Figure 4

Accumulation Poly-ADP-Ribose-Polymerase (PARP) in cells treated with PD166866 evidenced by imuno-histochemistry. Cells were treated with the drug (50 μM for 24 hours) and processed by immuno-histochemical techniques to visualize the intracellular accumulation of PARP. The dark nuclei indicate accumulation of this enzyme in treated cells (large panel). The immuno-reaction also occurs in positive control cells treated with H₂0₂ (left small panel) while it is almost absent in untreated control cells. These results indicate cell death.