RESUMEN
AIM: Inhibition of IDO1 is a strategy pursued in the immune-oncology pipeline for the development of novel anticancer therapies. At odds with an ever-increasing number of inhibitors being disclosed in the literature and patent applications, only very few compounds have hitherto advanced in clinical settings. MATERIALS & METHODS: We have used MicroScale Thermophoresis analysis and docking calculations to assess on a quantitative basis the binding properties of distinct categories of inhibitors to IDO1. RESULTS: Results shed further light on hidden molecular aspects governing the recognition by the enzyme of compounds with different mechanism of inhibition. CONCLUSION: Results pinpoint specific binding features of distinct inhibitors to IDO1 that offer clues for the design of next-generation inhibitors of the enzyme.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Indolamina-Pirrol 2,3,-Dioxigenasa/antagonistas & inhibidores , Temperatura , Sitios de Unión/efectos de los fármacos , Inhibidores Enzimáticos/química , Humanos , Indolamina-Pirrol 2,3,-Dioxigenasa/metabolismo , Simulación del Acoplamiento Molecular , Relación Estructura-ActividadRESUMEN
Itraconazole (ITZ) is a well-known antifungal agent that also has anticancer activity. In this study, we identify ITZ as a broad-spectrum inhibitor of enteroviruses (e.g., poliovirus, coxsackievirus, enterovirus-71, rhinovirus). We demonstrate that ITZ inhibits viral RNA replication by targeting oxysterol-binding protein (OSBP) and OSBP-related protein 4 (ORP4). Consistently, OSW-1, a specific OSBP/ORP4 antagonist, also inhibits enterovirus replication. Knockdown of OSBP inhibits virus replication, whereas overexpression of OSBP or ORP4 counteracts the antiviral effects of ITZ and OSW-1. ITZ binds OSBP and inhibits its function, i.e., shuttling of cholesterol and phosphatidylinositol-4-phosphate between membranes, thereby likely perturbing the virus-induced membrane alterations essential for viral replication organelle formation. ITZ also inhibits hepatitis C virus replication, which also relies on OSBP. Together, these data implicate OSBP/ORP4 as molecular targets of ITZ and point to an essential role of OSBP/ORP4-mediated lipid exchange in virus replication that can be targeted by antiviral drugs.