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Holme JA, Nyvold HE, Tat V, Arlt VM, Bhargava A, Gutzkow KB, Solhaug A, Låg M, Becher R, Schwarze PE, Ask K, Ekeren L, Øvrevik J. Mechanisms linked to differences in the mutagenic potential of 1,3-dinitropyrene and 1,8-dinitropyrene. Toxicol Rep 2014; 1:459-473. [PMID: 28962260 PMCID: PMC4547165 DOI: 10.1016/j.toxrep.2014.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 07/07/2014] [Accepted: 07/08/2014] [Indexed: 11/22/2022] Open
Abstract
This study explores and characterizes the toxicity of two closely related carcinogenic dinitro-pyrenes (DNPs), 1,3-DNP and 1,8-DNP, in human bronchial epithelial BEAS-2B cells and mouse hepatoma Hepa1c1c7 cells. Neither 1,3-DNP nor 1,8-DNP (3–30 μM) induced cell death in BEAS-2B cells. In Hepa1c1c7 cells only 1,3-DNP (10–30 μM) induced a mixture of apoptotic and necrotic cell death after 24 h. Both compounds increased the level of reactive oxygen species (ROS) in BEAS-2B as measured by CM-H2DCFDA-fluorescence. A corresponding increase in oxidative damage to DNA was revealed by the formamidopyrimidine-DNA glycosylase (fpg)-modified comet assay. Without fpg, DNP-induced DNA damage detected by the comet assay was only found in Hepa1c1c7 cells. Only 1,8-DNP formed DNA adduct measured by 32P-postlabelling. In Hepa1c1c cells, 1,8-DNP induced phosphorylation of H2AX (γH2AX) and p53 at a lower concentration than 1,3-DNP and there was no direct correlation between DNA damage/DNA damage response (DR) and induced cytotoxicity. On the other hand, 1,3-DNP-induced apoptosis was inhibited by pifithrin-α, an inhibitor of p53 transcriptional activity. Furthermore, 1,3-DNP triggered an unfolded protein response (UPR), as measured by an increased expression of CHOP, ATF4 and XBP1. Thus, other types of damage possibly linked to endoplasmic reticulum (ER)-stress and/or UPR could be involved in the induced apoptosis. Our results suggest that the stronger carcinogenic potency of 1,8-DNP compared to 1,3-DNP is linked to its higher genotoxic effects. This in combination with its lower potency to induce cell death may increase the probability of causing mutations.
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Key Words
- 1,3-DNP, 1,3-dinitropyrene
- 1,3-Dinitropyrene
- 1,8-DNP, 1,8-dinitropyrene
- 1,8-Dinitropyrene
- 1-NP, 1-nitropyrene
- 3-NBA, 3-nitrobenzanthrone
- AhR, aromatic hydrocarbon receptor
- Apoptosis
- B[a]P, benzo[a]pyrene
- CM-H2DCFDA or H2DCFDA, 5-(and 6-)chloromethyl-2,7-dichlorodihydrofluorescein diacetate
- CYP, cytochrome P450
- Chk, checkpoint kinases
- DDR, DNA damage response
- DHE, dihydroethidium
- DMSO, dimethyl sulfoxide
- DNA damage
- ER, endoplasmic reticulum
- Hoechst 33258, 2(2-(4-hydroxyphenyl)-6-benzimidazole-6-(1-methyl-4-piperazyl)benzimidazole hydrochloride)
- Hoechst 33342, 2′-(4-ethoxyphenyl)-2′,5′-bis-1H-benzimidazole hydrochloride)
- NR, nitro-reductasesnitro-PAHnitro substituted-polycyclic aromatic hydrocarbon
- Nitro-PAHs
- PAH, polycyclic aromatic hydrocarbon
- PARP, poly(ADP-ribose) polymerase
- PFT, pifithrin
- PI, propidium iodide
- PM, particular matter
- RNS, reactive nitrogen species
- ROS, reactive oxygen species
- SSB, single strand breaks
- UPR, unfolded protein response
- fpg, formamidopyrimidine-DNA glycosylase
- zVAD-FMK, benzyolcarbonayl-Val-Ala-Asp-fluoromethyl ketone
- γH2AX, phosphorylated H2AX
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Affiliation(s)
- J A Holme
- Division of Environmental Medicine, Norwegian Institute of Public Health, N-0403 Oslo, Norway
| | - H E Nyvold
- Division of Environmental Medicine, Norwegian Institute of Public Health, N-0403 Oslo, Norway
| | - V Tat
- Department of Medicine, McMaster University, Hamilton, ON, Canada
| | - V M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - A Bhargava
- Department of Medicine, McMaster University, Hamilton, ON, Canada
| | - K B Gutzkow
- Division of Environmental Medicine, Norwegian Institute of Public Health, N-0403 Oslo, Norway
| | - A Solhaug
- Norwegian Veterinary Institute, Oslo, Norway
| | - M Låg
- Division of Environmental Medicine, Norwegian Institute of Public Health, N-0403 Oslo, Norway
| | - R Becher
- Division of Environmental Medicine, Norwegian Institute of Public Health, N-0403 Oslo, Norway
| | - P E Schwarze
- Division of Environmental Medicine, Norwegian Institute of Public Health, N-0403 Oslo, Norway
| | - K Ask
- Department of Medicine, McMaster University, Hamilton, ON, Canada
| | - L Ekeren
- Division of Environmental Medicine, Norwegian Institute of Public Health, N-0403 Oslo, Norway
| | - J Øvrevik
- Division of Environmental Medicine, Norwegian Institute of Public Health, N-0403 Oslo, Norway
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