Figure 7. Down-regulation of the antioxidant defense system in cancer cells and up-regulation in normal cells after pretreatment with CGN and/or irradiation.

The antioxidant molecules expression were measured by western blotting in normal cells (MRC5 and BEAS-2B) and cancer cells (A549) at 24 h after pretreatment with or without 1 μM drugs for 24 h and then followed by 0 or 4 Gy X-ray irradiation. The cells (1×10⁶ cells/dish) were seeded in 60 mm dishes for 24 h, followed by CGN treatment for another 24 h and then exposed to 4 Gy X-rays. The cells were harvested at 24 h post-irradiation. The expressions of proteins were analyzed by western blotting. All experiments were repeated independently for three times and the typical images were presented.