Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California 92037, USA.
ACS Chem Biol. 2010 Oct 15;5(10):981-93. doi: 10.1021/cb100219n.
The NADPH oxidase (Nox) proteins catalyze the regulated formation of reactive oxygen species (ROS), which play key roles as signaling molecules in several physiological and pathophysiological processes. ROS generation by the Nox1 member of the Nox family is necessary for the formation of extracellular matrix (ECM)-degrading, actin-rich cellular structures known as invadopodia. Selective inhibition of Nox isoforms can provide reversible, mechanistic insights into these cellular processes in contrast to scavenging or inhibition of ROS production. Currently no specific Nox inhibitors have been described. Here, by high-throughput screening, we identify a subset of phenothiazines, 2-acetylphenothiazine (here referred to as ML171) (and its related 2-(trifluoromethyl)-phenothiazine) as nanomolar, cell-active, and specific Nox1 inhibitors that potently block Nox1-dependent ROS generation, with only marginal activity on other cellular ROS-producing enzymes and receptors including the other Nox isoforms. ML171 also blocks the ROS-dependent formation of ECM-degrading invadopodia in colon cancer cells. Such effects can be reversed by overexpression of Nox1 protein, which is suggestive of a selective mechanism of inhibition of Nox1 by this compound. These results elucidate the relevance of Nox1-dependent ROS generation in mechanisms of cancer invasion and define ML171 as a useful Nox1 chemical probe and potential therapeutic agent for inhibition of cancer cell invasion.
NADPH 氧化酶（Nox）蛋白催化活性氧（ROS）的调节形成，ROS 在几种生理和病理生理过程中作为信号分子发挥关键作用。Nox 家族的 Nox1 成员产生的 ROS 对于细胞外基质（ECM）降解、富含肌动蛋白的细胞结构的形成是必需的，这些细胞结构被称为侵袭小体。与清除或抑制 ROS 产生相比，选择性抑制 Nox 同工酶可以为这些细胞过程提供可逆的、机制上的见解。目前尚未描述特定的 Nox 抑制剂。在这里，我们通过高通量筛选，鉴定出一组吩噻嗪类化合物，2-乙酰吩噻嗪（此处称为 ML171）（及其相关的 2-（三氟甲基）吩噻嗪）为纳摩尔级、细胞活性和特异性 Nox1 抑制剂，可有效阻断 Nox1 依赖性 ROS 生成，对其他细胞 ROS 产生酶和受体（包括其他 Nox 同工酶）仅有轻微活性。ML171 还可阻断结肠癌细胞中 ROS 依赖性 ECM 降解侵袭小体的形成。这种效应可以通过 Nox1 蛋白的过表达逆转，这表明该化合物对 Nox1 的抑制作用具有选择性机制。这些结果阐明了 Nox1 依赖性 ROS 生成在癌症侵袭机制中的相关性，并将 ML171 定义为一种有用的 Nox1 化学探针和潜在的抗癌细胞侵袭抑制剂。
