ABSTRACT
The ability to restrict low molecular weight compounds to the gastrointestinal (GI) tract may enable an enhanced therapeutic index for molecular targets known to be associated with systemic toxicity. Using a triazolopyrazine CSF1R inhibitor scaffold, a broad range of prodrugs were synthesized and evaluated for enhanced delivery to the colon in mice. Subsequently, the preferred cyclodextrin prodrug moiety was appended to a number of CSF1R inhibitory active parent molecules, enabling GI-restricted delivery. Evaluation of a cyclodextrin prodrug in a dextran sodium sulfate (DSS)-induced mouse colitis model resulted in enhanced GI tissue levels of active parent. At a dose where no significant depletion of systemic monocytes were detected, the degree of pharmacodynamic effect-measured as reduction in macrophages in the colon-was inferior to that observed with a systemically available positive control. This suggests that a suitable therapeutic index cannot be achieved with CSF1R inhibition by using GI-restricted delivery in mice. However, these efforts provide a comprehensive frame-work in which to pursue additional gut-restricted delivery strategies for future GI targets.
Subject(s)
Colitis/immunology , Cyclodextrins/chemistry , Prodrugs/administration & dosage , Prodrugs/chemical synthesis , Receptors, Granulocyte-Macrophage Colony-Stimulating Factor/antagonists & inhibitors , Animals , Colitis/chemically induced , Colitis/drug therapy , Colon/chemistry , Dextran Sulfate/adverse effects , Disease Models, Animal , Drug Evaluation, Preclinical , Female , Macrophages/drug effects , Macrophages/metabolism , Mice , Models, Molecular , Molecular Structure , Prodrugs/chemistry , Prodrugs/pharmacokineticsABSTRACT
Previous work investigating tricyclic pyrrolopyrazines as kinase cores led to the discovery that 1-cyclohexyl-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazine (12) had Jak inhibitory activity. Herein we describe our initial efforts to develop orally bioavailable analogs of 12 with improved selectivity of Jak1 over Jak2.
Subject(s)
Janus Kinase 1/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , Pyrazines/pharmacology , Triazoles/pharmacology , Animals , Cell Line , Dose-Response Relationship, Drug , Humans , Janus Kinase 1/metabolism , Male , Models, Molecular , Molecular Structure , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Pyrazines/chemical synthesis , Pyrazines/chemistry , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship , Triazoles/chemical synthesis , Triazoles/chemistryABSTRACT
We previously demonstrated that selective inhibition of protein kinase Cθ (PKCθ) with triazinone 1 resulted in dose-dependent reduction of paw swelling in a mouse model of arthritis.1,2 However, a high concentration was required for efficacy, thus providing only a minimal safety window. Herein we describe a strategy to deliver safer compounds based on the hypothesis that optimization of potency in concert with good oral pharmacokinetic (PK) properties would enable in vivo efficacy at reduced exposures, resulting in an improved safety window. Ultimately, transformation of 1 yielded analogues that demonstrated excellent potency and PK properties and fully inhibited IL-2 production in an acute model. In spite of good exposure, twice-a-day treatment with 17l in the glucose-6-phosphate isomerase chronic in vivo mouse model of arthritis yielded only moderate efficacy. On the basis of the exposure achieved, we conclude that PKCθ inhibition alone is insufficient for complete efficacy in this rodent arthritis model.
Subject(s)
Anti-Inflammatory Agents/pharmacology , Arthritis, Experimental/drug therapy , Isoenzymes/antagonists & inhibitors , Protein Kinase C/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , Animals , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/metabolism , Arthritis, Experimental/metabolism , Crystallography, X-Ray , Disease Models, Animal , Humans , Interleukin-2/metabolism , Isoenzymes/chemistry , Isoenzymes/metabolism , Male , Mice , Models, Chemical , Models, Molecular , Molecular Structure , Protein Binding , Protein Kinase C/chemistry , Protein Kinase C/metabolism , Protein Kinase C-theta , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/metabolism , Protein Structure, Tertiary , Treatment OutcomeABSTRACT
Protein kinase Cθ (PKCθ) regulates a key step in the activation of T cells. On the basis of its mechanism of action, inhibition of this kinase is hypothesized to serve as an effective therapy for autoimmune diseases such as rheumatoid arthritis (RA), inflammatory bowel disease (IBD), and psoriasis. Herein, the discovery of a small molecule PKCθ inhibitor is described, starting from a fragment hit 1 and advancing to compound 41 through the use of structure-based drug design. Compound 41 demonstrates excellent in vitro activity, good oral pharmacokinetics, and efficacy in both an acute in vivo mechanistic model and a chronic in vivo disease model but suffers from tolerability issues upon chronic dosing.
