Cell-Based Selection Expands the Utility of DNA-Encoded Small-Molecule Library Technology to Cell Surface Drug Targets: Identification of Novel Antagonists of the NK3 Tachykinin Receptor.

DNA-encoded small-molecule library technology has recently emerged as a new paradigm for identifying ligands against drug targets. To date, this technology has been used with soluble protein targets that are produced and used in a purified state. Here, we describe a cell-based method for identifying small-molecule ligands from DNA-encoded libraries against integral membrane protein targets. We use this method to identify novel, potent, and specific inhibitors of NK3, a member of the tachykinin family of G-protein coupled receptors (GPCRs). The method is simple and broadly applicable to other GPCRs and integral membrane proteins. We have extended the application of DNA-encoded library technology to membrane-associated targets and demonstrate the feasibility of selecting DNA-tagged, small-molecule ligands from complex combinatorial libraries against targets in a heterogeneous milieu, such as the surface of a cell.

Identification of a series of 1,3,4-oxadiazol-2-amines as potent alpha-7 agonists with efficacy in the novel object recognition model of cognition.

A series of α7 nicotinic acetylcholine receptor full-agonists with a 1,3,4-oxadiazol-2-amine core has been discovered. Systematic exploration of the structure-activity relationships for both α7 potency and selectivity with respect to interaction with the hERG channel are described. Further profiling led to the identification of compound 22, a potent full agonist showing efficacy in the novel object recognition model of cognition enhancement.

The discovery of 2-fluoro-N-(3-fluoro-4-(5-((4-morpholinobutyl)amino)-1,3,4-oxadiazol-2-yl)phenyl)benzamide, a full agonist of the alpha-7 nicotinic acetylcholine receptor showing efficacy in the novel object recognition model of cognition enhancement.

A series of α7 nicotinic acetylcholine receptor full agonists with a 1,3,4-oxadiazol-2-amine core has been discovered. Early lead 1 was found to have a limited therapeutic index with respect to its potential for cardiovascular side effects. Further optimisation of this series led to the identification of 22 a potent full agonist showing efficacy at a dose of 0.1mg/kg in the novel object recognition model of cognition enhancement. Comparison of 1 with 22 demonstrated the latter to have an improved oral pharmacokinetic profile and cardiovascular therapeutic index.

Amino acid anthranilamide derivatives as a new class of glycogen phosphorylase inhibitors.

A series of amino acid anthranilamide derivatives identified from a high-throughput screening campaign as novel, potent, and glucose-sensitive inhibitors of human liver glycogen phosphorylase a are described. A solid-phase synthesis using Wang resin was also developed which provided efficient access to a variety of analogues, and resulted in the identification of key structure-activity relationships, and the discovery of a potent exemplar (IC(50)=80 nM). The SAR scope, synthetic strategy, and in vitro results for this series are presented herein.

Synthesis and structure-activity relationships of 3-phenyl-2-propenamides as inhibitors of glycogen phosphorylase a.

A series of 3-phenyl-2-propenamides discovered from a high-throughput screening campaign as novel, potent, glucose-sensitive inhibitors of human liver glycogen phosphorylase a is described. A solid-phase synthesis on DMHB resin was also developed which provided efficient access not only to certain analogues that could not be cleanly made using more traditional means, but also to a variety of additional analogues. The SAR scope and synthetic strategy are presented herein.