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Sleight TW, Sexton CN, Mpourmpakis G, Gilbertson LM, Ng CA. A Classification Model to Identify Direct-Acting Mutagenic Polycyclic Aromatic Hydrocarbon Transformation Products. Chem Res Toxicol 2021; 34:2273-2286. [PMID: 34662518 DOI: 10.1021/acs.chemrestox.1c00187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are a complex group of environmental contaminants, many having long environmental half-lives. As these compounds degrade, the changes in their structure can result in a substantial increase in mutagenicity compared to the parent compound. Over time, each individual PAH can potentially degrade into several thousand unique transformation products, creating a complex, constantly evolving set of intermediates. Microbial degradation is the primary mechanism of their transformation and ultimate removal from the environment, and this process can result in mutagenic activation similar to the metabolic activation that can occur in multicellular organisms. The diversity of the potential intermediate structures in PAH-contaminated environments renders hazard assessment difficult for both remediation professionals and regulators. A mixture of structural and energetic descriptors has proven effective in existing studies for classifying which PAH transformation products will be mutagenic. However, most existing studies of environmental PAH mutagens primarily focus on nitrogenated derivatives, which are prevalent in the atmosphere and not as relevant in soil. Additionally, PAH products commonly found in the environment can range from as large as five rings to as small as a single ring, requiring a broadly inclusive methodology to comprehensively evaluate mutagenic potential. We developed a combination of supervised and unsupervised machine learning methods to predict environmentally induced PAH mutagenicity with improved performance over currently available tools. K-means clustering with principal component analysis allows us to identify molecular clusters that we hypothesize to have similar mechanisms of action. Recursive feature elimination identifies the most influential descriptors. The cluster-specific regression outperforms available classifiers in predicting direct-acting mutagens resulting from the microbial biodegradation of PAHs and provides direction for future studies evaluating the environmental hazards resulting from PAH biodegradation.
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Affiliation(s)
- Trevor W Sleight
- Civil & Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Caitlin N Sexton
- Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Giannis Mpourmpakis
- Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Leanne M Gilbertson
- Civil & Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.,Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Carla A Ng
- Civil & Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.,Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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da Silva Junior FC, Felipe MBMC, Castro DEFD, Araújo SCDS, Sisenando HCN, Batistuzzo de Medeiros SR. A look beyond the priority: A systematic review of the genotoxic, mutagenic, and carcinogenic endpoints of non-priority PAHs. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 278:116838. [PMID: 33714059 DOI: 10.1016/j.envpol.2021.116838] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 02/06/2021] [Accepted: 02/21/2021] [Indexed: 06/12/2023]
Abstract
Knowledge of the toxic potential of polycyclic aromatic hydrocarbons (PAHs) has increased over time. Much of this knowledge is about the 16 United States - Environmental Protection Agency (US - EPA) priority PAHs; however, there are other US - EPA non-priority PAHs in the environment, whose toxic potential is underestimated. We conducted a systematic review of in vitro, in vivo, and in silico studies to assess the genotoxicity, mutagenicity, and carcinogenicity of 13 US - EPA non-priority parental PAHs present in the environment. Electronic databases, such as Science Direct, PubMed, Scopus, Google Scholar, and Web of Science, were used to search for research with selected terms without time restrictions. After analysis, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol, 249 articles, published between 1946 and 2020, were selected and the quality assessment of these studies was performed. The results showed that 5-methylchrysene (5-MC), 7,12-dimethylbenz[a]anthracene (7,12-DMBA), cyclopenta[cd]pyrene (CPP), and dibenzo[al]pyrene (Db[al]P) were the most studied PAHs. Moreover, 5-MC, 7,12-DMBA, benz[j]aceanthrylene (B[j]A), CPP, anthanthrene (ANT), dibenzo[ae]pyrene (Db[ae]P), and Db[al]P have been reported to cause mutagenic effects and have been being associated with a risk of carcinogenicity. Retene (RET) and benzo[c]fluorene (B[c]F), the least studied compounds, showed evidence of a strong influence on the mutagenicity and carcinogenicity endpoints. Overall, this systematic review provided evidence of the genotoxic, mutagenic, and carcinogenic endpoints of US - EPA non-priority PAHs. However, further studies are needed to improve the future protocols of environmental analysis and risk assessment in severely exposed populations.
