Figure 2.

Growth inhibition and apoptosis induction by gefitinib in HER2-overexpressing cancer cell lines both in vitro and in vivo. (A) Growth inhibition by gefitinib in vitro in various human gastric cancer cell lines. Cells were plated in 24-well dish and treated twice with increasing doses of gefitinib, followed by cell counting after a 4-day culture. (B) Flow cytometric analysis of cell cycle of HER2-overexpressing and low-expressing cells with or without gefitinib treatment. DNA histogram and % of each cell cycle phase are shown. (C) Apoptosis induction by gefitinib in HER2-overexpressing and low-expressing cells at the increasing drug concentrations of 0 μM (▪), 1.0 μM (░) and 10 μM (□), as evaluated by measuring caspase 3/7 activity. (D) Inhibitory effects of gefitinib on the growth of HER2-overexpressing and low-expressing tumour xenografts in nude mice. Tumour cells were injected subcutaneously into nude mice, and gefitinib was orally administered at a dose of 0 (□), 150 mg per kg per day (▪), five times per week for 3 weeks. Ns, not significant; ^*P<0.01; ^**P<0.001 (vs control). Bars=s.e.