Fig. 11.

Cisplatin-induced apoptosis/cell cycle arrest in A549 is p53 dependent. Western blot analysis of whole cell protein lysates obtained from A549WT cells treated with scramble siRNA or p53 siRNA. Protein expression of pp53 (Ser15), p21, Caspase-9 and β-Actin/Histone-3 (loading controls) was determined by Western blotting in 4 sets of experiments in cells treated with scramble siRNA or p53 siRNA (48 h) in the presence/absence of Cisplatin treatment (last 24 h, 10 μM). Protein of interest was quantified relative to the loading control, and the Cisplatin-induced increase in protein expression is presented as the protein expression ratio between cisplatin-treated cells and nontreated cells. Data represent mean ratios ± SE from 4 individual sets of experiments. *Expression is significantly reduced by p53 siRNA treatment (Students t-test).