中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
2-氨基-4-甲氧基苯并噻唑 | 4-methoxy-1,3-benzothiazol-2-amine | 5464-79-9 | C8H8N2OS | 180.23 |
Malignant cells display an increased sensitivity towards drugs that reduce the function of the ubiquitin-proteasome system (UPS), which is the primary proteolytic system for destruction of aberrant proteins. Here, we report on the discovery of the bioactivatable compound CBK77, which causes an irreversible collapse of the UPS, accompanied by a general accumulation of ubiquitylated proteins and caspase-dependent cell death. CBK77 caused accumulation of ubiquitin-dependent, but not ubiquitin-independent, reporter substrates of the UPS, suggesting a selective effect on ubiquitin-dependent proteolysis. In a genome-wide CRISPR interference screen, we identified the redox enzyme NAD(P)H:quinone oxidoreductase 1 (NQO1) as a critical mediator of CBK77 activity, and further demonstrated its role as the compound bioactivator. Through affinity-based proteomics, we found that CBK77 covalently interacts with ubiquitin. In vitro experiments showed that CBK77-treated ubiquitin conjugates were less susceptible to disassembly by deubiquitylating enzymes. In vivo efficacy of CBK77 was validated by reduced growth of NQO1-proficient human adenocarcinoma cells in nude mice treated with CBK77. This first-in-class NQO1-activatable UPS inhibitor suggests that it may be possible to exploit the intracellular environment in malignant cells for leveraging the impact of compounds that impair the UPS.
恶性细胞对降低泛素蛋白酶体系统(UPS)功能的药物表现出增加的敏感性,UPS是异常蛋白质降解的主要蛋白质系统。在这里,我们报告了生物活化化合物CBK77的发现,它导致UPS的不可逆性崩溃,伴随着泛素化蛋白的普遍积累和caspase依赖的细胞死亡。CBK77导致了依赖泛素而非独立于泛素的UPS报告底物的积累,表明对依赖泛素的蛋白质降解具有选择性影响。在全基因组CRISPR干扰筛选中,我们确定了氧化还原酶NAD(P)H:喹啉醌还原酶1(NQO1)作为CBK77活性的关键介导体,并进一步证明了其作为化合物生物活化剂的作用。通过亲和力基础蛋白质组学,我们发现CBK77与泛素发生共价作用。体外实验显示,CBK77处理后的泛素结合物对去泛素化酶的解聚作用较不敏感。在NQO1-proficient人类腺癌细胞中,用CBK77处理的裸鼠显示了CBK77的体内有效性。这种首创的NQO1活化的UPS抑制剂表明,可能可以利用恶性细胞内部环境来增强影响破坏UPS的化合物的作用。