Figure 2

IR induces Akt activation in U87MG cells through EGFR in a serum factor-dependent manner. A. U87MG cells were cultured in the absence or presence of 10% FBS for 18-20 hr, then irradiated at 6 Gy. Cell lysates were harvested 1 hr later and subjected to Western blot analysis with the indicated antibody. The ratio of P-Akt-Ser473 to total Akt pooled from three different experiments were shown in the lower panel. Results represent mean ± SEM, ***:p < 0.001 compared to 0 Gy; #: p < 0.05 compared to 10% FBS (one-way ANOVA) B. Cells were treated with 5 μM AG1478 for 1 hr, then were irradiated for 1 hr at the indicated dosage. Cell lysates were prepared and subjected to Western blot analysis with the indicated antibody. The fold induction of normalized P-Akt-Ser473 induced by 6 Gy pooled from two different experiments were shown in the lower panel. Results represent mean ± SEM, **:p < 0.01(Student's t-test).