ABSTRACT
A method is presented for the detection of circulating tumor cells (CTC) using mass spectrometry (MS), through reporter-ion amplification. Particles functionalized with short-chain peptides are bound to cells through antibody-antigen interactions. Selective release and MS detection of peptides is shown to detect as few as 690 cells isolated from a 10 mL blood sample. Here we present proof-of-concept results that pave the way for further investigations.
Subject(s)
Cell Separation/methods , Neoplastic Cells, Circulating , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Animals , Antibodies/chemistry , Antibodies/immunology , Cell Count , Cell Line, Tumor , Humans , Immunologic Techniques/methods , Limit of Detection , Mice , Molecular Weight , Nanoparticles/chemistry , Neoplastic Cells, Circulating/immunology , Peptides/chemistry , Silicon Dioxide/chemistryABSTRACT
Matrix metalloproteinase-13 (MMP-13) is a zinc-dependent protease responsible for the cleavage of type II collagen, the major structural protein of articular cartilage. Degradation of this cartilage matrix leads to the development of osteoarthritis. We previously have described highly potent and selective carboxylic acid containing MMP-13 inhibitors; however, nephrotoxicity in preclinical toxicology species precluded development. The accumulation of compound in the kidneys mediated by human organic anion transporter 3 (hOAT3) was hypothesized as a contributing factor for the finding. Herein we report our efforts to optimize the MMP-13 potency and pharmacokinetic properties of non-carboxylic acid leads resulting in the identification of compound 43a lacking the previously observed preclinical toxicology at comparable exposures.
Subject(s)
Matrix Metalloproteinase 13/drug effects , Matrix Metalloproteinase Inhibitors/chemical synthesis , Matrix Metalloproteinase Inhibitors/pharmacology , Osteoarthritis/drug therapy , Pyrimidines/chemical synthesis , Pyrimidines/pharmacology , Tetrazoles/chemical synthesis , Tetrazoles/pharmacology , Animals , Cartilage, Articular/drug effects , Cartilage, Articular/pathology , Collagenases/drug effects , Dogs , Drug Design , Humans , Kidney/metabolism , Macaca fascicularis , Male , Matrix Metalloproteinase Inhibitors/toxicity , Models, Molecular , Organic Anion Transporters, Sodium-Independent/metabolism , Protein Binding , Rats , Rats, Sprague-Dawley , Structure-Activity RelationshipABSTRACT
Microsomal prostaglandin E(2) synthase-1 (mPGES-1) is a novel therapeutic target for the treatment of inflammation and pain. In the preceding letter, we detailed the discovery of clinical candidate PF-04693627, a potent mPGES-1 inhibitor possessing a novel benzoxazole structure. While PF-04693627 was undergoing further preclinical profiling, we sought to identify a back-up mPGES-1 inhibitor that differentiated itself from PF-04693627. The design, synthesis, mPGES-1 activity and in vivo PK of a novel set of substituted benzoxazoles are described herein. Also described is a conformation-based hypothesis for mPGES-1 activity based on the preferred conformation of the cyclohexane ring within this class of inhibitors.
Subject(s)
Benzoxazoles/chemistry , Benzoxazoles/pharmacology , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Intramolecular Oxidoreductases/antagonists & inhibitors , Benzoxazoles/chemical synthesis , Drug Design , Enzyme Inhibitors/chemical synthesis , Humans , Intramolecular Oxidoreductases/chemistry , Intramolecular Oxidoreductases/metabolism , Models, Molecular , Molecular Conformation , Prostaglandin-E Synthases , Structure-Activity RelationshipABSTRACT
Potent, highly selective and orally-bioavailable MMP-13 inhibitors have been identified based upon a (pyridin-4-yl)-2H-tetrazole scaffold. Co-crystal structure analysis revealed that the inhibitors bind at the S(1)(') active site pocket and are not ligands for the catalytic zinc atom. Compound 29b demonstrated reduction of cartilage degradation biomarker (TIINE) levels associated with cartilage protection in a preclinical rat osteoarthritis model.
Subject(s)
Matrix Metalloproteinase Inhibitors , Osteoarthritis/drug therapy , Picolinic Acids/chemistry , Protease Inhibitors/chemistry , Tetrazoles/chemistry , Administration, Oral , Animals , Binding Sites , Cartilage/drug effects , Cartilage/metabolism , Catalytic Domain , Crystallography, X-Ray , Disease Models, Animal , Drug Discovery , Matrix Metalloproteinase 13/metabolism , Picolinic Acids/chemical synthesis , Picolinic Acids/pharmacology , Protease Inhibitors/chemical synthesis , Protease Inhibitors/pharmacology , Rats , Tetrazoles/chemical synthesis , Tetrazoles/pharmacology , Zinc/chemistryABSTRACT
NF-kappa B-induced gene expression contributes significantly to the pathogenesis of inflammatory diseases such as arthritis. I kappa B kinase (IKK) is the converging point for the activation of NF-kappa B by a broad spectrum of inflammatory agonists and is thus a novel target for therapeutic intervention. We describe a small molecule, selective inhibitor of IKK-2, SC-514, which does not inhibit other IKK isoforms or other serine-threonine and tyrosine kinases. SC-514 inhibits the native IKK complex or recombinant human IKK-1/IKK-2 heterodimer and IKK-2 homodimer similarly. IKK-2 inhibition by SC-514 is selective, reversible, and competitive with ATP. SC-514 inhibits transcription of NF-kappa B-dependent genes in IL-1 beta-induced rheumatoid arthritis-derived synovial fibroblasts in a dose-dependent manner. When the mechanism of NF-kappa B activation was evaluated in the presence of this inhibitor, several interesting observations were found. First, SC-514 did not inhibit the phosphorylation and activation of the IKK complex. Second, there was a delay but not a complete blockade in I kappa B alpha phosphorylation and degradation; likewise there was a slightly slowed, decreased import of p65 into the nucleus and a faster export of p65 from the nucleus. Finally, both I kappa B alpha and p65 were comparable substrates for IKK-2, with similar Km and Kcat values, and SC-514 inhibited the phosphorylation of either substrate similarly. Thus, the effect of SC-514 on cytokine gene expression may be a combination of inhibiting I kappa B alpha phosphorylation/degradation, affecting NF-kappa B nuclear import/export as well as the phosphorylation and transactivation of p65.