Hsa_circ_0000069 Accelerates Cervical Cancer Progression by Sponging MiR-1270 to Facilitate CPEB4 Expression

The critical importance of circular RNAs (circRNAs) in human cancers, including cervical cancer (CC), has been discovered in recent years. However, the function and mechanism of hsa_circ_0000069 (circ_0000069) in CC have been fully understood. The expression levels of circ_0000069, microRNAs (miR-1270, miR-1276 and miR-620) and cytoplasmic polyadenylation element binding protein 4 (CPEB4) mRNA were detected by quantitative real time polymerase chain reaction (qRT-PCR). Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, wound healing, transwell and tube formation assays were used to clarify the effects of circ_0000069 on the functional behaviors of CC cells. The binding relationships among miR-1270, circ_0000069 and CPEB4 were detected by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. A xenograft tumor model was established to explore the effect of circ_0000069 on tumor growth in vivo. Circ_0000069 was upregulated in CC clinical samples and cell lines, and its expression was associated with the clinical stage of CC patients. Circ_0000069 knockdown significantly decreased cell proliferation, invasion, migration, and tube formation and increased cell apoptosis in vitro. Moreover, miR-1270 was a direct target of circ_0000069, and CPEB4 was the downstream target of miR-1270. Knockdown of miR-1270 reversed the inhibitory effect of circ_0000069 knockdown on CC progression, and CPEB4 overexpression overturned the effect of miR-1270 on CC progression. In xenograft experiments, the oncogenic effect of circ_0000069 on tumor growth was verified. Altogether, circ_0000069 adsorbed miR-1270 to upregulate CPEB4 expression, thereby promoting the malignant phenotypes of CC cells. Circ_0000069 might be a potential target for treatment of CC.