Influence of Canine Macrophage-derived Extracellular Vesicles on Apoptosis in Canine Melanoma and Osteosarcoma Cell Lines

Abstract

Background/Aim: The purpose of this study was to evaluate the effect of extracellular vesicles derived from canine M1-polarized macrophages (M1EVs) on canine tumor cells, such as D17 (osteosarcoma cells) and LMeC (melanoma cells). Materials and Methods: Protein expression was determined by western blot analysis. Gene expression was determined by RT-qPCR. In addition, cell apoptosis was analyzed by Annexin V/PI staining. Results: In the case of M1EV, the levels of pro-inflammatory cytokines such as TNF-alpha, IL-6 and IL-1 beta were increased, and nitrate/nitrite levels were also increased. M1EV induced apoptosis of tumor cells by increasing caspase-3 and caspase-7 activation. In addition, M1EVs decreased expression of CCR4, Foxp3 and CTLA-4 in canine peripheral mononuclear cells cocultured with tumor cells. Conclusion: M1EV could be an effective anti-cancer therapeutic approach in melanoma and osteosarcoma and M1EVs can be used as immunomodulators in the tumor microenvironment for cancer treatment.