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Hölzl-Armstrong L, Kucab JE, Zwart EP, Luijten M, Phillips DH, Arlt VM. Mutagenicity of N-hydroxy-4-aminobiphenyl in human TP53 knock-in (Hupki) mouse embryo fibroblasts. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2021; 62:252-264. [PMID: 33620775 DOI: 10.1002/em.22429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 01/30/2021] [Accepted: 02/17/2021] [Indexed: 06/12/2023]
Abstract
TP53 harbors somatic mutations in more than half of human tumors with some showing characteristic mutation spectra that have been linked to environmental exposures. In bladder cancer, a unique distribution of mutations amongst several codons of TP53 has been hypothesized to be caused by environmental carcinogens including 4-aminobiphenyl (4-ABP). 4-ABP undergoes metabolic activation to N-hydroxy-4-aminobiphenyl (N-OH-4-ABP) and forms pre-mutagenic adducts in DNA, of which N-(deoxyguanosin-8-yl)-4-ABP (dG-C8-4-ABP) is the major one. Human TP53 knock-in mouse embryo fibroblasts (HUFs) are a useful model to study the influence of environmental carcinogens on TP53-mutagenesis. By performing the HUF immortalization assay (HIMA) TP53-mutant HUFs are generated and mutations can be identified by sequencing. Here we studied the induction of mutations in human TP53 after treatment of primary HUFs with N-OH-4-ABP. In addition, mutagenicity in the bacterial lacZ reporter gene and the formation of dG-C8-4-ABP, measured by 32 P-postlabelling analysis, were determined in N-OH-4-ABP-treated primary HUFs. A total of 6% TP53-mutants were identified after treatment with 40 μM N-OH-4-ABP for 24 hr (n = 150) with G>C/C>G transversion being the main mutation type. The mutation spectrum found in the TP53 gene of immortalized N-OH-4-ABP-treated HUFs was unlike the one found in human bladder cancer. DNA adduct formation (~40 adducts/108 nucleotides) was detected after 24 hr treatment with 40 μM N-OH-4-ABP, but lacZ mutagenicity was not observed. Adduct levels decreased substantially (sixfold) after a 24 hr recovery period indicating that primary HUFs can efficiently repair the dG-C8-4-ABP adduct possibly before mutations are fixed. In conclusion, the observed difference in the N-OH-4-ABP-induced TP53 mutation spectrum to that observed in human bladder tumors do not support a role of 4-ABP in human bladder cancer development.
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Affiliation(s)
- Lisa Hölzl-Armstrong
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, UK
| | - Jill E Kucab
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, UK
| | - Edwin P Zwart
- Center for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Mirjam Luijten
- Center for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - David H Phillips
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, UK
| | - Volker M Arlt
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, UK
- Toxicology Department, GAB Consulting GmbH, Heidelberg, Germany
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Hölzl-Armstrong L, Moody S, Kucab JE, Zwart EP, Bellamri M, Luijten M, Turesky RJ, Stratton MR, Arlt VM, Phillips DH. Mutagenicity of 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP) in human TP53 knock-in (Hupki) mouse embryo fibroblasts. Food Chem Toxicol 2020; 147:111855. [PMID: 33189884 DOI: 10.1016/j.fct.2020.111855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 10/03/2020] [Accepted: 11/06/2020] [Indexed: 02/07/2023]
Abstract
2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a possible human carcinogen formed in cooked fish and meat. PhIP is bioactivated by cytochrome P450 enzymes to form 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP), a genotoxic metabolite that reacts with DNA leading to the mutation-prone DNA adduct N-(deoxyguanosin-8-yl)-PhIP (dG-C8-PhIP). Here, we studied N-OH-PhIP-induced whole genome mutagenesis in human TP53 knock-in (Hupki) mouse embryo fibroblasts (HUFs) immortalised and subjected to whole genome sequencing (WGS). In addition, mutagenicity of N-OH-PhIP in TP53 and the lacZ reporter gene were assessed. TP53 mutant frequency in HUF cultures treated with N-OH-PhIP (2.5 μM for 24 h, n = 90) was 10% while no TP53 mutations were found in untreated controls (DMSO for 24 h, n = 6). All N-OH-PhIP-induced TP53 mutations occurred at G:C base pairs with G > T/C > A transversions accounting for 58% of them. TP53 mutations characteristic of those induced by N-OH-PhIP have been found in human tumours including breast and colorectal, which are cancer types that have been associated with PhIP exposure. LacZ mutant frequency increased 25-fold at 5 μM N-OH-PHIP and up to ~350 dG-C8-PhIP adducts/108 nucleosides were detected by ultra-performance liquid chromatography-electrospray ionisation multistage scan mass spectrometry (UPLC-ESI-MS3) at this concentration. In addition, a WGS mutational signature defined by G > T/C > A transversions was present in N-OH-PhIP-treated immortalised clones, which showed similarity to COSMIC SBS4, 18 and 29 signatures found in human tumours.
