蛋白酶体及其抑制剂的研究进展

蛋白酶体抑制剂通过阻断泛素蛋白酶体通路,影响细胞内多个周期蛋白的降解,诱导细胞凋亡。体内外试验已显示蛋白酶体抑制剂具有广泛抗肿瘤作用。蛋白酶体抑制剂Bortezomib已通过美国FDA批准应用于临床治疗多发性骨髓瘤。该文就蛋白酶体结构、蛋白酶体抑制剂作用途径、促凋亡作用机制的研究成果和现阶段临床应用作一综述。     

蛋白酶体抑制剂的研究进展

作为体内蛋白质降解的途径之一,蛋白酶体具有非常重要的生理作用,并与多种疾病密切相关。抑制蛋白酶体的功能已经成为肿瘤治疗的叉一有前景的新途径,并受到越来越多的关注。本文对蛋白酶体的组成结构、病理生理作用和现有抑制剂进行归纳总结。     

蛋白酶体抑制剂Carfilzomib

蛋白酶体是真核细胞中一种具多相催化活性的蛋白酶复合体,可降解大多数胞内蛋白,包括调节细胞周期和凋亡的关键蛋白。临床已验证,蛋白酶体可作为抗肿瘤治疗靶点,蛋白酶体抑制剂为新一类抗血液肿瘤药物。然而,某些蛋白酶体抑制剂[如已上市的多发性骨髓瘤（MM）标准治疗药borte—zomib]的使用易产生耐药性和毒性反应,所以亟待开发更具选择性的新型蛋白酶体抑制剂。     

蛋白酶体抑制剂药理活性的研究进展

蛋白酶体是一种庞大的、多价复合酶,它在承担细胞内蛋白质降解的泛蛋白-蛋白酶体通路（UPP）的关键步骤中起催化作用,UPP不仅可以催化降解异常蛋白质,而且在许多调控蛋白质的更新和加工过程中起重要作用,这些蛋白质的催化过程涉及到人类疾病发病机制的重要生化机制,目前,与UPP有关的酶已被认为是药物设计的分子靶位,蛋白酶体参与调节我种细胞功能,其特异性抑制剂不仅可以作为研究UPP的有利工具,而且也是潜在的抗肿瘤、抗炎药物,本文综述了蛋白酶体抑制剂的药理活性研究进展。     

蛋白酶体抑制剂筛选模型的建立

蛋白酶体对肿瘤生长相关蛋白的降解起十分重要的调控作用,能够通过多种机制抑制肿瘤生长和扩散,已成为一个新的抗癌靶点[1].特异性蛋白酶体抑制剂PS-341在体外和小鼠肿瘤模型中表现出明显的抗肿瘤活性,目前已在进行Ⅱ～Ⅲ期临床试验[1].寻找特异的蛋白酶体抑制剂,关键是建立特异、简便的筛选模型.我们根据荧光底物Suc-Leu-Leu-Val-Tyr-AMC在SDS活化的蛋白酶体作用下发生水解,释放出具有荧光的AMC(7-氨基-4-甲基香豆素)的原理,建立了蛋白酶体抑制剂的筛选模型.本文就该模型的建立作一介绍.     

泛素-蛋白酶体抑制剂用于肿瘤治疗

目的:综述近几年国内外有关蛋白酶体抑制剂的研究进展。方法:查阅相关文献,并进行分析、归纳、综述。结果:蛋白酶体抑制剂已成为肿瘤治疗的一个新靶点,在临床前期及临床试验中已显示出了抗肿瘤疗效。结论:泛素-蛋白酶体抑制剂有望成为抗肿瘤、抗炎、抗病毒以及神经系统疾病治疗的有效药物。     

共价型蛋白酶体抑制剂的研究进展

泛素-蛋白酶体系统广泛参与细胞的生命过程,在肿瘤的发生和发展过程中起到重要作用,目前已经成为肿瘤化学治疗的一个重要靶点,其抑制剂具有潜在的抗肿瘤活性。蛋白酶体抑制剂根据其与蛋白酶体作用方式可分为共价型和非共价型抑制剂。共价型抑制剂抑制作用强,发展较为迅速;非共价型抑制剂抑制作用较弱,研究相对较少。本文对共价型蛋白酶体抑制剂近年来的研究进展作一综述。     

