Figure 6

Depletion of the p53 protein does not lessen the camptothecin susceptibility in SMA fibroblasts. (A) A similar experiment was conducted as described for 5C. Cell survival of treated cells was measured and presented as percentage of the untreated ones. At least two independent experiments were performed and each sample was set up in replicates of four. The mean value ± sem of one representative experiment is presented here. Statistical analyses (unpaired t test) indicate that SMA fibroblasts are significantly more sensitive to camptothecin than control fibroblasts (*** p < 0.0001). There is no difference in survival among cells transfected with non-targeting control, p53, or no siRNA oligonucleotides for either control or SMA fibroblasts. (B) A similar experiment was conducted as described for 5C except cells were treated with 25 μM camptothecin for 16 h. Cell lysates were analyzed by Western blotting using antibodies against cleaved PARP, p53, and tubulin, respectively. NT = non-targeting control, CPT = camptothecin, and cPARP = cleaved poly ADP-ribose polymerase.