FIGURE 6.

Silencing ABCG2 in epithelial head and neck cancer MDA1586 cells decreased extracellular GSH levels. MDA1586 cells were transfected with a shRNA plasmid targeting ABCG2. A and B, silencing ABCG2 resulted in a 2.6-fold decrease in ABCG2 protein expression compared with the vector control. C and D, the loss of ABCG2 protein expression correlated with a 2.7-fold decrease in extracellular GSH levels compared with vector control (C) and no significant changes in intracellular GSH levels (D) over 48 h. Data are presented as the mean ± S.E. (error bars), and statistical significance was determined using Student's t test.