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Affiliation(s)
- Lisa Hölzl-Armstrong
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, SE1 9NH, UK
| | - Sarah Moody
- Cancer, Ageing and Somatic Mutation, Wellcome Trust Sanger Institute, Hinxton, CB10 1SA, UK
| | - Jill E Kucab
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, SE1 9NH, UK
| | - Edwin P Zwart
- Center for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, 3720 BA, the Netherlands
| | - Medjda Bellamri
- Masonic Cancer Center and Department of Medicinal Chemistry, University of Minnesota, Minneapolis, USA
| | - Mirjam Luijten
- Center for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, 3720 BA, the Netherlands
| | - Robert J Turesky
- Masonic Cancer Center and Department of Medicinal Chemistry, University of Minnesota, Minneapolis, USA
| | - Michael R Stratton
- Cancer, Ageing and Somatic Mutation, Wellcome Trust Sanger Institute, Hinxton, CB10 1SA, UK
| | - Volker M Arlt
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, SE1 9NH, UK.
| | - David H Phillips
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, SE1 9NH, UK
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3
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Hölzl-Armstrong L, Kucab JE, Moody S, Zwart EP, Loutkotová L, Duffy V, Luijten M, Gamboa da Costa G, Stratton MR, Phillips DH, Arlt VM. Mutagenicity of acrylamide and glycidamide in human TP53 knock-in (Hupki) mouse embryo fibroblasts. Arch Toxicol 2020; 94:4173-4196. [PMID: 32886187 PMCID: PMC7655573 DOI: 10.1007/s00204-020-02878-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/12/2020] [Indexed: 11/30/2022]
Abstract
Acrylamide is a suspected human carcinogen formed during high-temperature cooking of starch-rich foods. It is metabolised by cytochrome P450 2E1 to its reactive metabolite glycidamide, which forms pre-mutagenic DNA adducts. Using the human TP53 knock-in (Hupki) mouse embryo fibroblasts (HUFs) immortalisation assay (HIMA), acrylamide- and glycidamide-induced mutagenesis was studied in the tumour suppressor gene TP53. Selected immortalised HUF clones were also subjected to next-generation sequencing to determine mutations across the whole genome. The TP53-mutant frequency after glycidamide exposure (1.1 mM for 24 h, n = 198) was 9% compared with 0% in cultures treated with acrylamide [1.5 (n = 24) or 3 mM (n = 6) for 48 h] and untreated vehicle (water) controls (n = 36). Most glycidamide-induced mutations occurred at adenines with A > T/T > A and A > G/T > C mutations being the most common types. Mutations induced by glycidamide occurred at specific TP53 codons that have also been found to be mutated in human tumours (i.e., breast, ovary, colorectal, and lung) previously associated with acrylamide exposure. The spectrum of TP53 mutations was further reflected by the mutations detected by whole-genome sequencing (WGS) and a distinct WGS mutational signature was found in HUF clones treated with glycidamide that was again characterised by A > G/T > C and A > T/T > A mutations. The WGS mutational signature showed similarities with COSMIC mutational signatures SBS3 and 25 previously found in human tumours (e.g., breast and ovary), while the adenine component was similar to COSMIC SBS4 found mostly in smokers’ lung cancer. In contrast, in acrylamide-treated HUF clones, only culture-related background WGS mutational signatures were observed. In summary, the results of the present study suggest that glycidamide may be involved in the development of breast, ovarian, and lung cancer.
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Affiliation(s)
- Lisa Hölzl-Armstrong
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, SE1 9NH, UK
| | - Jill E Kucab
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, SE1 9NH, UK
| | - Sarah Moody
- Cancer, Ageing and Somatic Mutation, Wellcome Trust Sanger Institute, Hinxton, CB10 1SA, UK
| | - Edwin P Zwart
- Center for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, 3720, The Netherlands
| | - Lucie Loutkotová
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA.,Covance Inc., Salt Lake City, Utah, 84124, USA
| | - Veronica Duffy
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, SE1 9NH, UK
| | - Mirjam Luijten
- Center for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, 3720, The Netherlands
| | - Gonçalo Gamboa da Costa
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Michael R Stratton
- Cancer, Ageing and Somatic Mutation, Wellcome Trust Sanger Institute, Hinxton, CB10 1SA, UK
| | - David H Phillips
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, SE1 9NH, UK
| | - Volker M Arlt
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, SE1 9NH, UK. .,Toxicology Department, GAB Consulting GmbH, 69126, Heidelberg, Germany.
