Figure 6

HDM2 SMIs enhance p53 stability at the posttranslational level. A) WSU-FSCCL cells were exposed to 50 μM cyclohexamide (CHX) to stop protein translation or 10 μM MG132 to halt proteasome activity over the course of 4 h. B) Cells were pre-treated with 10 μM of Nutlin-3 (B1) or 10 μM MI-219 (B2) for 24 h and then exposed to 50 μM CHX for up to 4 additional hours. Samples were removed at 0.25, 0.5, 1.0, 2.0 and 4 h to evaluate the stability of p53 protein. RD represents relative density to time 0 for CHX and MG132 blots in (A) and time at 24 h 10 μM pre-treatment for blots in section (B). Changes in relative protein densities are plotted from values obtained (and listed below blots) to show effects of HDM2 SMIs on sustaining p53 protein expression in the presence of added 50 μM CHX.