FIG 5.

Replication of wild-type SARS-CoV-2 was impaired by PKC inhibitors. (A to C) CC₅₀s of Go 6983 (A), bisindolylmaleimide I (B), and enzastaurin (C) in A549-ACE2 cells. The cytotoxic effects of each drug at the indicated concentrations were determined by a CCK8 cell viability assay. CC₅₀ values are indicated above the curves. (D to F) Effect of PKC inhibitors on infection by SARS-CoV-2. A549-ACE2 cells were treated with DMSO, Go 6983, bisindolylmaleimide I, or enzastaurin for 1 h, followed by virus infection. At 24 h p.i., cells or supernatants were harvested for an immunofluorescence assay (D and E) or a qRT-PCR assay (F). Anti-SARS-CoV-2 N antibody was used to indicate the cells infected by virus (gold). The nucleus was stained with DAPI (blue). Representative images from three independent experiments are shown. Bar, 200 μm. The percentages of viral N-positive cells were calculated. Statistical analysis was carried out to reveal the proportion of cells infected by SARS-CoV-2 (E). qRT-PCR data are presented as means ± SD from three experiments. P values were calculated by ANOVA with Dunnett’s multiple-comparison test (*, P < 0.05; **, P < 0.01; ****, P < 0.0001).