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. 2012 Nov 14;7(11):e49232. doi: 10.1371/journal.pone.0049232

Figure 1. Cell cycle-dependent control of COX-2 expression.

Figure 1

(A) Cyclin D1, cyclin A and p27 in HsFb cultured in serum-free (SF) medium for 24 h vs. 24 h SR-HsFb were analyzed by Western blotting. SR denotes culture of washed SF-HsFb in medium containing 2.5% fetal bovine serum (FBS). The left panel shows representative blots and the right shows densitometry analysis. The error bars denote mean ± SD (n = 3). (B) PMA-induced COX-2 proteins in HsFb cultured in SF medium for 24, 48 or 96 h. The 24 h, 48 h, or 96 h SF-HsFb were washed and incubated in medium containing 2.5% FBS for 24 h. At the indicated time points, PMA (100 nM) was added for 4 h and COX-2 proteins were analyzed by Western blotting. (C) Time course of PMA-induced COX-2 expression in (a) 24 h, (b) 48 h and (c) 96 h SF-HsFb replenished with 2.5% FBS for various time periods. At the indicated time point, cells were treated with PMA for 4 h and COX-2 proteins were analyzed by Western blotting. Error bars denote mean ± SEM (n = 3). (D) Confluent HsFb cultured in 0.1% FBS for 72 h followed by SF-medium for 24 h (designated contact inhibited SF-HsFb, CI-SF) were washed and replenished with 2.5% FBS for 24 h (designated CI-SR HsFb). CI-SF and CI-SR HsFbs were treated with PMA for 4 h and COX-2 proteins were analyzed. Upper panel shows a representative Western blot and the lower panel mean ± SEM of densitometry of Western blots (n = 3). (E) Cell cycle analysis by flow cytometry. Upper panel, distribution of G0/G, S and Gs/M cells and lower panel, photograph of CI-SF vs. CI-SR HsFb. Nagnification: ×200.