顺铂对蛋白酶体抑制作用的研究

目的 研究顺铂对蛋白酶体的抑制作用。方法 采用蛋白酶体特异性底物S-LLVY-AMC、B-LRR-AMC及ZLLE-AMC观察了顺铂对纯化的人20S蛋白酶体及CCD-1103 KidTr细胞内蛋白酶体活力的影响，同时分析了受蛋白酶体降解的p53蛋白在蛋白质及mRNA水平的表达。结果顺铂对纯化的人20S蛋白酶体具有明显的抑制作用，对3种酶活力抑制作用的半数抑制浓度(IC50)分别为32．17(S-LLVY-AMC)、37．96(Z-LLE-AMC)和37．8lμg／ml(Z-LLE-AMC)。在30和60μg/ml顺铂作用下，CCD-1103 KidTr细胞内蛋白酶体活力也受到显著抑制。在30μg／ml顺铂作用下，p53 mRNA表达在3、6、12和24h未见明显改变，而p53蛋白质水平在3、6h明显增高。结论 顺铂对蛋白酶体活力有抑制作用，但对蛋白酶体3种酶活力的抑制没有特异性。顺铂作用CCD-1103 KidTr细胞后p53蛋白质表达增高，可能与蛋白酶体抑制有关。     

小分子蛋白酶体激动剂的研究进展

蛋白酶体控制着与生命活动密切相关蛋白的降解,对生物体内蛋白内稳态的维持起到了关键作用。随着衰老,体内蛋白酶体活性降低,导致一些受损蛋白的产生大于消耗,这些蛋白的堆积导致各种疾病的产生,如各种神经退行性疾病。因此,促进毒性蛋白降解被认为是治疗这类疾病的潜在方案,而提高蛋白酶体活性则是一种重要策略。但目前蛋白酶体激动剂的研究还处于初级阶段,本文将讨论目前各类小分子蛋白酶体激动剂的研究进展,包括研究方法、药理作用、构效关系和存在的问题等。     

泛素-蛋白酶体途径在病毒感染中的作用研究进展

泛素-蛋白酶体途径是真核生物中非溶酶体蛋白降解的主要系统,主要包括泛素,26S蛋白酶体和酶系统E1、E2、E3。泛素-蛋白酶体参与调节细胞周期进程、抗原递呈、转录和信号转导等多种细胞生理过程。研究发现,病毒可以利用泛素系统调控病毒的基因转录、抑制细胞凋亡、降解抗病毒蛋白、促使病毒出芽和释放等逃避宿主的免疫监视。深入理解泛素-蛋白酶体在病毒感染中的作用可以为抗病毒治疗提供新思路。     

Targeting the proteasome pathway

Background: The ubiquitin–proteasome pathway functions as a main pathway in intracellular protein degradation and plays a vital role in almost all cellular events. Various inhibitors of this pathway have been developed for research purposes. The recent approval of bortezomib (PS-341, Velcade^®), a proteasome inhibitor, for the treatment of multiple myeloma has opened the way to the discovery of drugs targeting the proteasome and other components of the ubiquitin–proteasome pathway. Objectives: We review the current understanding of the ubiquitin–proteasome pathway and inhibitors targeting this pathway, including proteasome inhibitors, as candidate drugs for chemical therapy. Methods: Preclinical and clinical data for inhibitors of the proteasome and the ubiquitin–proteasome pathway are discussed. Conclusions: The proteasome and other members in the ubiquitin–proteasome pathway have emerged as novel therapeutic targets.     

Pharmacophore modeling technique applied for the discovery of proteasome inhibitors

Introduction: The 26S proteasome has many important roles in the biological functions of the cells, and proteasome inhibitors have multiple and complex activities on cells. These compounds can be natural or synthesized. Most synthetic derivatives have been rationally designed, synthesized and optimized to obtain the best selectivity and increase the activity. The design of chemical entities with desired molecular identification, which plays an important role in biological systems, is provided by pharmacophore modeling. Indeed, pharmacophore models can be established either in a ligand-based manner or in a receptor-based manner.

Areas covered: The authors discuss the application of pharmacophore modeling techniques to proteasome inhibitors development. Furthermore, the article reviews the classification of the currently discovered proteasome inhibitors where the principal mechanism of action and clinical application are represented.

