ABSTRACT
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
New arylpiperazines related to buspirone, gepirone and NAN-190 were designed and screened in silico for their 5-HT(1A) affinity and potential sites of metabolism by human cytochrome p450 (CYP3A4). Modifications to these structures were assessed in silico for their influence on both 5HT(1A) affinity and metabolism. Selected new molecules were synthesized and purified in a parallel chemistry approach to determine structure activity relationships (SARs). The resulting molecules were assessed in vitro for their 5HT(1A) affinity and half-life in a heterologously expressed human CYP3A4 assay. Molecular features responsible for 5-HT(1A) affinity and CYP3A4 stability are described.
Subject(s)
Drug Design , Piperazines/metabolism , Receptor, Serotonin, 5-HT1A/metabolism , Serotonin Agents/metabolism , Cytochrome P-450 CYP3A , Cytochrome P-450 Enzyme System/metabolism , Humans , Ligands , Piperazines/chemical synthesis , Serotonin Agents/chemical synthesisABSTRACT
Calix[4]arenes, calix[4]resorcarenes, and anionic cyclodextrin derivatives were examined as chiral NMR solvating agents. The calix[4]arenes were prepared by attachment of amino acids through the hydroxyl groups of the phenol rings. Chloroform-, methanol-, and water-soluble derivatives were prepared and tested with a range of substrates. Chloroform-soluble chiral calix[4]resorcarenes were prepared by attachment of chiral primary and secondary amines and examined in NMR applications with a variety of substrates. Sulfated and carboxymethylated beta-cyclodextrin are effective at causing enantiomeric discrimination in the (1)H NMR spectra of organic cations. Lanthanide ions associate at the carboxymethyl groups and cause sizeable shifts and enhancements in enantiomeric discrimination in the spectra of organic cations. The enhancements caused by the lanthanide ion are large enough that much lower concentrations of the cyclodextrin can be used as compared to conventional analyses.
