Figure 4. Effects of combination of I3C and Adhz63 on A549 cell viability. (A) Cell viabilities were measured using crystal violet staining. A549 cells were pre-treated with various concentrations of I3C for 7 d and then infected with Ad5, Adhz63, AdGFP, or without virus for three days. (B) The dye retained by the adherent cells was solubilized with 2% SDS, and absorbance was recorded at 590 nm. Cell viability was expressed as the amount of dye in treated cells relative to that of untreated control cells. (C) The combined effects of I3C and Ad viruses were evaluated by combination index (CI) using the CalcuSyn software (Biosoft). CI = 1 indicates additivity; CI < 1 represents synergism, and CI > 1 indicates antagonism.