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Clinical Pharmacology and Therapeutics Sep 2023Targeted protein degradation (TPD) has emerged as a potentially transformational therapeutic modality with considerable promise. Molecular glue degraders remodel the... (Review)
Review
Targeted protein degradation (TPD) has emerged as a potentially transformational therapeutic modality with considerable promise. Molecular glue degraders remodel the surface of E3 ligases inducing interactions with neosubstrates resulting in their polyubiquitination and proteasomal degradation. Molecular glues are clinically precedented and have demonstrated the ability to degrade proteins-of-interest (POIs) previously deemed undruggable due to the absence of a traditional small molecule binding pocket. Heterobifunctional proteolysis targeting chimeras (PROTACs) possess ligands for an E3 complex and the POIs, which are chemically linked together, and similarly hijack the ubiquitin machinery to deplete the target. There has been a recent surge in the number of degraders entering clinical trials, particularly directed toward cancer. Nearly all utilize CRL4 as the E3 ligase, and a relatively limited diversity of POIs are currently targeted. In this review, we provide an overview of the degraders in clinical trials and provide a perspective on the lessons learned from their development and emerging human data that will be broadly useful to those working in the TPD field.
Topics: Humans; Proteins; Ubiquitin-Protein Ligases; Proteolysis; Neoplasms
PubMed: 37399310
DOI: 10.1002/cpt.2985 -
Trends in Pharmacological Sciences Nov 2023Targeted protein degradation (TPD) is an emerging modality for research and therapeutics. Most TPD approaches harness cellular ubiquitin-dependent proteolytic pathways.... (Review)
Review
Targeted protein degradation (TPD) is an emerging modality for research and therapeutics. Most TPD approaches harness cellular ubiquitin-dependent proteolytic pathways. Proteolysis-targeting chimeras (PROTACs) and molecular glue (MG) degraders (MGDs) represent the most advanced TPD approaches, with some already used in clinical settings. Despite these advances, TPD still faces many challenges, pertaining to both the development of effective, selective, and tissue-penetrant degraders and understanding their mode of action. In this review, we focus on progress made in addressing these challenges. In particular, we discuss the utility and application of recent proteomic approaches as indispensable tools to enable insights into degrader development, including target engagement, degradation selectivity, efficacy, safety, and mode of action.
Topics: Humans; Proteolysis; Proteomics; Proteolysis Targeting Chimera; Ubiquitin-Protein Ligases
PubMed: 37778939
DOI: 10.1016/j.tips.2023.08.007 -
Nature Structural & Molecular Biology Feb 2024Targeted protein degradation (TPD) by PROTAC (proteolysis-targeting chimera) and molecular glue small molecules is an emerging therapeutic strategy. To expand the roster...
Targeted protein degradation (TPD) by PROTAC (proteolysis-targeting chimera) and molecular glue small molecules is an emerging therapeutic strategy. To expand the roster of E3 ligases that can be utilized for TPD, we describe the discovery and biochemical characterization of small-molecule ligands targeting the E3 ligase KLHDC2. Furthermore, we functionalize these KLHDC2-targeting ligands into KLHDC2-based BET-family and AR PROTAC degraders and demonstrate KLHDC2-dependent target-protein degradation. Additionally, we offer insight into the assembly of the KLHDC2 E3 ligase complex. Using biochemical binding studies, X-ray crystallography and cryo-EM, we show that the KLHDC2 E3 ligase assembles into a dynamic tetramer held together via its own C terminus, and that this assembly can be modulated by substrate and ligand engagement.
Topics: Proteolysis; Ubiquitin-Protein Ligases; Ligands
PubMed: 38177675
DOI: 10.1038/s41594-023-01146-w -
Cell Chemical Biology Nov 2023Chemically induced protein degradation is a powerful strategy for perturbing cellular biochemistry. The predominant mechanism of action for protein degrader drugs...
