Figure 3.

Rescue from apoptosis after reconstitution of siRNA-insensitive mutant p53 R273H in MDA-MB-468 cells. (A) Apoptosis induced by endogenous mutant p53 knockdown was completely rescued after ectopic expression of siRNA-insensitive R273H p53 construct. MDA-MB-468 cells were transfected with R273H p53 expression construct, followed by a brief drug selection containing 500 μg ml⁻¹ G418 (Invitrogen). Cells were then transfected with an siRNA that targets the 5′-UTR of the endogenous mutant p53 (p53si-3). Western blot analysis was performed 72 h after transfection. (B) Quantitation of apoptosis by annexin V/PI staining of cells was performed 96 h after mutant p53 knockdown. Error bars represent s.d. for three independent experiments.