Abstract: Objective To investigate the role of hepatoblastoma（HB）⁃derived exosome miR⁃106a in cell communication and immune microenvironment. Methods Exosomes were isolated from HB cells by supercentrifu⁃ gation and phenotypes were observed by transmission electron microscope. The proliferation and migration of tumor cells were detected in vitro. Dual luciferase reporter assay was used to verify the 3′ ⁃UTR targeting relationship between miR⁃106a and phosphatase tension protein homolog（PTEN）. The effects of miR⁃106a on immune microen⁃ vironment and tumor growth were verified by animal experiments and flow cytometry. Results The exosomes released by HB cells were rich in miR⁃106a（P = 0.000 6），which enhanced the proliferation（P = 0.006 4）and migration（P = 0.000 3）of HB cells. In addition，the exosome miR⁃106a directly bound to the 3′⁃UTR of PTEN to inhibit its expression（P = 0.000 5），activating the AKT signaling pathway and promoting the secretion of vascular growth factor（VEGF）（P = 0.005 8）. Animal experiments confirmed that miR⁃106acould recruit myeloid suppressor cells（MDSCs）through VEGF to enter tumor microenvironment（P = 0.000 8）and promote tumor growth（P = 0.000 1）. Conclusion HB⁃derived exosomes promote the proliferation and migration of tumor cells ，up⁃regulate VEGF secretion，recruit MDSCs into tumor microenvironment，and promote tumor growth.

Key words:

hepatoblastoma, exosome, miR?106a, proliferation, immune?microenvironment