Chemically induced protein degradation is a powerful strategy for perturbing cellular biochemistry. The predominant mechanism of action for protein degrader drugs involves an induced proximity between the cellular ubiquitin-conjugation machinery and a target. Unlike traditional small molecule enzyme inhibition, targeted protein degradation can clear an undesired protein from cells. We demonstrate here the use of peptide ligands for Kelch-like homology domain-containing protein 2 (KLHDC2), a substrate adapter protein and member of the cullin-2 (CUL2) ubiquitin ligase complex, for targeted protein degradation. Peptide-based bivalent compounds that can induce proximity between KLHDC2 and target proteins cause degradation of the targeted factors. The cellular activity of these compounds depends on KLHDC2 binding. This work demonstrates the utility of KLHDC2 for targeted protein degradation and exemplifies a strategy for the rational design of peptide-based ligands useful for this purpose.
Topics: Ubiquitin; Ubiquitin-Protein Ligases; Proteolysis; Adaptor Proteins, Signal Transducing
PubMed: 37567174
DOI: 10.1016/j.chembiol.2023.07.008 -
Nature Communications Nov 2023Hundreds of E3 ligases play a critical role in recognizing specific substrates for modification by ubiquitin (Ub). Separating genuine targets of E3s from E3-interactors...
Hundreds of E3 ligases play a critical role in recognizing specific substrates for modification by ubiquitin (Ub). Separating genuine targets of E3s from E3-interactors remains a challenge. We present BioE3, a powerful approach for matching substrates to Ub E3 ligases of interest. Using BirA-E3 ligase fusions and bioUb, site-specific biotinylation of Ub-modified substrates of particular E3s facilitates proteomic identification. We show that BioE3 identifies both known and new targets of two RING-type E3 ligases: RNF4 (DNA damage response, PML bodies), and MIB1 (endocytosis, autophagy, centrosome dynamics). Versatile BioE3 identifies targets of an organelle-specific E3 (MARCH5) and a relatively uncharacterized E3 (RNF214). Furthermore, BioE3 works with NEDD4, a HECT-type E3, identifying new targets linked to vesicular trafficking. BioE3 detects altered specificity in response to chemicals, opening avenues for targeted protein degradation, and may be applicable for other Ub-likes (UbLs, e.g., SUMO) and E3 types. BioE3 applications shed light on cellular regulation by the complex UbL network.
Topics: Ubiquitin-Protein Ligases; Ubiquitin; Ubiquitination; Proteomics; Proteolysis
PubMed: 37996419
DOI: 10.1038/s41467-023-43326-8 -
European Journal of Medicinal Chemistry Nov 2023Inducing protein degradation by proteolysis targeting chimera (PROTAC) has provided great opportunities for scientific research and industrial applications. Histone... (Review)
Review
Inducing protein degradation by proteolysis targeting chimera (PROTAC) has provided great opportunities for scientific research and industrial applications. Histone deacetylase (HDAC)-PROTAC has been widely developed since the first report of its ability to induce the degradation of SIRT2 in 2017. To date, ten of the eighteen HDACs (HDACs 1-8, HDAC10, and SIRT2) have been successfully targeted and degraded by HDAC-PROTACs. HDAC-PROTACs surpass traditional HDAC inhibitors in many aspects, such as higher selectivity, more potent antiproliferative activity, and the ability to disrupt the enzyme-independent functions of a multifunctional protein and overcome drug resistance. Rationally designing HDAC-PROTACs is a main challenge in development because slight variations in chemical structure can lead to drastic effects on the efficiency and selectivity of the degradation. In the future, HDAC-PROTACs can potentially be involved in clinical research with the support of the increased amount of in vivo data, pharmacokinetic evaluation, and pharmacological studies.
Topics: Sirtuin 2; Histone Deacetylase Inhibitors; Proteolysis; Proteolysis Targeting Chimera
PubMed: 37607440
DOI: 10.1016/j.ejmech.2023.115746 -
Cell Reports. Medicine Aug 2023VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a pleiotropic, severe autoinflammatory disease caused by somatic mutations in the...
VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a pleiotropic, severe autoinflammatory disease caused by somatic mutations in the ubiquitin-like modifier activating enzyme 1 (UBA1) gene. To elucidate VEXAS pathophysiology, we performed transcriptome sequencing of single bone marrow mononuclear cells and hematopoietic stem and progenitor cells (HSPCs) from VEXAS patients. HSPCs are biased toward myeloid (granulocytic) differentiation, and against lymphoid differentiation in VEXAS. Activation of multiple inflammatory pathways (interferons and tumor necrosis factor alpha) occurs ontogenically early in primitive hematopoietic cells and particularly in the myeloid lineage in VEXAS, and inflammation is prominent in UBA1-mutated cells. Dysregulation in protein degradation likely leads to higher stress response in VEXAS HSPCs, which positively correlates with inflammation. TCR usage is restricted and there are increased cytotoxicity and IFN-γ signaling in T cells. In VEXAS syndrome, both aberrant inflammation and myeloid predominance appear intrinsic to hematopoietic stem cells mutated in UBA1.
