DNA damage and estrogenic activity induced by the environmental pollutant 2-nitrotoluene and its metabolite
DNA damage and estrogenic activity induced by the environmental pollutant 2-nitrotoluene and its metabolite
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DOI：
10.1007/s12199-010-0146-1
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发表时间：
2010-04
影响因子：
4.7
通讯作者：
C. Watanabe;Takashi Egami;K. Midorikawa;Y. Hiraku;S. Oikawa;S. Kawanishi;M. Murata
中科院分区：
文献类型：
--
作者：
C. Watanabe;Takashi Egami;K. Midorikawa;Y. Hiraku;S. Oikawa;S. Kawanishi;M. Murata
环境污染物2-硝基甲苯(2-NO2-T)对动物具有致癌和生殖毒性。方法用32P-5‘末端标记的DNA检测2-NO-T及其代谢产物2-亚硝基甲苯(2-NO-T)对DNA的损伤。我们测定了氧化损伤指标8-氧-7，8-二氢-2‘-脱氧鸟苷(8-oxodG)在小牛胸腺DNA和经2-NO-T和2-NO-T处理的人白血病(HL-60)细胞DNA中的含量。用实时定量聚合酶链式反应(RT-PCR)检测HL-60细胞中8-氧鸟苷DNA糖基酶(OGG1)基因的表达。结果在分离的DNA片段的实验中，2-NO-T在铜(II)和β-烟酰胺腺嘌呤二核苷酸二钠(还原型)(NADH)存在下引起氧化损伤，而2-NO-T不引起氧化损伤。2-NO-T显著增加HL-60细胞8-oxodG水平。实时定量聚合酶链式反应分析显示，2-NO-T诱导的OGG1基因表达上调。用人乳腺癌细胞系MCF-7进行的E-Screen分析显示，2-NO2-T诱导雌激素依赖的细胞增殖。相反，2-NO-T减少细胞数量，抑制17-β-雌二醇诱导的细胞增殖。结论2-NO-T引起的氧化损伤以及2-NO-T和2-NO-T引起的雌激素干扰作用可能在这些物质的生殖毒性和致癌性中起一定作用。
ObjectivesThe environmental pollutant 2-nitrotoluene (2-NO2-T) is carcinogenic and reproductively toxic in animals. In this study, we elucidated the mechanisms of its carcinogenicity and reproductive toxicity.MethodsWe examined DNA damage induced by 2-NO2-T and its metabolite, 2-nitrosotoluene (2-NO-T), using32P-5′-end-labeled DNA. We measured 8-oxo-7, 8-dihydro-2′-deoxyguanosine (8-oxodG), an indicator of oxidative DNA damage, in calf thymus DNA and cellular DNA in cultured human leukemia (HL-60) cells treated with 2-NO2-T and 2-NO-T. 8-Oxoguanine DNA glycosylase (OGG1) gene expression in HL-60 cells was measured by real-time polymerase chain reaction (PCR). We examined estrogenic activity using an E-screen assay and a surface plasmon resonance (SPR) sensor.ResultsIn experiments with isolated DNA fragments, 2-NO-T induced oxidative DNA damage in the presence of Cu (II) and β-nicotinamide adenine dinucleotide disodium salt (reduced form) (NADH), while 2-NO2-T did not. 2-NO-T significantly increased levels of 8-oxodG in HL-60 cells. Real-time polymerase chain reaction (PCR) analysis revealed upregulation ofOGG1gene expression induced by 2-NO-T. An E-screen assay using the human breast cancer cell line MCF-7 revealed that 2-NO2-T induced estrogen-dependent cell proliferation. In contrast, 2-NO-T decreased the cell number and suppressed 17β-estradiol-induced cell proliferation. The data obtained with the SPR sensor using estrogen receptor α and the estrogen response element supported the results of the E-screen assay.ConclusionsOxidative DNA damage caused by 2-NO-T and estrogen-disrupting effects caused by 2-NO2-T and 2-NO-T may play a role in the reproductive toxicity and carcinogenicity of these entities.