Figure 6

Rac is necessary for JNK activation in RA-FLS. (A) RA-FLS (RA3) were serum starved (control) or treated with 50 µM NSC23766 for 24 h. JNK activity was determined by western blotting using phospho-JNK antibody, tubulin expression was determined as loading control. Similar results were obtained with the RA1 and RA2 cultures. (B) The JNK-specific inhibitor SP600125 inhibits RA-FLS invasion. RA-FLS were pre-treated with 50 µM NSC23766 or 20 µM SP600125 or DMSO for 24 h. Cell invasion through Matrigel was quantified as described in Materials and Methods. Shown is the mean (± SEM) of three independent experiments performed in duplicate. ** = P < 0.01 and *** = P < 0.001, two-tailed t test.