LncRNA miR503HG interacts with miR-31-5p through multiple ways to regulate cancer cell invasion and migration in ovarian cancer

Abstract The role of lncRNA miR503HG has been investigated in several types of cancer, but its functions in ovarian cancer (OC) is unclear. Analysis of TCGA dataset revealed a 50-fold lower expression level of miR503HG in OC tissues than that in non-tumor tissues, indicating the involvement of miR503HG in OC. Results in this study showed that miR503HG was downregulated in OC and predicted poor survival. Expression of miR503HG negatively correlated with the expression of miR-31-5p across OC and non-tumor tissues. RNA-RNA interaction analysis revealed that miR503HG can interact with miR-31-5p. Dual-luciferase assay showed that miR-31-5p and miR503HG may directly interact with each other. Methylation specific PCR (MSP) showed that overexpression of miR503HG led to increased methylation level of miR-31-5p gene. Transwell assay showed that overexpression of miR-31-5p resulted in increased invasion and migration rates of OC cells. Overexpression of MiR503HG played an opposite role and attenuated the effects of overexpressing miR-31-5p. Therefore, miR503HG may promote the methylation of miR-31-5p and serve as its sponge to inhibit OC cell invasion and migration