Zhu Ting, Chen Rui, Li Ai-Ping, Liu Jia, Liu Qi-Zhan, Chang Hebron C, Zhou Jian-Wei
Department of Molecular Cell Biology and Toxicology, Jiangsu Provincial Key Laboratories of Human Functional Genomics and of Applied Toxicology; School of Public Health, Nanjing Medical University, 140 Hanzhong Road, Nanjing 210029, China.
J Biomed Sci. 2005;12(1):219-27. doi: 10.1007/s11373-004-8186-4.
Oxidative stress, or the production of oxygen-centered free radicals, has been hypothesized as the major source of DNA damage that can lead to a variety of diseases including cancer. It is known that 8-hydroxy-deoxyguanosine (8-oxo-dG) is a useful biomarker of oxidative DNA damage. Our recent data showed that JWA, initially being cloned as a novel cell differentiation-associated gene, was also actively responsive to environmental stressors, such as heat-shock, oxidative stress and so on. In the present study, we have applied a modified comet assay and bacterial repair endonucleases system (endonuclease III and formamidopyrimidine glycosylase) to investigate if JWA is involved in hydrogen peroxide (H2O2)-induced DNA damage and repair in K562 and MCF-7 cells, and to demonstrate if the damage is associated with 8-oxo-dG. The results from the comet assay have shown that the average tail length and the percentage of the cells with DNA tails are greatly induced by H2O2 treatment and further significantly enhanced by the post-treatment of repair endonucleases. The H2O2-induced 8-oxo-dG formation in K562 and MCF-7 cells is dose-dependent. In addition, the data have clearly demonstrated that JWA gene expression is actively induced by H2O2 treatment in K562 and MCF-7 cells. The results suggest that JWA can be regulated by oxidative stress and is actively involved in the signal pathways of oxidative stress in the cells.
氧化应激，即以氧为中心的自由基的产生，被认为是导致包括癌症在内的多种疾病的DNA损伤的主要来源。众所周知，8-羟基脱氧鸟苷（8-氧代-dG）是氧化DNA损伤的一种有用的生物标志物。我们最近的数据表明，最初作为一种新的细胞分化相关基因被克隆的JWA，也对环境应激源如热休克、氧化应激等有积极反应。在本研究中，我们应用了改良彗星试验和细菌修复核酸内切酶系统（核酸内切酶III和甲酰胺嘧啶糖基化酶）来研究JWA是否参与过氧化氢（H2O2）诱导的K562和MCF-7细胞中的DNA损伤与修复，并证明这种损伤是否与8-氧代-dG有关。彗星试验的结果表明，H2O2处理可显著诱导平均尾长和有DNA尾巴的细胞百分比，而修复核酸内切酶的后处理可进一步显著增强这一效应。H2O2诱导的K562和MCF-7细胞中8-氧代-dG的形成呈剂量依赖性。此外，数据清楚地表明，H2O2处理可在K562和MCF-7细胞中积极诱导JWA基因表达。结果表明，JWA可受氧化应激调节，并积极参与细胞内氧化应激的信号通路。
