Niclosamide treatment reduces viral protein expression and viral release in DENV serotype 2 PL046 (DENV2)-infected cells.

(A) LDH assays showing cytotoxicity in niclosamide (Niclo)-treated A549 (48 h) and BHK-21 (24 h) cells at various concentrations. (B) Representative Western blots showing viral NS3 and capsid protein expression. β-actin served as the internal control. The relative ratios of the measured proteins compared to β-actin are also shown. (C) Plaque assays showing viral release in DENV2 (MOI = 1)-infected A549 (48 h) and BHK-21 (24 h) cells in the presence of niclosamide (Niclo). (D) Plaque assays showing the production of infectious particles for a kinetic treatment (pre-, co-, and post-treatment) of niclosamide (Niclo) in DENV2 (MOI = 1)-infected BHK-21 (24 h) cells. Virus particles are shown as the desired pfu amount for infection and as calculated as the percentage (%) of inhibition. DMSO was used as a solvent control. The quantitative data are depicted as the mean ± SD of three independent experiments. * P 0.05 and ** P 0.01. ns, not significant.