Fig. 1

Figure 1. Breast cancer cells form protrusive structures during extravasation

(A–D) Lattice light-sheet microscopy of MDA-MB-231 cells expressing LifeAct Ruby injected intravenously in zebrafish xenografts. Yellow arrows point toward rolling BC cells in the blood. White arrows point to: (A and B) protrusions toward endothelium; (C) protrusions into the endothelium; (D) protrusions formed by tumor cell after extravasation. Scale bar, 10 μm. Time in min.

(E) Representative images of Ctrl, srGAP1 KD #1, and srGAP1 KD #2 MDA-MB-231-GFP cells injected into Tg(kdrl:RFP) zebrafish embryos and imaged 24 h post injection (hpi). Scale bar, 20 μm.

(F) Percent of extravasated MDA-MB-231 cells from zebrafish with extravasation events. n = 19 (Ctrl), 37 (srGAP KD #1), and 21 (srGAP1 KD #2) zebrafish. Mann Whitney U test, two-tailed. Data represented as a box and whisker plot, with median and interquartile range in the box and min and max as whiskers.

(G) Time-lapse images of MDA-MB-231 Ctrl and srGAP1 KD #1 cells in zebrafish vasculature. Yellow arrows point to protrusive structures. Scale bar, 20 μm.

(H) Tiled images showing extravasation events at the tailbud of fish. MDA-MB-231 cells. (Top) Ctrl cells imaged 24 h post injection (hpi). (Middle) srGAP KD #1 cells imaged 20 hpi; (bottom) srGAP KD #1 cells imaged 24 hpi. Three representative fish tails shown. Scale bar, 100 μm (left and middle panels), 25 μm (right).

(I) Schematic of zebrafish xenograft setup.