Fig. 6

Increased expression of NQO2 in Prx1– cells accounts for enhanced cell death in response to vitK3 treatment. a NQO2 mRNA and protein levels were detected by qRT-PCR and western blot, respectively. The inserts are western blot detecting NQO2. The cropped blot images for NQO2 and loading controls are from same western blot. Quantifications are mean ± SD of three independent experiments. b Inhibition of NQO2 activity attenuated vitK3 toxicity. Cells pretreated with quercetin (NQO2 inhibitor) were exposed to a combination of quercetin and vitK3. Cell viability was determined by MTT assay. Data are mean ± SD of at least three independent experiments. Global ROS levels were monitored by carboxy-H₂DCFDA staining. Gray shade, gray solid line, black solid line, and black dotted line indicate the fluorescence intensity of the control cells, cells treated with quercetin alone for 4 h, cells treated with vitK3 alone for 4 h, and cells treated with quercetin and vitK3 for 4 h, respectively. **P ≤ 0.01