Fig. 5

MDM2 is required for S9-induced p53 activation, apoptosis and cell cycle arrest. A U2OS cells were transfected with MDM2 siRNA followed with described concentration of S9 treatment for 24 h, MDM2, PARP cleavage and p53 protein levels were detected by western blot analysis. B The quantitation results of p53 and p21 western blotting images. C The quantitation results of cleaved PARP(CL)/total PARP(TL) western blotting images. D U2OS cells were transfected with MDM2 siRNA followed with described concentration of S9 treatment for 24 h, stained with PI and analyzed by flow cytometry