NQO1 over-expression attenuates the p53 pathway in KKU-M214 cells. A-D, Western blots of p53 (A), p21 (B), cyclin D1 (C), and Bax (D) protein in KKU-M214-NQO1 over-expressed cells after treatment with 5-FU 3 μM (48 hr), Doxo 0.1 μM (24 hr), and Gem 0.1 μM (48 hr). The relative bars that were normalized with β-actin of each band are shown below the Western blot images. *p < 0.05 vs the treated control vector transfected cells. **p < 0.05 vs the untreated control vector transfected cells.