotoxic events elicited by urban PM constituents, especially PAHs and their derivatives.

• MeSH
• adukty DNA účinky léků   MeSH
• apoptóza účinky léků   MeSH
• buněčné linie MeSH
• cytochrom P-450 CYP1A1 metabolismus   MeSH
• geny p53 účinky léků   MeSH
• játra účinky léků   MeSH
• krysa rodu rattus MeSH
• mutageny toxicita   MeSH
• organické látky toxicita   MeSH
• pevné částice toxicita   MeSH
• polycyklické aromatické uhlovodíky toxicita   MeSH
• poškození DNA účinky léků   MeSH
• proliferace buněk účinky léků   MeSH
• receptory aromatických uhlovodíků metabolismus   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

The methylated benzo[a]pyrenes (MeBaPs) are present at significant levels in the environment, especially in the sediments contaminated by petrogenic PAHs. However, the existing data on their toxic effects in vitro and/or in vivo are still largely incomplete. Transcription factor AhR plays a key role in the metabolic activation of PAHs to genotoxic metabolites, but the AhR activation may also contribute to the tumor promoting effects of PAHs. In this study, the AhR-mediated activity of five selected MeBaP isomers was estimated in the DR-CALUX reporter gene assay performed in rat hepatoma cells. Detection of other effects, including induction of CYP1A1, CYP1B1, and AKR1C9 mRNAs, DNA adduct formation, production of reactive oxygen species, oxidation of deoxyguanosine, and cell cycle modulation and apoptosis, was performed in the rat liver epithelial WB-F344 cell line, a model of liver progenitor cells. We identified 1-MeBaP as the most potent inducer of AhR activation, stable DNA adduct formation, checkpoint kinase 1 and p53 phosphorylation, and apoptosis. These effects suggest that 1-MeBaP is a potent genotoxin eliciting a typical sequence of events ascribed to carcinogenic PAHs: induction of CYP1 enzymes, formation of high levels of DNA adducts, activation of DNA damage responses (including p53 phosphorylation), and cell death. In contrast, 10-MeBaP, representing BaP isomers substituted with the methyl group in the angular ring, elicited only low levels DNA adduct formation and apoptosis. Other MeBaPs under study also elicited strong apoptotic responses associated with DNA adduct formation as the prevalent mode of toxic action of these compounds in liver cells. MeBaPs induced a weak production of ROS, which did not lead to significant oxidative DNA damage. Importantly, 1-MeBaP and 3-MeBaP were found to be potent AhR agonists, one order of magnitude more potent than BaP, thus suggesting that the AhR-dependent modulations of gene expression, deregulation of cell survival mechanisms, and further nongenotoxic effects associated with AhR activation may further contribute to their tumor promotion and carcinogenicity.

• MeSH
• adukty DNA metabolismus   MeSH
• apoptóza účinky léků   MeSH
• benzopyren chemie   toxicita   MeSH
• buněčné linie MeSH
• buněčný cyklus účinky léků   MeSH
• epitelové buňky účinky léků   metabolismus   MeSH
• játra cytologie   MeSH
• kmenové buňky účinky léků   metabolismus   MeSH
• krysa rodu rattus MeSH
• metylace MeSH
• mutageny chemie   toxicita   MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 metabolismus   MeSH
• oxidační stres účinky léků   MeSH
• proteinkinasy metabolismus   MeSH
• receptory aromatických uhlovodíků metabolismus   MeSH
• regulace genové exprese účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Exposure to polycyclic aromatic hydrocarbons (PAHs) has been positively associated with prostate cancer, but knowledge of the formation of PAH-DNA adducts and related genotoxic events in prostatic cells is limited. In the present study, benzo[a]pyrene (BaP), a potent mutagenic PAH, formed significant levels of DNA adducts in cell lines derived from human prostate carcinoma. When analyzing the effect of BaP on the induction of CYP1 enzymes participating in the metabolic activation of PAHs in LNCaP cells, we found that BaP induced expression of CYP1A1 and CYP1A2, but not CYP1B1 enzyme. Despite a significant amount of DNA adducts being formed by BaP and, to a lesser extent also by another strong genotoxin, dibenzo[a,l]pyrene, neither apoptosis nor cell-cycle arrest were induced in LNCaP cells. LNCaP cells were not sensitized to the induction of apoptosis by PAHs even through inhibition of the phosphoinositide-3-kinase/Akt pro-survival pathway. The lack of apoptosis was not due a disruption of expression of pro-apoptotic and pro-survival members of the Bcl-2 family of apoptosis regulators. In contrast to other genotoxic stimuli, genotoxic PAHs failed to induce DNA double-strand breaks, as illustrated by the lack of phosphorylation of histone H2AX or checkpoint kinase-2. BaP did not activate p53, as evidenced by the lack of p53 accumulation, phosphorylation at Ser15, or induction of p53 transcriptional targets. Taken together, although genotoxic PAHs produced significant levels of DNA adducts in a model of human prostate carcinoma cells, they did not activate the mechanisms leading to elimination of cells with significant damage to DNA, presumably due to their failure to activate the p53-dependent DNA damage response.

