Table 1

Inhibition of cell growth (IC₅₀) and covalent binding after incubation of AF with human tumor cells

Cell Line	Covalent Binding	IC₅₀
	pmol bound AF/mg protein	μM
MCF7	28	0.035
Caki-1	12	0.130
OVCAR5	41	0.028
MDA-MB-435	0.9	>86
M14-MEL	0.4	>37
HT-29	0.2	>29

AF was incubated with cells for 72 h, and IC₅₀ values determined with the MTT assay as described under Materials and Methods. Covalent binding was determined following 12-h exposure of 50 nM radiolabeled AF and isolation of cellular macromolecules by acetone precipitation followed by solvent washing (see Materials and Methods). Values are means of at least three experiments.