In U-373MG cells, the expression level of caspase-3 after co-infection of Adv-p53, Adv-APAF1 and Adv-Casp9 (Figure 3A, lane 8) was reduced in comparison with that after infection of Adv-p53 or co-infection of Adv-APAF1 and Adv-Casp9. Here, CASP3 is linked to infection.