Figure 1

Effects of the EGFR inhibitor gefitinib on phosphorylation of signalling proteins and DNA synthesis. A) MH₁C₁ cells were treated with gefitinib (1 μM) for 30 min before stimulation with EGF (10 nM) or PGE₂ (100 μM) for 5 min. B) Hepatocytes were treated with gefitinib (1 μM) for 30 min before stimulation with EGF (10 nM) or PGE₂ (100 μM) for 5 min. C) Gefitinib (1 μM) was added 30 min prior to stimulation with either PGE₂ (100 μM) or PGF_2α (100 μM) for 5 min. Cells were harvested and subjected to SDS-PAGE followed by immunoblotting with antibodies and detection with enhanced chemiluminescence as described in Materials and Methods. All blots are representative of at least 3 independent experiments. D) Effect of gefitinib on DNA synthesis in MH₁C₁ cells. Increasing concentrations of gefitinib were added to serum-starved MH₁C₁ cells. [³ H]thymidine was added, and DNA synthesis was assessed as described under Materials and Methods. The results are presented as percent of control ± S.E.M of four independent experiments.