Expert opinion: In the era of new drug development, database of compounds should be thoroughly evaluated with a combination of methods that consider both pharmacophore- and ligand-based virtual screening. The concept of pharmacophore helps to discover new active compounds and to evaluate their activity. The nature of proteasome inhibitor pharmacophore affects the secondary active-site specificity; indeed, increasing specificity decreases the cytotoxicity of the proteasome inhibitors. It is hypothesized that the balanced simultaneous modulation of a few druggable targets may have superior efficacy and fewer side effects than single-target or combination therapies for the treatment of human cancers. The discovery of new compounds should aim to find more active compounds that improve the compliance of patients.     

新型非共价结合拟肽类蛋白酶体抑制剂的合成及活性评价

目的 设计、合成系列非共价结合拟肽类蛋白酶体抑制剂,并对其进行活性评价。方法 根据非共价结合蛋白酶体抑制剂与蛋白酶体的结合特点,采用氨基酸替换、生物电子等排等经典的药物设计方法,选取邻氯苄胺作为化合物的羧基末端基团,同时在肽骨架结构中引入六元环以增强肽类化合物的稳定性,设计并合成了一系列短肽非共价结合类蛋白酶体抑制剂,并通过体外蛋白酶体活性抑制实验评价该类化合物的活性。结果 共合成了8个具有全新结构的二肽和三肽化合物,其结构经¹H-NMR、ESI-MS确证,该类化合物对蛋白酶体具有中等的抑制活性。结论 肽链的长短及氨基末端不同的取代基对化合物的蛋白酶体抑制活性都有影响,8个化合物在体外对蛋白酶体都具有不同程度的抑制活性。本研究丰富了蛋白酶体抑制剂的结构类型,为该类化合物的深入研究奠定了基础。     

蛋白酶体抑制剂的抗肿瘤作用及其临床应用

泛素．蛋白酶体通路介导细胞蛋白质的降解，在细胞周期、基因转录及表达、抗厚提呈和炎症演进等方面发挥调控作用。蛋白质酶体抑制剂可抑制肿瘤细胞的生长和增殖，诱导凋亡，逆转肿揎细胞的多药耐药性，增加其他化疗药物和放疗的敏感性，具有良好的抗肿瘤作用，是一个极有前是的抗肿瘤药物。现综述其作用机制、分类、抗肿瘤作用及临床应用进展。     

Threonine peptidases as drug targets against malaria

Introduction: Malaria is caused by the intracellular parasite Plasmodium falciparum. Although numerous therapies are available to fight the disease, the number of pharmacophores is small, and constant development of novel therapies, especially with new targets, is desirable to fight developing resistance against presently prescribed drugs.

Areas covered: This review discusses research on plasmodial threonine peptidases along with recent advances in proteasome inhibitor development.

Expert opinion: While PfHslV is an attractive drug target in malaria, more investigation is required to clarify its functional role in the parasite. More efforts should also be invested in assessing the plasmodial proteasome as a drug target. The few papers investigating the effect of proteasome inhibitors on different stages of the life cycle point towards important roles not only during asexual, but also in hepatic and sexual stages, in humans and the mosquito. If this holds true, this is a key argument to further develop proteasome inhibitors for use against malaria.     

Clinical development of novel proteasome inhibitors for cancer treatment

Background: Emerging evidence demonstrates that targeting the tumor proteasome is a promising strategy for cancer therapy. Objective: This review summarizes recent results from cancer clinical trials using specific proteasome inhibitors or some natural compounds that have proteasome-inhibitory effects. Methods: A literature search was carried out using PubMed. Results about the clinical application of specific proteasome inhibitors and natural products with proteasome-inhibitory activity for cancer prevention or therapy were reviewed. Results/conclusion: Bortezomib, the reversible proteasome inhibitor that first entered clinical trials, has been studied extensively as a single agent and in combination with glucocorticoids, cytotoxic agents, immunomodulatory drugs and radiation as treatment for multiple myeloma and other hematological malignancies. The results in some cases have been impressive. There is less evidence of bortezomib's efficacy in solid tumors. Novel irreversible proteasome inhibitors, NPI-0052 and carfilzomib, have also been developed and clinical trials are underway. Natural products with proteasome-inhibitory effects, such as green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG), soy isoflavone genistein, and the spice turmeric compound curcumin, have been studied alone and in combination with traditional chemotherapy and radiotherapy against various cancers. There is also interest in developing these natural compounds as potential chemopreventive agents.