FLI1 and metastatic melanoma: To evaluate whether combined autophagy and MEK inhibition reduces the invasive potential of MEKi‐resistant melanoma cells in vivo, we developed an embryonic zebrafish xenograft model of human metastatic melanoma in which DiI‐labelled melanoma cells were injected into the yolk sac of 2‐day postfertilization fli1‐GFP casper zebrafish embryos (Fig. 5a).37, 38, 39 Zebrafish injected with trametinib‐resistant A375 cells were treated with dimethyl sulfoxide, 16 nmol L−1 trametinib, 5 μmol L−1 PIK‐III or both drugs in combination for 3 days by addition of drugs to E3 aquarium water (Fig. 5b–e).