CircDHDDS/miR-361-3p/WNT3A Axis Promotes the Development of Retinoblastoma by Regulating Proliferation, Cell Cycle, Migration, and Invasion of Retinoblastoma Cells.

Retinoblastoma (RB) is a common intraocular malignant tumor. The growing evidence has reported that circular RNAs (circRNAs) play critical roles in RB development. Therefore, the purpose of the study is to investigate the regulatory mechanism of circDHDDS in RB. The real-time quantitative polymerase chain reaction (RT-qPCR) assay was used to quantify the expression levels of circDHDDS, miR-361-3p, and WNT3A in RB tissues and cells (RPCs, Y-79, and WERI-Rb-1). The proliferation and cell cycle of RB cells were assessed by colony formation assay and flow cytometry assays, respectively. The migration and invasion of RB cells were measured by transwell assay. The protein expression levels of Nectin-3 (CD113), SOX2, Nanog, and WNT3A were measured by Western blot assay. The functional targets of circDHDDS and miR-361-3p were predicted by bioinformatics databases, and the dual-luciferase reporter assay was used to confirm the interaction relationship between miR-361-3p and circDHDDS or WNT3A. The functional role of circDHDDS silencing in vivo was evaluated by xenograft experiment. We found that circDHDDS was overexpressed in RB tissues and cells compared with normal retinas tissues and retinal pigment epithelial cells, correspondingly. Furthermore, silencing of circDHDDS impeded proliferation, migration, invasion, and induced cell cycle arrest in vitro, which were abolished by knockdown of miR-361-3p. The in vivo experiments also suggested that tumor growth was inhibited by knockdown of circDHDDS. Moreover, we also found that miR-361-3p specifically bound to WNT3A, and overexpression of miR-361-3p suppressed RB development by decreasing WNT3A expression. Summarily, circDHDDS, a molecule sponge of miR-361-3p, regulated the expression of WNT3A. Therefore, circDHDDS/miR-361-3p/WNT3A axis stimulated the development of RB by regulation of proliferation, cell cycle program, migration, and invasion of RB cells.