• MeSH
• apoptóza účinky léků   MeSH
• karcinom metabolismus   MeSH
• látky znečišťující životní prostředí toxicita   MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 metabolismus   MeSH
• nádory prostaty metabolismus   MeSH
• polycyklické aromatické uhlovodíky toxicita   MeSH
• poškození DNA účinky léků   MeSH
• regulace genové exprese u nádorů účinky léků   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Monomethylated benz[ a]anthracenes (MeBaAs) are an important group of methylated derivatives of polycyclic aromatic hydrocarbons (PAHs). Although the methyl substitution reportedly affects their mutagenicity and tumor-initiating activity, little is known about the impact of methylation on the effects associated with activation of the aryl hydrocarbon receptor (AhR)-dependent gene expression and/or toxic events associated with tumor promotion. In the present study, we studied the effects of a series of MeBaAs on the above-mentioned end points in rat liver cell lines and compared them with the effects of benz[ a]anthracene (BaA) and the potent carcinogen 7,12-dimethylbenz[ a]anthracene (DMBA). Methyl substitution enhanced the AhR-mediated activity of BaA derivatives determined in a reporter gene assay, as the induction equivalency factors (IEFs) of all MeBaAs were higher than that of BaA. IEFs of 6-MeBaA and 9-MeBaA, two of the most potent MeBaAs, were more than two orders of magnitude higher than the IEF of BaA. Correspondingly, all MeBaAs induced higher levels of cytochrome P450 1A1 mRNA. Both BaA and MeBaAs had similar effects on the expression of cytochrome P450 1B1 or aldo-keto reductase 1C9 in rat liver epithelial WB-F344 cells. In contrast to genotoxic DMBA, MeBaAs induced low DNA adduct formation. Only 10-MeBaA induced apoptosis and accumulation of phosphorylated p53, which could be associated with the induction of oxidative stress, similar to DMBA. With the exception of 10-MeBaA, all MeBaAs induced cell proliferation in contact-inhibited WB-F344 cells, which corresponded with their ability to activate AhR. 1-, 2-, 8-, 10-, 11-, and 12-MeBaA inhibited gap junctional intercellular communication (GJIC) in WB-F344 cells. This mode of action, like disruption of cell proliferation control, might contribute to tumor promotion. Taken together, these data showed that the methyl substitution significantly influences those effects of MeBaAs associated with AhR activation or GJIC inhibition.

• MeSH
• 9,10-dimethyl-1,2-benzanthracen imunologie   metabolismus   toxicita   MeSH
• adukty DNA analýza   metabolismus   MeSH
• apoptóza účinky léků   MeSH
• benz(a)anthraceny chemie   metabolismus   toxicita   MeSH
• DNA metabolismus   účinky léků   MeSH
• enzymová indukce MeSH
• financování organizované MeSH
• hepatocelulární karcinom MeSH
• hepatocyty metabolismus   patologie   účinky léků   MeSH
• kmenové buňky metabolismus   patologie   účinky léků   MeSH
• krysa rodu rattus MeSH
• messenger RNA metabolismus   MeSH
• metylace MeSH
• mezerový spoj účinky léků   MeSH
• nádorové buněčné linie MeSH
• nádory jater MeSH
• potkani inbrední F344 MeSH
• proliferace buněk účinky léků   MeSH
• regulace genové exprese enzymů účinky léků   MeSH
• reportérové geny účinky léků   MeSH
• systém (enzymů) cytochromů P-450 genetika   metabolismus   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH