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Hölzl-Armstrong L, Kucab JE, Korenjak M, Luijten M, Phillips DH, Zavadil J, Arlt VM. Characterising Mutational Spectra of Carcinogens in the Tumour Suppressor Gene TP53 Using Human TP53 Knock-in (Hupki) Mouse Embryo Fibroblasts. Methods Protoc 2019; 2:E85. [PMID: 31766274 PMCID: PMC6961128 DOI: 10.3390/mps2040085] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/30/2019] [Accepted: 10/31/2019] [Indexed: 12/11/2022] Open
Abstract
DNA in dividing cells is prone to mutagenesis, with mutations making key contributions to human disease including cancer. The tumour suppressor gene TP53 is the most frequently mutated gene in human tumours. Here, we present a robust protocol for studying TP53 mutagenesis utilising human TP53 knock-in (Hupki) mouse embryonic fibroblasts (HUFs). In the HUF immortalisation assay (HIMA), primary HUFs are treated with known or suspected carcinogens at 3% oxygen and then transferred to 20% atmospheric oxygen to induce senescence. Cells containing mutations (e.g., in TP53) that allow bypassing of senescence eventually emerge as immortalised clonal cell lines after 2-3 months of serial passaging. As not all immortalised HUF cells contain TP53 mutations, we developed a Nutlin-3a counter-screen to select for TP53-mutated clones prior to sequencing. TP53 mutation spectra generated can be compared with those of human tumours recorded in the International Agency for Research on Cancer TP53 mutation database. Environmental mutagens that have demonstrated and validated the utility of the HIMA include ultraviolet radiation, aristolochic acid, and benzo[a]pyrene. The TP53 mutation patterns induced by these mutagens in the HIMA corresponded to those found in human tumours from patients exposed to these mutagens. The approach presented helps to deepen our understanding of human cancer aetiology.
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Affiliation(s)
- Lisa Hölzl-Armstrong
- Department of Analytical, Environmental and Forensic Sciences, King’s College London, London SE1 9NH, UK; (L.H.-A.); (J.E.K.); (D.H.P.)
| | - Jill E. Kucab
- Department of Analytical, Environmental and Forensic Sciences, King’s College London, London SE1 9NH, UK; (L.H.-A.); (J.E.K.); (D.H.P.)
| | - Michael Korenjak
- Molecular Mechanisms and Biomarkers Group, International Agency for Research on Cancer, 69008 Lyon, France; (M.K.); (J.Z.)
| | - Mirjam Luijten
- Center for Health Protection, National Institute for Public Health and the Environment (RIVM), 3721 MA Bilthoven, The Netherlands;
| | - David H. Phillips
- Department of Analytical, Environmental and Forensic Sciences, King’s College London, London SE1 9NH, UK; (L.H.-A.); (J.E.K.); (D.H.P.)
| | - Jiri Zavadil
- Molecular Mechanisms and Biomarkers Group, International Agency for Research on Cancer, 69008 Lyon, France; (M.K.); (J.Z.)
| | - Volker M. Arlt
- Department of Analytical, Environmental and Forensic Sciences, King’s College London, London SE1 9NH, UK; (L.H.-A.); (J.E.K.); (D.H.P.)
