CASC8 lncRNA Promotes the Proliferation of Retinoblastoma Cells Through Downregulating miR34a Methylation

BACKGROUND: CASC8 lncRNA has been proven to be oncogenic in a variety of cancers, but its role in other types of cancer remains unclear. This study was to investigate the role of CASC8 in retinoblastoma (Rb). METHODS: RT-qPCR was performed to determine the expression of CASC8 and miR34a in paired Rb and nontumor tissue. Overexpression of CASC8 and miR34a in Rb cells was achieved to evaluate the interaction between them. Methylation-specific PCR was used to analyze the effect of CASC8 overexpression on MIR34A gene methylation. CCK8 assays were used to analyze cell proliferation. RESULTS: The results showed that CASC8 expression was upregulated and miR34a expression downregulated in Rb tissue. Moreover, miR34a expression was negatively correlated with the of CASC8 expression in Rb tissue. Overexpression of CASC8 decreased expression of miR34a and increased methylation of MIR34A in Rb cells. In addition, overexpression of CASC8 reduced the inhibitory effects of miR34a on Rb-cell proliferation. CONCLUSION: CASC8 may promote Rb cell proliferation by downregulating miR34a methylation.