Dose-Dependent Response to 3-Nitrobenzanthrone Exposure in Human Urothelial Cancer Cells.
Dose-Dependent Response to 3-Nitrobenzanthrone Exposure in Human Urothelial Cancer Cells.
复制标题
人尿路上皮癌细胞对 3-硝基苯并蒽酮暴露的剂量依赖性反应
DOI：
10.1021/acs.chemrestox.7b00174
复制
发表时间：
2017
影响因子：
4.1
通讯作者：
S. Schmitz-Spanke
中科院分区：
文献类型：
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作者：
N. Verma;A. Zerries;S. Schmitz-Spanke
柴油燃料不完全燃烧的产物3-硝基苯并蒽酮（3-NBA）已被列为致癌物质。由于其在尿液中的代谢产物和DNA加合物的形成，它首先作为潜在的膀胱致癌物而受到关注。本研究的目的是通过毒理学和代谢组学方法表征暴露于0.0003 μM（环境相关）至80 μM浓度范围内的3-NBA在人尿路上皮癌细胞系（RT 4）中的剂量-反应关系。我们观察到RT 4细胞能够在暴露30分钟内生物活化3-NBA。在RT 4细胞中参与3-NBA转化的各种酶的活性测量表明NAD（P）H：醌氧化还原酶（NQO 1）是其生物活化的主要贡献者。此外，细胞毒性评估显示在低剂量下启动适应性机制，在较高剂量下减弱，表明这些机制的能力不再足够，导致细胞内活性氧水平增加，增殖减少和线粒体膜超极化。为了表征这种细胞反应的潜在机制，分析了3-NBA的代谢和细胞中的代谢组学变化。细胞（0.0003、0.01、0.08、10和80 μM 3-NBA）的代谢组学分析显示，在低浓度3-NBA下，各种抗氧化剂水平升高。然而，在较高的暴露浓度下，细胞似乎通过激活戊糖磷酸途径（PPP）重新编程其代谢以维持细胞稳态。
A product of incomplete combustion of diesel fuel, 3-nitrobenzanthrone (3-NBA), has been classified as a cancer-causing substance. It first gained attention as a potential urinary bladder carcinogen due to the presence of its metabolite in urine and formation of DNA adducts. The aim of the present study was to characterize the dose–response relationship of 3-NBA in human urothelial cancer cell line (RT4) exposed to concentrations ranging from 0.0003 μM (environmentally relevant) to 80 μM by utilizing toxicological and metabolomic approaches. We observed that the RT4 cells were capable of bioactivation of 3-NBA within 30 min of exposure. Activity measurements of various enzymes involved in the conversion of 3-NBA in RT4 cells demonstrated NAD(P)H:quinone oxidoreductase (NQO1) as the main contributor for its bioactivation. Moreover, cytotoxicity assessment exhibited an initiation of adaptive mechanisms at low dosages, which diminished at higher doses, indicating that the capacity of these mechanisms no longer suffices, resulting in increased levels of intracellular reactive oxygen species, reduced proliferation, and hyperpolarisation of the mitochondrial membrane. To characterize the underlying mechanisms of this cellular response, the metabolism of 3-NBA and metabolomic changes in the cells were analyzed. The metabolomic analysis of the cells (0.0003, 0.01, 0.08, 10, and 80 μM 3-NBA) showed elevated levels of various antioxidants at low concentrations of 3-NBA. However, at higher exposure concentrations, it appeared that the cells reprogrammed their metabolism to maintain the cell homeostasis via activation of pentose phosphate pathway (PPP).