ABSTRACT
Potent and selective substrate-based covalent inhibitors of MALT1 protease were developed from the tetrapeptide tool compound Z-VRPR-fmk. To improve cell permeability, we replaced one arginine residue. We further optimized a series of tripeptides and identified compounds that were potent in both a GloSensor reporter assay measuring cellular MALT1 protease activity, and an OCI-Ly3 cell proliferation assay. Example compounds showed good overall selectivity towards cysteine proteases, and one compound was selected for further profiling in ABL-DLBCL cells and xenograft efficacy models.
Subject(s)
Caspase Inhibitors/pharmacology , Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein/antagonists & inhibitors , Peptides/pharmacology , Caspase Inhibitors/chemical synthesis , Caspase Inhibitors/chemistry , Dose-Response Relationship, Drug , Humans , Molecular Structure , Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein/metabolism , Peptides/chemical synthesis , Peptides/chemistry , Structure-Activity RelationshipABSTRACT
Targeted covalent small molecules have shown promise for cancers driven by KRAS G12C. Allosteric compounds that access an inducible pocket formed by movement of a dynamic structural element in KRAS, switch II, have been reported, but these compounds require further optimization to enable their advancement into clinical development. We demonstrate that covalent quinazoline-based switch II pocket (SIIP) compounds effectively suppress GTP loading of KRAS G12C, MAPK phosphorylation, and the growth of cancer cells harboring G12C. Notably we find that adding an amide substituent to the quinazoline scaffold allows additional interactions with KRAS G12C, and remarkably increases the labeling efficiency, potency, and selectivity of KRAS G12C inhibitors. Structural studies using X-ray crystallography reveal a new conformation of SIIP and key interactions made by substituents located at the quinazoline 2-, 4-, and 7-positions. Optimized lead compounds in the quinazoline series selectively inhibit KRAS G12C-dependent signaling and cancer cell growth at sub-micromolar concentrations.
Subject(s)
Acrylamides/chemistry , Quinazolines/chemistry , ras Proteins/metabolism , A549 Cells , Acrylamides/metabolism , Acrylamides/pharmacology , Amides/chemistry , Apoptosis/drug effects , Binding Sites , Cell Line, Tumor , Crystallography, X-Ray , HCT116 Cells , Humans , MAP Kinase Signaling System/drug effects , Molecular Dynamics Simulation , Mutagenesis, Site-Directed , Phosphorylation/drug effects , Protein Structure, Tertiary , Quinazolines/metabolism , Quinazolines/pharmacology , Structure-Activity Relationship , ras Proteins/antagonists & inhibitors , ras Proteins/geneticsABSTRACT
A novel series of potent benzoxazole mPGES-1 inhibitors has been derived from a hit from a high throughput screen. Compound 37 displays mPGES-1 inhibition in an enzyme assay (0.018 µM) and PGE-2 inhibition in a cell-based assay (0.034 µM). It demonstrates 500- and 2500-fold selectivity for mPGES-1 over COX-2 and 6-keto PGF-1α, respectively. In vivo PK studies in dogs demonstrate 55% oral bioavailability and an 7 h half-life.
