ABSTRACT
Cycloxygenase (COX) pathways have long been targeted for the treatment of inflammatory pain, initially through the use of NSAIDs. With the demonstration of two major COX isoforms, COX-1 and COX-2, involved in the production of prostanoids, but with different distribution and regulation, selective COX-2 inhibitors have been developed. This review covers factors influencing COX enzyme activity, the role of their products in the development and maintenance of pain and discusses recent safety concerns of COX-2 inhibitors.
Subject(s)
Cyclooxygenase 1/metabolism , Cyclooxygenase 2 Inhibitors/chemistry , Cyclooxygenase 2/physiology , Pain/enzymology , Signal Transduction , Binding Sites , Cyclooxygenase 1/chemistry , Cyclooxygenase 1/genetics , Cyclooxygenase 2/chemistry , Cyclooxygenase 2 Inhibitors/standards , Cyclooxygenase 2 Inhibitors/therapeutic use , Humans , Models, Biological , Molecular Structure , Nociceptors/physiology , Pain/drug therapy , Pain/etiology , Protein Isoforms , Protein Structure, TertiaryABSTRACT
A recombinant vaccinia virus, expressing the NS3-to-NS5 region of the N clone of hepatitis C virus (HCV), was generated and utilized both in a gel-based assay and in an enzyme-linked immunosorbent assay (ELISA) to evaluate the pyrrolidine-5,5-trans-lactams, a series of inhibitors of the HCV NS3/4A protease. The absolute levels of processed, mature HCV nonstructural proteins in this system were found to decrease in the presence of the trans-lactams. Monitoring of this reduction enabled end points and 50% inhibitory concentrations to be calculated in order to rank the active compounds according to potency. These compounds had no effect on the transcription or translation of the NS3-5 polyprotein at concentrations shown to inhibit NS3/4A protease, and they were shown to be specific inhibitors of this protease. The ELISA, originally developed using the vaccinia virus expression system, was modified to utilize Huh-7 cells containing an HCV replicon. Results with this assay correlated well with those obtained with the recombinant vaccinia virus assays. These results demonstrate the utility of these assays for the characterization of NS3/4A protease inhibitors. In addition, inhibitors of other viral targets, such as polymerase and helicase, can be evaluated in the context of the replicon ELISA.
Subject(s)
Antiviral Agents/pharmacology , Hepacivirus/drug effects , Lactams/pharmacology , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Cell Line , Chlorocebus aethiops , Enzyme-Linked Immunosorbent Assay , Hepacivirus/enzymology , Humans , Lactams/chemistry , Microbial Sensitivity Tests/methods , Replicon , Vaccinia virus/enzymology , Vaccinia virus/genetics , Vero Cells , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolismABSTRACT
The term "promiscuous" inhibitors has been coined for compounds whose inhibition mechanism involves the interaction of aggregates of many compound molecules with the target protein, rather than the binding of individual molecules. This paper demonstrates that promiscuous inhibitors can be differentiated from classical 1:1 inhibitors by the judicious use of detergents, making it possible to configure assays that significantly reduce this undesirable mechanism of inhibition without compromising assay performance.
Subject(s)
Detergents/chemistry , Enzyme Inhibitors/chemistry , beta-Lactamase Inhibitors , Acetophenones/chemistry , Ampicillin/chemistry , Benzopyrans/chemistry , Boronic Acids/chemistry , Catalysis , Congo Red/chemistry , Enterobacter cloacae/chemistry , Indoles/chemistry , Thiophenes/chemistry , beta-Lactamases/chemistryABSTRACT
[reaction: see text] In this, the first of two letters, we outline the use of the pyrrolidine-5,5-trans-lactam template to design small, neutral, mechanism-based inhibitors of hepatitis C NS3/4A protease. The hitherto unreported reaction of the acyl iminium ion precursor 4 with dialkyl-substituted silyl ketene acetals (e.g., 8b) is described. Compound 12b, with a spirocyclobutyl P1 substituent and a cyclopropylacyl substituent on the lactam nitrogen, has a k(obs)/I of 400 M(-)(1) s(-)(1) and demonstrates activity in a replicon cell-based surrogate HCV assay.
