Figure 4

p21 knockdown decreases dl 922-947 activity in ovarian cancer cells. 4A: p21 is degraded in ovarian cancer cells following adenoviral infection. Protein was harvested from TOV21G and IGROV1 cells up to 72 h post-infection with dl 922-947 (MOI 10) and analyzed by immunoblot for p21 expression. 4B, C and D: siRNA-mediated p21 knockdown reduces dl 922-947 activity. TOV21G cells were transfected with 60pmol p21 siRNA or scrambled control. Expression of p21 assessed by immunoblot up to 96 hours later (4B left). DNA replication was assessed by BRDU incorporation 36 hours following siRNA transfection. ** p = 0.001 (4B right). TOV21G cells were transfected with p21 or scrambled control siRNA and infected 24 hours later with dl 922-947 (MOI 10). Protein was harvested up to 24 h thereafter and analyzed by immunoblot for E1A and p21 expression. Numbers below blots represent E1A:Ku70 ratio (4C left). In addition, intracellular virion production was assessed 48 h pi by TCID₅₀. * p < 0.05 (4C right). TOV21G cells (10⁴ cells/well) were transfected with 20 pmol p21 or scrambled control siRNA in 24 well plates. 24 hours later, they were infected with dl 922-947 (MOI 0, 0.1, 1 and 10). Cell survival was assessed 96 hours later by MTT assay. * p < 0.05. *** p < 0.001.