Apaf-1 protein expression analyzed by Western blotting in leukemia cell lines (Figure 3A) and AML blasts, AML-1, AML-2, and AML-3 (Figure 9). Ratios of Apaf-1 expression were analyzed in two groups: (1) K562:CEM:CEM/VLB₁₀₀ and (2) AML-1:AML-2:AML-3 by densitometry.

 UV light–induced apoptosis. Data presented for leukemic cell lines are from Figure 1B. Percentage apoptotic cells were shown at 4 hours. Percentages of apoptosis in AML blasts are shown as Figure 9.

 Cytochrome c/dATP induced activation of caspase-3 and -9. S-100 containing 50 μg/mL protein was incubated with cytochrome c and dATP at 30°C for 1 hour. Caspase activity was measured by fluorogenic substrates and expressed as μmol/L per hr/mg protein). Correlations of Apaf-1 protein levels with sensitivity to UV light–induced apoptosis and cytochromec–induced activation of caspases were analyzed by correlation matrices (Statistica 5.0).