ABSTRACT
This report documents the first example of a specific inhibitor of protein kinases with preferential binding to the activated kinase conformation: 5H-benzo[4,5]cyclohepta[1,2-b]pyridin-5-one 11r (MK-8033), a dual c-Met/Ron inhibitor under investigation as a treatment for cancer. The design of 11r was based on the desire to reduce time-dependent inhibition of CYP3A4 (TDI) by members of this structural class. A novel two-step protocol for the synthesis of benzylic sulfonamides was developed to access 11r and analogues. We provide a rationale for the observed selectivity based on X-ray crystallographic evidence and discuss selectivity trends with additional examples. Importantly, 11r provides full inhibition of tumor growth in a c-Met amplified (GTL-16) subcutaneous tumor xenograft model and may have an advantage over inactive form kinase inhibitors due to equal potency against a panel of oncogenic activating mutations of c-Met in contrast to c-Met inhibitors without preferential binding to the active kinase conformation.
Subject(s)
Benzocycloheptenes/metabolism , Benzocycloheptenes/pharmacology , Drug Discovery , Proto-Oncogene Proteins c-met/antagonists & inhibitors , Proto-Oncogene Proteins c-met/metabolism , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Sulfonamides/metabolism , Sulfonamides/pharmacology , Animals , Benzocycloheptenes/chemistry , Cell Line, Tumor , Dogs , Enzyme Activation/drug effects , Female , Humans , Mice , Models, Molecular , Protein Conformation , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/metabolism , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins c-met/chemistry , Rats , Substrate Specificity , Sulfonamides/chemistry , Xenograft Model Antitumor AssaysABSTRACT
c-Met is a transmembrane tyrosine kinase that mediates activation of several signaling pathways implicated in aggressive cancer phenotypes. In recent years, research into this area has highlighted c-Met as an attractive cancer drug target, triggering a number of approaches to disrupt aberrant c-Met signaling. Screening efforts identified a unique class of 5H-benzo[4,5]cyclohepta[1,2-b]pyridin-5-one kinase inhibitors, exemplified by 1. Subsequent SAR studies led to the development of 81 (MK-2461), a potent inhibitor of c-Met that was efficacious in preclinical animal models of tumor suppression. In addition, biochemical studies and X-ray analysis have revealed that this unique class of kinase inhibitors binds preferentially to the activated (phosphorylated) form of the kinase. This report details the development of 81 and provides a description of its unique biochemical properties.
Subject(s)
Antineoplastic Agents/chemical synthesis , Benzocycloheptenes/chemical synthesis , Pyridines/chemical synthesis , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Animals , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/pharmacology , Benzocycloheptenes/pharmacokinetics , Benzocycloheptenes/pharmacology , Cell Line, Tumor , Crystallography, X-Ray , Dogs , Drug Screening Assays, Antitumor , Female , Haplorhini , Humans , Mice , Mice, Nude , Models, Molecular , Mutation , Neoplasm Transplantation , Phosphorylation , Protein Binding , Pyrazoles/chemical synthesis , Pyrazoles/pharmacokinetics , Pyrazoles/pharmacology , Pyridines/pharmacokinetics , Pyridines/pharmacology , Rats , Receptor Protein-Tyrosine Kinases/genetics , Structure-Activity Relationship , Sulfonamides/chemical synthesis , Sulfonamides/pharmacokinetics , Sulfonamides/pharmacology , Transplantation, HeterologousABSTRACT
Methodology is outlined for the chemical synthesis of versatile photo-Bergman enediyne building blocks and their conjugates. Routes to both mono and bis conjugated enediyne templates are detailed together with representative examples of their bioconjugates, nanoconjugates, PEG derivatives and water soluble salts. The immunocompetence of antibody conjugates is retained, and application in the form of reagents for photodynamic therapy (PDT) advanced.
Subject(s)
Antineoplastic Agents/chemical synthesis , Enediynes/chemical synthesis , Photosensitizing Agents/chemical synthesis , Antibodies/chemistry , Antibodies/immunology , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Enediynes/chemistry , Enediynes/pharmacology , Gold/chemistry , Metal Nanoparticles/chemistry , Photosensitizing Agents/chemistry , Photosensitizing Agents/pharmacology , Polyethylene Glycols/chemistryABSTRACT
Efficient syntheses of a series of functionalized aryl enediynes have been developed. The building blocks were used to effect conjugation to carrier PEG templates which allowed subsequent coupling to a cardiac targeted monoclonal antibody. Immunocompetence of the enediyne-Mab conjugates was demonstrated by ELISA, and both parent enediynes and bioconjugates underwent successful photo-Bergman cyclization. Finally, surface modified (Au) nanoparticle conjugates were prepared and size confirmed by TEM analysis. Application as long-circulating photoactivated prodrugs is anticipated.
