Photodynamic Action of Benzo[a]pyrene in K562 Cells

Filgueira, Daza de Moraes Vaz Batista; Freitas, Diana Paula Salomão de; Votto, Ana Paula de Souza; Fillmann, Gilberto; Monserrat, José M.; Geracitano, Laura A.; Trindade, Gilma Santos

doi:10.1111/j.1751-1097.2007.00169.x

Cited by 13 publications

(6 citation statements)

References 36 publications

(49 reference statements)

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“…Production of hydrogen peroxide has been reported (13). This finding would be in agreement with increased damage measured by the Comet assay (14–16). Indeed, this last technique mostly visualizes strand breaks induced by hydroxyl radicals, a byproduct of H 2 O 2 .…”

Section: Introductionsupporting

confidence: 87%

“…Work was carried out either in cultured cells or in isolated DNA to determine the molecular processes leading to DNA damage upon co‐exposure to BaP and UV, and in particular UVA that was found to be the most active part of solar light (10). Induction of oxidative stress is likely to be the major consequence of combined exposure to PAH and UVA, as shown by redox‐sensitive fluorescent probes (16). Therefore, several studies tried to determine the favored photo‐oxidative pathway but yielded contradictory results, singlet oxygen being the most frequently proposed reactive oxygen species involved (18–21).…”

Section: Discussionmentioning

confidence: 99%

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Genotoxicity of Combined Exposure to Polycyclic Aromatic Hydrocarbons and UVA—A Mechanistic Study

Douki

Ksoury

Marie

et al. 2008

Photochem & Photobiology

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Solar UV radiation and benzo[a]pyrene (BaP) are two carcinogenic agents. When combined, their deleterious properties are synergistic. In order to get insights into the underlying processes, we carried out a mechanistic study within isolated DNA photosensitized to UVA radiation by either BaP, its diol epoxide metabolite (BPDE) or the tetraol arising from the hydrolysis of this last molecule. Measurement of the level of the oxidized base 8-oxo-7,8-dihydroguanine revealed that BaP is a poor sensitizer while BPDE and tetraol are more potent ones. None of these compounds was found to photosensitize formation of cyclobutane pyrimidine dimers through triplet energy transfer. On the basis of the distribution of oxidized DNA bases, we could show that photosensitization of DNA by BPDE involves electron abstraction (Type I) while tetraol acts mainly through singlet oxygen production (Type II). Under our experimental conditions, Type I was the major photosensitization process, which shows the lack of involvement of tetraol in the observed photo-oxidation reaction. Finally, we could show that the adducts, resulting from the alkylation of DNA by BPDE, are very potent sensitizers. Indeed, they are located in the close vicinity of the double helix and thus perfectly placed to induce oxidation reactions.

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Section: Introductionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Genotoxicity of Combined Exposure to Polycyclic Aromatic Hydrocarbons and UVA—A Mechanistic Study

Douki

Ksoury

Marie

et al. 2008

Photochem & Photobiology

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“…Various forms of DNA damages are observed when cells are exposed to the combination of light and PAHs 18–23 . These DNA damages include DNA single strand breaks, oxidation of DNA bases, and formation of DNA covalent adducts 6,18,22,24,25 .…”

Section: Discussionmentioning

confidence: 99%

DNA damage and repair of human skin keratinocytes concurrently exposed to pyrene derivatives and UVA light

Fullove

2013

Toxicol. Res.

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Polycyclic aromatic hydrocarbons (PAHs), a class of mutagenic environmental contaminants, insert toxicity through both metabolic activation and light irradiation. Pyrene, one of the most widely studied PAHs, along with its mono-substituted derivatives, 1-amino, 1-bromo, 1-hydroxy, and 1-nitropyrene, were chosen to study the effect of substituents on their phototoxicity, DNA damage and repair. Both alkaline Comet assay, which detects direct DNA damages, and Fpg endonuclease Comet assay, which detects oxidative DNA damages, were conducted at 0, 2, 4, 8, and 24 h of incubation of the cells in minimal growth medium after concomitant exposure to pyrene derivatives and UVA light. All these compounds are photocytotoxic and the phototoxicity is both incubation time and PAH dose dependent; whereas, those without light are not toxic. The LC50 obtained are in the range of 3.5 – 9.3 µM. Cellular DNA damages, both direct and oxidative, are observed immediately after the cells are treated with UVA light and the pyrene derivatives at a concentration of 1.0 µM. The amount of DNA damages (both direct and oxidative) increase from 0 to 4 h of incubation. After 4 hours, subsequent damage induction declines, and this is perceived to be mainly through DNA repair. After longer incubation of 8 h, the damaged cellular DNA start to be repaired, resulting in greatly reduced amount of DNA damages, and the DNA damage reaches the minimum at 24 h of incubation. 1-Amopyrene and 1-hydroxypyrene cause more DNA oxidative damages immediately after the exposure (0 h of incubation), and these damages are repaired within the same timeframe as the other tested compounds. The oxidative DNA damages caused by 1-bromopyrene are repaired starting at 2 h of incubation, earlier than the damages caused by all the other compounds.

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“…Joint exposure to benzopyrene and sun may cause squamous cell carcinoma of lips. Anthracene generates 1 O 2 ,

O_{2}^{• -}

, and • OH under sunlight exposure, which induces linoleic acid peroxidation, DNA damage, and cell cycle arrest . CBZ has persistence, bioaccumulative, toxicant properties and exists in the environment but its photostability and photosafety/phototoxicity mechanism is still poorly explored.…”

Section: Introductionmentioning

confidence: 99%

Oxidative stress–mediated photoactivation of carbazole inhibits human skin cell physiology

Srivastav

Dubey

Chopra

et al. 2019

J of Cellular Biochemistry

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Prolonged exposure of the earth's surface to the sun's ultraviolet radiation may result in various skin diseases and cataract. Carbazole (CBZ), as a polycyclic‐aromatic hydrocarbon (PAH), is blended with a five‐member nitrogen‐containing ring. It is found in cigarette smoke, coal, eye kohl, tattoo ink, and wood combustion and affects various types of flora and fauna. Our findings suggest that CBZ generates reactive oxygen species (ROS) like O2•− through type‐I photodynamic reaction and causes phototoxicity in the human keratinocyte cell line (HaCaT), which has been proved by mitochondrial dehydrogenase and neutral red uptake assays. CBZ induces single strand DNA damage. We have investigated the involvement of the apoptotic pattern of cell death and confirmed it by cytochrome C release from mitochondria and caspase‐9 activation. Similarly, photo‐micronuclei formation was associated to CBZ‐induced phototoxicity. The results of this study strongly support that the upregulation of bax, cyto‐C, apaf‐1, casp‐9 and down regulation of bcl2, keap‐1, nrf‐2, and hmox‐1 genes cause apoptopic cell death. Downregulation of antioxidant genes showed a significant amount of ROS generation by photosensitized CBZ. Therefore, the current study will be a step forward to safeguard human beings from sunlight‐induced photosensitive CBZ prolonged exposure.

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Photodynamic Action of Benzo[a]pyrene in K562 Cells

Cited by 13 publications

References 36 publications

Genotoxicity of Combined Exposure to Polycyclic Aromatic Hydrocarbons and UVA—A Mechanistic Study

Genotoxicity of Combined Exposure to Polycyclic Aromatic Hydrocarbons and UVA—A Mechanistic Study

DNA damage and repair of human skin keratinocytes concurrently exposed to pyrene derivatives and UVA light

Oxidative stress–mediated photoactivation of carbazole inhibits human skin cell physiology

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