HuR WT EVs are tumor promoting and directly decrease ICAM-1 expression on endothelial cells. A, Schematic of EV isolation from KPC WT and HuR-KO cells via SEC. B, Immunoblot of cell lysates (CL) and SEC fractions 1, 7–10 (EV containing), and 14 from KPC WT (HuR status +) and HuR-KO (HuR status −) cells. Blot probed for total protein (Ponceau), HuR, EV markers (TSG101 and CD81), and cell lysate control (cytochrome c). C, Particle size concentration normalized to final cell number measurements via fluorescent nanoparticle tracking analysis. (n = 4). D, Schematic of pancreatic orthotopic implantation of KPC KO cells into C57BL6 mice following intraperitoneal injection of WT vs. HuR-KO EVs every other day for 14 days and (E) tumor volume (mm3) after 14 days (WT EV n = 6; HuR-KO EV n = 5). IF staining for (F) proliferation (Ki-67, magenta; n = 5), (G) endothelial cells (endomucin, magenta; WT EV n = 5 and HuR-KO EV n = 8), and (H) co-staining of endothelial cells (endomucin, magenta) and ICAM-1 (white; WT EV n = 6 and HuR-KO EV n = 7; scale bar, 100 µm). P values were calculated using an unpaired two-tailed Student t test. *, P P P
Finan et al. (Wed,) studied this question.