3-氨基-1,2,4-苯并三氮唑-1,4-二氧化物（替拉帕宗、TPZ）和其他杂环异氧化物（ArN→O）具有抗肿瘤、抗细菌和抗原虫活性。它们的作用被归因于酶促单电子还原成自由基，引发前氧化反应。为了阐明ArN→O的有氧哺乳动物细胞毒性的机制，我们从小鼠肝癌MH22a细胞中得到了TPZ耐药亚系（抗性指数为5.64）。野生型和TPZ耐药型细胞的定量蛋白组学分析揭示了5818种蛋白质，其中237种上调，184种下调。抗氧化酶类选择性地上调表达，包括醛酸和醇脱氢酶、酮基还原酶、过氧化氢酶和谷胱甘肽还原酶，上调1.6-5.2倍，而谷胱甘肽过氧化物酶、超氧化物歧化酶、硫氧还蛋白还原酶和过氧化物酶表达的变化则较小。异丙肼转移酶药物代谢降解减少了1.6-2.6倍。另一方面，NADPH:细胞色素P450还原酶表达负责TPZ的单电子还原和抗性下降2.1倍。这些数据支持TPZ在有氧条件下的主要作用机制是氧化应激。细胞核内抗氧化蛋白，如过氧化氢酶、谷胱甘肽还原酶和硫氧还蛋白还原酶表达不变，而DNA损伤修复蛋白表达略有增加，这倾向于支持非位点特异性但不支持核内氧化应激作为TPZ氧化毒性的主要因素。

3-Amino-1,2,4-benzotriazine-1,4-dioxide (tirapazamine, TPZ) and other heteroaromatic N-oxides (ArN→O) exhibit tumoricidal, antibacterial, and antiprotozoal activities. Their action is attributed to the enzymatic single-electron reduction to free radicals that initiate the prooxidant processes. In order to clarify the mechanisms of aerobic mammalian cytotoxicity of ArN→O, we derived a TPZ-resistant subline of murine hepatoma MH22a cells (resistance index, 5.64). The quantitative proteomic of wild-type and TPZ-resistant cells revealed 5818 proteins, of which 237 were up- and 184 down-regulated. The expression of the antioxidant enzymes aldehyde- and alcohol dehydrogenases, carbonyl reductases, catalase, and glutathione reductase was increased 1.6-5.2 times, whereas the changes in the expression of glutathione peroxidase, superoxide dismutase, thioredoxin reductase, and peroxiredoxins were less pronounced. The expression of xenobiotics conjugating glutathione-S-transferases was increased by 1.6-2.6 times. On the other hand, the expression of NADPH:cytochrome P450 reductase was responsible for the single-electron reduction in TPZ and for the 2.1-fold decrease. These data support the fact that the main mechanism of action of TPZ under aerobic conditions is oxidative stress. The unchanged expression of intranuclear antioxidant proteins peroxiredoxin, glutaredoxin, and glutathione peroxidase, and a modest increase in the expression of DNA damage repair proteins, tend to support non-site-specific but not intranuclear oxidative stress as a main factor of TPZ aerobic cytotoxicity.