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Phi KK, Smith MC, Tokarsky EJ, Suo Z. Kinetic Investigation of Translesion Synthesis across a 3-Nitrobenzanthrone-Derived DNA Lesion Catalyzed by Human DNA Polymerase Kappa. Chem Res Toxicol 2019; 32:1699-1706. [PMID: 31286773 DOI: 10.1021/acs.chemrestox.9b00219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
3-Nitrobenzanthrone (3-NBA) is a byproduct of diesel exhaust and is highly present in industrial and populated areas. Inhalation of 3-NBA results in formation of N-(2'-deoxyguanosin-8-yl)-3-aminobenzanthrone (dGC8-N-ABA), a bulky DNA lesion that is of concern due to its mutagenic and carcinogenic potential. If dGC8-N-ABA is not bypassed during genomic replication, the lesion can stall cellular DNA replication machinery, leading to senescence or apoptosis. We have previously used running start assays to demonstrate that human DNA polymerases eta (hPolη) and kappa (hPolκ) are able to catalyze translesion DNA synthesis (TLS) across a site-specifically placed dGC8-N-ABA in a DNA template. Consistently, gene knockdown of hPolη and hPolκ in HEK293T cells reduces the efficiency of TLS across dGC8-N-ABA by ∼25 and ∼30%, respectively. Here, we kinetically investigated why hPolκ paused when bypassing and extending from dGC8-N-ABA. Our kinetic data show that correct dCTP incorporation efficiency of hPolκ dropped by 116-fold when opposite dGC8-N-ABA relative to undamaged dG, leading to hPolκ pausing at the lesion site observed in the running start assays. The already low nucleotide incorporation fidelity of hPolκ was further decreased by 10-fold during lesion bypass, and thus, incorrect nucleotides, especially dATP, were incorporated opposite dGC8-N-ABA with comparable efficiencies as correct dCTP. With regard to the dGC8-N-ABA bypass product extension step, hPolκ incorporated correct dGTP onto the damaged DNA substrate with a 786-fold lower efficiency than onto the corresponding undamaged DNA substrate, which resulted in hPolκ pausing at the site in the running start assays. Furthermore, hPolκ extended the primer-terminal matched base pair dC:dGC8-N-ABA with a 100-1000-fold lower fidelity than it extended the undamaged dC:dG base pair. Together, our kinetic results strongly indicate that hPolκ was error-prone during TLS of dGC8-N-ABA.
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Affiliation(s)
| | | | | | - Zucai Suo
- Department of Biomedical Sciences , Florida State University College of Medicine , Tallahassee , Florida 32306 , United States
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Murray JR, Mesaros CA, Arlt VM, Seidel A, Blair IA, Penning TM. Role of Human Aldo-Keto Reductases in the Metabolic Activation of the Carcinogenic Air Pollutant 3-Nitrobenzanthrone. Chem Res Toxicol 2018; 31:1277-1288. [PMID: 30406992 DOI: 10.1021/acs.chemrestox.8b00250] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
3-Nitrobenzanthrone (3-NBA) is a potent mutagen and suspected human carcinogen detected in diesel exhaust particulate and ambient air pollution. It requires metabolic activation via nitroreduction to promote DNA adduct formation and tumorigenesis. NAD(P)H:quinone oxidoreductase 1 (NQO1) has been previously implicated as the major nitroreductase responsible for 3-NBA activation, but it has recently been reported that human aldo-keto reductase 1C3 (AKR1C3) displays nitroreductase activity toward the chemotherapeutic agent PR-104A. We sought to determine whether AKR1C isoforms could display nitroreductase activity toward other nitrated compounds and bioactivate 3-NBA. Using discontinuous enzymatic assays monitored by UV-HPLC, we determined that AKR1C1-1C3 catalyze three successive two-electron nitroreductions toward 3-NBA to form the reduced product 3-aminobenzanthrone (3-ABA). Evidence of the nitroso- and hydroxylamino- intermediates were obtained by UPLC-HRMS. Km, kcat, and kcat/ Km values were determined for recombinant AKR1C and NQO1 and compared. We found that AKR1C1, AKR1C3, and NQO1 have very similar apparent catalytic efficiencies (8 vs 7 min-1 mM-1) despite the higher kcat of NQO1 (0.058 vs 0.012 min-1). AKR1C1-1C3 possess a Km much lower than that of NQO1, which suggests that they may be more important than NQO1 at the low concentrations of 3-NBA to which humans are exposed. Given that inhalation represents the primary source of 3-NBA exposure, we chose to evaluate the relative importance of AKR1C1-1C3 and NQO1 in human lung epithelial cell lines. Our data suggest that the combined activities of AKR1C1-1C3 and NQO1 contribute equally to the reduction of 3-NBA in A549 and HBEC3-KT cell lines and together represent approximately 50% of the intracellular nitroreductase activity toward 3-NBA. These findings have significant implications for the metabolism of nitrated polycyclic aromatic hydrocarbons and suggest that the hitherto unrecognized nitroreductase activity of AKR1C enzymes should be further investigated.
