Fig. 6

Extravasation and invasion of NB cells treated with nEVs-210mimic in zebrafish embryos. SK-N-AS cells were labelled with DiI dye and injected into the Duct of Cuvier of 2 dpf Tg(fli1:EGFP) zebrafish embryo (n = 45 per condition). All images show xenografts anterior to the left, posterior to the right, dorsal up and ventral down. A. Schematic representation of the site of injection (Duct of Cuvier) and the site of z-stack confocal acquisition in the caudal plexus region. B. Representative z-stack images of NB cancer cells (in red, white arrows) inside the vasculature (in green) that did not extravasate or invade the avascular tail region. Scale bar 50 µm. C. Representative z-stack images of NB cancer cells (in red, white arrows) extravasated through the vasculature (in green). Scale bar 50 µm. D. NB cells (in red, white arrows) invaded the avascular tail region (vasculature in green). Scale bar 50 µm. E. Quantification at 24 hpi revealed a higher number of embryos with invaded cells in those injected with cells treated with nEVs-210mimic compared to those injected with cells treated with nEVs-NC. The invasion rate was calculated as follows: invasion rate (%) = (the number of zebrafish with cell extravasated / the initial number of xenografted zebrafish) × 100. Values are expressed as mean ± SEM from 3 independent experiments