Quantitative Measurement of Rate of Targeted Protein Degradation.

Targeted protein degradation (TPD) is a therapeutic approach that leverages the cell's natural machinery to degrade targets instead of inhibiting them. This is accomplished by using mono- or bifunctional small molecules designed to induce the proximity of target proteins and E3 ubiquitin ligases, leading to ubiquitination and subsequent proteasome-dependent degradation of the target. One of the most significant attributes of the TPD approach is its proposed catalytic mechanism of action, which permits substoichiometric exposure to achieve the desired pharmacological effects.

CRISPR Screen Reveals BRD2/4 Molecular Glue-like Degrader via Recruitment of DCAF16.

Molecular glues (MGs) are monovalent small molecules that induce an interaction between proteins (native or non-native partners) by altering the protein-protein interaction (PPI) interface toward a higher-affinity state. Enhancing the PPI between a protein and E3 ubiquitin ligase can lead to degradation of the partnering protein. Over the past decade, retrospective studies of clinical drugs identified that immunomodulatory drugs (e.

The HPK1 Inhibitor A-745 Verifies the Potential of Modulating T Cell Kinase Signaling for Immunotherapy.

Hematopoietic progenitor kinase 1 (HPK1) is an MAP4K family member within the Ste20-like serine/threonine branch of the kinome. HPK1 expression is limited to hematopoietic cells and has a predominant role as a negative regulator of T cell function. Because of the central/dominant role in negatively regulating T cell function, HPK1 has long been in the center of interest as a potential pharmacological target for immune therapy.

Emerging Approaches for the Identification of Protein Targets of Small Molecules - A Practitioners' Perspective.

Small-molecule (SM) leads in the early drug discovery pipeline are progressed primarily based on potency against the intended target(s) and selectivity against a very narrow slice of the proteome. So, why is there a tendency to wait until SMs are matured before probing for a deeper mechanistic understanding? For one, there is a concern about the interpretation of complex -omic data outputs and the resources needed to test these hypotheses. However, with recent advances in broad endpoint profiling assays that have companion reference databases and refined technology integration strategies, we argue that data complexity can translate into meaningful decision-making.

Discovery of N-(4-(2,4-Difluorophenoxy)-3-(6-methyl-7-oxo-6,7-dihydro-1H-pyrrolo[2,3-c]pyridin-4-yl)phenyl)ethanesulfonamide (ABBV-075/Mivebresib), a Potent and Orally Available Bromodomain and Extraterminal Domain (BET) Family Bromodomain Inhibitor.

The development of bromodomain and extraterminal domain (BET) bromodomain inhibitors and their examination in clinical studies, particularly in oncology settings, has garnered substantial recent interest. An effort to generate novel BET bromodomain inhibitors with excellent potency and drug metabolism and pharmacokinetics (DMPK) properties was initiated based upon elaboration of a simple pyridone core. Efforts to develop a bidentate interaction with a critical asparagine residue resulted in the incorporation of a pyrrolopyridone core, which improved potency by 9-19-fold.

Preclinical Characterization of BET Family Bromodomain Inhibitor ABBV-075 Suggests Combination Therapeutic Strategies.

ABBV-075 is a potent and selective BET family bromodomain inhibitor that recently entered phase I clinical trials. Comprehensive preclinical characterization of ABBV-075 demonstrated broad activity across cell lines and tumor models, representing a variety of hematologic malignancies and solid tumor indications. In most cancer cell lines derived from solid tumors, ABBV-075 triggers prominent G cell-cycle arrest without extensive apoptosis.

Fragment-Based, Structure-Enabled Discovery of Novel Pyridones and Pyridone Macrocycles as Potent Bromodomain and Extra-Terminal Domain (BET) Family Bromodomain Inhibitors.