Topics: Humans; Hematopoietic Stem Cells; Proteolysis; Cell Differentiation; Inflammation
PubMed: 37586319
DOI: 10.1016/j.xcrm.2023.101160 -
Chemical Society Reviews Jul 2023Proteolysis-targeting chimeras (PROTACs) are heterobifunctional small molecules that induce the ternary complex formation between a protein-of-interest (POI) and an E3... (Review)
Review
Proteolysis-targeting chimeras (PROTACs) are heterobifunctional small molecules that induce the ternary complex formation between a protein-of-interest (POI) and an E3 ligase, leading to targeted polyubiquitination and degradation of the POI. Particularly, PROTACs have the distinct advantage of targeting both canonical and noncanonical functions of epigenetic targets over traditional inhibitors, which typically target canonical functions only, resulting in greater therapeutic efficacy. In this review, we methodically analyze published PROTAC degraders of epigenetic writer, reader, and eraser proteins and their and effects. We highlight the mechanism of action of these degraders and their advantages in targeting both canonical and noncanonical functions of epigenetic targets in the context of cancer treatment. Furthermore, we present a future outlook for this exciting field. Overall, pharmacological degradation of epigenetic targets has emerged as an effective and attractive strategy to thwart cancer progression and growth.
Topics: Proteolysis; Ubiquitin-Protein Ligases; Proteins; Ubiquitination; Epigenesis, Genetic
PubMed: 37314393
DOI: 10.1039/d3cs00100h -
Cell Chemical Biology Jul 2023The multi-step degradation process of PROteolysis TArgeting Chimeras (PROTACs) poses a challenge for their rational development, as the rate-limiting steps that...
The multi-step degradation process of PROteolysis TArgeting Chimeras (PROTACs) poses a challenge for their rational development, as the rate-limiting steps that determine PROTACs efficiency remain largely unknown. Moreover, the slow throughput of currently used endpoint assays does not allow the comprehensive analysis of larger series of PROTACs. Here, we developed cell-based assays using the NanoLuciferase and HaloTag that allow measuring PROTAC-induced degradation and ternary complex formation kinetics and stability in cells. Using PROTACs developed for the degradation of WD40 repeat domain protein 5 (WDR5), the characterization of the mode of action of these PROTACs in the early degradation cascade revealed a key role of ternary complex formation and stability. Comparing a series of ternary complex crystal structures highlighted the importance of an efficient E3-target interface for ternary complex stability. The developed assays outline a strategy for the rational optimization of PROTACs using a series of live cell assays monitoring key steps of the early PROTAC-induced degradation pathway.
Topics: Proteolysis; Proteins; Ubiquitin-Protein Ligases
PubMed: 37354907
DOI: 10.1016/j.chembiol.2023.06.002 -
Cell Chemical Biology Aug 2023The cancer genomics revolution has served up a plethora of promising and challenging targets for the drug discovery community. The field of targeted protein degradation... (Review)
Review
The cancer genomics revolution has served up a plethora of promising and challenging targets for the drug discovery community. The field of targeted protein degradation (TPD) uses small molecules to reprogram the protein homeostasis system to destroy desired target proteins. In the last decade, remarkable progress has enabled the rational development of degraders for a large number of target proteins, with over 20 molecules targeting more than 12 proteins entering clinical development. While TPD has been fully credentialed by the prior development of immunomodulatory drug (IMiD) class for the treatment of multiple myeloma, the field is poised for a "Gleevec moment" in which robust clinical efficacy of a rationally developed novel degrader against a preselected target is firmly established. Here, we endeavor to provide a high-level evaluation of exciting developments in the field and comment on steps that may realize the full potential of this new therapeutic modality.
Topics: Humans; Proteins; Proteolysis; Multiple Myeloma; Drug Discovery; Genomics
PubMed: 37494935
DOI: 10.1016/j.chembiol.2023.06.020