The bipotent liver progenitor cells, so called oval cells, may participate at the early stages of hepatocarcinogenesis induced by chemical carcinogens. Unlike in mature parenchymal cells, little is known about formation of DNA adducts and other genotoxic events in oval cells. In the present study, we employed spontaneously immortalized rat liver WB-F344 cell line, which is an established in vitro model of oval cells, in order to study genotoxic effects of selected carcinogenic polycyclic aromatic hydrocarbons (PAHs). With exception of dibenzo[a,l]pyrene, and partly also benzo[g]chrysene and benz[a]anthracene, all other PAHs under the study induced high levels of CYP1A1 and CYP1B1 mRNA. In contrast, we observed distinct genotoxic and cytotoxic potencies of PAHs. Dibenzo[a,l]pyrene, and to a lesser extent also benzo[a]pyrene, benzo[g]chrysene and dibenzo[a,e]pyrene, formed high levels of DNA adducts. This was accompanied with accumulation of Ser-15 phosphorylated form of p53 protein and induction of apoptosis. Contrary to that, benz[a]anthracene, chrysene, benzo[b]fluoranthene and dibenzo[a,h]anthracene induced only low amounts of DNA adducts formation and minimal apoptosis, without exerting significant effects on p53 phosphorylation. Finally, we studied effects of 2,4,3',5'-tetramethoxystilbene and fluoranthene, inhibitors of CYP1B1 activity, which plays a central role in metabolic activation of dibenzo[a,l]pyrene. In a dose-dependent manner, both compounds inhibited apoptosis induced by dibenzo[a,l]pyrene, suggesting that it interferes with the metabolic activation of the latter one. The present data show that in model cell line sharing phenotypic properties with oval cells, PAHs can be efficiently metabolized to form ultimate genotoxic metabolites. Liver progenitor cells could be thus susceptible to this type of genotoxic insult, which makes WB-F344 cell line a useful tool for studies of genotoxic effects of organic contaminants in liver cells. Our results also suggest that, unlike in mature hepatocytes, CYP1B1 might be a primary enzyme responsible for formation of DNA adducts in liver progenitor cells.

• MeSH
• adukty DNA metabolismus   MeSH
• apoptóza MeSH
• aromatické hydroxylasy genetika   MeSH
• cytochrom P-450 CYP1A1 genetika   MeSH
• financování organizované MeSH
• játra cytologie   MeSH
• kmenové buňky metabolismus   MeSH
• krysa rodu rattus MeSH
• kultivované buňky MeSH
• messenger RNA analýza   MeSH
• polycyklické aromatické uhlovodíky farmakologie   MeSH
• potkani inbrední F344 MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH

Polycyclic aromatic hydrocarbons (PAHs) with molecular weight 278 are a group of PAHs that are mostly not covered by the current monitoring programs, despite their relative abundance in environmental samples and possible carcinogenicity. Although benzo[g]chrysene (BgChry) and dibenz[a,h]anthracene (DBahA) have been for a long time studied as genotoxic, tumour-initiating compounds, little is known about the potential tumour-promoting effects of this group of PAHs. In the present study, we investigated their impact on activation of the aryl hydrocarbon receptor (AhR), induction of enzymes involved in metabolic activation of PAHs, disruption of cell cycle control in confluent cell population and inhibition of gap junctional intercellular communication (GJIC), using the rat liver epithelial cell line WB-F344 as a model of liver progenitor cells. We found that BgChry was the weakest inducer of the AhR-mediated activity, while relative potencies of benzo[b]chrysene (BbChry) and benzo[c]chrysene (BcChry) were comparable to the previously reported values for dibenzanthracenes. All compounds increased expression of cytochromes P450 1A1 and 1B1, and aldo-keto reductase 1C9. BgChry was found to induce high amounts of DNA adducts, which corresponded with induction of p53 phosphorylation at Ser15, apoptosis and accumulation of cells in S-phase of cell cycle, leading to a decrease in cell numbers. All other compounds were found to stimulate cell proliferation in contact-inhibited WB-F344 cells in a dose-dependent manner. We found that only BgChry, and to a lesser extent also BcChry, inhibited GJIC at high concentrations. Taken together, dibenzanthracenes and benzochrysenes, with exception of BgChry, seem to act primarily through deregulation of cell proliferation in liver epithelial cells, which is related to their relatively high AhR-mediated activity. The disruption of cell cycle control might contribute to their carcinogenic effects, as well as to carcinogenicity of complex environmental mixtures containing high levels of PAHs with molecular weight 278.

