Inhibition of Vps34 reduces invasion and increases death of trametinib‐resistant melanoma cells in an in vivo zebrafish xenograft of metastatic melanoma. (a) Schematic of zebrafish xenograft assay showing injection of approximately 250 DiI‐labelled melanoma cells into the yolk sac of 2‐day postfertilization (dpf) zebrafish embryos prior to incubation at 33°C in atmospheric air for 72 h and subsequent analysis of melanoma invasion. (b–e) Representative confocal images of zebrafish embryos following injection with DiI‐labelled trametinib‐resistant A375 cell and treatment for 72 h with (bi, ii) dimethyl sulfoxide (DMSO), (ci, ii) 16 nmol L⁻¹trametinib (Tram), (di, ii) 5 μmol L⁻¹ PIK‐III or (ei, ii) 16 nmol L⁻¹ trametinib (Tram) + 5 μmol L⁻¹PIK‐III (16 Tram + 5 PIK‐III) by addition of drugs to E3 media. (f) Invasive distance of trametinib (Tram)‐resistant A375 cells from injection site [n = 10 fish for each condition from five independent experiments; mean ± 95% confidence interval, Kruskal–Wallis test with Tukey's post‐hoc correction (****P < 0·001)]. GFP, green fluorescent protein; PBS, phosphate‐buffered saline.