Rational Control of Molecular Properties Is Mandatory to Exploit the Potential of PROTACs as Oral Drugs

To obtain new oral drugs in the beyond rule of five space, PROTACs among others, molecular properties should be optimized in early drug discovery. Degraders call for design strategies which focus on intramolecular interaction and chameleonicity. In parallel, tailored revalidation of permeability assessment and prediction methods becomes fundamental in this innovative chemical space.     

The rise and rise of protein degradation: Opportunities and challenges ahead

The transformational mechanism of action underpinning targeted protein degradation strategies, including proteolysis-targeting chimeras (PROTACs), gives potential for potent in vivo pharmacology and has allowed projects to move rapidly to the clinic. Despite this remarkable progress, there remain many opportunities to improve current, first-generation approaches even further. Our expanding knowledge will allow discovery of new degrading mechanisms with potential to address several limitations of current approaches, including improving scope and efficiency of degradation, improving drug-like properties of degraders, and reducing potential for the emergence of acquired resistance. Here, we discuss potential routes to realize these advances to expand TPD utility even further.     

蛋白降解靶向嵌合体药物(PROTAC)的非临床评价策略分析

蛋白降解靶向嵌合体(PROTAC)将靶向蛋白募集到E3泛素连接酶进行泛素化标记,然后通过泛素-蛋白酶体途径将其降解,从而将过表达和突变的致病蛋白清除。本文基于已有的文献报道,总结PROTAC药物研发进展,针对其存在的相对分子质量较大、生物利用度低、稳定性和血管穿透能力差等问题提出应对策略,并从药理药效、代谢和安全性评价等方面对该类药物的非临床评价研究需要考虑的问题进行分析,为制定PROTAC药物非临床评价研究方案提供参考。     

线粒体质量控制体系介导心肌缺血再灌注损伤的治疗策略

冠状动脉疾病是最常见的心血管疾病,最初的器官血流中断和随后的器官血流恢复所产生的心肌缺血/再灌注(ischemia reperfusion,I/R)损伤是急性心肌梗死后伴随各种心脏再灌注治疗策略的重要临床难题。虽然血流量的恢复对于氧气的供应是必要的,但再灌注在促进心肌梗死边缘区血流恢复和心肌细胞挽救的同时,也加重了心肌损伤。线粒体功能障碍已被报道为I/R损伤的原因之一,在介导心肌损伤病理生理过程中起着至关重要的作用。主要综述了I/R损伤中线粒体质量控制系统的分子机制以及确立了以线粒体为潜在治疗靶点的可能性。     

Small-molecule MDM2/X inhibitors and PROTAC degraders for cancer therapy: advances and perspectives

Blocking the MDM2/X–P53 protein–protein interaction has been widely recognized as an attractive therapeutic strategy for the treatment of cancers. Numerous small-molecule MDM2 inhibitors have been reported since the release of the structure of the MDM2–P53 interaction in 1996, SAR405838, NVP-CGM097, MK-8242, RG7112, RG7388, DS-3032b, and AMG232 currently undergo clinical evaluation for cancer therapy. This review is intended to provide a comprehensive and updated overview of MDM2 inhibitors and proteolysis targeting chimera (PROTAC) degraders with a particular focus on how these inhibitors or degraders are identified from starting points, strategies employed, structure–activity relationship (SAR) studies, binding modes or co-crystal structures, biochemical data, mechanistic studies, and preclinical/clinical studies. Moreover, we briefly discuss the challenges of designing MDM2/X inhibitors for cancer therapy such as dual MDM2/X inhibition, acquired resistance and toxicity of P53 activation as well as future directions.     

Sweet and Blind Spots in E3 Ligase Ligand Space Revealed by a Thermophoresis-Based Assay

Repurposing E3 ubiquitin ligases for targeted protein degradation via customized molecular glues or proteolysis-targeting chimeras (PROTACs) is an increasingly important therapeutic modality. Currently, a major limitation in the design of suitable molecular glues and PROTACs is our fragmentary understanding of E3 ligases and their ligand space. We here describe a quantitative assay for the discovery and characterization of E3 ligase ligands that is based on the thermophoretic behavior of a custom reporter ligand. Thereby, it is orthogonal to commonly employed fluorescence-based assays and less affected by the optical properties of test compounds. It can be employed for the high-throughput screening of compound libraries for a given ligase but also for hit validation, which we demonstrate with the identification of unexpected well-binders and non-binders, yielding new insights into the ligand space of cereblon (CRBN).     

Degradation of proteins by PROTACs and other strategies

Blocking the biological functions of scaffold proteins and aggregated proteins is a challenging goal. PROTAC proteolysis-targeting chimaera (PROTAC) technology may be the solution, considering its ability to selectively degrade target proteins. Recent progress in the PROTAC strategy include identification of the structure of the first ternary eutectic complex, extra-terminal domain-4-PROTAC-Von-Hippel-Lindau (BRD4-PROTAC-VHL), and PROTAC ARV-110 has entered clinical trials for the treatment of prostate cancer in 2019. These discoveries strongly proved the value of the PROTAC strategy. In this perspective, we summarized recent meaningful research of PROTAC, including the types of degradation proteins, preliminary biological data in vitro and in vivo, and new E3 ubiquitin ligases. Importantly, the molecular design, optimization strategy and clinical application of candidate molecules are highlighted in detail. Future perspectives for development of advanced PROTAC in medical fields have also been discussed systematically.