Exposure of mammalian cell cultures to benzo[a]pyrene and light results in oxidative DNA damage as measured by 8-hydroxydeoxyguanosine formation.
Exposure of mammalian cell cultures to benzo[a]pyrene and light results in oxidative DNA damage as measured by 8-hydroxydeoxyguanosine formation.
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DOI：
10.1093/carcin/16.1.133
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发表时间：
1995
期刊：
影响因子：
4.7
通讯作者：
R. Mauthe;Vanessa M. Cook;S. Coffing;William M. Baird
中科院分区：
文献类型：
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作者：
R. Mauthe;Vanessa M. Cook;S. Coffing;William M. Baird
致癌多环芳烃通过与细胞中DNA的核苷酸直接共价相互作用诱导DNA损伤，在细胞中它们被激活为“最终致癌代谢物”。为了确定它们是否在相同的情况下也诱导DNA的氧化损伤，将早期传代的叙利亚仓鼠胚胎和人乳腺癌细胞系MCF-7培养物用0-5 μ g/ml苯并[a]芘（BaP）处理24小时或用0-100 μ M亚甲蓝（作为氧化损伤的阳性对照）处理1小时。然后将细胞暴露于荧光下1或4小时或保留在黑暗中。在细胞收获、DNA分离和DNA酶消化为脱氧核糖核苷后，通过反相HPLC和电化学检测和UV检测分别测定存在的8-羟基-2 '脱氧鸟苷（8-OH-dGuo）和未修饰的脱氧鸟苷的量。用亚甲蓝处理1小时，然后暴露于光1小时的培养物含有比用亚甲蓝未暴露于光处理的细胞或用亚甲蓝未暴露于光的未处理细胞或暴露于光的未处理细胞高5倍（10 μ M）和8至28倍（100 μ M）的8-OH-dGuo水平。在无光条件下，用1-5微克/毫升BaP处理培养物24小时，8-OH-dGuo水平没有显著变化。然而，用BaP处理然后暴露于荧光4小时的人和仓鼠细胞培养物含有比未暴露于光或未用BaP处理的细胞高3倍（1微克/ml）和8至10倍（5微克/ml）的8-OH-dGuo水平。这些结果表明，BaP处理不会导致保持在黑暗中的细胞的DNA中形成8-OH-dGuo。BaP处理的细胞暴露于荧光导致形成显著量的氧化DNA损伤，如通过8-OH-dGuo形成所测量的。这些研究结果表明，DNA的氧化损伤可能参与BaP在组织（如皮肤）中的肿瘤诱导，其中BaP暴露可能在光的存在下发生。
Carcinogenic polycyclic aromatic hydrocarbons induce DNA damage through direct covalent interactions with nucleotides of the DNA in cells in which they are activated to 'ultimate carcinogenic metabolites'. To determine whether they also induce oxidative damage to DNA under the same circumstances, early passage Syrian hamster embryo and human mammary carcinoma cell line MCF-7 cultures were treated for 24 h with 0-5 micrograms/ml benzo[a]pyrene (BaP) or for 1 h with 0-100 microM methylene blue (as a positive control for oxidative damage). The cells were then exposed to fluorescent light for 1 or 4 h or retained in darkness. After cell harvest, DNA isolation and enzymatic digestion of the DNA to deoxyribonucleosides, the amounts of 8-hydroxy-2'deoxyguanosine (8-OH-dGuo) and unmodified deoxyguanosine present were determined by reverse-phase HPLC with electrochemical and UV detection respectively. Cultures treated with methylene blue for 1 h followed by light exposure for 1 h contained 5-fold (10 microM) and 8- to 28-fold (100 microM) higher 8-OH-dGuo levels than cells treated with methylene blue not exposed to light or untreated cells with methylene blue not exposed to light or untreated cells exposed to light. There was no significant change in 8-OH-dGuo levels in cultures treated with 1-5 micrograms/ml BaP for 24 h in the absence of light. However, both the human and hamster cell cultures treated with BaP and then exposed to fluorescent light for 4 h contained 3-fold (1 micrograms/ml) and 8- to 10-fold (5 micrograms/ml) higher 8-OH-dGuo levels than those not exposed to light or not treated with BaP. These results indicate that BaP treatment does not cause 8-OH-dGuo formation in DNA of cells maintained in darkness. Exposure of BaP-treated cells to fluorescent light causes formation of significant amounts of oxidative DNA damage as measured by 8-OH-dGuo formation. These findings suggest that oxidative damage of DNA could be involved in tumor induction by BaP in tissues, such as skin, in which exposure to BaP can occur in the presence of light.