RESUMEN
BACKGROUND: The proteasome is a large multicatalytic protease complex (700 kDa) involved in a number of highly regulated processes. It has three major catalytic activities: a chymotrypsin-like activity, a trypsin-like activity and a post-glutamyl peptide hydrolyzing (PGPH) activity. To be useful as molecular probes, which could help dissect the cellular functions of the proteasome, inhibitors should be specific for the proteasome, active in vivo and selectively block only one of the three catalytic activities. To date, few inhibitors fulfill these requirements so we set out to make novel proteasome inhibitors that incorporate these characteristics. RESULTS: A panel of amino-terminally acetylated peptide alpha',beta'-epoxyketones with leucine in P1 and various aliphatic or aromatic amino acids in P2-P4 were prepared and evaluated. Most compounds selectively inhibited the chymotrypsin-like activity, while only weakly inhibiting the trypsin-like and PGPH activities. After optimization, one inhibitor, Ac-hFLFL-epoxide, was found to be more potent and selective for the inhibition of the chymotrypsin-like activity than several previously described inhibitors. This inhibitor also exhibited strong in vivo anti-inflammatory activity. CONCLUSIONS: Optimization of amino-terminally acetylated peptide alpha',beta'-epoxyketones furnished a potent proteasome inhibitor, Ac-hFLFL-epoxide, that has an excellent selectivity for the chymotrypsin-like activity. The inhibitor also proved to be a potent antiproliferative and anti-inflammatory agent. The strong in vivo and in vitro activities suggest that this class of proteasome inhibitors could be both molecular probes and therapeutic agents.
Asunto(s)
Cisteína Endopeptidasas/química , Cisteína Endopeptidasas/metabolismo , Inhibidores de Cisteína Proteinasa/síntesis química , Compuestos Epoxi/síntesis química , Complejos Multienzimáticos/química , Complejos Multienzimáticos/metabolismo , Péptidos/síntesis química , Animales , Aorta , Bovinos , División Celular/efectos de los fármacos , Células Cultivadas , Quimotripsina/metabolismo , Inhibidores de Cisteína Proteinasa/farmacología , Diseño de Fármacos , Endotelio Vascular/citología , Endotelio Vascular/efectos de los fármacos , Compuestos Epoxi/farmacología , Glutamatos , Indicadores y Reactivos , Irritantes , Cinética , Sustancias Macromoleculares , Ratones , Conformación Molecular , Péptidos/farmacología , Complejo de la Endopetidasa Proteasomal , Tripsina/metabolismoRESUMEN
The new field of chemical biology brings together chemists and biologists who are seeking to understand and mimic the natural world. One research strategy in this new field is the development of biologically active small molecules as molecular probes. This approach, which has been called 'chemical' genetics, has allowed elucidation of several pathways that have been difficult to study using traditional genetic approaches.