Members of the BET family of bromodomain containing proteins have been identified as potential targets for blocking proliferation in a variety of cancer cell lines. A two-dimensional NMR fragment screen for binders to the bromodomains of BRD4 identified a phenylpyridazinone fragment with a weak binding affinity (1, K = 160 μM). SAR investigation of fragment 1, aided by X-ray structure-based design, enabled the synthesis of potent pyridone and macrocyclic pyridone inhibitors exhibiting single digit nanomolar potency in both biochemical and cell based assays.

Methylpyrrole inhibitors of BET bromodomains.

An NMR fragment screen for binders to the bromodomains of BRD4 identified 2-methyl-3-ketopyrroles 1 and 2. Elaboration of these fragments guided by structure-based design provided lead molecules with significant activity in a mouse tumor model. Further modifications to the methylpyrrole core provided compounds with improved properties and enhanced activity in a mouse model of multiple myeloma.

Target Identification of Compounds from a Cell Viability Phenotypic Screen Using a Bead/Lysate-Based Affinity Capture Platform.

The pharmaceutical industry has been continually challenged by dwindling target diversity. To obviate this trend, phenotypic screens have been adopted, complementing target-centric screening approaches. Phenotypic screens identify drug leads using clinically relevant and translatable mechanisms, remaining agnostic to targets.

Role of cytochrome P450c17α in dibromoacetic acid-induced testicular toxicity in rats.

Dibromoacetic acid (DBAA), a by-product formed during disinfection of drinking water, alters spermatogenesis in rats through defective spermiation. The mechanism underlying this toxicity is not fully understood. In this study, gene expression data generated with microarrays from testes were used to generate a mechanistic understanding of DBAA-induced testicular toxicity.

Bcl-XL represents a druggable molecular vulnerability during aurora B inhibitor-mediated polyploidization.

Aurora kinase B inhibitors induce apoptosis secondary to polyploidization and have entered clinical trials as an emerging class of neocytotoxic chemotherapeutics. We demonstrate here that polyploidization neutralizes Mcl-1 function, rendering cancer cells exquisitely dependent on Bcl-XL/-2. This "addiction" can be exploited therapeutically by combining aurora kinase inhibitors and the orally bioavailable BH3 mimetic, ABT-263, which inhibits Bcl-XL, Bcl-2, and Bcl-w.

Reducing agent-mediated precipitation of high-abundance plasma proteins.

Depletion of high-abundance proteins is regarded as a critical sample preparation step for most plasma proteomic analyses and profiling strategies. This report describes a process that rapidly and reproducibly precipitates high-abundance disulfide-rich proteins, including albumin and transferrin, from serum and plasma. A low volume of concentrated reducing agent, viz.

Discovery, identification, and characterization of candidate pharmacodynamic markers of methionine aminopeptidase-2 inhibition.

The catalytic activity of methionine aminopeptidase-2 (MetAP2) has been pharmacologically linked to cell growth, angiogenesis, and tumor progression, making this an attractive target for cancer therapy. An assay for monitoring specific protein changes in response to MetAP2 inhibition, allowing pharmacokinetic (PK)/pharmacodynamic (PD) models to be established, could dramatically improve clinical decision-making. Candidate MetAP2-specific protein substrates were discovered from undigested cell culture-derived proteomes by MALDI-/SELDI-MS profiling and a biochemical method using (35)S-Met labeled protein lysates.

Gene expression analysis in rats treated with experimental acetyl-coenzyme A carboxylase inhibitors suggests interactions with the peroxisome proliferator-activated receptor alpha pathway.

Acetyl CoA carboxylase (ACC) 2, which catalyzes the carboxylation of acetyl-CoA to form malonyl-CoA, has been identified as a potential target for type 2 diabetes and obesity. Small-molecule inhibitors of ACC2 would be expected to reduce de novo lipid synthesis and increase lipid oxidation. Treatment of ob/ob mice with compound A-908292 (S) ({(S)-3-[2-(4-isopropoxy-phenoxy)-thiazol-5-yl]-1-methyl-prop-2-ynyl}-carbamic acid methyl ester), a small-molecule inhibitor with an IC(50) of 23 nM against ACC2, resulted in a reduction of serum glucose and triglyceride levels.