Fig. 4

Promoting roles of FMC-EV in the formation of a pre-metastatic niche (PMN) in the liver. A Schematic illustration for a mouse model established to verify an EV-educated liver PMN. NPG mice were intraperitoneally injected with FMC-EV (1 × 10¹⁰ particles) or PBS every two or three days for nine times and then intrasplenically injected with RFP-expressing tumor cells. Livers of the mice were harvested three weeks later and subjected to IVIS imaging to detect tumor cells colorized in the liver. B, D, F Representative results of ex vivo imaging of livers harvested from the mice intraperitoneally injected with FMC-EVs or PBS, followed by intrasplenic injection with FMC-1807-RFP (B), FMC-1806-RFP (D), or MDA-MB-231 (F). C, E, G Fluorescence intensity of FMC-1807-RFP (C), FMC-1806-RFP (E), or MDA-MB-231 (G) in liver was acquired as radiant efficiency with a setting of excitation at 570 nm and emission at 620 nm. The PBS-injected group was denoted as Control. n = 3 in each group. Quantitation data are presented as the mean ± SD. The Student’s t-test was used to determine the statistical significance