Bárta František, Levová Kateřina, Frei Eva, Schmeiser Heinz H, Arlt Volker M, Stiborová Marie
Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic.
Division of Preventive Oncology, National Center for Tumour Diseases, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
Mutat Res Genet Toxicol Environ Mutagen. 2014 Jul 1;768:1-7. doi: 10.1016/j.mrgentox.2014.01.012. Epub 2014 Apr 24.
Aristolochic acid is the cause of aristolochic acid nephropathy (AAN) and Balkan endemic nephropathy (BEN) and their associated urothelial malignancies. Using Western blotting, we investigated the expression of
NAD(P)H: quinone oxidoreductase (NQO1), the most efficient cytosolic enzyme that reductively activates aristolochic acid I (AAI) in mice and rats. In addition, the effect of AAI on the expression of the NQO1 protein and its enzymatic activity in these experimental animal models was examined. We found that NQO1 protein levels in cytosolic fractions isolated from liver, kidney and lung of mice differed from those expressed in these organs of rats. In mice, the highest levels of NQO1 protein and NQO1 activity were found in the kidney, followed by lung and liver. In contrast, the NQO1 protein levels and enzyme activity were lowest in rat-kidney cytosol, whereas the highest amounts of NQO1 protein and activity were found in lung cytosols, followed by those of liver. NQO1 protein and enzyme activity were induced in liver and kidney of AAI-pretreated mice compared with those of untreated mice. NQO1 protein and enzyme activity were also induced in rat kidney by AAI. Furthermore, the increase in hepatic and renal NQO1 enzyme activity was associated with AAI bio-activation and elevated AAI-DNA adduct levels were found in ex vivo incubations of cytosolic fractions with DNA and AAI. In conclusion, our results indicate that AAI can increase its own metabolic activation by inducing NQO1, thereby enhancing its own genotoxic potential.
马兜铃酸是马兜铃酸肾病（AAN）和巴尔干地方性肾病（BEN）及其相关尿路上皮恶性肿瘤的病因。我们使用蛋白质印迹法研究了NAD(P)H：醌氧化还原酶（NQO1）的表达，NQO1是小鼠和大鼠中还原激活马兜铃酸I（AAI）最有效的胞质酶。此外，还研究了AAI对这些实验动物模型中NQO1蛋白表达及其酶活性的影响。我们发现，从小鼠肝脏、肾脏和肺中分离的胞质部分中的NQO1蛋白水平与大鼠这些器官中表达的水平不同。在小鼠中，肾脏中NQO1蛋白和NQO1活性水平最高，其次是肺和肝脏。相比之下，大鼠肾脏胞质溶胶中的NQO1蛋白水平和酶活性最低，而肺胞质溶胶中NQO1蛋白和活性含量最高，其次是肝脏。与未处理的小鼠相比，AAI预处理的小鼠肝脏和肾脏中NQO1蛋白和酶活性被诱导。AAI也可诱导大鼠肾脏中的NQO1蛋白和酶活性。此外，肝脏和肾脏中NQO1酶活性的增加与AAI生物激活相关，并且在胞质部分与DNA和AAI的体外孵育中发现AAI-DNA加合物水平升高。总之，我们的结果表明，AAI可通过诱导NQO1增加其自身的代谢激活，从而增强其自身的遗传毒性潜力。
