ABSTRACT
2-aminothiazole (1) was discovered as a novel Src family kinase inhibitor template through screening of our internal compound collection. Optimization through successive structure-activity relationship iterations identified analogs 2 (Dasatinib, BMS-354825) and 12m as pan-Src inhibitors with nanomolar to subnanomolar potencies in biochemical and cellular assays. Molecular modeling was used to construct a putative binding model for Lck inhibition by this class of compounds. The framework of key hydrogen-bond interactions proposed by this model was in agreement with the subsequent, published crystal structure of 2 bound to structurally similar Abl kinase. The oral efficacy of this class of inhibitors was demonstrated with 12m in inhibiting the proinflammatory cytokine IL-2 ex vivo in mice (ED50 approximately 5 mg/kg) and in reducing TNF levels in an acute murine model of inflammation (90% inhibition in LPS-induced TNFalpha production when dosed orally at 60 mg/kg, 2 h prior to LPS administration). The oral efficacy of 12m was further demonstrated in a chronic model of adjuvant arthritis in rats with established disease when administered orally at 0.3 and 3 mg/kg twice daily. Dasatinib (2) is currently in clinical trials for the treatment of chronic myelogenous leukemia.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/chemical synthesis , Pyrimidines/chemical synthesis , Thiazoles/chemical synthesis , src-Family Kinases/antagonists & inhibitors , Administration, Oral , Animals , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Arthritis, Experimental/drug therapy , Cell Proliferation/drug effects , Chronic Disease , Dasatinib , Female , Humans , In Vitro Techniques , Inflammation/blood , Inflammation/chemically induced , Interleukin-2/antagonists & inhibitors , Lipopolysaccharides , Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/antagonists & inhibitors , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Models, Molecular , Protein Binding , Pyrimidines/chemistry , Pyrimidines/pharmacology , Rats , Rats, Inbred Lew , Structure-Activity Relationship , T-Lymphocytes/cytology , T-Lymphocytes/drug effects , Thiazoles/chemistry , Thiazoles/pharmacology , Tumor Necrosis Factor-alpha/metabolismABSTRACT
A series of substituted 2-(aminoheteroaryl)-thiazole-5-carboxamide analogs have been synthesized as novel, potent inhibitors of the Src-family kinase p56Lck. Among them, compound 2 displayed superior in vitro potency and excellent in vivo efficacy.
Subject(s)
Amides/pharmacology , Anti-Inflammatory Agents/pharmacology , Enzyme Inhibitors/pharmacology , Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/antagonists & inhibitors , Thiazoles/pharmacology , src-Family Kinases/antagonists & inhibitors , Administration, Oral , Amides/chemical synthesis , Amides/pharmacokinetics , Animals , Anti-Inflammatory Agents/chemical synthesis , Anti-Inflammatory Agents/pharmacokinetics , Arthritis, Experimental/therapy , Disease Models, Animal , Dose-Response Relationship, Drug , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacokinetics , Male , Models, Molecular , Molecular Structure , Rats , Structure-Activity Relationship , Thiazoles/chemical synthesis , Thiazoles/pharmacokineticsABSTRACT
A series of novel anilino 5-azaimidazoquinoxaline analogues possessing potent in vitro activity against p56Lck and T cell proliferation have been discovered. Subsequent SAR studies led to the identification of compound 4 (BMS-279700) as an orally active lead candidate that blocks the production of proinflammatory cytokines (IL-2 and TNFalpha) in vivo. In addition, an expanded set of imidazoquinoxalines provided several descriptive QSAR models highlighting the influence of significant steric and electronic features. The H-bonding (Met319) contribution to observed binding affinities within a tightly congeneric series was found to be significant.
Subject(s)
Anti-Inflammatory Agents/chemistry , Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/antagonists & inhibitors , Quantitative Structure-Activity Relationship , Quinoxalines/chemistry , Quinoxalines/pharmacokinetics , Animals , Anti-Inflammatory Agents/pharmacokinetics , Anti-Inflammatory Agents/pharmacology , Biological Availability , Cytokines/drug effects , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacokinetics , Enzyme Inhibitors/pharmacology , Female , Hydrogen Bonding , Inhibitory Concentration 50 , Mice , Mice, Inbred C57BL , Models, Molecular , Pyrazines/chemistry , Pyrazines/pharmacology , Quinoxalines/pharmacology , src-Family Kinases/antagonists & inhibitorsABSTRACT
A novel series of 2-amino-5-carboxamidothiazoles were identified as inhibitors of Lck. Structure-activity studies demonstrate the structural requirements for potent Lck activity. Cyclopropylamide 11d is a potent Lck inhibitor having sub-micromolar activity in a PBL proliferation assay.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/antagonists & inhibitors , Thiazoles/chemical synthesis , Thiazoles/pharmacology , Amino Acid Sequence , Binding Sites , Drug Design , Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/chemistry , Models, Molecular , Molecular Structure , Structure-Activity RelationshipABSTRACT
A series of anilino(imidazoquinoxaline) analogues bearing solubilizing side chains at the 6- and 7-positions of the fused phenyl ring has been prepared and evaluated for inhibition against Lck enzyme and of T-cell proliferation. Significant improvement of the cellular activity was achieved over the initial lead, compound 2.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/antagonists & inhibitors , Quinoxalines/chemical synthesis , Quinoxalines/pharmacology , Cell Division/drug effects , Humans , Indicators and Reagents , Structure-Activity Relationship , T-Lymphocytes/drug effectsABSTRACT
Hypochlorous acid is an important oxidizing agent produced by neutrophils to aid in defense against pathogens. Although hypochlorous acid is known to cause tissue damage due to its cytotoxicity, the effect of this oxidizing agent on signal transduction by cells of the immune system and its effects on their responses are not well understood. In this study, hypochlorous acid was found to induce cellular tyrosine phosphorylation in both T and B lymphocytes, activate the ZAP-70 tyrosine kinase, and induce cellular calcium signaling in a tyrosine kinase-dependent manner. These signaling events also occurred in T cell lines that did not express the T-cell receptor, indicating the ability of hypochlorous acid to bypass normal receptor control. Hypochlorous acid induced tumor necrosis factor-alpha production in peripheral blood mononuclear cells in a tyrosine kinase-dependent manner. These results suggest that hypochlorous acid may contribute to inflammatory responses by activating signal pathways in cells of the immune system.
Subject(s)
Calcium Signaling/physiology , Hypochlorous Acid/pharmacology , Lymphocytes/drug effects , Oxidants/pharmacology , Tumor Necrosis Factor-alpha/metabolism , Tyrosine/metabolism , Cytokines/metabolism , Enzyme Activation , Enzyme Inhibitors/pharmacology , Humans , Lymphocytes/immunology , Phosphorylation , Protein-Tyrosine Kinases/metabolism , Receptors, Antigen, T-Cell/genetics , Receptors, Antigen, T-Cell/metabolism , Tumor Cells, Cultured , ZAP-70 Protein-Tyrosine KinaseABSTRACT
We have identified a novel series of 1,5-imidazoquinoxalines as inhibitors of Lck with excellent potency (IC50s<5 nM) as well as good cellular activity against T-cell proliferation (IC50s<1 microM). Structure-activity studies demonstrate the requirement for the core heterocycle in addition to an optimal 2,6-disubstituted aniline group.
