ABSTRACT
Inhibitor of apoptosis proteins (IAPs) are important regulators of apoptosis and pro-survival signaling pathways whose deregulation is often associated with tumor genesis and tumor growth. IAPs have been proposed as targets for anticancer therapy, and a number of peptidomimetic IAP antagonists have entered clinical trials. Using our fragment-based screening approach, we identified nonpeptidic fragments binding with millimolar affinities to both cellular inhibitor of apoptosis protein 1 (cIAP1) and X-linked inhibitor of apoptosis protein (XIAP). Structure-based hit optimization together with an analysis of protein-ligand electrostatic potential complementarity allowed us to significantly increase binding affinity of the starting hits. Subsequent optimization gave a potent nonalanine IAP antagonist structurally distinct from all IAP antagonists previously reported. The lead compound had activity in cell-based assays and in a mouse xenograft efficacy model and represents a highly promising start point for further optimization.
Subject(s)
Antineoplastic Agents/pharmacology , Inhibitor of Apoptosis Proteins/antagonists & inhibitors , Inhibitor of Apoptosis Proteins/drug effects , Peptide Fragments/pharmacology , X-Linked Inhibitor of Apoptosis Protein/antagonists & inhibitors , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacokinetics , Cell Proliferation/drug effects , Computational Biology , Drug Design , Drug Discovery , High-Throughput Screening Assays , Humans , Mice , Mice, Inbred BALB C , Models, Molecular , Peptide Fragments/chemical synthesis , Peptide Fragments/pharmacokinetics , Piperazines/chemical synthesis , Piperazines/pharmacology , Xenograft Model Antitumor AssaysABSTRACT
We describe here the identification and characterization of 2 novel inhibitors of the fibroblast growth factor receptor (FGFR) family of receptor tyrosine kinases. The compounds exhibit selective inhibition of FGFR over the closely related VEGFR2 receptor in cell lines and in vivo. The pharmacologic profile of these inhibitors was defined using a panel of human tumor cell lines characterized for specific mutations, amplifications, or translocations known to activate one of the four FGFR receptor isoforms. This pharmacology defines a profile for inhibitors that are likely to be of use in clinical settings in disease types where FGFR is shown to play an important role.
Subject(s)
Antineoplastic Agents/pharmacology , Fibroblast Growth Factors/metabolism , Protein Kinase Inhibitors/pharmacology , Receptors, Fibroblast Growth Factor/antagonists & inhibitors , Animals , Antineoplastic Agents/chemistry , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Drug Design , Drug Evaluation, Preclinical , Humans , Mice , Mice, Inbred BALB C , Mice, Nude , Models, Molecular , Neoplasms/drug therapy , Neoplasms/metabolism , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/therapeutic use , Receptors, Fibroblast Growth Factor/genetics , Signal Transduction/drug effects , Treatment Outcome , Xenograft Model Antitumor AssaysABSTRACT
Multiplexed photoaptamer-based arrays that allow for the simultaneous measurement of multiple proteins of interest in serum samples are described. Since photoaptamers covalently bind to their target analytes before fluorescent signal detection, the arrays can be vigorously washed to remove background proteins, providing the potential for superior signal-to-noise ratios and lower limits of quantification in biological matrices. Data are presented here for a 17-plex photoaptamer array exhibiting limits of detection below 10 fM for several analytes including interleukin-16, vascular endothelial growth factor, and endostatin and able to measure proteins in 10% serum samples. The assays are simple, scalable, and reproducible. Affinity of the capture reagent is shown to be directly correlated to the limit of detection for the analyte on the array.
