Fig. 5

The effect of the rous sarcoma proto‐oncogene (cSRC) inhibitor dasatinib in zebrafish embryos. The effect of the cSRC inhibitor dasatinib on xenografted DsRed‐labelled canine mammary tumor cell line (CMT)‐U27 cells in zebrafish embryos. Three days post‐injection (3 dpi) in the yolk sac of untreated cells (A) cell proliferation in the yolk sac and cells in the tail veins were observed, whereas 10 μM dasatinib‐treated cells (B) remained in the yolk sac. At 5 dpi for the control cells (C), further yolk sac proliferation and clear extravasation in the tail veins were observed, whereas after dasatinib pretreatment, only limited survival in the yolk sac was observed (D). When the control cells were directly injected in the duct of Cuvier at 3 dpi (E) tumorous masses were observed to have formed in the tail veins, and extravasation was observed near the heart, which is an effect that was not observed in dasatinib‐treated cells (F). At 5 dpi, tumorous masses of control cells were extended (G), whereas only some of the dasatinib‐treated cells (H) ended in the tail veins but did not form tumorous masses. Statistical analysis was performed (I, J) using Fisher's exact test. *P < 0.05 was considered significant