Micromolar concentrations of hydrogen peroxide induce oxidative DNA lesions more efficiently than millimolar concentrations in mammalian cells
Micromolar concentrations of hydrogen peroxide induce oxidative DNA lesions more efficiently than millimolar concentrations in mammalian cells
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DOI：
10.1093/nar/gkg263
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发表时间：
2003-03-15
影响因子：
14.9
通讯作者：
Swenberg, JA
中科院分区：
文献类型：
--
作者：
Nakamura, J;Purvis, ER;Swenberg, JA
活性氧在哺乳动物细胞中产生氧化碱基、脱氧核糖损伤和DNA链断裂。以前，我们证明了在哺乳动物细胞中由10 mM过氧化氢（H2 O2）诱导的DNA损伤（ADL）。有趣的是，一个双峰过氧化氢的剂量-反应关系的细胞毒性已被报道为大肠杆菌缺乏DNA修复以及中国仓鼠卵巢（CHO）细胞。此外，它已被证明，过氧化氢在铁的存在下，导致纯化的DNA单链断裂，并诱导CHO细胞中的线粒体DNA损伤与双相剂量-反应曲线。在这里，我们表明，过氧化氢产生ADL浓度低至0.06 mM的HeLa细胞和较低浓度的过氧化氢比高浓度更有效地诱导ADL。该剂量-反应曲线与暴露于H2 O2的DNA修复缺陷的大肠杆菌中的细胞杀伤效应惊人地相似。有趣的是，连续治疗亚毫摩尔水平的H2 O2诱导大量积累的ADL。细胞内NAD（P）H测定H2 O2的毒性与ADL的形成密切相关。此外，联吡啶，铁（II）特异性螯合剂，显着保护DNA损伤和细胞毒性从亚毫摩尔，但不是毫摩尔，量的H2 O2。这些结果表明，亚毫摩尔水平的H2 O2诱导的ADL可能是由于在哺乳动物细胞中H2 O2和细胞内铁离子之间的芬顿型反应。
Reactive oxygen species produce oxidized bases, deoxyribose lesions and DNA strand breaks in mammalian cells. Previously, we demonstrated that aldehydic DNA lesions (ADLs) were induced in mammalian cells by 10 mM hydrogen peroxide (H2O2). Interestingly, a bimodal H2O2 dose-response relationship in cell toxicity has been reported for Escherichia coli deficient in DNA repair as well as Chinese hamster ovary (CHO) cells. Furthermore, it has been demonstrated that H2O2 causes single-strand breaks in purified DNA in the presence of iron and induces mitochondrial DNA damage in CHO cells with a biphasic dose-response curve. Here we show that H2O2 produces ADLs at concentrations as low as 0.06 mM in HeLa cells and that lower concentrations of H2O2 were much more efficient at inducing ADLs than higher concentrations. This dose-response curve is strikingly similar to that for cell killing effects in E.coli deficient in DNA repair exposed to H2O2. Interestingly, serial treatment of submillimolar levels of H2O2 induced a massive accumulation of ADLs. The toxicity arising from H2O2 determined by intracellular NAD(P)H in cells correlated well with the formation of ADLs. The addition of dipyridyl, an iron (II)-specific chelator, significantly protected against DNA damage and cell toxicity from submillimolar, but not millimolar, amounts of H2O2. These results suggest that ADLs induced by submillimolar levels of H2O2 may be due to a Fenton-type reaction between H2O2 and intracellular iron ions in mammalian cells.