Figure 2. Kinetics of PMA-induced COX-2 expression and cell cycle progression.

(A) WI38, (C) A549 and (D) MF7 cells cultured in SF-medium for 24 h were washed and incubated in medium containing 2.5% FBS. At the indicated time point, cells were treated with PMA for 4 h and COX-2 proteins in the cell lysate were analyzed by Western blotting. Upper panels show representative blots and lower panels, densitometry analysis. Error bars indicate mean ± SEM (n = 3). (B) and (E) WI38 or A549 cells were treated identically as above. At the indicated time points, cells at different phases of cell cycle were analyzed by flow cytometry as previously described [7].