Fig. 5.

TOP2α/90 siRNA knockdown in K/VP.5 cells enhances etoposide-induced DNA damage. (A) K/VP.5 cells were transfected with negative control or TOP2α/90-specific Silencer Select Custom Designed siRNAs at the concentrations indicated. Twenty-four hours after transfection, cellular extracts were prepared and immunoblotting experiments were performed using the TOP2α/90/170 Ab. (B) K/VP.5 cells were transfected as above in (A). Twenty-four hours later cells were incubated for 1 hour with etoposide (25 µM) or DMSO (control) and alkaline or neutral comet assays were performed. Results shown are the mean ± S.E.M. for five to six experiments run on separate days. For all experimental conditions in each experiment, greater than 100 cells were evaluated by OpenComet software, *P < 0.025, comparing TOP2α/90 siRNA-transfected to negative control siRNA transfected K/VP.5 cells.