Induced protein degradation: an emerging drug discovery paradigm
TL;DR: Induced protein degradation has the potential to reduce systemic drug exposure, the ability to counteract increased target protein expression that often accompanies inhibition of protein function and the potential ability to target proteins that are not currently therapeutically tractable, such as transcription factors, scaffolding and regulatory proteins.
Abstract: Small-molecule drug discovery has traditionally focused on occupancy of a binding site that directly affects protein function, and this approach typically precludes targeting proteins that lack such amenable sites. Furthermore, high systemic drug exposures may be needed to maintain sufficient target inhibition in vivo, increasing the risk of undesirable off-target effects. Induced protein degradation is an alternative approach that is event-driven: upon drug binding, the target protein is tagged for elimination. Emerging technologies based on proteolysis-targeting chimaeras (PROTACs) that exploit cellular quality control machinery to selectively degrade target proteins are attracting considerable attention in the pharmaceutical industry owing to the advantages they could offer over traditional small-molecule strategies. These advantages include the potential to reduce systemic drug exposure, the ability to counteract increased target protein expression that often accompanies inhibition of protein function and the potential ability to target proteins that are not currently therapeutically tractable, such as transcription factors, scaffolding and regulatory proteins.
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TL;DR: The chemical and biophysical principles common to all bifunctional, proximity-inducing small molecules are described and the underappreciated diversity of their chemical structures and biological mechanisms are discussed.
Abstract: Nature uses a variety of tools to mediate the flow of information in cells, many of which control distances between key biomacromolecules. Researchers have thus generated compounds whose activities stem from interactions with two (or more) proteins simultaneously. In this Perspective, we describe how these 'bifunctional' small molecules facilitate the study of an increasingly wide range of complex biological phenomena and enable the drugging of otherwise challenging therapeutic targets and processes. Despite their structural and functional differences, all bifunctional molecules employ Nature's strategy of altering interactomes and inducing proximity to modulate biology. They therefore exhibit a shared set of chemical and biophysical principles that have not yet been appreciated fully. By highlighting these commonalities-and their wide-ranging consequences-we hope to chip away at the artificial barriers that threaten to constrain this interdisciplinary field. Doing so promises to yield remarkable benefits for biological research and therapeutics discovery.
99 citations
TL;DR: Proteolysis-targeting chimeras (PROTACs), which selectively degrade targeted proteins by the ubiquitin-proteasome system, have emerged as a novel therapeutic technology with potential advantages over traditional inhibition strategies, and a web-based open-access database that integrates structural information and experimental data of PROTACs is presented.
Abstract: Proteolysis-targeting chimeras (PROTACs), which selectively degrade targeted proteins by the ubiquitin-proteasome system, have emerged as a novel therapeutic technology with potential advantages over traditional inhibition strategies. In the past few years, this technology has achieved substantial progress and two PROTACs have been advanced into phase I clinical trials. However, this technology is still maturing and the design of PROTACs remains a great challenge. In order to promote the rational design of PROTACs, we present PROTAC-DB, a web-based open-access database that integrates structural information and experimental data of PROTACs. Currently, PROTAC-DB consists of 1662 PROTACs, 202 warheads (small molecules that target the proteins of interest), 65 E3 ligands (small molecules capable of recruiting E3 ligases) and 806 linkers, as well as their chemical structures, biological activities, and physicochemical properties. Except the biological activities of warheads and E3 ligands, PROTAC-DB also provides the degradation capacities, binding affinities and cellular activities for PROTACs. PROTAC-DB can be queried with two general searching approaches: text-based (target name, compound name or ID) and structure-based. In addition, for the convenience of users, a filtering tool for the searching results based on the physicochemical properties of compounds is also offered. PROTAC-DB is freely accessible at http://cadd.zju.edu.cn/protacdb/.
99 citations
Cites background from "Induced protein degradation: an eme..."
