ABSTRACT
A novel series of small-molecule inhibitors has been developed to target the double mutant form of the epidermal growth factor receptor (EGFR) tyrosine kinase, which is resistant to treatment with gefitinib and erlotinib. Our reported compounds also show selectivity over wild-type EGFR. Guided by molecular modeling, this series was evolved to target a cysteine residue in the ATP binding site via covalent bond formation and demonstrates high levels of activity in cellular models of the double mutant form of EGFR. In addition, these compounds show significant activity against the activating mutations, which gefitinib and erlotinib target and inhibition of which gives rise to their observed clinical efficacy. A glutathione (GSH)-based assay was used to measure thiol reactivity toward the electrophilic functionality of the inhibitor series, enabling both the identification of a suitable reactivity window for their potency and the development of a reactivity quantitative structure-property relationship (QSPR) to support design.
Subject(s)
ErbB Receptors/antagonists & inhibitors , ErbB Receptors/chemistry , ErbB Receptors/genetics , Models, Molecular , Mutation , Structure-Activity RelationshipABSTRACT
Wide-ranging exploration of analogues of an ATP-competitive pyrrolopyrimidine inhibitor of Akt led to the discovery of clinical candidate AZD5363, which showed increased potency, reduced hERG affinity, and higher selectivity against the closely related AGC kinase ROCK. This compound demonstrated good preclinical drug metabolism and pharmacokinetics (DMPK) properties and, after oral dosing, showed pharmacodynamic knockdown of phosphorylation of Akt and downstream biomarkers in vivo, and inhibition of tumor growth in a breast cancer xenograft model.
Subject(s)
Protein Kinase Inhibitors/chemical synthesis , Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Pyrimidines/chemical synthesis , Pyrroles/chemical synthesis , Administration, Oral , Cell Line, Tumor , Female , Humans , Inhibitory Concentration 50 , Models, Molecular , Protein Kinase Inhibitors/administration & dosage , Protein Kinase Inhibitors/pharmacology , Pyrimidines/pharmacology , Pyrroles/pharmacology , Structure-Activity Relationship , Xenograft Model Antitumor AssaysABSTRACT
AKT is a key node in the most frequently deregulated signaling network in human cancer. AZD5363, a novel pyrrolopyrimidine-derived compound, inhibited all AKT isoforms with a potency of 10 nmol/L or less and inhibited phosphorylation of AKT substrates in cells with a potency of approximately 0.3 to 0.8 µmol/L. AZD5363 monotherapy inhibited the proliferation of 41 of 182 solid and hematologic tumor cell lines with a potency of 3 µmol/L or less. Cell lines derived from breast cancers showed the highest frequency of sensitivity. There was a significant relationship between the presence of PIK3CA and/or PTEN mutations and sensitivity to AZD5363 and between RAS mutations and resistance. Oral dosing of AZD5363 to nude mice caused dose- and time-dependent reduction of PRAS40, GSK3ß, and S6 phosphorylation in BT474c xenografts (PRAS40 phosphorylation EC(50) ~ 0.1 µmol/L total plasma exposure), reversible increases in blood glucose concentrations, and dose-dependent decreases in 2[18F]fluoro-2-deoxy-D-glucose ((18)F-FDG) uptake in U87-MG xenografts. Chronic oral dosing of AZD5363 caused dose-dependent growth inhibition of xenografts derived from various tumor types, including HER2(+) breast cancer models that are resistant to trastuzumab. AZD5363 also significantly enhanced the antitumor activity of docetaxel, lapatinib, and trastuzumab in breast cancer xenografts. It is concluded that AZD5363 is a potent inhibitor of AKT with pharmacodynamic activity in vivo, has potential to treat a range of solid and hematologic tumors as monotherapy or a combinatorial agent, and has potential for personalized medicine based on the genetic status of PIK3CA, PTEN, and RAS. AZD5363 is currently in phase I clinical trials.
Subject(s)
Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Pyrimidines/pharmacology , Pyrroles/pharmacology , Animals , Breast Neoplasms/drug therapy , Breast Neoplasms/enzymology , Cell Line, Tumor , Cell Proliferation , Female , Humans , Male , Mice , Mice, Nude , Mice, SCID , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/enzymology , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction , Xenograft Model Antitumor AssaysABSTRACT
Wide-ranging exploration of potential replacements for a quinoline-based inhibitor of activation of AKT kinase led to number of alternative, novel scaffolds with potentially improved potency and physicochemical properties. Examples showed predictable DMPK properties, and one such compound demonstrated pharmacodynamic knockdown of phosphorylation of AKT and downstream biomarkers in vivo and inhibition of tumor growth in a breast cancer xenograft model.
