Mammalian thioredoxin reductase (TrxR) enzymes play a crucial role in regulating multiple redox-based signaling pathways and have attracted increasing attention as promising anticancer drug targets. We report here the synthesis of a panel of naphthazarin derivatives and discovery of 2-methyl-5,8-dihydroxy-1,4-naphthoquinone (3, 2-methylnaphthazarin) as a potent cytotoxic agent with a submicromolar half maximal inhibitory concentration to the human promyelocytic leukemia HL-60 cells. Mechanism studies reveal that the compound selectively inhibits TrxR to induce oxidative stress-mediated apoptosis of HL-60 cells. Knockdown of TrxR sensitizes the cells to 3 insults, while overexpression of the functional enzyme confers resistance to the compound treatment, underpinning the physiological significance of targeting TrxR by 3. Clarification of the interaction of compound 3 with TrxR unveils a mechanism underlying the cellular action of the compound, and sheds light in considering development of the compound as a potential cancer chemotherapeutic agent.

哺乳动物的硫氧还蛋白还原酶（TrxR）酶在调节多个基于氧化还原的信号通路中起着至关重要的作用，作为有希望的抗癌药物靶点，引起了越来越多的关注。我们在这里报告萘茜衍生物的面板和2-甲基-5,8-二羟基-1,4-萘醌（发现的合成3，2-methylnaphthazarin）为具有亚微摩尔的半数最大抑制浓度的一种有效的细胞毒性剂人早幼粒细胞白血病HL-60细胞。机制研究表明，该化合物选择性抑制TrxR，以诱导氧化应激介导的HL-60细胞凋亡。敲低TrxR可使细胞敏感至3侮辱，虽然功能性酶的过表达赋予了对化合物治疗的抗性，但仍以3为靶标来支持TrxR的生理学意义。化合物3与TrxR的相互作用的澄清揭示了该化合物的细胞作用的基础机理，并且在考虑将化合物开发为潜在的癌症化学治疗剂方面提供了启示。