H9c2 cells stably transfected with empty vector (EV), GILZ, or no vector (Mock) were challenged with Dox at the indicated doses for 24 hr (A) or with 0.75 μM Dox for the indicated times (B). Cell viability was determined by quantifying the ability to convert 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide into formazan. Results are expressed as means ± standard deviations from four independent experiments with triplicated samples for each experiment. The raw data from four independent experiments were used for statistical analyses by ANOVA. Different letters indicate significant differences between treatment groups (p<0.05). Therefore, the data groups labeled with “a” are significantly different from that labeled with “b”, “c” or “d”, while “b” indicates significant differences from the means labeled with “a”, “c” or “d”. The means labeled with two letters such as “ab” are not significantly different from those labeled with either letter “a” or “b”. The mean labeled with three letters “abc” is not significantly different from those labeled with letter “a”, “b” or “c”.