Figure 5

Western blot analysis of SC-1–induced cells. Cell line 23132 was induced with 40 μg/ml of SC-1 for the periods indicated above, and then whole cell lysates and Western blots were prepared. Coomassie-stained gels shown below the blots were used as controls for equal protein concentrations loaded on lanes. a, Determination of poly(ADP-ribose)polymerase (PARP) cleavage by anti-PARP antibody. CP indicates expected size of PARP cleavage product. Cleavage of PARP was not detectable at all. b, Staining with anti-topoisomerase IIα antibody as marker for cellular proliferation. A reduced expression of topoisomerase IIα could be observed after SC-1–induced apoptosis. Expression of c-myc detected by staining with anti–c-myc antibody. Five minutes after induction of apoptosis, an increased c-myc expression was found, followed by a decrease after 1 hour.