DNA lesions induced by UV A1 and B radiation in human cells:: Comparative analyses in the overall genome and in the p53 tumor suppressor gene
DNA lesions induced by UV A1 and B radiation in human cells:: Comparative analyses in the overall genome and in the p53 tumor suppressor gene
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DOI：
10.1073/pnas.0502311102
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发表时间：
2005-07-19
影响因子：
11.1
通讯作者：
Pfeifer, GP
中科院分区：
文献类型：
--
作者：
Besaratinia, A;Synold, TW;Pfeifer, GP
阳光中的紫外线成分（UVA和UVB）与人类皮肤癌的病因有关。UVB致癌的潜在作用机制已明确定义;然而，UVA参与致癌的机制尚未完全阐明。我们研究了UVA 1与UVB在正常人皮肤成纤维细胞的整个基因组和p53肿瘤抑制基因中的遗传毒性。免疫斑点印迹分析确定了顺式-顺式环丁烷嘧啶二聚体（CPD）作为一个独特的UVB诱导的病变，并确认其形成的UVA 1照射细胞的基因组DNA依赖于辐射剂量。HPLC/串联MS分析显示仅在UVA 1照射的细胞的基因组DNA中诱导8-氧代-7，8-二氢-2 '-脱氧鸟苷。通过末端转移酶依赖性PCR对DNA损伤的定位显示，在UVB和UVA 1照射的细胞中，沿着p53基因外显子5-8形成聚合酶阻断病变和/或链断裂，但不相同。通过末端转移酶-PCR检测到的UVB诱导的病变几乎完全映射到富含嘧啶的序列;然而，UVA 7诱导的病变映射到嘌呤和嘧啶的序列沿着p53基因。与连接介导的PCR结合的损伤特异性DNA修复酶的切割试验显示，在UVB和UVA 1照射的细胞中，CPD沿着p53基因形成优先，但不相同。此外，剂量依赖性的氧化和开环嘌呤和脱碱基位点的形成建立在p53基因中只有UVA 1照射的细胞。我们的结论是，UVA 1诱导promutagenic CPD和氧化DNA损伤的基因组和核苷酸分辨率水平在正常人皮肤成纤维细胞。
The UV components of sunlight (UVA and UVB) are implicated in the etiology of human skin cancer. The underlying mechanism of action for UVB carcinogenicity is well defined; however, the mechanistic involvement of UVA in carcinogenesis is not fully delineated. We investigated the genotoxicity of UVA1 versus UVB in the overall genome and in the p53 tumor suppressor gene in normal human skin fibroblasts. Immuno-dot blot analysis identified the cis-syn cyclobutane pyrimidine-dimer (CPD) as a distinctive UVB-induced lesion and confirmed its formation in the genomic DNA of UVA1-irradiated cells dependent on radiation dose. HPLC/tandem MS analysis showed an induction of 8-oxo-7,8-dihydro-2 '-deoxyguanosine in the genomic DNA of UVA1-irradiated cells only. Mapping of DNA damages by terminal transferase-dependent PCR revealed preferential, but not identical, formation of polymerase-blocking lesions and/or strand breaks along exons 5-8 of the p53 gene in UVB- and UVA1-irradiated cells. The UVB-induced lesions detected by terminal transferase-PCR were almost exclusively mapped to pyrimidine-rich sequences; however, the UVA7-induced lesions were mapped to purine- and pyrimidine-containing sequences along the p53 gene. Cleavage assays with lesion-specific DNA repair enzymes coupled to ligation-mediated PCR showed preferential, but not identical, formation of CPDs along the p53 gene in UVB- and UVA1-irradiated cells. Additionally, dose-dependent formation of oxidized and ring-opened purines and abasic sites was established in the p53 gene in only UVA1-irradiated cells. We conclude that UVA1 induces promutagenic CPDs and oxidative DNA damage at both the genomic and nucleotide resolution level in normal human skin fibroblasts.