Objective : To study the expression of QSOX1 in osteosarcoma tissues and cells and its role in prolifera- tion，migration and invasion． Methods : Western blot and immunohistochemistry were used to verify the expression of QSOX1 in osteosarcoma tissues and cells，and the cell line MG63 with the highest expression was selected．Slow virus knocked down and selected stable strains shQSOX1 group and shCtrl group．Western blot was used to detect the expression level of QSOX1 protein in MG63 after transfection．CCK-8 assay was used to detect the level of cell proliferation．Scratch test verified the level of cell migration．Transwell test was used to detect the invasion ability of cells ; Western blot was used to detect the mRNA expression level of NF-κB signal pathway in shCtrl group and shQ- SOX1 group. Results : Western blot and immunohistochemistry showed that QSOX1 was low expressed in human osteoblast line hFOB1. 19 and adjacent tissues，but high expressed in osteosarcoma tissue and osteosarcoma cells(P < 0. 001) ．CCK-8 experiment showed that the proliferation ability of shQSOX1 group was inhibited compared with shCtrl group (P＜0. 05) ; In the scratch test，the migration ability of shQSOX1 group decreased (P＜0. 001) ; Transwell proved that the invasive ability of shQSOX1 group was affected (P＜0. 001) ; NF-κB was highly expressed in shCtrl group and low expressed in shQSOX1 group (P＜0. 001) ． Conclusion QSOX1 is highly expressed in osteo- sarcoma．Knockout of QSOX1 gene can inhibit the proliferation，migration and invasion of osteosarcoma．Knockout of QSOX1 makes NF-κB signal pathway is deactivated.

Objective : To investigate the expression of milk fat globule epidermal growth factor 8 protein(MFGE8) in osteosarcoma cell lines and its effects on the proliferation，apoptosis，invasion and migration ability of osteosarco- ma cells(U2OS) ． Methods : The expression of MFGE8 protein in normal osteoblasts and osteosarcoma cell lines was examined by Western blot method．The relationship between MFGE8 mRNA expression and prognosis of osteo- sarcoma patients was analyzed by GEO database．The effects of down-regulation of MFGE8 on proliferation，apopto- sis，migration and invasion of U2OS cells were examined. Results : Western blot method showed that the expres- sion of MFGE8 protein was higher in osteosarcoma cells than that in normal osteoblasts and its was negatively corre- lated with the prognosis of osteosarcoma patients ( all P ＜0. 05) ; compared with sh-Ctrl ( U2OS cells transfected with the null group) group，the U2OS cells in sh-MFGE8 (U2OS cells transfected with sh-MFGE8) group had de- creased healing rate and invasion number while increased proliferation inhibition rate and apoptosis rate ，and all differences were statistically significant (P＜0. 05) ． Conclusion MFGE8 is highly expressed in U2OS ofosteosar- coma cells，and down-regulation of MFGE8 can inhibit the proliferation，invasion and migration of U2OS and in- duce their apoptosis.