Antiangiogenic and antitumor activity of ScA. (A–F) Transgenic Tg(fli1:EGFP) zebrafish embryos in which GFP is expressed in endothelial cells were incubated without (A) or with increasing concentrations of ScA: 80 nM (B), 160 nM (C), 300 nM (D) 1.6 µM (E), or 3 µM (F). Blood vessel morphology was recorded by fluorescence microscopy. (G) Filter disks impregnated with 100 ng of basic FGF were placed on the chorioallantoic membrane of 11-day-old chicks to induce angiogenesis in the absence or presence of ScA, as shown. After 72 h, disks were removed and the vascularity of the underlying chorioallantoic membrane determined by direct counting of branch points using a dissecting microscope. (H) NB7 neuroblastoma cells lacking caspase 8 (filled bar) or NB7C8 cells reconstituted for caspase 8 expression (open bars) were seeded into 10-day-old chick chorioallantoic membranes to form tumors. After 72 h, ScA was added topically to each growing tumor mass. Tumors were harvested and resected on day 8, and mass (wet weight) was determined. Data shown is the mean ± SD (n = 8–12). The mass of the NB7C8 is significantly decreased (P < 0.002).