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Affiliation(s)
- Francisco Carlos da Silva Junior
- Department of Cell Biology and Genetics, Biosciences Center, Federal University of Rio Grande Do Norte, Natal, RN, Brazil; Graduate Program in Molecular Biology and Biochemistry, Biosciences Center, Federal University of Rio Grande Do Norte, Natal, RN, Brazil
| | | | - Denis Elvis Farias de Castro
- Department of Cell Biology and Genetics, Biosciences Center, Federal University of Rio Grande Do Norte, Natal, RN, Brazil; Graduate Program in Molecular Biology and Biochemistry, Biosciences Center, Federal University of Rio Grande Do Norte, Natal, RN, Brazil
| | - Sinara Carla da Silva Araújo
- Department of Cell Biology and Genetics, Biosciences Center, Federal University of Rio Grande Do Norte, Natal, RN, Brazil; Graduate Program in Molecular Biology and Biochemistry, Biosciences Center, Federal University of Rio Grande Do Norte, Natal, RN, Brazil
| | - Herbert Costa Nóbrega Sisenando
- Department of Cell Biology and Genetics, Biosciences Center, Federal University of Rio Grande Do Norte, Natal, RN, Brazil; Department of Clinical and Toxicological Analysis, Health Sciences Center, Federal University of Rio Grande Do Norte, Natal, RN, Brazil
| | - Silvia Regina Batistuzzo de Medeiros
- Department of Cell Biology and Genetics, Biosciences Center, Federal University of Rio Grande Do Norte, Natal, RN, Brazil; Graduate Program in Molecular Biology and Biochemistry, Biosciences Center, Federal University of Rio Grande Do Norte, Natal, RN, Brazil.
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Coquin L, Canipa SJ, Drewe WC, Fisk L, Gillet VJ, Patel M, Plante J, Sherhod RJ, Vessey JD. New structural alerts for Ames mutagenicity discovered using emerging pattern mining techniques. Toxicol Res (Camb) 2015. [DOI: 10.1039/c4tx00071d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The discovered patterns are used to develop new structural alerts for mutagenicity in the Derek Nexus expert system.
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Borosky GL, Laali KK. Oxidized metabolites from cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs). A DFT model study of their carbocations formed by epoxide ring opening. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1666] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Otero-Lobato MJ, Kaats-Richters VEM, Koper C, Vlietstra EJ, Havenith RWA, Jenneskens LW, Seinen W. CP-arene oxides: the ultimate, active mutagenic forms of cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs). MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2005; 581:115-32. [PMID: 15725611 DOI: 10.1016/j.mrgentox.2004.11.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2004] [Revised: 11/12/2004] [Accepted: 11/27/2004] [Indexed: 10/25/2022]
Abstract
The bacterial mutagenic response (Ames-assay, Salmonella typhimurium strain TA98+/-S9-mix) of a series of monocyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs) identified in combustion exhausts, viz. cyclopenta[cd]pyrene (1), acephenanthrylene (2), aceanthrylene (3) and cyclopenta[hi]chrysene (4), is re-evaluated. The mutagenic effects are compared with those exerted by the corresponding partially hydrogenated derivatives, 3,4-dihydrocyclopenta[cd]pyrene (5), 4,5-dihydroacephenanthrylene (6), 1,2-dihydroaceanthrylene (7) and 4,5-dihydrocyclopenta[hi]chrysene (8). It is shown that the olefinic bond of the externally fused five-membered ring of 1, 3 and 4 is of importance for a positive mutagenic response. In contrast, whilst CP-PAH 2 is found inactive, its dihydro analogue (6) shows a weak metabolism-dependent response. The importance of epoxide formation at the external olefinic bond in the five-membered ring is substantiated by the bacterial mutagenic response of independently synthesized cyclopenta[cd]pyrene-3,4-epoxide (9), acephenanthrylene-4,5-epoxide (10), aceanthrylene-1,2-epoxide (11) and cyclopenta[hi]chrysene-4,5-epoxide (12). Their role as ultimate, active mutagenic forms, when CP-PAHs 1, 3 and 4 exhibit a positive mutagenic response, is confirmed. Semi-empirical Austin Model 1 (AM1) calculations on the formation of the CP-arene oxides (9-12) and their conversion into the monohydroxy-carbocations (9a-12a and 9b-12b) via epoxide-ring opening support our results. For 2 and 4, which also possess a bay-region besides an annelated cyclopenta moiety, the calculations rationalize that epoxidation at the olefinic bond of the cyclopenta moiety is favoured.
