RESUMEN
The purpose of this work is to investigate the protein kinase inhibitory activity of constituents from Acacia auriculiformis stem bark. Column chromatography and NMR spectroscopy were used to purify and characterize betulin from an ethyl acetate soluble fraction of acacia bark. Betulin, a known inducer of apoptosis, was screened against a panel of 16 disease-related protein kinases. Betulin was shown to inhibit Abelson murine leukemia viral oncogene homolog 1 (ABL1) kinase, casein kinase 1ε (CK1ε), glycogen synthase kinase 3α/ß (GSK-3 α/ß), Janus kinase 3 (JAK3), NIMA Related Kinase 6 (NEK6), and vascular endothelial growth factor receptor 2 kinase (VEGFR2) with activities in the micromolar range for each. The effect of betulin on the cell viability of doxorubicin-resistant K562R chronic myelogenous leukemia cells was then verified to investigate its putative use as an anti-cancer compound. Betulin was shown to modulate the mitogen-activated protein (MAP) kinase pathway, with activity similar to that of imatinib mesylate, a known ABL1 kinase inhibitor. The interaction of betulin and ABL1 was studied by molecular docking, revealing an interaction of the inhibitor with the ABL1 ATP binding pocket. Together, these data demonstrate that betulin is a multi-target inhibitor of protein kinases, an activity that can contribute to the anticancer properties of the natural compound and to potential treatments for leukemia.
Asunto(s)
Acacia/química , Antineoplásicos Fitogénicos/farmacología , Regulación Leucémica de la Expresión Génica/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-abl/antagonistas & inhibidores , Triterpenos/farmacología , Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/aislamiento & purificación , Apoptosis/efectos de los fármacos , Apoptosis/genética , Sitios de Unión , Caseína Cinasa 1 épsilon/antagonistas & inhibidores , Caseína Cinasa 1 épsilon/genética , Caseína Cinasa 1 épsilon/metabolismo , Proliferación Celular/efectos de los fármacos , Proteínas de Fusión bcr-abl/antagonistas & inhibidores , Proteínas de Fusión bcr-abl/genética , Proteínas de Fusión bcr-abl/metabolismo , Glucógeno Sintasa Quinasa 3/antagonistas & inhibidores , Glucógeno Sintasa Quinasa 3/genética , Glucógeno Sintasa Quinasa 3/metabolismo , Humanos , Janus Quinasa 3/antagonistas & inhibidores , Janus Quinasa 3/genética , Janus Quinasa 3/metabolismo , Células K562 , Proteína Quinasa 1 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 1 Activada por Mitógenos/genética , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 3 Activada por Mitógenos/genética , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Modelos Moleculares , Quinasas Relacionadas con NIMA/antagonistas & inhibidores , Quinasas Relacionadas con NIMA/genética , Quinasas Relacionadas con NIMA/metabolismo , Corteza de la Planta/química , Extractos Vegetales/química , Unión Proteica , Conformación Proteica , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/aislamiento & purificación , Proteínas Proto-Oncogénicas c-abl/química , Proteínas Proto-Oncogénicas c-abl/genética , Proteínas Proto-Oncogénicas c-abl/metabolismo , Transducción de Señal , Triterpenos/química , Triterpenos/aislamiento & purificación , Receptor 2 de Factores de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Receptor 2 de Factores de Crecimiento Endotelial Vascular/genética , Receptor 2 de Factores de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Since the early 1970's, investigators at Station Biologique de Roscoff (SBR), France, have been using marine organisms as models to describe molecular pathways conserved through evolution in mammalian cells (e.g. the cyclin-dependent kinases involved in the control of the cell division cycle). Some kinases are misregulated in various human pathologies, including cancers. Using a specialized screening approach, chemical libraries were analysed, using on-site facilities at Roscoff, in order to identify small chemical inhibitors of protein kinases. Eight chemical scaffolds produced by marine organisms were characterized as candidate drugs by our screening facility, some of which are being considered as chemical tools to pinpoint specific cellular functions of the targeted kinases. In this review, we describe our existing screening facilities and we discuss new perspectives related to marine bioprospecting.