Circular RNA hsa_circ_0007444 inhibits ovarian cancer progression through miR-23a-3p/DICER1 axis: hsa_circ_0007444/miR-23a-3p/DICER1 in ovarian cancer

Ovarian cancer is the second leading cause of death in women with gynecological malignancy in China. Circular RNAs are a class of noncoding regulatory RNAs reported to be involved in cancer development and progression. Previous studies, including our own, have indicated that hsa_circ_0007444 is downregulated in ovarian cancer tissues. This study aims to elucidate the function and mechanism of hsa_circ_0007444 in ovarian cancer progression. The expression of hsa_circ_0007444 is determined by quantitative real-time PCR (qRT-PCR). Cell proliferation, invasion, migration and apoptosis are examined by cell counting-kit 8 (CCK-8), transwell and flow cytometry assays. Tumor growth and metastasis are assessed in vivo using Balb/c nude mouse xenograft model and tail vein injection model. And the mechanism of action of hsa_circ_0007444 is analysed by RNA-binding protein immunoprecipitation (RIP), luciferase reporter and rescue assays. hsa_circ_0007444 is downregulated in ovarian cancer tissues and cell lines compared with that in normal ovarian tissues and normal epithelial cell line. Gain- and loss-of-function results indicate that hsa_circ_0007444 inhibits cell proliferation, invasion, migration and increases cell apoptosis of ovarian cancer cells in vitro, and inhibits tumor growth and lung metastasis in vivo. Mechanistically, hsa_circ_0007444 can interact with AGO2 and sponge miR-23a-3p, thereby upregulating DICER1 expression, which is an important tumor suppressor in ovarian cancer. And miR-23a-3p mimics can rescue the inhibitory effect of hsa_circ_0007444 on ovarian cancer cell proliferation, invasion and migration. Therefore, hsa_circ_0007444 can inhibit ovarian cancer progression through the hsa_circ_0007444/miR-23a-3p/DICER1 axis.