Fig. 8. JNK activity is important for v-Src-stimulated cell invasion and MMP-2 secretion. (A) Matrigel invasion assays were performed with v-Src3T3s in the presence of DMSO or the indicated concentrations of MEK1 (PD98059) or JNK (SP600125) inhibitors added to both chambers. Values are means ± SD from two experiments. (B and C) v-Src3T3s were mock treated with DMSO or incubated in the presence of 25 µM of either PD98059 or SP600125 for 18 h in starved conditions. Protein lysates were analyzed for (B) ERK2 in vitro kinase activity or (C) JNK in vitro kinase activity. Values are means ± SD from two experiments. Whole-cell lysates were blotted for either activated ERK (pERK) or activated JNK (pJNK1) and re-probed for either total ERK2 or JNK1 protein expression, respectively. (D) Conditioned media from either serum-starved, mock-treated (DMSO) or 25 µM SP600125-treated (18 h) v-Src3T3s were analyzed by gelatin zymography. A conditioned medium sample from the same number of serum-starved NIH-3T3 fibroblasts is shown for comparison.