ABSTRACT
The bromodomain and extra-terminal (BET) family of epigenetic proteins has attracted considerable attention in drug discovery given its involvement in regulating gene transcription. Screening a focused small molecule library based on the bromodomain pharmacophore resulted in the identification of 2-methylisoquinoline-1-one as a novel BET bromodomain-binding motif. Structure guided SAR exploration resulted in >10,000-fold potency improvement for the BRD4-BD1 bromodomain. Lead compounds exhibited excellent potencies in both biochemical and cellular assays in MYC-dependent cell lines. Compound 36 demonstrated good physicochemical properties and promising exposure levels in exploratory PK studies.
Subject(s)
Drug Design , Isoquinolines/chemistry , Nuclear Proteins/antagonists & inhibitors , Transcription Factors/antagonists & inhibitors , Binding Sites , Cell Cycle Proteins , Cell Line, Tumor , Cell Survival/drug effects , Crystallography, X-Ray , Humans , Inhibitory Concentration 50 , Isoquinolines/chemical synthesis , Isoquinolines/pharmacology , Molecular Dynamics Simulation , Nuclear Proteins/metabolism , Protein Structure, Tertiary , Structure-Activity Relationship , Transcription Factors/metabolismABSTRACT
Axl has been a target of interest in the oncology field for several years based on its role in various oncogenic processes. To date, no wild-type Axl crystal structure has been reported. Herein, we describe the structure-based optimization of a novel chemotype of Axl inhibitors, 1H-imidazole-2-carboxamide, using a mutated kinase homolog, Mer(I650M), as a crystallographic surrogate. Iterative optimization of the initial lead compound (1) led to compound (21), a selective and potent inhibitor of wild-type Axl. Compound (21) will serve as a useful compound for further in vivo studies.
Subject(s)
Imidazoles/chemistry , Imidazoles/pharmacology , Mutation , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins/antagonists & inhibitors , Proto-Oncogene Proteins/genetics , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Receptor Protein-Tyrosine Kinases/genetics , Crystallography, X-Ray , Molecular Structure , c-Mer Tyrosine Kinase , Axl Receptor Tyrosine KinaseABSTRACT
A new series of NS3/4A protease boronic acid inhibitors is described. The compounds show good biochemical potency and cellular activity. The peptidomimetic inhibitors were evaluated against proteases from different HCV genotypes and clinically relevant NS3/4A mutants. Compound 28 displayed subnanomolar to single digit nanomolar potencies in the enzymatic assays and an EC50 of 25 nM in the replicon cell-based assay.
Subject(s)
Antiviral Agents/chemical synthesis , Boronic Acids/chemical synthesis , Carrier Proteins/antagonists & inhibitors , Hepacivirus/drug effects , Protease Inhibitors/chemical synthesis , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Proteins/antagonists & inhibitors , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Boronic Acids/chemistry , Boronic Acids/pharmacology , Carrier Proteins/genetics , Carrier Proteins/metabolism , Cell Line, Tumor , Genotype , Hepacivirus/genetics , Hepatitis C/drug therapy , Humans , Intracellular Signaling Peptides and Proteins , Mutant Proteins/antagonists & inhibitors , Mutant Proteins/metabolism , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolism , Viral Proteins/genetics , Viral Proteins/metabolismABSTRACT
Inhibition of the vascular endothelial growth factor (VEGF) signaling pathway has emerged as one of the most promising new approaches for cancer therapy. We describe herein the key steps starting from an initial screening hit leading to the discovery of pazopanib, N(4)-(2,3-dimethyl-2H-indazol-6-yl)-N(4)-methyl-N(2)-(4-methyl-3-sulfonamidophenyl)-2,4-pyrimidinediamine, a potent pan-VEGF receptor (VEGFR) inhibitor under clinical development for renal-cell cancer and other solid tumors.
Subject(s)
Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Pyrimidines/chemistry , Pyrimidines/pharmacology , Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitors , Sulfonamides/chemistry , Sulfonamides/pharmacology , Animals , Cells, Cultured , Crystallography, X-Ray , Cytochrome P-450 Enzyme Inhibitors , Cytochrome P-450 Enzyme System/metabolism , Humans , Indazoles , Isoenzymes/antagonists & inhibitors , Isoenzymes/metabolism , Mice , Models, Molecular , Molecular Structure , Neoplasms/blood supply , Neoplasms/drug therapy , Neoplasms/enzymology , Protein Kinase Inhibitors/therapeutic use , Pyrimidines/therapeutic use , Receptors, Vascular Endothelial Growth Factor/chemistry , Receptors, Vascular Endothelial Growth Factor/metabolism , Sulfonamides/therapeutic use , Xenograft Model Antitumor AssaysABSTRACT
With the development of targeted therapeutics, especially for small-molecule inhibitors, it is important to understand whether the observed in vivo efficacy correlates with the modulation of desired/intended target in vivo. We have developed a small-molecule inhibitor of all three vascular endothelial growth factor (VEGF) receptors (VEGFR), platelet-derived growth factor receptor, and c-Kit tyrosine kinases, pazopanib (GW786034), which selectively inhibits VEGF-induced endothelial cell proliferation. It has good oral exposure and inhibits angiogenesis and tumor growth in mice. Because bolus administration of the compound results in large differences in C(max) and C(trough), we investigated the effect of continuous infusion of a VEGFR inhibitor on tumor growth and angiogenesis. GW771806, which has similar enzyme and cellular profiles to GW786034, was used for these studies due to higher solubility requirements for infusion studies. Comparing the pharmacokinetics by two different routes of administration (bolus p.o. dosing and continuous infusion), we showed that the antitumor and antiangiogenic activity of VEGFR inhibitors is dependent on steady-state concentration of the compound above a threshold. The steady-state concentration required for these effects is consistent with the concentration required for the inhibition of VEGF-induced VEGFR2 phosphorylation in mouse lungs. Furthermore, the steady-state concentration of pazopanib determined from preclinical activity showed a strong correlation with the pharmacodynamic effects and antitumor activity in the phase I clinical trial.
Subject(s)
Antineoplastic Agents/pharmacology , Antineoplastic Agents/pharmacokinetics , Indazoles/pharmacology , Indazoles/pharmacokinetics , Neovascularization, Pathologic/pathology , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/pharmacokinetics , Pyrimidines/pharmacology , Pyrimidines/pharmacokinetics , Sulfonamides/pharmacology , Sulfonamides/pharmacokinetics , Sulfones/pharmacology , Sulfones/pharmacokinetics , Animals , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/blood , Cell Line, Tumor , Cell-Free System , Cornea/pathology , Dose-Response Relationship, Drug , Female , Fibroblast Growth Factor 2/pharmacology , Humans , Indazoles/administration & dosage , Indazoles/blood , Inhibitory Concentration 50 , Mice , Mice, Nude , Phosphorylation/drug effects , Phosphotyrosine/metabolism , Protein Kinase Inhibitors/administration & dosage , Protein Kinase Inhibitors/blood , Pyrimidines/administration & dosage , Pyrimidines/blood , Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitors , Sulfonamides/administration & dosage , Sulfonamides/blood , Sulfones/administration & dosage , Sulfones/blood , Vascular Endothelial Growth Factor A/pharmacologyABSTRACT
An efficient and regioselective synthesis of 2-methyl-2H-indazoles and 2-ethyl-2H-indazoles using trimethyloxonium tetrafluoroborate or triethyloxonium hexafluorophosphate is reported.
