Figure 7. Effects of p53 knockdown on apoptosis and DNA fragmentation in D556 cells. (A) The proportion of cells undergoing apoptotic cell death as a result of p53 shRNA knockdown in D556 cells treated for 18 hrs with DMSO, VMY (30uM) or doxorubicin (1uM) as assessed using annexin V and propidium iodide (PI) staining and measured by flow cytometry. Data are shown as percent change in staining versus pLKO-control infected cells. (B) D556 cells were infected with pLKO or p53shRNA and treated with DMSO, VMY or doxorubicin for 18hrs. DNA fragmentation of nuclear DNA was assessed by ethidium bromide-agarose gel electrophoresis.