(H) A549 cells expressing control or p53 shRNA were transfected with pGL3-BS1 and Renilla luciferase plasmids. Twenty-four hours later, cells were treated with or without Nutlin (10 μM) for another 12 h. Reporter activity was then measured. Data shown are mean ± SD; n = 3 independent experiments. **, P ˂ 0.01; two-tailed Student's t-test. 