Epithelial ovarian cancer is the most lethal malignancy in gynecology. Numerous studies have confirmed that long noncoding RNAs (lncRNAs) are abnormally expressed in ovarian cancer and are closely associated with the cell proliferation and senescence in cancers. However, the role and underlying molecular mechanism of long noncoding RNA high expression in hepatocellular carcinoma (HEIH) in ovarian cancer remain unknown.
Experiments including Real-time quantitative polymerase chain reaction, RNA immunoprecipitation, luciferase reporter, Fluorescence in situ hybridization, western blot, colony formation assays, β-galactosidase senescence assay, cell apoptosis, proliferation, invasion, and migration assays were applied to investigate the role of HEIH in ovarian cancer. The data were expressed as the mean ± standard deviation. Student t test was used to compare the data between two groups. The one-way analysis of variance was applied to compare the data among multiple groups with Tukey post hoc test. All experiments were repeated three times. P < 0.05 was considered statistically significant.
Herein, HEIH expression was found to be up-regulated in ovarian cancer tissues (n = 25; twofold higher than normal tissues, P < 0.05) and cell lines (sixfold higher than normal ovarian epithelial cell line on average, P < 0.05), and high HEIH expression predicted poor prognosis (survival rate is about 25% after 40 mo; P < 0.05). Moreover, we found that HEIH accelerated proliferation, migration, and invasion, whereas inhibited cell senescence in ovarian cancer (P < 0.05). In mechanism, HEIH was confirmed to serve as a sponge for miR-3619-5p, and miR-3619-5p counteracted HEIH-mediated regulation of ovarian cancer (P < 0.05). Besides, cortactin-binding protein 2 (CTTNBP2) was found to be the downstream target of miR-3619-5p. Rescue assays validated that CTTNBP2 up-regulation significantly reversed the inhibitory effects of HEIH knockdown on ovarian cancer progression (P < 0.05). Furthermore, we found that HEIH facilitated tumor growth in vivo by regulating CTTNBP2 expression (P < 0.05).
In conclusion, our research revealed that HEIH accelerated cell proliferation, migration and invasion, whereas inhibited cell senescence in ovarian cancer via targeting the miR-3619-5p/CTTNBP2 axis. These findings may be valuable for finding new therapeutic targets to improve ovarian cancer treatment.