Structure-guided design of a domain-selective bromodomain and extra terminal N-terminal bromodomain chemical probe

Small molecule mediated disruption of the protein-protein interactions between acetylated histone tails and the tandem bromodomains of the bromodomain and extra terminal (BET) family of proteins is an important mechanism of action for the potential modulation of immuno-inflammatory and oncology disease. High quality chemical probes have proven invaluable in elucidating profound BET bromodomain biology, with seminal publications of both pan- and domain-selective BET family bromodomain inhibitors enabling academic and industrial research. To enrich the toolbox of structurally differentiated N-terminal bromodomain (BD1) BET family chemical probes, this work describes an analysis of the GSK BRD4 bromodomain dataset through a lipophilic efficiency lens, which enabled identification of a BD1 domain biased benzimidazole series. Structure guided growth targeting a key Asp/His BD1/BD2 switch enabled delivery of GSK023, a high-quality chemical probe with 300–1000-fold BET BD1 domain selectivity and a phenotypic cellular fingerprint consistent with BET bromodomain inhibition

Structure-based design of a bromodomain and extraterminal domain (BET) inhibitor selective for the N-terminal bromodomains that retains an anti-inflammatory and antiproliferative phenotype

The bromodomain and extraterminal domain (BET) family of epigenetic regulators comprises four proteins (BRD2, BRD3, BRD4, BRDT), each containing tandem bromodomains. To date, small molecule inhibitors of these proteins typically bind all eight bromodomains of the family with similar affinity, resulting in a diverse range of biological effects. To enable further understanding of the broad phenotype characteristic of pan-BET inhibition, the development of inhibitors selective for individual, or sets of, bromodomains within the family is required. In this regard, we report the discovery of a potent probe molecule possessing up to 150-fold selectivity for the N-terminal bromodomains (BD1s) over the C-terminal bromodomains (BD2s) of the BETs. Guided by structural information, a specific amino acid difference between BD1 and BD2 domains was targeted for selective interaction with chemical functionality appended to the previously developed I-BET151 scaffold. Data presented herein demonstrate that selective inhibition of BD1 domains is sufficient to drive anti-inflammatory and antiproliferative effects

Enhanced Raman signal of CH3 on carbon nanotubes

ABSTRACTWe find that functionalized SWCNT and DWCNT's (mainly double wall carbon nanotubes) in composites, DWCNTs under hydrostatic pressure and blue illuminated DWCNTs in methanol show the same up shift of the Raman G band and the appearance of a new band at 1455cm−1. This is attributed to the interaction of the CH3 group of the amphiphilic molecule in composites or the CH3 group of alcohol with the outer tube of DWCNT's and indicates that laser heating of DWCNT's in methanol can induce the chemical adsorption of CH3 onto the CNT (carbon nanotube) surface

Optimization of naphthyridones into selective TATA-binding protein associated factor 1 (TAF1) bromodomain inhibitors

Bromodomain containing proteins and the acetyl-lysine binding bromodomains contained therein are increasingly attractive targets for the development of novel epigenetic therapeutics. To help validate this target class and unravel the complex associated biology, there has been a concerted effort to develop selective small molecule bromodomain inhibitors. Herein we describe the structure-based efforts and multiple challenges encountered in optimizing a naphthyridone template into selective TAF1(2) bromodomain inhibitors which, while unsuitable as chemical probes themselves, show promise for the future development of small molecules to interrogate TAF1(2) biology. Key to this work was the introduction and modulation of the basicity of a pendant amine which had a substantial impact on not only bromodomain selectivity but also cellular target engagement

The optimization of potent ATAD2 and CECR2 bromodomain inhibitors with an atypical binding mode

Most bromodomain inhibitors mimic the interactions of the natural acetylated lysine (KAc) histone substrate through key interactions with conserved asparagine and tyrosine residues within the binding pocket. Herein we report the optimization of a series of phenyl sulfonamides that exhibit a novel mode of binding to non-bromodomain and extra terminal domain (non-BET) bromodomains through displacement of a normally conserved network of four water molecules. Starting from an initial hit molecule, we report its divergent optimization toward the ATPase family AAA domain containing 2 (ATAD2) and cat eye syndrome chromosome region, candidate 2 (CECR2) domains. This work concludes with the identification of (R)-55 (GSK232), a highly selective, cellularly penetrant CECR2 inhibitor with excellent physicochemical properties

Synthesis and structure-activity relationships of a series of (1H-pyrazol-4-yl)acetamide antagonists of the P2X7 receptor

High-throughput screening identified compound 1 as a potent P2X(7) receptor antagonist suitable for lead optimisation. Structure-activity relationships (SAR) of a series of (1H-pyrazol-4-yl)acetamides were investigated and compound 32 was identified as a potent P2X(7) antagonist with enhanced potency and favourable physicochemical and pharmacokinetic properties

Discovery of Tetrahydroquinoxalines as Bromodomain and Extra-Terminal Domain (BET) Inhibitors with Selectivity for the Second Bromodomain

The bromodomain and extra-terminal domain (BET) family of proteins bind acetylated lysine residues on histone proteins. The four BET bromodomainsBRD2, BRD3, BRD4, and BRDTeach contain two bromodomain modules. BET bromodomain inhibition is a potential therapy for various cancers and immunoinflammatory diseases, but few reported inhibitors show selectivity within the BET family. Inhibitors with selectivity for the first or second bromodomain are desired to aid investigation of the biological function of these domains. Focused library screening identified a series of tetrahydroquinoxalines with selectivity for the second bromodomains of the BET family (BD2). Structure-guided optimization of the template improved potency, selectivity, and physicochemical properties, culminating in potent BET inhibitors with BD2 selectivity

Discovery of Tetrahydroquinoxalines as Bromodomain and Extra-Terminal Domain (BET) Inhibitors with Selectivity for the Second Bromodomain

The bromodomain and extra-terminal domain (BET) family of proteins bind acetylated lysine residues on histone proteins. The four BET bromodomainsBRD2, BRD3, BRD4, and BRDTeach contain two bromodomain modules. BET bromodomain inhibition is a potential therapy for various cancers and immunoinflammatory diseases, but few reported inhibitors show selectivity within the BET family. Inhibitors with selectivity for the first or second bromodomain are desired to aid investigation of the biological function of these domains. Focused library screening identified a series of tetrahydroquinoxalines with selectivity for the second bromodomains of the BET family (BD2). Structure-guided optimization of the template improved potency, selectivity, and physicochemical properties, culminating in potent BET inhibitors with BD2 selectivity