Antineoplastic activity in the zebrafish embryo model. (a) Effects on zebrafish embryo development. Compounds were added to the water and the number of normal embryos determined after incubation; (left) incubation day 0 to day 3 (72 hours); (right) incubation day 2 to day 5 (72 hours). (b,d) Assessment of tumor cell growth in zebrafish embryos. Embryos (n = 20) were injected with labeled MelJuSo cells and fluorescence determined after injection (basal level) and after 72 hours (average + S.E.M.). Not all compounds were tested due to observations of precipitation. (c,e) Assessment of tumor cell dissemination in zebrafish embryos. Embryos (n = 20) were injected with labeled MelJuSo cells and labeled cells in dorsal regions were recorded after 72 hours (average + S.E.M.). (f) MelJuSo-Ub^G76VYFP cells were injected into zebrafish embryos and allowed to establish for 72 hours. The indicated compounds were added to the water and yellow and red fluorescence recorded after 12 hours. Note the induction of Ub^G76VYFP by each compound. Statistical significance calculated by t-test; *p < 0.05, **p < 0.01, ***p < 0.001.