Research Paper Volume 7, Issue 10 pp 854—867

The p53 tumor suppressor protein protects against chemotherapeutic stress and apoptosis in human medulloblastoma cells

Figure 6. Effects of silencing of p53 on cell survival. (A) Genetic silencing of p53. D556 and DAOY cells were infected with p53siRNA or pLKO lentivirus'. The cells were left untreated or exposed for 18 hrs to DMSO or 30uM VMY as indicated, and western blots for p53 and β-actin were run. (B) The effects of p53shRNA knockdown (left) and Pifithrin (Pif, right) on cell viability were determined via colony forming assays. D556 cells were treated with DMSO, doxorubicin or VMY for 18 hrs. Fresh media was added and the cells cultured for an addition 3-5 days, followed by staining with crystal violet. (C) Quantification of the number of colonies in (B). (D) Dose response curves of D556 cells treated with VMY at the concentrations shown in the presence and absence of Pifithrin. The data are shown as average + standard deviation of N=3 separate experiments.