Li Jing, Yakushi Tanya, Parlati Francesco, Mackinnon Andrew L, Perez Christian, Ma Yuyong, Carter Kyle P, Colayco Sharon, Magnuson Gavin, Brown Brock, Nguyen Kevin, Vasile Stefan, Suyama Eigo, Smith Layton H, Sergienko Eduard, Pinkerton Anthony B, Chung Thomas D Y, Palmer Amy E, Pass Ian, Hess Sonja, Cohen Seth M, Deshaies Raymond J
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA.
Proteome Exploration Laboratory, Beckman Institute, California Institute of Technology, Pasadena, California, USA.
Nat Chem Biol. 2017 May;13(5):486-493. doi: 10.1038/nchembio.2326. Epub 2017 Feb 28.
The proteasome is a vital cellular machine that maintains protein homeostasis, which is of particular importance in multiple myeloma and possibly other cancers. Targeting of proteasome 20S peptidase activity with bortezomib and carfilzomib has been widely used to treat myeloma. However, not all patients respond to these compounds, and those who do eventually suffer relapse. Therefore, there is an urgent and unmet need to develop new drugs that target proteostasis through different mechanisms. We identified quinoline-8-thiol (8TQ) as a first-in-class inhibitor of the proteasome 19S subunit Rpn11. A derivative of 8TQ, capzimin, shows >5-fold selectivity for Rpn11 over the related JAMM proteases and >2 logs selectivity over several other metalloenzymes. Capzimin stabilized proteasome substrates, induced an unfolded protein response, and blocked proliferation of cancer cells, including those resistant to bortezomib. Proteomic analysis revealed that capzimin stabilized a subset of polyubiquitinated substrates. Identification of capzimin offers an alternative path to develop proteasome inhibitors for cancer therapy.
蛋白酶体是维持蛋白质稳态的重要细胞机器，这在多发性骨髓瘤以及可能的其他癌症中尤为重要。用硼替佐米和卡非佐米靶向蛋白酶体20S肽酶活性已被广泛用于治疗骨髓瘤。然而，并非所有患者对这些化合物都有反应，而且那些有反应的患者最终也会复发。因此，迫切需要开发通过不同机制靶向蛋白质稳态的新药。我们鉴定出喹啉-8-硫醇（8TQ）是蛋白酶体19S亚基Rpn11的一流抑制剂。8TQ的衍生物卡齐明对Rpn11的选择性比对相关JAMM蛋白酶高5倍以上，对其他几种金属酶的选择性高2个对数以上。卡齐明稳定了蛋白酶体底物，诱导了未折叠蛋白反应，并阻断了癌细胞的增殖，包括那些对硼替佐米耐药的癌细胞。蛋白质组学分析表明，卡齐明稳定了多泛素化底物的一个子集。卡齐明的鉴定为开发用于癌症治疗的蛋白酶体抑制剂提供了一条替代途径。
