Figure 9. NQO1 siRNA transfection significantly inhibits the effect of sulindac and its metabolites on β-lapachone-induced cell death.

CL1-1 cells (left) or CL1-5 cells (right) were transfected with control siRNA (−) or NQO1 siRNA (+) for 24 h, then were left untreated or were incubated for 6 h with 100 or 250 µM sulindac (A), sulindac sulfone (B), or sulindac sulfide (C), then 2 µM β-lapachone or medium was added and the cells incubated for 12 h, when cell survival was measured using crystal violet staining and expressed as percentage survival compared to the untreated cells. * : p<0.05 for the indicated comparison.