A new platform using bioluminescence imaging and zebrafish xenograft. Application in [gamma]-secretase inhibitors affect tumorigenesis

The aim of the present study is to establish a zebrafish tumor xenograft model for drug screening and investigate the effects of γ-secretase inhibitors (DAPT, Compound E) on tumorigenesis in the model. Mouse melanoma B16F (B16F-Luc) cells stably expressing firefly Luciferase were used for the transplantation. For embryos model, prior to injecting cancer cells on 6 hpf (hours post fertilization), approximately 100 cancer cells were injected into the yolk sac with glass micropipette by 10.8 psi positive pressure. Embryos were then transferred in fresh E3 egg water in 96-well plates to an incubator up to 4 dpi (days post injection). For the adult fish model, 1-year old zebrafish were anaesthetized with MESAB. Approximately 4,000 cells in Matrigel (20ml) were injected into the abdomen. Fishes were then put in fresh fish water for up to 7 dpi. The embryos as well as the adult fishes were treated with DAPT and Compound E. To assess cancer cells proliferation of the embryos, at 3 hpi, 20 hpi, 44 hpi and 68 hpi, all the embryos in 96-well plates were assayed by bioluminescent imaging. Similarly adult fish were assayed by bioluminescent imaging at the time points of 1hpi, 4hpi, 16hpi, 28hpi, 40hpi, 52hpi and 68hpi continually. In adult fish model, the results showed that 90% melanoma cells were cleaned out within 48 hpi and the melanoma cells could survive in dead fish body for almost 20 hours. In embryos models, DAPT, but not compound E inhibited melanoma cells proliferation, which might due to the block of Notch signaling. Zebrafish embryo xenotransplant model combining with quantitative bioluminescent imaging could be used for a high through put drug screening model assay.