ABSTRACT
Dysregulation of Fibroblast Growth Factor Receptor (FGFR) signaling through amplifications, mutations, and gene fusions has been implicated in a broad array of cancers (e.g. liver, gastric, ovarian, endometrial, and bladder). ARQ 087 is a novel, ATP competitive, small molecule, multi-kinase inhibitor with potent in vitro and in vivo activity against FGFR addicted cell lines and tumors. Biochemically, ARQ 087 exhibited IC50 values of 1.8 nM for FGFR2, and 4.5 nM for FGFR1 and 3. In cells, inhibition of FGFR2 auto-phosphorylation and other proteins downstream in the FGFR pathway (FRS2α, AKT, ERK) was evident by the response to ARQ 087 treatment. Cell proliferation studies demonstrated ARQ 087 has anti-proliferative activity in cell lines driven by FGFR dysregulation, including amplifications, fusions, and mutations. Cell cycle studies in cell lines with high levels of FGFR2 protein showed a positive relationship between ARQ 087 induced G1 cell cycle arrest and subsequent induction of apoptosis. In addition, ARQ 087 was effective at inhibiting tumor growth in vivo in FGFR2 altered, SNU-16 and NCI-H716, xenograft tumor models with gene amplifications and fusions. ARQ 087 is currently being studied in a phase 1/2 clinical trial that includes a sub cohort for intrahepatic cholangiocarcinoma patients with confirmed FGFR2 gene fusions (NCT01752920).
Subject(s)
Aniline Compounds/pharmacology , Quinazolines/pharmacology , Receptors, Fibroblast Growth Factor/antagonists & inhibitors , Animals , Antineoplastic Agents/pharmacology , Blotting, Western , COS Cells/drug effects , COS Cells/physiology , Cell Cycle/drug effects , Cell Line , Cell Proliferation/drug effects , Chlorocebus aethiops , Female , Mice, Nude , Mice, SCID , Neoplasm Transplantation , Neoplasms/drug therapyABSTRACT
The work in this paper describes the optimization of the 3-(3-phenyl-3H-imidazo[4,5-b]pyridin-2-yl)pyridin-2-amine chemical series as potent, selective allosteric inhibitors of AKT kinases, leading to the discovery of ARQ 092 (21a). The cocrystal structure of compound 21a bound to full-length AKT1 confirmed the allosteric mode of inhibition of this chemical class and the role of the cyclobutylamine moiety. Compound 21a demonstrated high enzymatic potency against AKT1, AKT2, and AKT3, as well as potent cellular inhibition of AKT activation and the phosphorylation of the downstream target PRAS40. Compound 21a also served as a potent inhibitor of the AKT1-E17K mutant protein and inhibited tumor growth in a human xenograft mouse model of endometrial adenocarcinoma.
Subject(s)
Aminopyridines/pharmacology , Antineoplastic Agents/pharmacology , Carcinoma, Endometrioid/drug therapy , Drug Discovery , Endometrial Neoplasms/drug therapy , Imidazoles/pharmacology , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Administration, Oral , Allosteric Regulation/drug effects , Aminopyridines/administration & dosage , Aminopyridines/chemistry , Animals , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/chemistry , Carcinoma, Endometrioid/pathology , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Endometrial Neoplasms/pathology , Female , Humans , Imidazoles/administration & dosage , Imidazoles/chemistry , Mice , Molecular Structure , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/pathology , Protein Kinase Inhibitors/administration & dosage , Protein Kinase Inhibitors/chemistry , Proto-Oncogene Proteins c-akt/genetics , Proto-Oncogene Proteins c-akt/metabolism , Structure-Activity RelationshipABSTRACT
This paper describes the implementation of a biochemical and biophysical screening strategy to identify and optimize small molecule Akt1 inhibitors that act through a mechanism distinct from that observed for kinase domain ATP-competitive inhibitors. With the aid of an unphosphorylated Akt1 cocrystal structure of 12j solved at 2.25 Å, it was possible to confirm that as a consequence of binding these novel inhibitors, the ATP binding cleft contained a number of hydrophobic residues that occlude ATP binding as expected. These Akt inhibitors potently inhibit intracellular Akt activation and its downstream target (PRAS40) in vitro. In vivo pharmacodynamic and pharmacokinetic studies with two examples, 12e and 12j, showed the series to be similarly effective at inhibiting the activation of Akt and an additional downstream effector (p70S6) following oral dosing in mice.
Subject(s)
Adenosine Triphosphate/physiology , Antineoplastic Agents/chemical synthesis , Imidazoles/chemical synthesis , Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Pyridines/chemical synthesis , Adaptor Proteins, Signal Transducing/antagonists & inhibitors , Administration, Oral , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Biological Availability , Catalytic Domain , Cell Line, Tumor , Cell Proliferation/drug effects , Crystallography, X-Ray , Humans , Imidazoles/chemistry , Imidazoles/pharmacology , Mice , Microsomes, Liver/metabolism , Models, Molecular , Phosphorylation , Protein Binding , Protein Conformation , Pyridines/chemistry , Pyridines/pharmacology , Ribosomal Protein S6 Kinases, 70-kDa/antagonists & inhibitors , Structure-Activity RelationshipABSTRACT
A novel class of highly selective inhibitors of p38 MAP kinase was discovered from high throughput screening. The synthesis and optimization of a series of 5-amino-N-phenyl-1H-pyrazol-4-yl-3-phenylmethanones is described. An X-ray crystal structure of this series bound in the ATP binding pocket of unphosphorylated p38alpha established the presence of a unique hydrogen bond between the exocyclic amine of the inhibitor and threonine 106 which likely contributes to the selectivity for p38. The crystallographic information was used to optimize the potency and physicochemical properties of the series. The incorporation of the 2,3-dihydroxypropoxy moiety on the pyrazole scaffold resulted in a compound with excellent drug-like properties including high oral bioavailability. These efforts identified 63 (RO3201195) as an orally bioavailable and highly selective inhibitor of p38 which was selected for advancement into Phase I clinical trials.
Subject(s)
Anti-Inflammatory Agents/chemical synthesis , Pyrazoles/chemical synthesis , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , Adenosine Triphosphate/chemistry , Administration, Oral , Animals , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Arthritis, Experimental/drug therapy , Binding Sites , Biological Availability , Cell Line , Crystallography, X-Ray , Dogs , Female , Haplorhini , Humans , Interleukin-1/antagonists & inhibitors , Interleukin-1/biosynthesis , Interleukin-6/antagonists & inhibitors , Interleukin-6/biosynthesis , Models, Molecular , Pyrazoles/chemistry , Pyrazoles/pharmacology , Rats , Rats, Inbred Lew , Stereoisomerism , Structure-Activity Relationship , Tumor Necrosis Factor-alpha/antagonists & inhibitors , p38 Mitogen-Activated Protein Kinases/chemistryABSTRACT
A parallel strategy incorporating predictive modeling of both sodium site 2 blocking activity and cytochrome p450 CYP2D6 enzyme activity as well as experimental data from ADME profiling (eADME) has been applied to the design of new small molecule sodium channel blockers. New structural motifs were identified, which combined sodium channel activity with decreased ADME liabilities. Compounds 10h (site 2, IC(50) =531 nM) and 7j (site 2, IC(50) =149 nM) were identified from two structural classes as sodium channel blockers with favorable in vitro eADME profiles.
