EMP1 promotes the malignant progression of osteosarcoma through the IRX2/MMP9 axis.

BACKGROUND Previous studies have demonstrated that EMP1 is an oncogene. In this paper, we aim to uncover the role of EMP1 in stimulating the malignant progression of osteosarcoma (OS) by the IRX2/MMP9 axis. METHODS EMP1 levels in 49 OS tissues and adjacent ones were detected. Potential correlation between EMP1 level and clinical data of OS patients was determined. Migratory and invasive abilities in SaOS-2 and U2OS cells influenced by EMP1 were examined by Transwell and wound healing assay. The involvement of IRX2 in OS cell metastasis regulated by EMP1 was finally explored. RESULTS EMP1 was upregulated in OS tissues than those of normal ones. Higher rates of lymphatic metastasis and distant metastasis were found in OS patients expressing higher level of EMP1, who suffered a worse prognosis. Knockdown of EMP1 inhibited migratory and invasive abilities in OS cells. Protein levels of IRX2 and MMP9 were upregulated after overexpression of EMP1. Rescue experiments verified that IRX2 was involved in EMP1-regulated malignant progression of OS. CONCLUSIONS EMP1 is upregulated in OS tissues and closely linked to lymphatic metastasis and distant metastasis. It stimulates the malignant progression of OS through the IRX2/MMP9 axis.