Subject(s)
Isoenzymes/antagonists & inhibitors , Isoenzymes/chemistry , Protein Kinase C/antagonists & inhibitors , Protein Kinase C/chemistry , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Administration, Oral , Animals , Area Under Curve , Arthritis, Experimental/drug therapy , Biological Availability , Cells, Cultured , Chromatography, Liquid , Crystallography, X-Ray , Dose-Response Relationship, Drug , Drug Design , Drug Discovery , Female , Humans , Isoenzymes/metabolism , Mass Spectrometry , Mice, Inbred BALB C , Mice, Inbred DBA , Models, Molecular , Molecular Structure , Protein Binding , Protein Kinase C/metabolism , Protein Kinase C-theta , Protein Kinase Inhibitors/pharmacokinetics , Protein Structure, Tertiary , Rats , Small Molecule Libraries/chemistry , Small Molecule Libraries/pharmacokinetics , Small Molecule Libraries/pharmacology , T-Lymphocytes/drug effectsABSTRACT
Interest in therapeutic kinase inhibitors continues to grow beyond success in oncology. To date, ATP-mimetic kinase inhibitors have focused primarily on monocyclic and bicyclic heterocyclic cores. We sought to expand on the repertoire of potential cores for kinase inhibition by exploring tricyclic variants of classical bicyclic hinge binding motifs such as pyrrolopyridine and pyrrolopyrazine. Herein we describe the syntheses of eight alternative tricyclic cores as well as in vitro screening results for representative kinases of potential therapeutic interest.
Subject(s)
Drug Design , Protein Kinase Inhibitors , Cells, Cultured , Cyclization , Enzyme Activation/drug effects , Inhibitory Concentration 50 , Molecular Structure , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Pyrazines/chemical synthesis , Pyrazines/chemistry , Pyrazines/pharmacology , Pyridines/chemical synthesis , Pyridines/chemistry , Pyridines/pharmacology , Pyrroles/chemical synthesis , Pyrroles/chemistry , Pyrroles/pharmacologyABSTRACT
COT (Tpl2 in mice) is a serine/threonine MAP3 kinase that regulates production of TNF-alpha and other pro-inflammatory cytokines such as IL-1beta via the ERK/MAP kinase pathway. As TNF-alpha and IL-1beta are clinically validated targets for therapeutic intervention in rheumatoid arthritis (RA), blocking COT provides a potential avenue for amelioration of disease. Herein we describe identification of a cellular active selective small molecule inhibitor of COT kinase.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , MAP Kinase Kinase Kinases/antagonists & inhibitors , Proto-Oncogene Proteins/antagonists & inhibitors , Pyridines/chemical synthesis , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Animals , Arthritis, Rheumatoid/drug therapy , Chemistry, Pharmaceutical/methods , Drug Design , Extracellular Signal-Regulated MAP Kinases/metabolism , Humans , Hydrogen Bonding , Inhibitory Concentration 50 , Interleukin-1beta/metabolism , Ligands , MAP Kinase Kinase Kinases/chemistry , Mice , Molecular Structure , Proto-Oncogene Proteins/chemistry , Pyridines/pharmacology , Tumor Necrosis Factor-alpha/chemistry , Tumor Necrosis Factor-alpha/metabolismABSTRACT
Evaluation of hit chemotypes from high throughput screening identified a novel series of 2,4-disubstituted thieno[2,3-c]pyridines as COT kinase inhibitors. Structural modifications exploring SAR at the 2- and 4-positions resulting in inhibitors with improved enzyme potency and cellular activity are disclosed.
Subject(s)
MAP Kinase Kinase Kinases/antagonists & inhibitors , Models, Molecular , Proto-Oncogene Proteins/antagonists & inhibitors , Pyridines/chemical synthesis , Pyridines/pharmacology , Thiophenes/chemical synthesis , Thiophenes/pharmacology , Combinatorial Chemistry Techniques , Crystallography, X-Ray , Humans , Molecular Conformation , Molecular Structure , Pyridines/chemistry , Structure-Activity Relationship , Thiophenes/chemistryABSTRACT
High-throughput screening identified a low molecular weight antagonist of CXCR3 displaying micromolar activity in a membrane filtration-binding assay. Systematic modification of the benzimidazole core and tethered acetophenone moiety established tractable SAR of analogs with improved physicochemical properties and sub-micromolar activity across both human and murine receptors.
