Reactions induced in vitro between model DNA and benzo[A]pyrene by near-ultraviolet radiation

Hoard, Donald E.; Ratliff, Robert L.; Bingham, Judy M.; Strniste, G.F.

doi:10.1016/0009-2797(81)90039-9

Cited by 8 publications

(5 citation statements)

References 15 publications

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“…Therefore, no light-indcued PAH-DNA adducts have been isolated and characterized so far. Hoard et al (128) and Strniste et al (75) have attempted to compare B[a]P-DNA adduct from both enzymatic and light-activation pathways. Upon irradiation of 14 C-labeled B[a]P with single strand DNA, the DNA was enzyme digested and the adducts were compared using HPLC with the microsome-metabolized B[a]P adducts.…”

Section: Pah Molecular Phototoxicitymentioning

confidence: 99%

Environmental Carcinogenic Polycyclic Aromatic Hydrocarbons: Photochemistry and Phototoxicity

2002

Journal of Environmental Science and Health, Part C

341

252

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Section: Pah Molecular Phototoxicitymentioning

confidence: 99%

Environmental Carcinogenic Polycyclic Aromatic Hydrocarbons: Photochemistry and Phototoxicity

2002

Journal of Environmental Science and Health, Part C

341

252

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“…The increase in toxicity due to simulated solar radiation can exceed 100-fold (26). Reports on a well-studied PAH, benzo[a]pyrene, showed that it can form a DNA covalent adduct or cause DNA strand breakage under light (27)(28)(29)(30)(31)(32)(33)(34). The presence of benzo [a]pyrene can increase the level of formation of 8-hydroxy-2′-deoxyguanine induced by UV light (35), a compound generated due to oxidative damage to DNA.…”

Section: Introductionmentioning

confidence: 99%

UVA-Induced DNA Single-Strand Cleavage by 1-Hydroxypyrene and Formation of Covalent Adducts between DNA and 1-Hydroxypyrene

Dong

Hwang

Shi

et al. 2000

Chem. Res. Toxicol.

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1-Hydroxypyrene (HOP), a metabolite found in the urine of humans and laboratory animals exposed to polycyclic aromatic hydrocarbons (PAHs), is known to be both acutely toxic and genotoxic. It has been widely used as a biomarker for studying PAH exposure. In this research, we have found that, upon UVA irradiation, HOP causes DNA single-strand cleavages and forms HOP-DNA covalent adducts. The UVA-induced cleavage of supercoiled plasmid PhiX174 DNA is dependent upon both HOP concentration and UVA dosage. A longer irradiation time or higher HOP concentration induces more DNA cleavage. Results of the photocleavage experiments carried out in the presence of reactive oxygen species scavengers, histidine, sodium azide, mannitol, SOD, and desferal indicate that both the superoxide free radical and singlet oxygen are likely involved in causing DNA single-strand cleavage. The photocleavage is inhibited by the presence of an excited singlet-state quencher, KI, indicating that it is an excited-state reaction. Along with light-induced DNA cleavage, HOP also forms DNA covalent adducts while being degraded upon light irradiation. Light-induced degradation of 20 microM HOP follows first-order reaction kinetics in a 10% methanolic buffer (10 mM phosphate) solution in the absence or presence of 40 microM calf thymus DNA, with degradation half-lives of 20 or 15 min, respectively. The shorter degradation half-life in the presence of DNA is due to the formation of the HOP-DNA covalent adduct. The formation of the HOP-DNA covalent adduct is evidenced by comparing the UV-vis absorption and fluorescence emission spectra of the pure HOP with those of the HOP-DNA adduct. The covalent HOP-DNA adduct produced due to irradiation was purified by either extensive dialysis (3 x 500 mL buffer solutions), phenol and chloroform extraction followed by ethanol precipitation, or chloroform extraction alone. The isolated HOP-DNA adduct has an absorption peak at 353 nm, which is 8 nm red-shifted compared to that of free HOP. The fluorescence emission for HOP-DNA is at least 70 times weaker than that for free HOP in solution. In summary, the findings with HOP reveal that, in addition to metabolic activation that eventually leads to the formation of alkylated DNA adducts or other forms of DNA damage, HOP may be activated by light to produce DNA single-strand cleavage and covalent DNA adducts. These DNA lesions can be sources of toxicity.

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“…Metabolically activated BaP binds covalently with DNA and nucleic acid components both in vivo and in vitro (3). It was reported that irradiation of BaP by near-ultraviolet (UV) light initiated covalent binding with DNA molecules in vitro, although the mechanism remained skeptical (6). In vivo, it is not clear whether BaP photoinduced modifications of DNA (7,8).…”

mentioning

confidence: 99%

Benzo[a]pyrene Enhances the Formation of 8-Hydroxy-2‘-deoxyguanosine by Ultraviolet A Radiation in Calf Thymus DNA and Human Epidermoid Carcinoma Cells

Liu

Rosenstein

et al. 1998

Biochemistry

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The objective of this study is to investigate if benzo[a]pyrene (BaP) and ultraviolet (UV) radiation synergistically induce oxidative DNA damage. Calf thymus DNA was incubated with BaP and irradiated with UVB (280-320 nm) and UVA (335-400 nm). BaP substantially enhanced the formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) by UVA, but only moderately increased the level of 8-OHdG by UVB. Formation of 8-OHdG proportionally correlated with both UV dose and BaP concentration. Human epidermoid carcinoma cells were incubated with 10 microg of BaP/mL for 24 h and then exposed to 10 kJ/m2 UVB and 25 kJ/m2 UVA. UVB plus BaP did not affect the level of 8-OHdG in cultured cells, whereas UVA plus BaP substantially increased 8-OHdG by over 4-fold compared to BaP and UVA controls. To confirm what reactive oxygen species (ROS) are involved in BaP plus UVA-induced oxidative DNA damage, less or more specific ROS quenchers were added to DNA solution. The results showed that only superoxide dismutase and genistein significantly quenched BaP plus UVA-induced 8-OHdG, whereas catalase, sodium azide, and mannitol exhibited no effect. Our studies suggest that BaP enhances the formation of 8-OHdG in purified DNA and cultured cells by UVA, but not by UVB, and that superoxide anion plays an important role in the synergistic induction of oxidative DNA damage.

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Reactions induced in vitro between model DNA and benzo[A]pyrene by near-ultraviolet radiation

Cited by 8 publications

References 15 publications

Environmental Carcinogenic Polycyclic Aromatic Hydrocarbons: Photochemistry and Phototoxicity

Environmental Carcinogenic Polycyclic Aromatic Hydrocarbons: Photochemistry and Phototoxicity

UVA-Induced DNA Single-Strand Cleavage by 1-Hydroxypyrene and Formation of Covalent Adducts between DNA and 1-Hydroxypyrene

Benzo[a]pyrene Enhances the Formation of 8-Hydroxy-2‘-deoxyguanosine by Ultraviolet A Radiation in Calf Thymus DNA and Human Epidermoid Carcinoma Cells

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