RESUMEN
We report the design of novel, potent cPLA(2)α inhibitors that possess an α-methyl-2-ketothiazole that acts as a serine-reactive moiety. We describe the optimization of the series for potency and metabolic stability towards ketone reduction. This was achieved by attenuating the reactivity of the ketone using a combination of electronic and steric effects.
Asunto(s)
Diseño de Fármacos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Fosfolipasas A2 Grupo IV/antagonistas & inhibidores , Cetonas/química , Tiazoles/síntesis química , Tiazoles/farmacología , Animales , Estabilidad de Medicamentos , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/química , Células HL-60 , Humanos , Concentración 50 Inhibidora , Cetonas/síntesis química , Cetonas/farmacología , Espectroscopía de Resonancia Magnética , Estructura Molecular , Oxidación-Reducción , Ratas , Serina/química , Tiazoles/químicaRESUMEN
Using knowledge of the substrate specificity of cPLA(2) (phospholipases A(2)), a novel series of inhibitors of this enzyme were designed based upon a three point model of inhibitor binding to the enzyme active site comprising a lipophilic anchor, an electrophilic serine "trap", and an acidic binding moiety. The resulting 1,3-diheteroatom-substituted propan-2-ones were evaluated as inhibitors of cPLA(2) in both aggregated bilayer and soluble substrate assays. Systematic variation of the lipophilic, electrophilic, and acidic groups revealed a well-defined structure-activity relationship against the enzyme. Optimization of each group led to compound 22 (AR-C70484XX), which contains a decyloxy lipophilic side chain, a 1,3-diaryloxypropan-2-one moiety as a unique serine trap, and a benzoic acid as the acidic binding group. AR-C70484XX was found to be among the most potent in vitro inhibitors of cPLA(2) described to date being more than 20-fold more active against the isolated enzyme (IC(50) = 0.03 microM) than the standard cPLA(2) inhibitor, arachidonyl trifluoromethyl ketone (AACOCF(3)), and also greater than 10-fold more active than AACOCF(3) against the cellular production of arachidonic acid by HL60 cells (IC(50) = 2.8 microM).