Abstract
Numerous studies have demonstrated that microRNAs (miRNAs or miRs) are abnormally expressed in retinoblastoma (RB). miRNAs may serve a role in oncogene or tumor-suppressor activity in RB genesis and development by modulating various biological processes. miRNAs therefore, may be effective therapeutic targets for miRNA-based therapy in patients with RB. Recently it has been revealed that miR-503 may serve a role in various types of human cancer. However, the expression and functional roles of miR-503 are rarely reported in RB. In the current study, the expression of miR-503 was significantly upregulated in RB tissues and cell lines. In addition, Cell Counting Kit-8 and in vitro invasion assays were performed to assess cell proliferation and invasion, respectively. The results of the present study revealed that miR-503 inhibition impeded RB in vitro cell proliferation and invasion. Furthermore, protein tyrosine phosphatase nonreceptor type 12 (PTPN12) was demonstrated to be a direct target gene of miR-503 in RB cells. PTPN12 overexpression also led to the downregulation of miR-503 in RB cell proliferation and invasion. PTPN12 knockdown could therefore abrogate the effects of miR-503 downregulation in RB cells. In conclusion, the results demonstrated that miR-503 may serve a role in RB oncogenic activity progression by directly targeting PTPN12. Therefore, miR-503 may be a target for effective therapy in patients with RB.