ABSTRACT
The Aurora family of serine/threonine kinases is essential for mitosis. Their crucial role in cell cycle regulation and aberrant expression in a broad range of malignancies have been demonstrated and have prompted intensive search for small molecule Aurora inhibitors. Indeed, over 10 of them have reached the clinic as potential anticancer therapies. We report herein the discovery and optimization of a novel series of tricyclic molecules that has led to SAR156497, an exquisitely selective Aurora A, B, and C inhibitor with in vitro and in vivo efficacy. We also provide insights into its mode of binding to its target proteins, which could explain its selectivity.
Subject(s)
Antineoplastic Agents/pharmacology , Aurora Kinases/antagonists & inhibitors , Benzimidazoles/pharmacology , Protein Kinase Inhibitors/pharmacology , Quinolones/pharmacology , Small Molecule Libraries/pharmacology , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/metabolism , Aurora Kinase A/antagonists & inhibitors , Aurora Kinase A/chemistry , Aurora Kinase A/metabolism , Aurora Kinase B/antagonists & inhibitors , Aurora Kinase B/chemistry , Aurora Kinase B/metabolism , Aurora Kinase C/antagonists & inhibitors , Aurora Kinase C/chemistry , Aurora Kinase C/metabolism , Aurora Kinases/chemistry , Aurora Kinases/metabolism , Benzimidazoles/chemistry , Benzimidazoles/metabolism , Female , HCT116 Cells , Humans , Mice, SCID , Models, Chemical , Models, Molecular , Molecular Structure , Neoplasms/drug therapy , Neoplasms/pathology , Protein Binding , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/metabolism , Protein Structure, Tertiary , Quinolones/chemistry , Quinolones/metabolism , Sf9 Cells , Small Molecule Libraries/chemistry , Small Molecule Libraries/metabolism , Xenograft Model Antitumor AssaysABSTRACT
A solid phase combinatorial library was designed based on X-ray structures and in-silico models to explore an inducible S4+ pocket, which is formed by a simple side-chain rotation of Tyr95. This inducible S4+ pocket is unique to ß-tryptase and does not exist for other trypsin-like serine proteases of interest. Therefore, inhibitors utilizing this pocket have inherent advantages for being selective against other proteases in the same family. A member of this library was found to be a potent and selective ß-tryptase inhibitor with a suitable pharmacokinetic profile for further clinical evaluation.
Subject(s)
Enzyme Inhibitors/pharmacology , Mast Cells/enzymology , Small Molecule Libraries/pharmacology , Tryptases/antagonists & inhibitors , Administration, Oral , Animals , Combinatorial Chemistry Techniques , Crystallography, X-Ray , Dose-Response Relationship, Drug , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/chemical synthesis , Humans , Models, Molecular , Molecular Structure , Rats , Recombinant Proteins/antagonists & inhibitors , Small Molecule Libraries/administration & dosage , Small Molecule Libraries/chemical synthesis , Structure-Activity RelationshipABSTRACT
A new series of IGF-1R inhibitors related to hydantoins were identified from a lead originating from HTS. Their noncompetitive property as well as their slow binding characteristics provided a series of compounds with unique selectivity and excellent cellular activities.
Subject(s)
Protein Kinase Inhibitors/chemistry , Receptor, IGF Type 1/antagonists & inhibitors , Adenosine Triphosphate/chemistry , Animals , Binding Sites , Binding, Competitive , Computer Simulation , Drug Evaluation, Preclinical , Mice , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/pharmacokinetics , Receptor, IGF Type 1/metabolismABSTRACT
From an azaindole lead, identified in high throughput screen, a series of potent bis-azaindole inhibitors of IGF1-R have been synthesized using rational drug design and SAR based on a in silico binding mode hypothesis. Although the resulting compounds produced the expected improved potency, the model was not validated by the co-crystallization experiments with IGF1-R.
Subject(s)
Indoles/chemistry , Insulin-Like Growth Factor I/antagonists & inhibitors , Protein Kinase Inhibitors/chemistry , Animals , Binding Sites , Cell Line, Tumor , Crystallography, X-Ray , Drug Design , Drug Screening Assays, Antitumor , Humans , Indoles/chemical synthesis , Indoles/pharmacokinetics , Insulin-Like Growth Factor I/metabolism , Mice , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/pharmacokinetics , Structure-Activity RelationshipABSTRACT
From an HTS hit, a series of potent and selective inhibitors of GSK3beta have been designed based on a Cdk2-homology model and with the help of several crystal structures of the compounds within Cdk2.