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Affiliation(s)
| | | | - Volker M Arlt
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health , King's College London , SE1 9NH , United Kingdom.,NIHR Health Protection Research Unit in Health Impact of Environmental Hazards , King's College London in partnership with Public Health England and Imperial College London , London SE1 9NH , United Kingdom
| | - Albrecht Seidel
- Biochemical Institute for Environmental Carcinogens, Prof. Dr. Gernot Grimmer-Foundation , Grosshansdorf 22927 , Germany
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Wohak LE, Baranski AC, Krais AM, Schmeiser HH, Phillips DH, Arlt VM. The impact of p53 function on the metabolic activation of the carcinogenic air pollutant 3-nitrobenzanthrone and its metabolites 3-aminobenzanthrone and N-hydroxy-3-aminobenzanthrone in human cells. Mutagenesis 2018; 33:311-321. [PMID: 30215795 PMCID: PMC6180618 DOI: 10.1093/mutage/gey025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/10/2018] [Accepted: 08/17/2018] [Indexed: 12/16/2022] Open
Abstract
The tumour suppressor p53, encoded by TP53, is a key player in a wide network of signalling pathways. We investigated its role in the bioactivation of the environmental carcinogen 3-nitrobenzanthrone (3-NBA)found in diesel exhaust and its metabolites 3-aminobenzanthrone (3-ABA) and N-hydroxy-3-aminobenzanthrone (N-OH-3-ABA) in a panel of isogenic human colorectal HCT116 cells differing only with respect to their TP53 status [i.e. TP53(+/+), TP53(+/-), TP53(-/-), TP53(R248W/+) or TP53(R248W/-)]. As a measure of metabolic competence, DNA adduct formation was determined using 32P-postlabelling. Wild-type (WT) p53 did not affect the bioactivation of 3-NBA; no difference in DNA adduct formation was observed in TP53(+/+), TP53(+/-) and TP53(-/-) cells. Bioactivation of both metabolites 3-ABA and N-OH-3-ABA on the other hand was WT-TP53 dependent. Lower 3-ABA- and N-OH-3-ABA-DNA adduct levels were found in TP53(+/-) and TP53(-/-) cells compared to TP53(+/+) cells, and p53's impact was attributed to differences in cytochrome P450 (CYP) 1A1 expression for 3-ABA whereas for N-OH-3-ABA, an impact of this tumour suppressor on sulphotransferase (SULT) 1A1/3 expression was detected. Mutant R248W-p53 protein function was similar to or exceeded the ability of WT-p53 in activating 3-NBA and its metabolites, measured as DNA adducts. However, identification of the xenobiotic-metabolising enzyme(s) (XMEs), through which mutant-p53 regulates these responses, proved difficult to decipher. For example, although both mutant cell lines exhibited higher CYP1A1 induction after 3-NBA treatment compared to TP53(+/+) cells, 3-NBA-derived DNA adduct levels were only higher in TP53(R248W/-) cells but not in TP53(R248W/+) cells. Our results show that p53's influence on carcinogen activation depends on the agent studied and thereby on the XMEs that mediate the bioactivation of that particular compound. The phenomenon of p53 regulating CYP1A1 expression in human cells is consistent with other recent findings; however, this is the first study highlighting the impact of p53 on sulphotransferase-mediated (i.e. SULT1A1) carcinogen metabolism in human cells.
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Affiliation(s)
- Laura E Wohak
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King’s College London, London, UK
- Section of Molecular Carcinogenesis, Institute of Cancer Research, Sutton, Surrey, UK
| | - Ann-Christin Baranski
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King’s College London, London, UK
| | - Annette M Krais
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King’s College London, London, UK
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Im Neuenheimer Feld, Heidelberg, Germany
| | - David H Phillips
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King’s College London, London, UK
- NIHR Health Protection Research Unit, Health Impact of Environmental Hazards, King’s College London, Public Health England and Imperial College London, London, UK
| | - Volker M Arlt
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King’s College London, London, UK
- NIHR Health Protection Research Unit, Health Impact of Environmental Hazards, King’s College London, Public Health England and Imperial College London, London, UK
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Long AS, Wills JW, Krolak D, Guo M, Dertinger SD, Arlt VM, White PA. Benchmark dose analyses of multiple genetic toxicity endpoints permit robust, cross-tissue comparisons of MutaMouse responses to orally delivered benzo[a]pyrene. Arch Toxicol 2018; 92:967-982. [PMID: 29177888 PMCID: PMC5818629 DOI: 10.1007/s00204-017-2099-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 10/17/2017] [Indexed: 12/14/2022]
Abstract
Genetic damage is a key event in tumorigenesis, and chemically induced genotoxic effects are a human health concern. Although genetic toxicity data have historically been interpreted using a qualitative screen-and-bin approach, there is increasing interest in quantitative analysis of genetic toxicity dose-response data. We demonstrate an emerging use of the benchmark dose (BMD)-approach for empirically ranking cross-tissue sensitivity. Using a model environmental carcinogen, we quantitatively examined responses for four genetic damage endpoints over an extended dose range, and conducted cross-tissue sensitivity rankings using BMD100 values and their 90% confidence intervals (CIs). MutaMouse specimens were orally exposed to 11 doses of benzo[a]pyrene. DNA adduct frequency and lacZ mutant frequency (MF) were measured in up to 8 tissues, and Pig-a MF and micronuclei (MN) were assessed in immature (RETs) and mature red blood cells (RBCs). The cross-tissue BMD pattern for lacZ MF is similar to that observed for DNA adducts, and is consistent with an oral route-of-exposure and differences in tissue-specific metabolism and proliferation. The lacZ MF BMDs were significantly correlated with the tissue-matched adduct BMDs, demonstrating a consistent adduct conversion rate across tissues. The BMD CIs, for both the Pig-a and the MN endpoints, overlapped for RETs and RBCs, suggesting comparable utility of both cell populations for protracted exposures. Examination of endpoint-specific response maxima illustrates the difficulty of comparing BMD values for a fixed benchmark response across endpoints. Overall, the BMD-approach permitted robust comparisons of responses across tissues/endpoints, which is valuable to our mechanistic understanding of how benzo[a]pyrene induces genetic damage.
