Abstract: Objective To elucidate the molecular mechanism of lncRNA ANRIL in regulating the invasion and stem cell-like characteristics of ovarian cancer, and to analyze its dual role in mediating chemotherapy resistance and tumor recurrence. Methods ANRIL stable knockdown SKOV-3cell model was established (Control group, shRNA-NC group, ANRIL-shRNA1 group). The ability of cell invasion and metastasis was evaluated by Transwell assay, wound-healing assay, and the expression of VEGF and Fibronectin. The characteristics of stem cells were analyzed by tumor sphere formation assay combined with stem-cell marker CD44 / SOX2 / OCT4 detection. The targeting interaction between ANRIL-shRNA1 and miR-324-5p was verified by dual luciferase reporter assay. A functional recovery experiment ( ANRIL-shRNA1 + miR-324-5p inhibitor co-transfection group) was designed to clarify the mediating effect of miR-324-5p on the regulation of VEGF and CD44 by ANRIL-shRNA1. Results  ANRIL knockdown decreased the invasion and migration ability of SKOV-3cells, and the expression levels of VEGF and Fibronectin were significantly down-regulated. At the same time, the number of spheres was decreased, and the expression levels of CD44, SOX2, and OCT4 were decreased significantly compared with those in the control group. Dual luciferase assay confirmed that ANRIL directly binded to miR-324-5p. The inhibition of miR-324-5p could reverse the inhibitory effect of ANRIL knockdown on VEGF and CD44. Conclusion LncRNA ANRIL can promote cell invasion and help maintain the characteristics of tumor stem cells by targeting miR-324-5p.

Key words: ovarian cancer, lncRNA ANRIL, miR-324-5p, cancer stem cells