Fig. 2. Stimulation of cell motility by serum or TGF-ß1. Confluent cultures of T2 cells were incubated in serum-free DMEM for 3 days prior to scrape-wounding. Cells were maintained in the FBS-free medium to assess basal migration (A). The percent (%) wound closure was determined 24 hours later. Data plotted are the means±s.d. of 20 individual measurements made on each of triplicate cultures for each treatment condition. Asterisks indicate a statistically significant difference (Student’s t-test, P>0.01) in cell migration for TGF-ß1- and FBS-supplemented cultures compared with basal (FBS-free) motility. The effect of targeted PAI-1 ablation on basal (-TGF-ß1) as well as TGF-ß1-induced (+TGF-ß1) cell locomotion was assessed in EC-1 and 4HH cell cultures by evaluation of the extent (%) of wound closure in the absence and presence of growth factor (1 ng/ml) (B). Data plotted are the means±s.d. of 15 individual measurements on duplicate cultures/treatment group. Asterisk indicates a statistically significant difference (P<0.01) between motility under growth factor-free and supplemented conditions for EC-1 cells. By contrast, 4HH cells were unresponsive to TGF-ß1 in this assay.