Cooke M S, Mistry N, Ladapo A, Herbert K E, Lunec J
Oxidative Stress Group, University of Leicester, Leicester Royal Infirmary, UK.
Free Radic Res. 2000 Oct;33(4):369-81. doi: 10.1080/10715760000300911.
There is growing evidence to suggest that solar radiation-induced, oxidative DNA damage may play an important role in skin carcinogenesis. Numerous methods have been developed to sensitively quantitate 8-oxo-2'deoxyguanosine (8-oxodG), a recognised biomarker of oxidative DNA damage. Immunoassays may represent a means by which the limitations of many techniques, principally derived from DNA extraction and sample workup, may be overcome. We report the evaluation of probes to thymine dimers and oxidative damage in UV-irradiated cells and the DNA derived therefrom. Thymine dimers were most readily recognised, irrespective of whether in situ in cells or in extracted DNA. However, using antibody-based detection the more subtle oxidative modifications required extraction and, in the case of 8-oxodG, denaturation of the DNA prior to successful recognition. In contrast, a recently described novel probe for 8-oxodG detection showed strong recognition in cells, although appearing unsuitable for use with extracted DNA. The probes were subsequently applied to examine the relative induction of lesions in cells following UV irradiation. Guanine-glyoxal lesions predominated over thymine dimers subsequent to UVB irradiation, whereas whilst oxidative lesions increased significantly following UVA irradiation, no induction of thymine dimers was seen. These data support the emerging importance of oxidative DNA damage in UV-induced carcinogenesis.
越来越多的证据表明，太阳辐射诱导的氧化性DNA损伤可能在皮肤癌发生过程中起重要作用。已经开发出许多方法来灵敏地定量8-氧代-2'-脱氧鸟苷（8-氧代dG），这是一种公认的氧化性DNA损伤生物标志物。免疫测定可能是一种克服许多技术局限性的方法，这些局限性主要源于DNA提取和样品处理。我们报告了对紫外线照射细胞及其衍生DNA中胸腺嘧啶二聚体和氧化性损伤探针的评估。胸腺嘧啶二聚体最容易被识别，无论其是在细胞内原位还是在提取的DNA中。然而，使用基于抗体的检测方法，更细微的氧化性修饰需要进行提取，并且对于8-氧代dG，在成功识别之前需要对DNA进行变性处理。相比之下，最近描述的一种用于检测8-氧代dG的新型探针在细胞中显示出强烈的识别能力，尽管似乎不适用于提取的DNA。随后将这些探针应用于检查紫外线照射后细胞中损伤的相对诱导情况。在UVB照射后，鸟嘌呤-乙二醛损伤比胸腺嘧啶二聚体更占优势，而在UVA照射后，氧化性损伤显著增加，未观察到胸腺嘧啶二聚体的诱导。这些数据支持了氧化性DNA损伤在紫外线诱导的致癌作用中日益重要的观点。
