Page 03 1. (continued) To investigate the involvement of caspases in this process of apoptosis, the experiment was repeated using a single dose of extract (10 µg/cm3) but with the addition of a variety of caspase inhibitors (drugs known to prevent the activation of one or more caspases). Inhibitors used included an inhibitor known to prevent activation of all caspases (all ci) and individual inhibitors of caspase 3 (ci 3), caspase 8 (ci 8) and caspase 9 (ci 9). Percentage changes in the number of cells undergoing apoptosis compared to untreated cancer cells are shown in Figure 3. Figure 3 Change in number of cells undergoing apoptosis (%) ci 9 + Extract ci 8 + Extract ci 3 + Extract all ci + Extract Extract Treatment 500 400 300 200 100 0 −100 The distribution of the cancer cells across the different phases of the cell cycle was then investigated by measuring the DNA content of the cells. Cultures of cells were treated with 10 µg/cm3 extract or left untreated for 24 hours as a control and then the DNA content of 10,000 cells was analysed for each cell culture. Results for treated cells are shown in Figure 4A and for control cells in Figure 4B. DNA content is displayed with arbitrary units where 200 units represents the DNA content of a non-dividing diploid cell. 300 300 240 240 180 180 120 120 60 60 0 0 600 600 400 400 200 200 0 0 DNA content (arbitrary units) DNA content (arbitrary units) Number of cells counted Number of cells counted Figure 4A Figure 4B Treated cells Untreated cells Page 04 [BLANK PAGE] DO NOT WRITE ON THIS PAGE