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Affiliation(s)
- María José Otero-Lobato
- Debye Institute, Department of Physical Organic Chemistry, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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Johnsen NM, Nyholm SH, Haug K, Scholz T, Holme JA. Metabolism and activation of cyclopenta polycyclic aromatic hydrocarbons in liver tissue from rats and humans. Chem Biol Interact 1998; 113:217-37. [PMID: 9717520 DOI: 10.1016/s0009-2797(98)00037-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The metabolism of radiolabelled benz(j)aceanthrylene (B(j)A) was studied by high performance liquid chromatography (HPLC) using suspensions of hepatocytes and liver microsomes from control- or Aroclor 1254 (PCB)-treated rats, or with human liver microsomes (five different donors) as activation systems. The major metabolites formed in hepatocytes were sulfate conjugates, indicating that sulfation is an important detoxication pathway for B(j)A. In incubations with B(j)A and rat or human liver microsomes, the major metabolite formed was B(j)A-1,2-diol. Studies with rat liver microsomes using antibodies (Ab) towards either P4501A1, 1A2 or 3A2, resulted in approximately 30% reduction in covalent binding with all Ab-using microsomes from control animals, whereas with microsomes from PCB-treated animals an 85% reduction was observed using Ab towards P4501A2, and only minor reductions were observed with 1A1 or 3A2. When compared to B(j)A and benzo(a)pyrene (B(a)P), benz(1)aceanthrylene (B(l)A) caused higher numbers of revertants in the Salmonella assay when plated with rat liver microsomes from control animals or human liver microsomes. The total DNA adduct levels in hepatocytes from control animals after 2 h exposure to 30 micrograms/ml (120 microM) B(j)A or B(l)A, as measured by the 32P-postlabelling technique, were 3.8 +/- 1.5 and 10.1 +/- 5.8 fmol/microgram DNA, respectively. PCB-treatment decreased the total level of B(j)A adducts slightly (1.8 +/- 0.5 fmol/microgram DNA), whereas in contrast the level of B(1)A adducts was increased (24.5 +/- 20.1 fmol/microgram DNA). The major DNA adduct formed in control hepatocytes exposed to B(j)A co-chromatographed with B(j)A-1,2-oxide, which also appeared to be the major adduct formed when rat or human liver microsomes were co-incubated with calf thymus DNA. The total DNA adduct levels in the modified calf thymus DNA after 30 min exposure to 30 micrograms/ml B(j)A, B(l)A or B(a)P using rat liver microsomes form control animals, were 3.6, 66.3 and 1.4 fmol/microgram DNA, respectively. These levels increased to 22.7, 93.3 and 7.4 fmol/microgram DNA, respectively, using microsomes from PCB-treated animals. With human liver microsomes, the total DNA adduct levels after exposure to B(j)A, B(l)A or B(a)P, ranged between 0.4-1.0, 0.3-4.3, and 0.1-0.3 fmol/microgram DNA, respectively. Overall, the present data supports the notion that oxidation at the cyclopenta-ring is an important activation pathway for B(j)A, and indicate that the activation mechanism for B(j)A is similar in rat and human liver tissue.
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Affiliation(s)
- N M Johnsen
- Department of Environmental Medicine, National Institute of Public Health, Oslo, Norway
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Busby WF, Smith H, Plummer EF, Lafleur AL, Mulder PP, Boere BB, Cornelisse J, Lugtenburg J. Mutagenicity of cyclopenta-fused polynuclear aromatic hydrocarbons and a non-polar fraction from a fuel combustion sample in a Salmonella forward mutation assay without exogenous metabolic activation. Mutat Res 1997; 391:117-25. [PMID: 9268036 DOI: 10.1016/s0165-1218(97)00028-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A series of cyclopenta-fused polynuclear aromatic hydrocarbons (PAH) were tested for mutagenicity in a bacterial forward mutation assay based on resistance to 8-azaguanine (8-AG) in Salmonella typhimurium TM677 in the absence of Aroclor-induced rat liver postmitochondrial supernatant (PMS). All of the aceanthrylenes tested were mutagenic in the absence of PMS, whereas none of the acephenanthrylenes were active. The following mutagenic potency series expressed as the minimum detectable mutagen concentration (MDMC) in nmol/ml was obtained: aceanthrylene (AA) (5.5); cyclopent[h,i]aceanthrylene (CPAA)(18.2); 6-methylaceanthrylene (6-MeAA)(112); 1,2,6,7-tetrahydrocyclopent[h,i]aceanthrylene (THCPAA) (166); 1,2-dihydroaceanthrylene (DHAA) (298). Saturation of the cyclopenta rings or methylation at the 6-position of AA reduced, but did not eliminate, mutagenicity measured in the absence of PMS. AA was unusual because it was approximately 4-fold more mutagenic in the absence of PMS than in its presence. The other aceanthrylenes tested were 1.3-10.7 times more mutagenic in the presence of PMS than in its absence to give an MDMC potency series of: CPAA (3.8); 6-MeAA (10.5); AA (19.9); THCPAA (52.9); DHAA (229). Approximately 20% of the PMS-independent mutagenicity in a combustion sample from ethylene burned under fuel-rich conditions was found in a fraction containing only non-polar, 4-7 ring PAHs, widely attributed to be mutagenic only in the presence of PMS. None of this mutagenicity could be attributed to aceanthrylenes, thus other non-polar PAHs appear to possess significant PMS-independent mutagenicity as well.
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Affiliation(s)
- W F Busby
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge 02139, USA
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