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Affiliation(s)
- Alexandra S Long
- Mechanistic Studies Division, Environmental Health Science and Research Bureau, Health Canada, 50 Colombine Driveway, Tunney's Pasture, A/L 0803A, Ottawa, ON, K1A 0K9, Canada.
- Department of Biology, University of Ottawa, Ottawa, ON, Canada.
| | - John W Wills
- Mechanistic Studies Division, Environmental Health Science and Research Bureau, Health Canada, 50 Colombine Driveway, Tunney's Pasture, A/L 0803A, Ottawa, ON, K1A 0K9, Canada
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Dorothy Krolak
- Mechanistic Studies Division, Environmental Health Science and Research Bureau, Health Canada, 50 Colombine Driveway, Tunney's Pasture, A/L 0803A, Ottawa, ON, K1A 0K9, Canada
| | - Matthew Guo
- Mechanistic Studies Division, Environmental Health Science and Research Bureau, Health Canada, 50 Colombine Driveway, Tunney's Pasture, A/L 0803A, Ottawa, ON, K1A 0K9, Canada
| | | | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, UK
| | - Paul A White
- Mechanistic Studies Division, Environmental Health Science and Research Bureau, Health Canada, 50 Colombine Driveway, Tunney's Pasture, A/L 0803A, Ottawa, ON, K1A 0K9, Canada
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
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Arlt VM, Meinl W, Florian S, Nagy E, Barta F, Thomann M, Mrizova I, Krais AM, Liu M, Richards M, Mirza A, Kopka K, Phillips DH, Glatt H, Stiborova M, Schmeiser HH. Impact of genetic modulation of SULT1A enzymes on DNA adduct formation by aristolochic acids and 3-nitrobenzanthrone. Arch Toxicol 2017; 91:1957-1975. [PMID: 27557898 PMCID: PMC5364269 DOI: 10.1007/s00204-016-1808-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 08/04/2016] [Indexed: 02/06/2023]
Abstract
Exposure to aristolochic acid (AA) causes aristolochic acid nephropathy (AAN) and Balkan endemic nephropathy (BEN). Conflicting results have been found for the role of human sulfotransferase 1A1 (SULT1A1) contributing to the metabolic activation of aristolochic acid I (AAI) in vitro. We evaluated the role of human SULT1A1 in AA bioactivation in vivo after treatment of transgenic mice carrying a functional human SULT1A1-SULT1A2 gene cluster (i.e. hSULT1A1/2 mice) and Sult1a1(-/-) mice with AAI and aristolochic acid II (AAII). Both compounds formed characteristic DNA adducts in the intact mouse and in cytosolic incubations in vitro. However, we did not find differences in AAI-/AAII-DNA adduct levels between hSULT1A1/2 and wild-type (WT) mice in all tissues analysed including kidney and liver despite strong enhancement of sulfotransferase activity in both kidney and liver of hSULT1A1/2 mice relative to WT, kidney and liver being major organs involved in AA metabolism. In contrast, DNA adduct formation was strongly increased in hSULT1A1/2 mice compared to WT after treatment with 3-nitrobenzanthrone (3-NBA), another carcinogenic aromatic nitro compound where human SULT1A1/2 is known to contribute to genotoxicity. We found no differences in AAI-/AAII-DNA adduct formation in Sult1a1(-/-) and WT mice in vivo. Using renal and hepatic cytosolic fractions of hSULT1A1/2, Sult1a1(-/-) and WT mice, we investigated AAI-DNA adduct formation in vitro but failed to find a contribution of human SULT1A1/2 or murine Sult1a1 to AAI bioactivation. Our results indicate that sulfo-conjugation catalysed by human SULT1A1 does not play a role in the activation pathways of AAI and AAII in vivo, but is important in 3-NBA bioactivation.
