Table 10.

Six library compounds induce potent cell death of U-937 cells (human lymphoma) in both 24-h^a and 72-h^b experiments and enhance enzymatic activity of procaspase-3 in vitro.^c

Compound	U-937 72h IC50 (μM)	U-937 %Cell Death (24h, 7.5 μM)	%Procaspase-3 Activity (25 μM)
PAC-1 (1)	3.8 ± 0.4	21	42 ± 1.8
S-PAC-1 (37)	4.4 ± 0.7	23	4 ± 0.6
36{2,7}	1.8 ± 0.2	90	53 ± 4.1
36{4,7}	1.6 ± 0.2	53	64 ± 2.5
B-PAC-1 (36{18,7})	1.4 ± 0.2	97	36 ± 1.6
36{20,24}	0.9 ± 0.03	83	82 ± 2.4
36{25,7}	1.0 ± 0.04	50	69 ± 5.3
36{28,7}	2.0 ± 0.2	70	60 ± 2.4

^aCell viability determined by Annexin V-FITC/propidium iodide staining.

^bBiomass quantified using the sulforhodamine B assay.

^cCompounds were tested at a concentration of 50 μM with 1 μM procaspase-3 (wild-type) and 3.5 μM ZnSO₄. Cleavage of the Ac-DEVD-pNA substrate was monitored at 405 nm and normalized to a DMSO-treated control (0%) and a zinc-free control (100%). [46]