Nitric oxide enhances catechol estrogen-induced oxidative stress in LNCaP cells
Nitric oxide enhances catechol estrogen-induced oxidative stress in LNCaP cells
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DOI：
10.1080/10715760400029710
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发表时间：
2005-04
影响因子：
3.3
通讯作者：
K. Muzandu;Z. Shaban;M. Ishizuka;A. Kazusaka;S. Fujita
中科院分区：
文献类型：
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作者：
K. Muzandu;Z. Shaban;M. Ishizuka;A. Kazusaka;S. Fujita
儿茶酚类雌激素（CEs），如4-羟基雌二醇（4-OHE2），经过氧化还原循环，在此过程中产生活性氧（ROS），如超氧化物和化学反应性雌激素半醌（CE-SQ）和醌（CE-Q）中间体。活性氧和/或活性氮可能会增强醌的致突变性。在炎症条件下存在高浓度的一氧化氮（NO）可能与形成过氧亚硝酸盐（ONOO−）反应，这是一种与许多病理条件有关的强氧化剂。本研究探讨了ce与NO相互作用产生过氧亚硝酸盐的可能性及其对质粒DNA和完整细胞的影响。与无金属缓冲系统中的对照相比，4-OHE2和NO的组合使质粒DNA中的单链断裂（SSB）水平增加了60%以上。4-OHE2单用或NO单用均无效果。使用不同的抗氧化剂和活性氧清除剂获得的结果表明过氧亚硝酸盐在氧化应激中的作用。在细胞中，4-OHE2或NO单独诱导剂量依赖性DNA损伤，通过单细胞凝胶电泳评估。在较低剂量下，4-OHE2和NO共处理具有加性效应。通过将羧基-2′，7′-二氯荧光素二醋酸酯氧化生成荧光化合物羧基-2′，7′-二氯荧光素来测定细胞内ROS的生成。在含氧介质中，NO单独产生的ROS很少，而4-OHE2产生的荧光增加了约70%。当4-OHE2和NO一起加入时，ROS增加了2倍。过氧亚硝酸盐的产生和参与这种增加是隐含的，因为尿酸抑制它。用二氢膦胺123也观察了过氧亚硝酸盐的生成。因此，我们得出结论，4-OHE2和NO联合处理产生过氧亚硝酸盐，从荧光增强和尿酸或SOD和过氧化氢酶联合处理对过氧亚硝酸盐的抑制来看。本文报道的结果表明，当ce和NO同时存在时，过氧亚硝酸盐会引起生物分子的损伤。这可能具有生物学相关性，因为炎症条件下形成的高浓度NO可能会因雌激素而加剧癌症。
Catechol estrogens (CEs), such as 4-hydroxyestradiol (4-OHE2), undergo redox cycling during which reactive oxygen species (ROS) such as superoxide and the chemically reactive estrogen semiquinone (CE-SQ) and quinone (CE-Q) intermediates are produced. The quinone's putative mutagenicity may be enhanced by ROS and/or reactive nitrogen species. High concentrations of nitric oxide (NO) present during inflammatory conditions may react with to form peroxynitrite (ONOO−), a potent oxidant implicated in many pathological conditions. In this study, the possible generation of peroxynitrite from the interaction of CEs and NO and its effect on plasmid DNA and intact cells were investigated. A combination of 4-OHE2 and NO increased the level of single strand breaks (SSB) in plasmid DNA by more than 60% compared to vehicle controls in a metal-free buffer system. 4-OHE2 alone or NO alone had no effect. Results obtained from use of different antioxidants and ROS scavengers suggested a role of peroxynitrite in oxidative stress. In cells, 4-OHE2 or NO alone induced dose-dependent DNA damage as assessed by single cell gel electrophoresis. Co-treatment with 4-OHE2 and NO had an additive effect at lower doses. Generation of intracellular ROS was measured by the oxidation of carboxy-2′,7′-dichlorofluorescein diacetate to the fluorescent compound carboxy-2′,7′-dichlorofluorescein. NO alone, in oxygenated media, generated little ROS whereas 4-OHE2 produced approximately 70% increase in fluorescence. When added together 4-OHE2 and NO, produced a 2-fold increase in ROS. The generation and involvement of peroxynitrite to this increase was implied since uric acid inhibited it. Generation of peroxynitrite was also observed by use of dihydrorhodamine 123. Therefore, we conclude that combined treatments with 4-OHE2 and NO generated peroxynitrite seen from increased fluorescence and its inhibition by uric acid or combined SOD and catalase treatments. Results reported here suggest a role of peroxynitrite in causing damage to biomolecules when CEs and NO are present simultaneously. This may have biological relevance as high concentrations of NO formed during inflammatory conditions may exacerbate cancers due to estrogens.