...In contrast to traditional occupancy-based inhibitors that have sufficient binding affinities to druggable active sites, PROTACs require only transient binding to target proteins to catalytically induce ubiquitination and degradation (5,6)....
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...Furthermore, since it is unnecessary for warheads to occupy druggable binding sites which modulate protein functions, PROTACs can exploit all surface binding sites on the targeted proteins and hence have the potential to modulate ‘undruggable’ targets (6)....
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TL;DR: In this article, the authors developed ON and OFF switches for CAR T cells using the clinically approved drug lenalidomide, which mediates the proteasomal degradation of several target proteins by inducing interactions between the CRL4CRBN E3 ubiquitin ligase and a C2H2 zinc finger degron motif.
Abstract: Cell-based therapies are emerging as effective agents against cancer and other diseases. As autonomous “living drugs,” these therapies lack precise control. Chimeric antigen receptor (CAR) T cells effectively target hematologic malignancies but can proliferate rapidly and cause toxicity. We developed ON and OFF switches for CAR T cells using the clinically approved drug lenalidomide, which mediates the proteasomal degradation of several target proteins by inducing interactions between the CRL4CRBN E3 ubiquitin ligase and a C2H2 zinc finger degron motif. We performed a systematic screen to identify “super-degron” tags with enhanced sensitivity to lenalidomide-induced degradation and used these degradable tags to generate OFF-switch degradable CARs. To create an ON switch, we engineered a lenalidomide-inducible dimerization system and developed split CARs that required both lenalidomide and target antigen for activation. Subtherapeutic lenalidomide concentrations controlled the effector functions of ON- and OFF-switch CAR T cells. In vivo, ON-switch split CARs demonstrated lenalidomide-dependent antitumor activity, and OFF-switch degradable CARs were depleted by drug treatment to limit inflammatory cytokine production while retaining antitumor efficacy. Together, the data showed that these lenalidomide-gated switches are rapid, reversible, and clinically suitable systems to control transgene function in diverse gene- and cell-based therapies.
98 citations
TL;DR: It is demonstrated thatBTK degradation results in potent suppression of signaling and proliferation in cancer cells and that BTK degraders efficiently degrade C481S-BTK, thereby addressing a major unmet need in the treatment of MCL and other B-cell lymphomas.
96 citations
TL;DR: A detail summary on the latest one year progress of PROTAC target various proteins and elucidate the advantages of PROTac technology are provided.
95 citations
References
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TL;DR: Experimental and computational approaches to estimate solubility and permeability in discovery and development settings are described in this article, where the rule of 5 is used to predict poor absorption or permeability when there are more than 5 H-bond donors, 10 Hbond acceptors, and the calculated Log P (CLogP) is greater than 5 (or MlogP > 415).
14,026 citations
TL;DR: This study reveals a family of endonucleases that use dual-RNAs for site-specific DNA cleavage and highlights the potential to exploit the system for RNA-programmable genome editing.
Abstract: Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems provide bacteria and archaea with adaptive immunity against viruses and plasmids by using CRISPR RNAs (crRNAs) to guide the silencing of invading nucleic acids. We show here that in a subset of these systems, the mature crRNA that is base-paired to trans-activating crRNA (tracrRNA) forms a two-RNA structure that directs the CRISPR-associated protein Cas9 to introduce double-stranded (ds) breaks in target DNA. At sites complementary to the crRNA-guide sequence, the Cas9 HNH nuclease domain cleaves the complementary strand, whereas the Cas9 RuvC-like domain cleaves the noncomplementary strand. The dual-tracrRNA:crRNA, when engineered as a single RNA chimera, also directs sequence-specific Cas9 dsDNA cleavage. Our study reveals a family of endonucleases that use dual-RNAs for site-specific DNA cleavage and highlights the potential to exploit the system for RNA-programmable genome editing.
12,865 citations
TL;DR: The type II prokaryotic CRISPR (clustered regularly interspaced short palindromic repeats)/Cas adaptive immune system has been shown to facilitate RNA-guided site-specific DNA cleavage as discussed by the authors.
