Fig. 3. Pin1 is essential for tumor cell survival. A, HeLa, 293, and SK-N-AS-cells, transiently transfected with GFP (GFP), GFP-Pin1 (Pin1), and GFP-Pin1 antisense (Pin1-AS) were analyzed for the frequency of apoptotic nuclei 48 h after transfection. B, HeLa cells, transiently transfected with GFP, GFP-tagged Pin1, or the indicated GFP-tagged mutant proteins, were analyzed for the frequency of apoptotic nuclei 72 h after transfection. A and B, average of three independent experiments is shown; bars, SE. C, juglone induces apoptosis in human tumor cells. Flow cytometric DNA analysis of HeLa cells grown for 72 h in the presence of the indicated concentration of juglone.