(1) Background: LncRNAs could be a promising biomarker to predict the prognosis of various cancers. The significance of E2F4antisense lncRNA remains unclear in cancer. In this study, we examined the expression level of E2F4as in the serum of ovarian cancer patients and the functional role of E2F4as. (2) Methods: Serum samples were obtained from 108 OC patients and 32 normal patients to measure the expression of E2F4as in the serum. Ovarian cancer cells were used to investigate the role of E2F4as in cell proliferation, invasion, migration and apoptosis, and the expression of E2F4as was knocked down using RNA interference. In addition, E2F4as knockdown cell lines were used in in vivo experiments. (3) Results: The expression of E2F4as was significantly higher in the serum of OC patients than in that of control patients (p < 0.05). The knockdown of E2F4as in ovarian cancer cells led to a decrease in cell proliferation, invasion and migration and an increase in apoptosis. E2F4as knockdown also reduced the expression of epithelium-mesenchymal metastasis (EMT) genes. (4) Conclusion: These findings highlight the clinical significance of E2F4as in predicting the prognosis of OC patients and suggest its potential in promoting tumour aggressiveness by the regulation of EMT-related mechanisms.
Keywords: E2F4 antisense (E2F4as); biomarker; epithelial–mesenchymal transition (EMT); long noncoding RNAs (lncRNAs); ovarian cancer (OC).