RESUMEN
Centromere-associated protein-E (CENP-E) is a mitotic kinesin which plays roles in cell division, and is regarded as a promising therapeutic target for the next generation of anti-mitotic agents. We designed novel fused bicyclic CENP-E inhibitors starting from previous reported dihydrobenzofuran derivative (S)-(+)-1. Our design concept was to adjust the electron density distribution on the benzene ring of the dihydrobenzofuran moiety to increase the positive charge for targeting the negatively charged L5 loop of CENP-E, using predictions from electrostatic potential map (EPM) analysis. For the efficient synthesis of our 2,3-dihydro-1-benzothiophene 1,1-dioxide derivatives, a new synthetic method was developed. As a result, we discovered 6-cyano-7-trifluoromethyl-2,3-dihydro-1-benzothiophene 1,1-dioxide derivative (+)-5d (Compound A) as a potent CENP-E inhibitor with promising potential for in vivo activity. In this Letter, we discuss the design and synthetic strategy used in the discovery of (+)-5d and structure-activity relationships for its analogs possessing various fused bicyclic L5 binding moieties.
Asunto(s)
Compuestos Bicíclicos Heterocíclicos con Puentes/síntesis química , Proteínas Cromosómicas no Histona/antagonistas & inhibidores , Óxidos S-Cíclicos/síntesis química , Sistemas de Liberación de Medicamentos , Diseño de Fármacos , Imidazoles/síntesis química , Antineoplásicos/síntesis química , Antineoplásicos/química , Antineoplásicos/farmacología , Sitios de Unión , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacología , Óxidos S-Cíclicos/química , Óxidos S-Cíclicos/farmacología , Células HeLa , Humanos , Imidazoles/química , Imidazoles/farmacología , Concentración 50 Inhibidora , Estructura Molecular , Unión Proteica/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
Centromere-associated protein-E (CENP-E), a mitotic kinesin that plays an important role in mitotic progression, is an attractive target for cancer therapeutic drugs. For the purpose of developing novel CENP-E inhibitors as cancer therapeutics, we investigated a fused bicyclic compound identified by high throughput screening, 4-oxo-4,5-dihydrothieno[3,4-c]pyridine-6-carboxamide 1a. Based on this scaffold, we designed inhibitors for efficient binding at the L5 site in CENP-E utilizing homology modeling as well as electrostatic potential map (EPM) analysis to enhance CENP-E inhibitory activity. This resulted in a new lead, 5-bromoimidazo[1,2-a]pyridine 7, which showed potent CENP-E enzyme inhibition (IC50: 50nM) and cellular activity with accumulation of phosphorylated histone H3 in HeLa cells. Our homology model and EPM analysis proved to be useful tools for the rational design of CENP-E inhibitors.