Abstract: Functional elucidation of causal genetic variants and elements requires precise genome editing technologies. The type II prokaryotic CRISPR (clustered regularly interspaced short palindromic repeats)/Cas adaptive immune system has been shown to facilitate RNA-guided site-specific DNA cleavage. We engineered two different type II CRISPR/Cas systems and demonstrate that Cas9 nucleases can be directed by short RNAs to induce precise cleavage at endogenous genomic loci in human and mouse cells. Cas9 can also be converted into a nicking enzyme to facilitate homology-directed repair with minimal mutagenic activity. Lastly, multiple guide sequences can be encoded into a single CRISPR array to enable simultaneous editing of several sites within the mammalian genome, demonstrating easy programmability and wide applicability of the RNA-guided nuclease technology.
12,265 citations
01 Feb 2013
TL;DR: Two different type II CRISPR/Cas systems are engineered and it is demonstrated that Cas9 nucleases can be directed by short RNAs to induce precise cleavage at endogenous genomic loci in human and mouse cells, demonstrating easy programmability and wide applicability of the RNA-guided nuclease technology.
Abstract: Genome Editing Clustered regularly interspaced short palindromic repeats (CRISPR) function as part of an adaptive immune system in a range of prokaryotes: Invading phage and plasmid DNA is targeted for cleavage by complementary CRISPR RNAs (crRNAs) bound to a CRISPR-associated endonuclease (see the Perspective by van der Oost). Cong et al. (p. 819, published online 3 January) and Mali et al. (p. 823, published online 3 January) adapted this defense system to function as a genome editing tool in eukaryotic cells. A bacterial genome defense system is adapted to function as a genome-editing tool in mammalian cells. [Also see Perspective by van der Oost] Functional elucidation of causal genetic variants and elements requires precise genome editing technologies. The type II prokaryotic CRISPR (clustered regularly interspaced short palindromic repeats)/Cas adaptive immune system has been shown to facilitate RNA-guided site-specific DNA cleavage. We engineered two different type II CRISPR/Cas systems and demonstrate that Cas9 nucleases can be directed by short RNAs to induce precise cleavage at endogenous genomic loci in human and mouse cells. Cas9 can also be converted into a nicking enzyme to facilitate homology-directed repair with minimal mutagenic activity. Lastly, multiple guide sequences can be encoded into a single CRISPR array to enable simultaneous editing of several sites within the mammalian genome, demonstrating easy programmability and wide applicability of the RNA-guided nuclease technology.
10,746 citations
TL;DR: The results indicate that large, annotated cell-line collections may help to enable preclinical stratification schemata for anticancer agents and the generation of genetic predictions of drug response in the preclinical setting and their incorporation into cancer clinical trial design could speed the emergence of ‘personalized’ therapeutic regimens.
Abstract: The systematic translation of cancer genomic data into knowledge of tumour biology and therapeutic possibilities remains challenging. Such efforts should be greatly aided by robust preclinical model systems that reflect the genomic diversity of human cancers and for which detailed genetic and pharmacological annotation is available. Here we describe the Cancer Cell Line Encyclopedia (CCLE): a compilation of gene expression, chromosomal copy number and massively parallel sequencing data from 947 human cancer cell lines. When coupled with pharmacological profiles for 24 anticancer drugs across 479 of the cell lines, this collection allowed identification of genetic, lineage, and gene-expression-based predictors of drug sensitivity. In addition to known predictors, we found that plasma cell lineage correlated with sensitivity to IGF1 receptor inhibitors; AHR expression was associated with MEK inhibitor efficacy in NRAS-mutant lines; and SLFN11 expression predicted sensitivity to topoisomerase inhibitors. Together, our results indicate that large, annotated cell-line collections may help to enable preclinical stratification schemata for anticancer agents. The generation of genetic predictions of drug response in the preclinical setting and their incorporation into cancer clinical trial design could speed the emergence of 'personalized' therapeutic regimens.
6,417 citations