The exosome secreted by B16 cells promoted the proliferation and migration of mesenchymal stromal cell

Objective To investigate the interactions between melanoma-derived exosomes and the microenvironment. Methods The exosomes were isolated from the culture medium of mouse melanoma cells and then co-cultured with mesenchymal stromal cells (MSC) after identification. Immunofluorescence assay was performed to observe the exosomes engulfed by MSC. CCK-8 and transwell assays were used to evaluate the proliferation and migration of MSC. Effects of the exosomes on the expression of α-smooth muscle actin (α-SMA) in MSC were analyzed by Western blot. Results Co-culture of MSC with melanoma cell-derived exosomes enhanced the proliferation and migration of MSC as well as the expression of α-SMA. All of the changes mediated by the exosomes could be blocked by using the inhibitor of TGF-β receptor. Conclusion Melanoma cell-derived exosomes enhanced the proliferation and migration of MSC as well as the expression of α-SMA through TGF-β signaling pathway, which provided an advantageous microenvironment for melanoma progression. Key words: Exosome; Melanoma; Mesenchymal stromal cell; Tumor microenvironment; α-smooth muscle actin