Interference of ROR1 gene expression inhibits epithelial-mesenchymal transition of osteosarcoma MG-63 cells

Objective: To investigate the effect of interferencing receptor tyrosine kinase-like orphan receptor 1 (ROR1) gene expression on epithelial-mesenchymal transition (EMT) of osteosarcoma MG-63 cells. Methods: The specific siRNA targeting ROR1 gene (ROR1-siRNA) was transfected into osteosarcoma MG-63 cells with the relative high expression of ROR1 protein, then the down-regulation of ROR1 expression was confirmed by Western blotting. The migration and invasion abilities of MG-63 cells were examined by scratch wound healing assay and Transwell chamber assay. The morphological changes of MG-63 cells were observed under an inverted optical microscope. Finally, the expressions of EMT-associated E-cadherin and vimentin, and tumor metastasis-related zinc finger E-box binding homeobox protein 1 (ZEB1), matrix metalloproteinase 2 (MMP-2) and MMP-9 proteins in MG-63 cells were detected by Western blotting and immunofluoresence staining, respectively. Results: ROR1-siRNA transfection significantly inhibited the expression of ROR1 in MG-63 cells (P < 0.05). After down-regulating ROR1 gene expression by ROR1-siRNA transfection, the migration and invasion abilities of MG-63 cells were significantly reduced (both P < 0.05), the morphology of MG-63 cells conversed from mesenchymal phenotype to epithelial phenotype, and the expression level of E-cadherin was significantly up-regulated (P < 0.05), while the expression level of vimentin was significantly down-regulated (P < 0.05). Furthermore, the expressions of ZEB1, MMP-2 and MMP-9 in MG-63 cells transfected with ROR1-siRNA were decreased as compared with those in the untransfected group (all P < 0.05).  Conclusion: RNA interference of ROR1 gene expression can reduce the migration and invasion abilities of osteosarcoma MG-63 cells through inhibiting the occurrence of EMT. DOI:10.3781/j.issn.1000-7431.2018.11.743