Effect of miR-515-5p on Proliferation and Drug Sensitivity of Retinoblastoma Cells

Background: Retinoblastoma (RB) is a common malignancy in children eyes. Aberrant microRNA (miR) expression is observed in many cancer cases. miR-515-5p is reported to be concerned with the course of many cancers. This study explores the role of miR-515-5p in proliferation and drug sensitivity of RB cells. Methods: Human RB cell lines (WERI-RB1, SO-RB50 and Y79) and human retinal pigment epithelial cell line ARPE-19 were utilized in this study. Drug-resistant cells SORB50/VCR and SO-RB50/CBP were constructed for the following experiments. The expressions of miR-515-5p and Notch1 in RB cells were detected. Notch1 was significantly upregulated in RB cells while miR-515-5p was notably downregulated. Then, the binding relationship between miR-515-5p and Notch1 was predicted and verified. Results: miR-515-5p negatively regulated Notch1 expression. In vitro and in vivo experiments revealed that overexpressed miR-515-5p inhibited RB cell proliferation and enhanced drug sensitivity. Functional rescue experiment suggested that miR-515-5p regulated RB cell proliferation and drug sensitivity via inhibiting Notch1 expression. Conclusion: It could be concluded that overexpressed miR-515-5p suppressed proliferation and drug resistance of RB cells by targeting Notch1 expression, indicating that miR-515-5p might constitute a promising therapy target for RB.