ABSTRACT
Optimization of our previously described pyrrolopiperidone series led to the identification of a new benzamide sub-series, which exhibits consistently high potency in biochemical and cell-based assays throughout the series. Strong inhibition of LPS-induced production of the cytokine TNFα is coupled to the regulation of HSP27 phosphorylation, indicating that the observed cellular effects result from the inhibition of MK2. X-ray crystallographic and computational analyses provide a rationale for the high potency of the series.
Subject(s)
Benzamides/pharmacology , Chemistry, Pharmaceutical/methods , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Intracellular Signaling Peptides and Proteins/pharmacology , Piperidones/pharmacology , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/antagonists & inhibitors , Protein Serine-Threonine Kinases/pharmacology , Tumor Necrosis Factor-alpha/metabolism , Computer Simulation , Crystallography, X-Ray/methods , Cytokines/metabolism , Drug Design , HSP27 Heat-Shock Proteins/metabolism , Heat-Shock Proteins , Humans , Models, Chemical , Molecular Chaperones , Phosphorylation , Pyrroles/chemistryABSTRACT
The identification of a potent, selective, and orally available MK2 inhibitor series is described. The initial absence of oral bioavailability was successfully tackled by moving the basic nitrogen of the spiro-4-piperidyl moiety towards the electron-deficient pyrrolepyridinedione core, thereby reducing the pK(a) and improving Caco-2 permeability. The resulting racemic spiro-3-piperidyl analogues were separated by chiral preparative HPLC, and the activity towards MK2 inhibition was shown to reside mostly in the first eluting stereoisomer. This led to the identification of new MK2 inhibitors, such as (S)-23, with low nanomolar biochemical inhibition (EC(50) 7.4 nM) and submicromolar cellular target engagement activity (EC(50) 0.5 µM).
Subject(s)
Drug Discovery , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Piperidines/chemical synthesis , Protein Serine-Threonine Kinases/antagonists & inhibitors , Spiro Compounds/chemical synthesis , Administration, Oral , Animals , Binding, Competitive , Biological Availability , Caco-2 Cells , Chromatography, High Pressure Liquid , Crystallography, X-Ray , Disease Models, Animal , Enzyme Activation/drug effects , Humans , Inhibitory Concentration 50 , Intracellular Signaling Peptides and Proteins/chemistry , Molecular Structure , Piperidines/chemistry , Piperidines/pharmacology , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/chemistry , Rats , Spiro Compounds/chemistry , Spiro Compounds/pharmacology , Stereoisomerism , Structure-Activity Relationship , Substrate SpecificityABSTRACT
Here, we report the identification and optimization of 1-(4-(pyridin-2-yl)benzyl)imidazolidine-2,4-dione derivatives as a novel chemotype with selective cannabinoid CB2 receptor agonist activity. 1 is a potent and selective cannabinoid CB2 receptor agonist (hCB2 pEC(50) = 8.6). The compound was found to be metabolically unstable, which resulted in low oral bioavailability in rat (F(po) = 4%) and possessed off-target activity at the hERG ion channel (pK(i) = 5.5). Systematic modification of physicochemical properties, such as lipophilicity and basicity, was used to optimize the pharmacokinetic profile and hERG affinity of this novel class of cannabinoid CB2 receptor agonists. This led to the identification of 44 as a potent, selective, and orally bioavailable cannabinoid CB2 receptor agonist (hCB2 pEC(50) = 8.0; hERG pK(i) < 4; F(po) = 100%), which was active in a rat spinal nerve ligation model of neuropathic pain.