• MeSH
• adukty DNA metabolismus   MeSH
• aktivace enzymů MeSH
• apoptóza účinky léků   MeSH
• aromatické hydroxylasy biosyntéza   genetika   metabolismus   MeSH
• benz(a)anthraceny toxicita   MeSH
• chryseny toxicita   MeSH
• cytochrom P-450 CYP1A1 biosyntéza   genetika   metabolismus   MeSH
• financování organizované MeSH
• hydroxysteroiddehydrogenasy biosyntéza   genetika   metabolismus   MeSH
• játra cytologie   enzymologie   metabolismus   účinky léků   MeSH
• karcinogeny toxicita   MeSH
• krysa rodu rattus MeSH
• messenger RNA biosyntéza   genetika   MeSH
• mezerový spoj účinky léků   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• proliferace buněk účinky léků   MeSH
• receptory aromatických uhlovodíků metabolismus   MeSH
• vystavení vlivu životního prostředí MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH

Alkylated polycyclic aromatic hydrocarbons (PAHs) are important environmental pollutants. In the present study, we determined levels of monomethylated naphthalenes (MeNap), phenanthrenes (MePhe), and anthracenes (MeAnt) in Czech river sediments. The levels of MePhe generally were lower than the concentrations of phenanthrene. In contrast, both MeNap and MeAnt were found at levels higher than their respective parent compounds in the majority of sampling sites. We then investigated their aryl hydrocarbon receptor (AhR)-mediated activity, accumulation of phosphorylated p53 protein, induction of expression of cytochrome P450 1A1 (CYP1A1), inhibition of gap junctional intercellular communication (GJIC), and effects on cell proliferation in rat liver cell models to evaluate the relative importance of these toxicity mechanisms of low-molecular-weight methylated PAHs. Methylated phenanthrene and anthracene compounds were weak inducers of AhR-mediated activity as determined both in a reporter gene assay system and by detection of the endogenous gene (Cyp1a1) induction. 2-Methylphenanthrene was the most potent AhR ligand. Contribution of MeAnt and MePhe to overall AhR-inducing potencies should be taken into account in PAH-contaminated environments. Nevertheless, their effects on AhR were not sufficient to modulate cell proliferation in a normal rat liver progenitor cell model system. These PAHs only had a marginal effect on p53 phosphorylation at high doses of 1-, 3-, and 9-MePhe as well as 1 MeAnt. On the other hand, both 2- and 9-MeAnt as well as all the MePhe under study were efficient inhibitors of GJIC, suggesting that these compounds might act as tumor promoters. In summary, inhibition of GJIC and partial activation of AhR seem to be the most prominent toxic effects of the methylated PAHs in the present study.

• MeSH
• anthraceny toxicita   MeSH
• cytochrom P-450 CYP1A1 genetika   metabolismus   MeSH
• fenantreny toxicita   MeSH
• financování organizované MeSH
• geologické sedimenty chemie   MeSH
• játra cytologie   patologie   MeSH
• karcinogeny toxicita   MeSH
• krysa rodu rattus MeSH
• látky znečišťující životní prostředí toxicita   MeSH
• metylace MeSH
• mezerový spoj metabolismus   účinky léků   MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 metabolismus   MeSH
• naftaleny toxicita   MeSH
• proliferace buněk účinky léků   MeSH
• receptory aromatických uhlovodíků metabolismus   MeSH
• regulace genové exprese fyziologie   účinky léků   MeSH
• řeky MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Geografické názvy
• Česká republika MeSH