Subject(s)
CDC2 Protein Kinase/antagonists & inhibitors , Cyclin-Dependent Kinase 2/antagonists & inhibitors , Glycogen Synthase Kinase 3/antagonists & inhibitors , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Drug Design , Glycogen Synthase Kinase 3 beta , Models, Molecular , Substrate SpecificityABSTRACT
Tryptase is a serine protease found almost exclusively in mast cells. It has trypsin-like specificity, favoring cleavage of substrates with an arginine (or lysine) at the P1 position, and has optimal catalytic activity at neutral pH. Current evidence suggests tryptase beta is the most important form released during mast cell activation in allergic diseases. It is shown to have numerous pro-inflammatory cellular activities in vitro, and in animal models tryptase provokes broncho-constriction and induces a cellular inflammatory infiltrate characteristic of human asthma. Screening of in-house inhibitors of factor Xa (a closely related serine protease) identified beta-amidoester benzamidines as potent inhibitors of recombinant human betaII tryptase. X-ray structure driven template modification and exchange of the benzamidine to optimize potency and pharmacokinetic properties gave selective, potent and orally bioavailable 4-(3-aminomethyl phenyl)piperidinyl-1-amides.
Subject(s)
Amides , Piperidines , Serine Endopeptidases/drug effects , Administration, Oral , Amides/chemical synthesis , Amides/chemistry , Amides/pharmacology , Animals , Biological Availability , Caco-2 Cells , Crystallography, X-Ray , Drug Design , Factor Xa Inhibitors , Humans , Liver/enzymology , Models, Molecular , Molecular Structure , Piperidines/chemical synthesis , Piperidines/chemistry , Piperidines/pharmacology , Protein Conformation , Rats , Recombinant Proteins/drug effects , Serine Proteinase Inhibitors/chemical synthesis , Serine Proteinase Inhibitors/chemistry , Serine Proteinase Inhibitors/pharmacology , Structure-Activity Relationship , TryptasesABSTRACT
In this manuscript, the synthesis and SAR evaluation of a novel pyrazinone class of tryptase inhibitors is described. Chemical optimization of the P1 and P4 groups led to the identification of 7p (K(i)=93 nM) as a potent inhibitor of mast cell tryptase.
Subject(s)
Pyrazines/chemical synthesis , Serine Endopeptidases/drug effects , Serine Proteinase Inhibitors/chemical synthesis , Pyrazines/pharmacology , Serine Endopeptidases/chemistry , Serine Proteinase Inhibitors/pharmacology , Structure-Activity Relationship , TryptasesABSTRACT
The discovery and SAR of ketopiperazino methylazaindole factor Xa inhibitors are described. Structure-activity data suggesting that this class of inhibitors does not bind in the canonical mode were confirmed by an X-ray crystal structure showing the neutral haloaromatic bound in the S(1) subsite. The most potent azaindole, 33 (RPR209685), is selective against related serine proteases and attains higher levels of exposure upon oral dosing than comparable benzamidines and benzamidine isosteres. Compound 33 was efficacious in the canine AV model of thrombosis.
Subject(s)
Aza Compounds/chemical synthesis , Factor Xa Inhibitors , Indoles/chemical synthesis , Piperazines/chemical synthesis , Serine Proteinase Inhibitors/chemical synthesis , Sulfonamides/chemical synthesis , Administration, Oral , Animals , Aza Compounds/chemistry , Aza Compounds/pharmacology , Biological Availability , Crystallography, X-Ray , Dogs , In Vitro Techniques , Indoles/chemistry , Indoles/pharmacology , Ligands , Microsomes, Liver/drug effects , Microsomes, Liver/metabolism , Piperazines/chemistry , Piperazines/pharmacology , Rats , Serine Proteinase Inhibitors/chemistry , Serine Proteinase Inhibitors/pharmacology , Structure-Activity Relationship , Sulfonamides/chemistry , Sulfonamides/pharmacologyABSTRACT
The structures of the noncovalent complex of human factor Xa (fXa) with four non-peptide inhibitors containing a central sulfonylpiperazinone scaffold have been determined to about 2.1 A resolution. Highly potent fXa inhibitors containing both neutral groups such as chlorobenzothiophene or chlorothiophene and basic groups such as benzamidine were shown to interact in the S1 pocket through the neutral group whereas the S4 pocket is occupied by the basic moiety. The scaffold comprising the sulfonyl keto piperazine moiety might play a pivotal role in the orientation of substituents, since there is a strong hydrogen bond between Gly219 of fXa and the carbonyl oxygen of the piperazine. This unique "reverse" binding mode is heretofore unreported in fXa and shows that electrostatic interactions in the S1 subsite are not an absolute requirement to maintain high affinity. Selectivity against other serine proteases can be readily explained in light of these structural results. It has opened up new prospects for designing fXa inhibitors with increased oral bioavailability.
