Figure 1.

M1 macrophage-derived EVs displayed a tropism for tumor cells. (A) Total protein contents of EVs produced by M0 macrophages and M1 macrophages, normalized per ten million cells (n = 6). (B) The representative fluorescence intensities of DiD-positive cells at 4 h were displayed. (C) Cellular uptake efficiency of CHO cells or SKOV3 cells after incubation with EVs or Lipo labeled with DiD was measured by flow cytometry at 4 h. (D) CCL2 mRNA expression levels in SKOV3 cells and CHO cells. (n = 6). (E) CCL2 mRNA expression in tumor nodules, liver and ovary (n =6). (F) Bright-field and composite bright field/fluorescence images of excised organs from mouse models of metastatic ovarian cancer at 24 h post-injection of DiD-labeled EVs, Lipo or free DiD with the same molar amount of DiD (amount 5 nmol per mouse, n = 3). For CCR2 antagonist experiments, INCB3344 was administered to mice by oral gavage for 12 hours later prior to injection of EVs. Green arrow heads indicate the metastatic nodules. Color bars show the low- and high-intensity values in units of counts/s. (G) Biodistribution profiles of each experimental group at 24 h measured by fluorescence imaging in the heart (He), liver (Li), spleen (Sp), lung (Lu), kidneys (Ki), gastrointestinal tract (GI), uterine appendages (UA) and tumors. (H) Bar graph showed calculated tumor to liver tissue uptake ratios. The data were shown as mean ± s.d., ** = p < 0.01, *** was p < 0.001, **** was p < 0.0001 by Student's t test, one-way ANOVA test or two-way ANOVA test.