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Affiliation(s)
- Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK.
| | - Walter Meinl
- Department of Nutritional Toxicology, German Institute of Human Nutrition (DIfE) Potsdam-Rehbrücke, 14558, Nuthetal, Germany
| | - Simone Florian
- Department of Nutritional Toxicology, German Institute of Human Nutrition (DIfE) Potsdam-Rehbrücke, 14558, Nuthetal, Germany
| | - Eszter Nagy
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
| | - Frantisek Barta
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 12840, Prague 2, Czech Republic
| | - Marlies Thomann
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
| | - Iveta Mrizova
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 12840, Prague 2, Czech Republic
| | - Annette M Krais
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
- Division of Occupational and Environmental Medicine, Lund University, 221 85, Lund, Sweden
| | - Maggie Liu
- Division of Cancer Therapeutics, Institute of Cancer Research, Sutton, Surrey, SM2 5NG, UK
| | - Meirion Richards
- Division of Cancer Therapeutics, Institute of Cancer Research, Sutton, Surrey, SM2 5NG, UK
| | - Amin Mirza
- Division of Cancer Therapeutics, Institute of Cancer Research, Sutton, Surrey, SM2 5NG, UK
| | - Klaus Kopka
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - David H Phillips
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
| | - Hansruedi Glatt
- Department of Nutritional Toxicology, German Institute of Human Nutrition (DIfE) Potsdam-Rehbrücke, 14558, Nuthetal, Germany
- Department of Food Safety, Federal Institute for Risk Assessment (BfR), 10589, Berlin, Germany
| | - Marie Stiborova
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 12840, Prague 2, Czech Republic
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
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White PA, Douglas GR, Phillips DH, Arlt VM. Quantitative relationships between lacZ mutant frequency and DNA adduct frequency in Muta™Mouse tissues and cultured cells exposed to 3-nitrobenzanthrone. Mutagenesis 2017; 32:299-312. [PMID: 28096451 PMCID: PMC5638019 DOI: 10.1093/mutage/gew067] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 12/13/2016] [Indexed: 02/07/2023] Open
Abstract
The frequency of stable DNA adducts in a target tissue can be used to assess biologically effective dose; however, the utility of the metric in a risk assessment context depends on the likelihood that the DNA damage will be manifested as mutation. Previously, we employed the Muta™Mouse system to examine the induction of lacZ mutants and DNA adducts following exposure to the well-studied mutagenic carcinogen 3-nitrobenzanthrone (3-NBA). In this follow-up work, we examined the empirical relationships between total adduct frequency and mutant frequency (MF) in tissues and cultured cells following acute 3-NBA exposure. The results show a significant induction of DNA damage and lacZ mutants in liver, colon and bone marrow, as well as FE1 pulmonary epithelial cells. In contrast, lung and small intestine samples had low, but significantly elevated adduct levels, with no significant increases in lacZ MF. Additional analyses showed a significant relationship between the mutagenic efficiency of total adducts, measured as the slope of the relationships between MF and total adduct frequency, and tissue-specific mitotic index (MI). The lack of mutation response in lung, in contrast to the high in vitro MF in FE-1 lung cells, is likely related to the 100-fold difference in MI. The lack of small intestine mutagenic response may be related to limited metabolic capacity, differences in DNA repair, and /or chemically induced apoptosis that has been observed for other potent mutagens. The results indicate that interpretation of adduct frequency values in a risk assessment context can be improved by considering the MI of the target tissue; however, more generalised interpretation is hampered by tissue-specific variations in metabolic capacity and damage processing. The work provides a proof of principle regarding the use of the Muta™Mouse system to critically examine the health risks associated with tissue-specific adduct loads.
