FIG. 2.

Antineoplastic drugs stimulate neither JNK1 activity nor AP-1 binding and do not cause an increase in c-Jun protein level. (A and B) Logarithmically growing NIH 3T3 cells were treated with various cytostatic drugs (mafosfamide, 60 μM; treosulfan, 500 μM; HeCNU, 60 μM; mitomycin C, 0.5 μg/ml) and, as a control, MMS (2 mM). One and four hours after treatment, cells were harvested for determination of JNK1 activity (A) and AP-1 binding activity (B), respectively. (C) Four hours after exposure to the agents indicated, the amount of c-Jun protein was determined by Western blot analysis. Thirty micrograms of protein from total cell extracts was separated by SDS-polyacrylamide gel electrophoresis, and after blotting to nitrocellulose, c-Jun protein was detected with c-Jun-specific antibody (Santa Cruz).