Fig. 2
Exosomes from pulmonary metastatic TNBC advance lung micro-metastasis spread. (A) In vitro metastasis assay representation simulating extravasation, invasion into distant tissue, and subsequent metastatic colonization/growth of distant locales. (B-C) After treating LuECs with PBS or 231-derived exosomes for 24 h, GFP-labeled 231 LuT3 cells were implanted into transwell inserts (n = 5). Scale bars: 200 μm. (B) Extravasation (3 days). (C) Invasion through the basement membrane, followed by the development of a mammosphere (7 days). (D-F) Post 3-week intravenous exosome or PBS injection, mice were further given 5 × 105 GFP-Luc-labeled 231 LuT3 cells intravenously (n = 6). (D) Schematic of the exosome-induced TNBC lung metastasis model. (E) Bioluminescent lung images and metastasis quantification at days 5, 10, and 15 post cell injection (n = 6). (F) Full lung section images highlighting GFP lung metastasis 15 days post cell administration (n = 6). Scale bars: 10 mm and 1 mm. (G-I) Mouse left lung was inoculated with 231 LuT3CD63 − pEGFP shNC or 231 LuT3CD63 − pEGFP shRab27a cells, and the right lung was harvested after 10 days (n = 5). (G) Diagram detailing the TNBC lung micro-metastasis dissemination animal model. (H) Images of the mouse right lung, with quantitative lung metastatic lesion analysis (n = 5). (I) Endothelial cell exosome uptake in the right lung via flow cytometry (n = 5). Data shown as mean ± SD