PF-4 and PD98059 inhibit FGF2-induced DNA biosynthesis.

(A) Detection of phosphorylated ERK1 and ERK2. ACE cells were left unstimulated or were stimulated for 10 minutes with FGF2 (10 ng/mL) in the presence or absence of PD98059 (20 μM). Cell lysates were analyzed by Western blotting, using polyclonal antibodies against ERK-P and total ERK. Results are representative of 4 experiments. (B) Detection of phosphorylated ERK. Serum-deprived ACE cells were incubated with anti-FGF2 and anti–FGF-R1 antibodies or nonimmune IgG. Cell lysates were analyzed by Western blotting using polyclonal antibodies against ERK-P and total ERK. Results are representative of 3 experiments. (C) Effect of PD98059 on [³H]TdR uptake. Serum-deprived cells were stimulated (black bar) or not (white bar) with FGF2 (10 ng/mL) in the presence (hatched bars) or absence of PD98059 (20 μM). DNA biosynthesis was determined by [³H]TdR incorporation during 20 hours of incubation, as described in “Materials and methods.” Data are expressed as the means of triplicate values ± SEM and are representative of 6 experiments. (D) Effect of PF-4 and PD98059 on FGF2-induced [³H]TdR uptake. Serum-deprived cells were stimulated with FGF2 (10 ng/mL) with (hatched bar) or without (black bar) PD98059 (20 μM) in the presence of various concentrations of PF-4. Data are expressed as the means of triplicate values ± SEM and are representative of 3 independent experiments.