RESUMEN
Nicotinamide phosphoribosyltransferase (NAMPT) is a promising anticancer target. Using high throughput screening system targeting NAMPT, we obtained a potent NAMPT inhibitor MS0 (China Patent ZL201110447488.9) with excellent in vitro activity (IC50 = 9.87 ± 1.15 nM) and anti-proliferative activity against multiple human cancer cell lines including stem-like cancer cells. Structure-activity relationship studies yielded several highly effective analogues. These inhibitors specifically bound NAMPT, rather than downstream NMNAT. We provided the first chemical case using cellular thermal shift assay to explain the difference between in vitro and cellular activity; MS7 showed best in vitro activity (IC50 = 0.93 ± 0.29 nM) but worst cellular activity due to poor target engagement in living cells. Site-directed mutagenesis studies identified important residues for NAMPT catalytic activity and inhibitor binding. The present findings contribute to deep understanding the action mode of NAMPT inhibitors and future development of NAMPT inhibitors as anticancer agents.
Asunto(s)
Descubrimiento de Drogas , Inhibidores Enzimáticos/farmacología , Nicotinamida Fosforribosiltransferasa/antagonistas & inhibidores , Antineoplásicos/química , Antineoplásicos/farmacología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Evaluación Preclínica de Medicamentos , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/química , Ensayos Analíticos de Alto Rendimiento , Humanos , Concentración 50 Inhibidora , Modelos Moleculares , Conformación Molecular , Células Madre Neoplásicas/efectos de los fármacos , Células Madre Neoplásicas/metabolismo , Nicotinamida Fosforribosiltransferasa/química , Unión Proteica , Bibliotecas de Moléculas Pequeñas , Relación Estructura-ActividadRESUMEN
AIM: To investigate the effect of chronic nicotine treatment on vascular function and to identify the underlying mechanisms. METHODS: Adult rats were treated with nicotine (3 mg·kg(-1)·d(-1), sc) for 6 weeks. After the rats were sacrificed, aortic rings were prepared for detecting vascular reactivity, and thoracic aorta and periaortic fat samples were collected for histological and molecular biology studies. RESULTS: Chronic nicotine treatment significantly reduced periaortic fat, and specifically enhanced smooth muscle relaxation without altering the aortic adventitial fat and endothelium function. Pretreatment with the soluble guanylyl cyclase inhibitor ODQ (3 µmol/L) or PKG inhibitor Rp-8-Br-PET-cGMP (30 µmol/L) abolished the nicotine-induced enhancement of smooth muscle relaxation, whereas the cGMP analogue 8-Br-cGMP could mimic the nicotine-induced enhancement of smooth muscle relaxation. However, the chronic nicotine treatment did not alter PKG protein expression and activity in aortic media. CONCLUSION: Chronic nicotine treatment enhances vascular smooth muscle relaxation of rats via activation of PKG pathway.