Characterization of A Novel Proteasome Inhibitor

人类蛋白酶体在蛋白质动态平衡和蛋白质代谢中起着重要的作用。 从信号转导到转导的多种细胞过程的调控 抄写。它也已成为开发治疗药物的已被证实的靶点。 包括多发性骨髓瘤和淋巴瘤在内的多种疾病。几种抗癌药物 蛋白酶体，包括bortezomib、carfilzomib和ixazomib已被使用 在临床上，负责延长多发性骨髓瘤患者的生命。 然而，现有的蛋白酶体靶向药物具有严重的毒性和 迅速出现抗药性，这也限制了它们在治疗方面的潜力 其他类型的疾病。我们已经开发出一种受雷帕霉素启发的大循环 通过融合FKBP结合结构域(FKBD)而被称为Rapafucins的文库 雷帕霉素与一个组合多肽文库。年的Rapafucin图书馆的屏幕 多发性骨髓瘤细胞系NCI-H929导致了一种有效的抑制剂的鉴定， 雷帕普汀可诱导NCI-H929细胞凋亡。展示了雷帕普汀 对癌细胞的选择性毒性高于正常细胞。它也有一个独特的机制 的作用，需要由细胞内的蛋白酶通过裂解 大循环为线性形式，雷帕普汀-L，它抑制所有三种类型的 蛋白酶体的蛋白酶活性。此外，雷帕普汀具有协同作用 Bortezomib，能够使耐Bortezomib的癌细胞对 毒品。在这个应用中，我们将研究激活的机制 利用细胞蛋白酶鉴定雷帕蛋白-L为活性物种 因为它的细胞活动。我们将获得一个高分辨率的低温电磁结构 蛋白酶体与Rapaprotin-L的复合体我们将优化效率和 通过设计和合成新的雷帕普汀研究其药代动力学 类比。优化的雷帕蛋白类似物将用于评估它们在 多发性骨髓瘤和其他疾病的动物模型。新开发的 雷帕蛋白类似物将作为有用的化学探针，以促进对 蛋白酶体的功能和药理作用及其可能的研究方向 开发低成本的新型抗癌免疫抑制药物 不良影响。

The human proteasome plays an essential role in both protein homeostasis and in the regulation of multiple cellular processes from signal transduction to transcription. It has also become a proven target for developing drugs for treating multiple diseases including multiple myeloma and lymphoma. Several inhibitors of the proteasome, including bortezomib, carfilzomib and ixazomib, have been used in the clinic, responsible for prolonging lives of multiple myeloma patients. However, the existing proteasome-targeted drugs suffer from severe toxicity and rapid emergence of drug resistance, which also limits their potential in treating other types of diseases. We have developed a rapamycin-inspired macrocycle library known as rapafucins by fusing the FKBP-binding domain (FKBD) of rapamycin with a combinatorial peptide library. A screen of the rapafucin library in multiple myeloma cell line NCI-H929 led to the identification of a potent inhibitor, Rapaprotin that induces apoptosis in NCI-H929 cells. Rapaprotin exhibited selective toxicity to cancer cells over normal cells. It also has a unique mechanism of action, requiring activation by an intracellular protease through cleavage of the macrocycle into a linear form, Rapaprotin-L, which inhibits all three types of protease activities of the proteasome. Moreover, Rapaprotin is synergistic with bortezomib and is capable of resensitizing bortezomib-resistant cancer cells to the drug. In this application, we will investigate the mechanism of activation of Rapaprotin by the cellular protease, validating Rapaprotin-L as the active species for its cellular activity. We will obtain a high-resolution cryo-EM structure of the complex between proteasome and Rapaprotin-L. We will optimize the potency and pharmacokinetic property of Rapaprotin through design and synthesis of new analogs. The optimized analogs of Rapaprotin will be assessed for their efficacy in animal models of multiple myeloma and other diseases. The newly developed Rapaprotin analogs will serve as useful chemical probes to facilitate the study of the function and pharmacology of the proteasome and promising leads for developing a new class of anticancer and immunosuppressive drugs with lower adverse effects.