Effect of exosomes released from chronic myeloid leukemia K562cells on human umbilical cord mesenchymal stem cells

Objective To investigate the effects of exosomes released from chronic myeloid leukemia K562 cells on human umbilical cord mesenchymal stem cells(hucMSCs).Methods The exosomes were extracted and purified from the supernatant of K562 cell culture with ultrafiltration and sucrose density gradient ultracentrifugation.The morphology of the exosomes was observed by transmission electron microscope(TEM).The effect of exosomes on the proliferation of hucMSCs was determined by cytometry after co-incubating exosomes with hucMSCs.The expressions of FAP,α-SMA and IL-6 genes in carcinoma-associated fibroblasts(CAFs) were analyzed with real-time fluorescence quantitative PCR(qRT-PCR),and the levels of CD9,CD81,FAP and α-SMA were determined by Western blot.Results The exosome exhibited elliptic or saucer-like vesicle with membrane structure under TEM and its diameter ranged from 30 to 100 nm.The proliferations of hucMSCs were inhibited by different concentrations of exosomes with a dose-dependent manner(P0.05).qRT-PCR showed that the levels of FAP,α-SMA and IL-6 expression in hucMSCs treated with different concerntrations of exosomes were increased significantly(P0.05).Western blot analysis also showed that the exosomes expressed the markers as CD9 and CD81,and the levels of FAP and α-SMA in hucMSCs treated with exosomes were increased significantly.Conclusion The exosomes released from K562 cells may inhibit the proliferation of hucMSCs in vitro,and promote the differentiation of hucMSCs to CAFs.