Long Noncoding RNA LINC00202 Promotes Tumor Progression by Sponging miR-3619-5p in Retinoblastoma

: Retinoblastoma (RB) is the most common intraocular malignancy in childhood, and the prognosis in the advanced RB is poor. It is urgent to find novel therapeutic targets. Long noncoding RNAs (lncRNAs) have critical functions in cancer progression, and lncRNA LINC00202 is found associated with poor prognosis in RB. However, the functions of LINC00202 in RB remain unclear. We employed qRT-PCR and immunoblot to detect the expression levels of mRNAs and proteins, respectively. Cell proliferation was determined by CCK-8 assay and colony formation assay. Transwell assays were applied to evaluate the cell abilities of migration and invasion. Luciferase reporter assay was applied to examine RNA stability, and RNA pulldown assays were used to detect interaction between lncRNA and microRNA (miRNA). LINC00202 expression in RB tissues is higher than that in the paired adjacent normal tissues, which has correlation with poor prognosis in RB. RB cell proliferation, migration and invasion were weakened by LINC00202 depletion, but enhanced by LINC00202 overexpression. MiR-3619-5p was identified to directly bind and mediate LINC00202-promoted RB progression, meanwhile, miR-3619-5p directly regulated expression of an oncongene, RIN1. Moreover, RIN1 knockdown completely blocked miR-3619-5p-enhanced RB progression. In summary, high LINC00202 levels are correlated with poor prognosis in RB, and it promotes RB progression by sponging miR-3619-5p and therefore up-regulating RIN1 expression.Key words: LINC00202, miR-3619-5p, retinoblastoma, progression, RIN1.