Proinflammatory macrophage-derived microvesicles exhibit tumor tropism dependent on CCL2/CCR2 signaling axis and promote drug delivery via SNARE-mediated membrane fusion.

Background: Exosome (Exo)-based chemotherapeutic drug delivery systems have been extensively investigated; however, the therapeutic potential of other subtypes of extracellular vesicles (EVs), in particular microvesicles (MiV), seem to be overlooked. Moreover, despite a general agreement on organ tropism of EVs, few studies have clearly demonstrated that EVs specifically target tumor tissue. Methods: Proinflammatory macrophage-derived EV subpopulations comprising apoptotic bodies (ApB), MiV and Exo were isolated under differential ultracentrifugation, and further analyzed using comparative proteomic and lipid approach. Results: On the basis of EV biogenesis pathways, our data demonstrated that MiV acquire the tumor-targeting capacity probably through inheritance of CCR2-enriched cell membrane which also drives the recruitment of donor cells to tumor sites. Further, our data validate MiV utilize SNARE-mediated membrane fusion to directly discharge doxorubicin to nucleus and bypass endocytic degradation. Conclusions: Compared with other EV subtypes, MiV loaded with doxorubicin gain significant benefits in chemotherapeutic outcomes including survival rate improvements in metastatic ovarian cancer. Therefore, MiV represent a potent alterative to Exo and synthetic liposomes (Lipo) for tumor-targeting drug delivery.