Abstract: Objective: To investigate the effects of transfecting the MRP-1/CD9 gene into the human ovarian carcinoma cell line SKOV-3 on tumor cell proliferation and motility and to observe the relationship between CD9 and the PI4K/AKT signaling pathway. Methods: Full-length cDNA was obtained for CD9 using RT-PCR and was inserted into the pcDNA3.1 expression vector. The recombinant plasmid was introduced into the SKOV-3 cells. RT-PCR, CFSE-flow cytometry and monostratal wound healing were used to determine the expression levels of PI4K and AKT, cell proliferation and motility of the SKOV-3 cells, respectively, before and after the transfection. Results: The eukaryotic expression vector was constructed successfully and clones with stable overexpression of CD9 were obtained. Compared with mock plasmid-transfected and untransfected cells, the mRNA expression of the PI4K gene was significantly inhibited by 40% and AKT mRNA expression was upregulated 3.13-fold in cells containing the CD9 expression vector. Both tumor cell proliferation and cell motility were notably enhanced in SKOV-3/CD9 cell clones. Conclusion: CD9 overexpression increased cell proliferation and motility of SKOV-3 cells, and these functions may be induced by activating the PI4K/AKT signaling pathway. This study suggests overexpression of CD9 is associated with a more malignant progression in ovarian carcinoma.