33 Prichard and Shipman’s method34 was also used to analyze interaction effects using a three-dimensional (3D) approach. This method presents complete drug interactions. Prism v5.0c software (GraphPad Software, Inc., La Jolla, CA) was used to prepare graphs, calculate IC50 values, and determine statistical significance of differences between Trametinib data sets. Chemical structures of FQ and CQ are presented in Fig. 1A. To test the effect of FQ on the HCV life cycle, the compound was added to Huh-7 target cells before, as well as during, infection. FQ exhibited a dose-dependent inhibition of HCV, indicating that FQ specifically affects the HCV life cycle with

an estimated IC50 value of 0.8 μM (± 0.26) and an 90% inhibitory concentration (IC90) of 1.86 μM (± 0.08) (Fig. 1B,D). Similar results were obtained using the HepG2 cell line expressing CD81 (data not shown). The inhibitory effect was not the result of cytotoxicity, because parallel experiments did not show any toxic effect of the drug at the concentrations tested (Supporting Fig. 1). Furthermore, no cytotoxicity was observed in primary human hepatocytes at the concentrations used in our experiments (Supporting Fig. 1). FQ showed a 50% cytotoxic concentration

(CC50) of 5.34 μM and a therapeutic index of 6.7. Similar inhibitory effects were observed with FQ-treated cells infected with a chimeric virus containing the structural proteins of a genotype 3a isolate (Supporting Fig. 2), indicating that the antiviral effect is not specific to JFH-1 isolate. Parallel control experiments with well-characterized selleck products HCV inhibitors are presented in Supporting Fig. 3. CQ was less effective against HCV (Fig. 1C,E). Indeed, IC50 and IC90 values for CQ were 3.93 (± 1.87) and 4.33 μM (± 0.53), respectively. Furthermore, CQ had a CC50 of 19.58 μM and a therapeutic index of 5. To determine whether HCV is the only member of the Flaviviridae family to be affected by FQ, we tested this compound on two other members of this viral

family (BVDV and YFV). BVDV and YFV infections were performed on MDBK and Huh-7 cells, respectively. FQ showed selleck chemicals some antiviral effect on these two viruses, albeit at a much higher concentration. Indeed, IC50 values were 6.74 (± 0.48) and 3.63 μM (± 0.64) for BVDV and YFV, respectively. Altogether, these results indicate that FQ has a potent antiviral activity against HCV. To determine whether FQ has any effect on HCV entry, the compound was added or removed at different time points before, during, and after inoculation of Huh-7 cells with JFH-1 (Fig. 2). The highest decrease in HCVcc infection was observed when FQ was present during viral infection, and only a weak antiviral effect was detected when FQ was added postinfection (Fig. 2A,B). Similar results were obtained with CQ (Fig. 2C,D), and parallel control experiments with well-characterized HCV inhibitors are presented in Supporting Figs. 4 and 5.