Design and synthesis of novel bispecific molecules for inducing BRD4 protein degradation

PROTAC'ing oncoproteins: targeted protein degradation for cancer therapy

Molecularly targeted cancer therapies substantially improve patient outcomes, although the durability of their effectiveness can be limited. Resistance to these therapies is often related to adaptive changes in the target oncoprotein which reduce binding affinity. The arsenal of targeted cancer therapies, moreover, lacks coverage of several notorious oncoproteins with challenging features for inhibitor development. Degraders are a relatively new therapeutic modality which deplete the target protein by hijacking the cellular protein destruction machinery. Degraders offer several advantages for cancer therapy including resiliency to acquired mutations in the target protein, enhanced selectivity, lower dosing requirements, and the potential to abrogate oncogenic transcription factors and scaffolding proteins. Herein, we review the development of proteolysis targeting chimeras (PROTACs) for selected cancer therapy targets and their reported biological activities. The medicinal chemistry of PROTAC design has been a challenging area of active research, but the recent advances in the field will usher in an era of rational degrader design.

Recent Advances in the Design and Development of Anticancer Molecules based on PROTAC Technology

PROTAC (Proteolysis Targeting Chimera) degraders based on protein knockdown technology are now suggested as a novel option for the treatment of various diseases. Over the last couple of years, the application of PROTAC technology has spread in a wide range of disorders, and plenty of PROTAC molecules with high potency have been reported. Mostly developing for anticancer therapy, these molecules showed high selectivities to target proteins, the ability to significantly induce degradation of oncoproteins, good in vitro and in vivo results. In this review, we summarized the recent development of PROTAC technology in the anticancer therapy field, including molecular design, types of targeted proteins, in vitro and in vivo results. Additionally, we also discuss the prospects and challenges for the application of candidates based on PROTAC strategy in clinical trials.

Proteolysis targeting chimeras (PROTACs) are emerging therapeutics for hematologic malignancies

Proteolysis targeting chimeras (PROTACs) are heterobifunctional small molecules that utilize the ubiquitin proteasome system (UPS) to degrade proteins of interest (POI). PROTACs are potentially superior to conventional small molecule inhibitors (SMIs) because of their unique mechanism of action (MOA, i.e., degrading POI in a sub-stoichiometric manner), ability to target “undruggable” and mutant proteins, and improved target selectivity. Therefore, PROTACs have become an emerging technology for the development of novel targeted anticancer therapeutics. In fact, some of these reported PROTACs exhibit unprecedented efficacy and specificity in degrading various oncogenic proteins and have advanced to various stages of preclinical and clinical development for the treatment of cancer and hematologic malignancy. In this review, we systematically summarize the known PROTACs that have the potential to be used to treat various hematologic malignancies and discuss strategies to improve the safety of PROTACs for clinical application. Particularly, we propose to use the latest human pan-tissue single-cell RNA sequencing data to identify hematopoietic cell type-specific/selective E3 ligases to generate tumor-specific/selective PROTACs. These PROTACs have the potential to become safer therapeutics for hematologic malignancies because they can overcome some of the on-target toxicities of SMIs and PROTACs.

Proteolysis-targeting chimera (PROTAC) for targeted protein degradation and cancer therapy

Proteolysis-targeting chimera (PROTAC) has been developed to be a useful technology for targeted protein degradation. A bifunctional PROTAC molecule consists of a ligand (mostly small-molecule inhibitor) of the protein of interest (POI) and a covalently linked ligand of an E3 ubiquitin ligase (E3). Upon binding to the POI, the PROTAC can recruit E3 for POI ubiquitination, which is subjected to proteasome-mediated degradation. PROTAC complements nucleic acid-based gene knockdown/out technologies for targeted protein reduction and could mimic pharmacological protein inhibition. To date, PROTACs targeting ~ 50 proteins, many of which are clinically validated drug targets, have been successfully developed with several in clinical trials for cancer therapy. This article reviews PROTAC-mediated degradation of critical oncoproteins in cancer, particularly those in hematological malignancies. Chemical structures, cellular and in vivo activities, pharmacokinetics, and pharmacodynamics of these PROTACs are summarized. In addition, potential advantages, challenges, and perspectives of PROTAC technology in cancer therapy are discussed.

Proteolysis-targeting chimeras for targeting protein for degradation

Proteolysis-targeting chimeras (PROTACs) are an emerging tool for therapeutic intervention by reducing or eliminating disease-causing proteins. PROTACs are bifunctional molecules that consist of a target protein ligand, a linker and an E3 ligase ligand, which mediate the polyubiquitination of the target protein, ultimately leading to the target protein degradation by the ubiquitin–proteasome pathway. We review some of the main PROTACs that have been reported recently and discuss their potential therapeutic benefits over classical enzyme inhibition. Future research is expected to focus on the delivery and bioavailability of PROTACs due to their high molecular weight (700–1000 Da).