OGE induced activation of intrinsic/mitochondrial apoptotic pathway. A549 cells were treated with 0, 500 and 800 for 48 hr, and then were lyzed for the determination of protein levels of caspase-3, cleaved caspase-3, caspase-9, cleaved caspase-9 and Apaf-1 by immunoblotting. -actin was used as control. The apparent molecular weights for detected proteins were indicated.