Figure 4. ROS induces cell death and mitochondrial apoptotic signaling in FHs74 Int cells.

(A) FHs74 Int cells were treated with H₂O₂ (500 μM) as before. Apoptosis was measured by DNA fragmentation ELISA. Data represent triplicate determinations (mean ±SEM; *p<0.05 vs. control). H₂O₂ treatment resulted in significant cellular apoptosis. (B) FHs74 Int cells were serum starved, pretreated with IGF-1, EGF or in combination and then treated with H₂O₂ as before. Apoptosis was measured by DNA fragmentation ELISA. Data represent triplicate determinations (mean ±SEM; *p<0.05 vs. control, ^†p<0.05 vs. H₂O₂-treated FHs74 Int cells). IGF-1- and EGF-pretreated FHs74 Int cells showed increased survival during oxidative stress. (C) FHs74 Int cells were serum starved, pretreated with IGF-1, EGF or in combination and then treated with H₂O₂ as before. H₂O₂ treatment resulted in significant increases in AIF, APAF-1 and cytochrome C expression by Western blotting. There was significant attenuation of this effect when FHs74 Int cells were pretreated with both IGF-1 and EGF, suggesting synergistic effect on modulating mitochondrial apoptotic pathway activation. Equal β-actin levels indicate even loading.