Ferric iron increases ROS formation, modulates cell growth and enhances genotoxic damage by 4-hydroxynonenal in human colon tumor cells
Ferric iron increases ROS formation, modulates cell growth and enhances genotoxic damage by 4-hydroxynonenal in human colon tumor cells
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DOI：
10.1016/j.tiv.2005.11.009
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发表时间：
2006-09-01
影响因子：
3.2
通讯作者：
Pool-Zobel, B. L.
中科院分区：
文献类型：
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作者：
Knoebel, Y.;Glei, M.;Pool-Zobel, B. L.
由于铁的遗传毒性，铁是结直肠癌的相关风险因素。在这里，我们假设铁超载导致其他毒性作用，这有助于致癌。为此，我们研究了用次氮基三乙酸铁（Fe-NTA，0-2000 μ M）处理的人结肠肿瘤细胞（HT 29克隆19 A）中活性氧（ROS）、DNA修复、细胞生长和谷胱甘肽（GSH）的形成。用过氧化物不稳定的荧光染料羧基-二氯二氢荧光素-二乙酸酯分析细胞内ROS的形成。用彗星试验测定DNA修复，反映为由选定的遗传毒素诱导的DNA损伤的持续性。荧光分析法测定细胞生长和GSH。关键发现是ROS形成随时间增加（1000 μ M Fe-NTA，p < 0.001）。DNA损伤在120分钟后基本修复，但不受10 μ M Fe-NTA的影响。相反，10 μ M Fe-NTA显著增加4-羟基壬烯醛诱导的DNA损伤。25 μ M Fe-NTA剂量增加细胞生长（p < 0.05），而高浓度（2000 μ M）导致生长停滞（p < 0.05），这伴随着GSH水平增加（p < 0.01）。总之，高浓度的Fe-NTA引起细胞效应，这反映了应激反应，并导致ROS的形成。三价铁的致癌风险也可能来自较低的浓度，这会促进肿瘤细胞生长并引起前基因毒性效应。(c)2005爱思唯尔有限公司保留所有权利。
Iron is a relevant risk factor for colorectal cancer due to its genotoxic properties. Here we hypothesised that iron-overload causes other toxic effects, which contribute to carcinogenesis. For this, we investigated formation of reactive oxygen species (ROS), DNA repair, cell growth and glutathione (GSH) in human colon tumor cells (HT29 clone 19A) treated with ferric nitrilotriacetate (Fe-NTA, 0-2000 mu M). Intracellular formation of ROS was analysed with the peroxide-labile fluorescent dye carboxy-dichlorodihydrofluorescine-diacetate. DNA repair, reflected as the persistency of DNA damage induced by selected genotoxins, was determined with the Comet assay. Cell growth and GSH were measured by fluorimetrical analysis. Key findings were that ROS formation increased with time (1000 mu M Fe-NTA, p < 0.001). DNA damage was largely repaired after 120 min, but was not affected by 10 mu M Fe-NTA. In contrast, 10 mu M Fe-NTA significantly increased DNA damage induced by 4-hydroxynonenal. Doses of 25 mu M Fe-NTA increased cell growth (p < 0.05), whereas high concentrations (2000 mu M) resulted in growth arrest (p < 0.05), that was accompanied by increased GSH levels (p < 0.01). In conclusion, high concentrations of Fe-NTA caused cellular effects, which reflect a stress response, and resulted in formation of ROS. Carcinogenic risks from ferric iron could be derived also from lower concentrations, which enhance tumor cell growth and cause progenotoxic effects. (c) 2005 Elsevier Ltd. All rights reserved.