Abstract: Objective To investigate the effects of silencing BMP4 on mesenchymal epithelial transition, invasion and migration ability of osteosarcoma cell line MG-63. Methods BMP4 shRNA plasmid was transfected into MG-63 cells,MG-63 cells were divided into MG-63 control group(normal culture control)，empty control group（transfected empty plasmid），MG-63silence group（transfected BMP4 silence shRNA）. Reverse transcription polymerase chain reaction （RT-PCR） and Western blotting were used to detect the changes of E-cadherin，vimentin、twist and snail mRNA and protein levels after the cells BMP4 was silenced. Transwell invasion assay and wound healing assay were conducted when the BPM4 was silenced to detect the changes of the invasion and migration ability of MG-63 cells. Results Silencing BMP4 decreased MG-63 cells twist and snail expression, increased the expression of epithelial cell marker E-cadherin, and decreased expression of vimentin. Invasion and migration assays showed that the transmembrane cell number and migration distance of BMP4 silence group were significantly less than those of the MG-63 control group and empty control group（P<0.05）.Conclusions The silence of BMP4 gene may change MG-63 osteosarcoma cells from mesenchymal phenotype to epithelial phenotype, reducing tumor cell invasion and migration ability effectively.

Key words: osteosarcoma, BMP4, epithelial mesenchymal transition, invasion, migration