Cells were serum starved for 36 hrs, followed by exposed to OU (30 nM) or DG (100 nM) for indicated periods of time, and analyzed by western blotting. (B) p53 reduction rescued by Src inhibitor, PP2: Cells were left untreated or treated with DG or OU alone or in combination with increasing concentrations of PP2 for 24 hrs. (C). p53 reduction rescued by MAPK or PI3K inhibitor: Cells were left untreated or treated with DG alone or in combination with MEK inhibitor, PD098059 or PI3K inhibitor, LY294002 for 24 hrs. Cell lysates were prepared for western blotting.