FIG. 7.

Inhibition of p38 activity blocks cell transformation by v-Src and not by v-Ras. (A) NIH 3T3/v-Src/TKS3 cells stably transfected with the Stat3-dependent luciferase reporter, pLucTKS3, were treated with the indicated inhibitors for 6 h prior to cytosolic extract preparation and luciferase assays as described for Fig. 1. Values are the means and standard deviations of six independent assays. (B) NIH 3T3/v-Src fibroblasts seeded in soft-agar suspension were treated once weekly with the indicated inhibitors until large-colony formation was evident. Values are the means and standard deviations of 12 independent assays. (C) NIH 3T3/v-Ras fibroblasts seeded in soft-agar suspension were treated once weekly with the indicated inhibitors, and colonies were counted as in panel B. Values are the means and standard deviations of nine independent assays. DMSO, dimethyl sulfoxide.