ABSTRACT
The initial structure activity relationships around an isoindoline uHTS hit will be described. Information gleaned from ligand co-crystal structures allowed for rapid refinements in both MARK potency and kinase selectivity. These efforts allowed for the identification of a compound with properties suitable for use as an in vitro tool compound for validation studies on MARK as a viable target for Alzheimer's disease.
Subject(s)
Drug Design , Protein Kinase Inhibitors/pharmacology , Pyrimidinones/pharmacology , Pyrroles/pharmacology , Alzheimer Disease/drug therapy , Alzheimer Disease/metabolism , Cell Line , Crystallography, X-Ray , Dose-Response Relationship, Drug , Humans , Models, Molecular , Molecular Structure , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Protein Serine-Threonine Kinases/antagonists & inhibitors , Protein Serine-Threonine Kinases/metabolism , Pyrimidinones/chemical synthesis , Pyrimidinones/chemistry , Pyrroles/chemical synthesis , Pyrroles/chemistry , Structure-Activity RelationshipABSTRACT
Attempts to optimize pharmacokinetic properties in a promising series of pyrrolopyrimidinone MARK inhibitors for the treatment of Alzheimer's disease are described. A focus on physical properties and ligand efficiency while prosecuting this series afforded key tool compounds that revealed a large discrepancy in the rat in vitro-in vivo DMPK (Drug Metabolism/Pharmacokinetics) correlation. These differences prompted an in vivo rat disposition study employing a radiolabeled representative of the series, and the results from this experiment justified the termination of any further optimization efforts.
Subject(s)
Alzheimer Disease/drug therapy , Protein Kinase Inhibitors/pharmacology , Pyrimidinones/pharmacology , Pyrroles/pharmacology , Alzheimer Disease/metabolism , Animals , Dose-Response Relationship, Drug , Humans , Isoenzymes/antagonists & inhibitors , Isoenzymes/metabolism , Molecular Structure , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/metabolism , Protein Serine-Threonine Kinases/antagonists & inhibitors , Protein Serine-Threonine Kinases/metabolism , Pyrimidinones/chemistry , Pyrimidinones/metabolism , Pyrroles/chemistry , Pyrroles/metabolism , Rats , Structure-Activity RelationshipABSTRACT
Alzheimer's disease is a major unmet medical need with pathology characterized by extracellular proteinaceous plaques comprised primarily of ß-amyloid. γ-Secretase is a critical enzyme in the cellular pathway responsible for the formation of a range of ß-amyloid peptides; one of which, Aß42, is believed to be responsible for the neuropathological features of the disease. Herein, we report 4,4 disubstituted piperidine γ-secretase inhibitors that were optimized for in vitro cellular potency and pharmacokinetic properties in vivo. Key agents were further characterized for their ability to lower cerebral Aß42 production in an APP-YAC mouse model. This structural series generally suffered from sub-optimal pharmacokinetics but hypothesis driven lead optimization enabled the discovery of γ-secretase inhibitors capable of lowering cerebral Aß42 production in mice.
Subject(s)
Amides/chemical synthesis , Amyloid Precursor Protein Secretases/antagonists & inhibitors , Enzyme Inhibitors/chemistry , Piperidines/chemistry , Alzheimer Disease/drug therapy , Amides/pharmacology , Amyloid beta-Peptides/biosynthesis , Animals , Brain/drug effects , Brain/metabolism , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Mice , Peptide Fragments/biosynthesisABSTRACT
A primary pathological feature of Alzheimer's disease is beta-amyloid (Abeta)-containing plaques in brain and cerebral vasculature. Reductions in the formation of Abeta peptides by gamma-secretase inhibitors may be a viable therapy for reducing Abeta in Alzheimer's disease. Here we report on the effects of two orally active gamma-secretase inhibitors. BMS-289948 (4-chloro-N-(2,5-difluorophenyl)-N-((1R)-{4-fluoro-2-[3-(1H-imidazol-1-yl)propyl]phenyl}ethyl)benzenesulfonamide hydrochloride) and BMS-299897 (4-[2-((1R)-1-{[(4-chlorophenyl)sulfonyl]-2,5-difluoroanilino}ethyl)-5-fluorophenyl]butanoic acid) markedly reduced both brain and plasma Abeta(1-40) in APP-YAC mice with ED(50) values of 86 and 22 mg/kg per os (po), respectively, for BMS-289948, and 30 and 16 mg/kg po, respectively, for BMS-299897. Both compounds also dose-dependently increased brain concentrations of APP carboxy-terminal fragments, consistent with inhibition of gamma-secretase. BMS-289948 and BMS-299897 (100 mg/kg po) reduced brain and plasma Abeta(1-40) rapidly (within 20min) and maximally within 3 h. BMS-299897 also dose-dependently reduced cortical, cerebrospinal fluid (CSF), and plasma Abeta in guinea pigs with ED(50) values of 30 mg/kg intraperitoneally, without affecting CSF levels of alpha-sAPP. The reductions in cortical Abeta correlated significantly with the reductions in both plasma (r(2) = 0.77) and CSF (r(2) = 0.61) Abeta. The decreases in Abeta were apparent at 3 and 6 h post-administration of BMS-299897, but not at 12h. These results demonstrate that BMS-289948 and BMS-299897 are orally bioavailable, functional gamma-secretase inhibitors with the ability to markedly reduce Abeta peptide concentrations in APP-YAC transgenic mice and in guinea pigs. These compounds may be useful pharmacologically for examining the effects of reductions in beta-amyloid peptides in both animal models and in Alzheimer's disease.
