ABSTRACT
Inhibitors of the MAP kinase p38 are potentially useful for the treatment for osteoporosis, arthritis, and other inflammatory diseases. A series of thienyl, furyl, and pyrrolyl ureas has been identified as potent p38 inhibitors, displaying in vitro activity in the nanomolar range.
Subject(s)
Arthritis/drug therapy , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Mitogen-Activated Protein Kinases/antagonists & inhibitors , Osteoporosis/drug therapy , Urea/analogs & derivatives , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Furans/chemical synthesis , Furans/chemistry , Furans/pharmacology , Furans/therapeutic use , Humans , Inhibitory Concentration 50 , Interleukin-6/antagonists & inhibitors , Interleukin-6/metabolism , Molecular Structure , Pyrroles/chemical synthesis , Pyrroles/chemistry , Pyrroles/pharmacology , Pyrroles/therapeutic use , Thiophenes/chemical synthesis , Thiophenes/chemistry , Thiophenes/pharmacology , Thiophenes/therapeutic use , Tumor Cells, Cultured , p38 Mitogen-Activated Protein KinasesABSTRACT
The MAP kinase p38 has been implicated in cytokine signaling, and its inhibitors are potentially useful for the treatment of arthritis and osteoporosis. Novel small-molecule inhibitors of p38 kinase were derived from a combinatorial chemistry effort and exhibit activity in the nanomolar range. Very steep structure-activity relationships are observed within this class.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Mitogen-Activated Protein Kinases/antagonists & inhibitors , Antirheumatic Agents/chemical synthesis , Antirheumatic Agents/chemistry , Combinatorial Chemistry Techniques , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Heterocyclic Compounds/chemistry , Humans , Hydrocarbons, Chlorinated/chemistry , Inhibitory Concentration 50 , Osteoporosis/drug therapy , Phenylurea Compounds/chemical synthesis , Phenylurea Compounds/pharmacology , Structure-Activity Relationship , p38 Mitogen-Activated Protein KinasesABSTRACT
[reaction: see text] An efficient method for the preparation of 3-aminofuran-2-carboxylate esters has been developed. This method is based on the reaction of an alpha-cyanoketone with ethyl glyoxylate under Mitsunobu conditions to produce a vinyl ether in good yield. Subsequent treatment of the vinyl ether with sodium hydride afforded the 3-aminofuran. It was also found that a one-pot procedure using the Mitsunobu reaction followed by cyclization afforded the 3-aminofuran in comparable yield. Currently, this method is limited to the synthesis of 5-alkyl-, 5-aryl-, and 4,5-fused bicyclic furans.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/chemical synthesis , Esters/chemical synthesis , Furans/chemical synthesis , AlkylationABSTRACT
We examined the role of A328(F330) in the binding of various inhibitors to cholinesterases (ChEs) using human butyrylcholinesterase (BChE) mutants to determine if the conclusions drawn from studies with acetylcholinesterase (AChE) mutants could be extended to BChE. For huperzine A and edrophonium, the results obtained with AChE mutants could be directly correlated with those obtained with native ChEs and site-specific mutants of human BChE. Inhibition studies of ethopropazine with BChE mutants, where A328 was modified to either F or Y, suggested that A328 was not solely responsible for the selectivity of ethopropazine. Volume calculations for the active-site gorge showed that the poor inhibitory activity of ethopropazine towards AChE was due to the smaller dimension of the active-site gorge. The volume of the BChE active-site gorge is approximately 200 A3 larger than that of the AChE gorge, which allows the accommodation of ethopropazine in two different orientations as demonstrated by rigid-body refinement and molecular dynamics calculations. These results suggest that, although the overall scaffolding of the two enzymes may be highly similar, the dimensions and the micro-environment of the gorge play a significant role in determining the selectivity of substrate and inhibitors for ChEs.
Subject(s)
Butyrylcholinesterase/chemistry , Butyrylcholinesterase/metabolism , Cholinesterase Inhibitors/metabolism , Acetylcholinesterase/chemistry , Acetylcholinesterase/metabolism , Animals , Binding Sites , Cholinesterase Inhibitors/chemistry , Cholinesterase Inhibitors/pharmacology , Crystallography, X-Ray , Humans , Kinetics , Models, Molecular , Mutation , Phenothiazines/chemistry , Phenothiazines/metabolism , Protein Binding , Structure-Activity Relationship , Substrate Specificity , TorpedoABSTRACT
Amino acid sequence alignments of cholinesterases revealed that 6 of 14 aromatic amino acid residues lining the active center gorge of acetylcholinesterase are replaced by aliphatic amino acid residues in butyrylcholinesterase. The Y337 (F330) in mammalian acetylcholinesterase, which is replaced by A328 in human butyrylcholinesterase, is implicated in the binding of ligands such as huperzine A, edrophonium, and acridines and one end of bisquaternary compounds such as BW284C51 and decamethonium. Y337 may sterically hinder the binding of phenothiazines such as ethopropazine, which contains a bulky exocyclic substitution. Inhibition studies of (-)-huperzine A with human butyrylcholinesterase mutants, where A328 (KI = 194.6 microM) was modified to either F (KI = 0.6 microM, as in Torpedo acetylcholinesterase) or Y (KI = 0.032 microM, as in mammalian acetylcholinesterase), confirmed previous observations made with acetylcholinesterase mutants that this residue is important for binding huperzine A. Inhibition studies of ethopropazine with butyrylcholinesterase mutants, where A328 (KI = 0.18 microM) was modified to either F (KI = 0.82 microM) or Y (KI = 0.28 microM), suggested that A328 was not solely responsible for the selectivity of ethopropazine. Volume calculations for the active site gorge showed that the poor inhibitory activity of ethopropazine toward acetylcholinesterase was due to the smaller dimension of the active site gorge which was unable to accommodate the bulky inhibitor molecule. The volume of the butyrylcholinesterase active site gorge is approximately 200 A3 larger than that of the acetylcholinesterase gorge, which allows the accommodation of ethopropazine in two different orientations as demonstrated by rigid-body refinement and molecular dynamics calculations.