Fig. 5. The MEK inhibitor PD98059 attenuates both basal and TGF-ß1-stimulated T2 cell migration. Initial experiments were designed to determine the optimal concentration of TGF-ß1 on wound-induced motility (A). After scrape-injury, TGF-ß1 was added (in the concentrations indicated) and extent of migration determined 24 hours later. Data plotted is % increase in wound closure relative to non-supplemented (FBS-free) cultures. Asterisks indicate those concentrations for which motility was significantly different from basal migration (Student’s t-test, P>0.0005). To assess the requirement for MEK activity in stimulated cell movement, monolayer scrape wound-closure assays were carried out in TGF-ß1-supplemented (concentration range 0, 1, 2 and 5 ng/ml) serum-free medium in the presence (P) or absence of PD98059 (50 µM) (B). TGF-ß1 at 1 and 2 ng/ml significantly increased T2 cell directional motility (Student’s t-test, P>0.001; asterisks) relative to basal mobility (0 ng). In this series of experiments, cells exposed to 5 ng/ml of the growth factor actually had a decreased rate of locomotion relative to unsupplemented controls. At each concentration of TGF-ß1, PD98059 effectively reduced wound closure; there was no significant difference in the % closure rate among any of the treatment groups in the presence of PD98059.