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Affiliation(s)
- Paul A White
- Environmental Health Science and Research Bureau, Health Canada, Tunney’s Pasture, Colombine Driveway, Ottawa, Ontario, Canada
| | - George R Douglas
- Environmental Health Science and Research Bureau, Health Canada, Tunney’s Pasture, Colombine Driveway, Ottawa, Ontario, Canada
| | - David H Phillips
- King’s College London, Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, Franklin-Wilkins Building, London, UK
| | - Volker M Arlt
- King’s College London, Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, Franklin-Wilkins Building, London, UK
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Kucab JE, Hollstein M, Arlt VM, Phillips DH. Nutlin-3a selects for cells harbouring TP53 mutations. Int J Cancer 2017; 140:877-887. [PMID: 27813088 PMCID: PMC5215675 DOI: 10.1002/ijc.30504] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 10/03/2016] [Accepted: 10/14/2016] [Indexed: 12/27/2022]
Abstract
TP53 mutations occur in half of all human tumours. Mutagen-induced or spontaneous TP53 mutagenesis can be studied in vitro using the human TP53 knock-in (Hupki) mouse embryo fibroblast (HUF) immortalisation assay (HIMA). TP53 mutations arise in up to 30% of mutagen-treated, immortalised HUFs; however, mutants are not identified until TP53 sequence analysis following immortalisation (2-5 months) and much effort is expended maintaining TP53-WT cultures. In order to improve the selectivity of the HIMA for HUFs harbouring TP53 mutations, we explored the use of Nutlin-3a, an MDM2 inhibitor that leads to stabilisation and activation of wild-type (WT) p53. First, we treated previously established immortal HUF lines carrying WT or mutated TP53 with Nutlin-3a to examine the effect on cell growth and p53 activation. Nutlin-3a induced the p53 pathway in TP53-WT HUFs and inhibited cell growth, whereas most TP53-mutated HUFs were resistant to Nutlin-3a. We then assessed whether Nutlin-3a treatment could discriminate between TP53-WT and TP53-mutated cells during the HIMA (n = 72 cultures). As immortal clones emerged from senescent cultures, each was treated with 10 µM Nutlin-3a for 5 days and observed for sensitivity or resistance. TP53 was subsequently sequenced from all immortalised clones. We found that all Nutlin-3a-resistant clones harboured TP53 mutations, which were diverse in position and functional impact, while all but one of the Nutlin-3a-sensitive clones were TP53-WT. These data suggest that including a Nutlin-3a counter-screen significantly improves the specificity and efficiency of the HIMA, whereby TP53-mutated clones are selected prior to sequencing and TP53-WT clones can be discarded.
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Affiliation(s)
- Jill E. Kucab
- King's College London, Analytical and Environmental Sciences Division, MRC‐PHE Centre for Environment & HealthLondonUnited Kingdom
| | - Monica Hollstein
- German Cancer Research Center (Deutsches Krebsforschungszentrum), Division of Genetic Alterations in CarcinogenesisHeidelbergGermany
- University of Leeds, Faculty of Medicine and HealthLeedsUnited Kingdom
| | - Volker M. Arlt
- King's College London, Analytical and Environmental Sciences Division, MRC‐PHE Centre for Environment & HealthLondonUnited Kingdom
| | - David H. Phillips
- King's College London, Analytical and Environmental Sciences Division, MRC‐PHE Centre for Environment & HealthLondonUnited Kingdom
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Imanikia S, Galea F, Nagy E, Phillips DH, Stürzenbaum SR, Arlt VM. The application of the comet assay to assess the genotoxicity of environmental pollutants in the nematode Caenorhabditis elegans. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2016; 45:356-61. [PMID: 27389785 PMCID: PMC4962771 DOI: 10.1016/j.etap.2016.06.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/13/2016] [Accepted: 06/18/2016] [Indexed: 05/04/2023]
Abstract
This study aimed to establish a protocol for cell dissociation from the nematode Caenorhabditis elegans (C. elegans) to assess the genotoxicity of the environmental pollutant benzo[a]pyrene (BaP) using the alkaline version of the single cell electrophoresis assay (comet assay). BaP genotoxicity was assessed in C. elegans (wild-type [WT]; N2, Bristol) after 48h exposure (0-40μM). Induction of comets by BaP was concentration-dependent up to 20μM; comet% tail DNA was ∼30% at 20μM BaP and ∼10% in controls. Similarly, BaP-induced DNA damage was evaluated in C. elegans mutant strains deficient in DNA repair. In xpa-1 and apn-1 mutants BaP-induced comet formation was diminished to WT background levels suggesting that the damage formed by BaP that is detected in the comet assay is not recognised in cells deficient in nucleotide and base excision repair, respectively. In summary, our study provides a protocol to evaluate DNA damage of environmental pollutants in whole nematodes using the comet assay.
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Affiliation(s)
- Soudabeh Imanikia
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - Francesca Galea
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - Eszter Nagy
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - David H Phillips
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom; NIHR Health Protection Research Unit in Health Impact of Environmental Hazards at King's College London in partnership with Public Health England, London, United Kingdom
| | - Stephen R Stürzenbaum
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom; NIHR Health Protection Research Unit in Health Impact of Environmental Hazards at King's College London in partnership with Public Health England, London, United Kingdom.
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