Circ-CCDC66 upregulates REXO1 expression to aggravate cervical cancer progression via restraining miR-452-5p

Cervical cancer is one most common cancer types among females over the world. While its underlying mechanisms remain unclear. Circ-CCDC66 has been revealed to participate in multiple biological functions, and contribute to various diseases' progression. In the current study, we aimed to demonstrate the role of circ-CCDC66 in cervical cancer progression.

Real-time quantitative PCR (RT-qPCR) was conducted to measure the expression of circ-CCDC66, miR-452-5p, and REXO1 mRNA. Cell fractionation assay and RNA fluorescence in situ hybridization (FISH) were performed to locate circ-CCDC66 in cells. Cell account kit 8 (CCK-8) was used to detect cell proliferation ability. Transwell assay was applied to evaluate cell migration or invasion ability. Bioinformatics analysis, biotinylated RNA pull-down, RNA immunoprecipitation, and dual-luciferase reporter assays were conducted to assess the association between miR-452 and circ-CCDC66 or REXO1. Western blot was applied to measure the protein expression of REXO1. The animal tumor model was used to assess the effect of circ-CCDC66 in vivo.

The expression of circ-CCDC66 was upregulated in cervical cancer tumor tissues in comparison with normal tissues, and correlated with later tumor stage and larger tumor size. Downregulated circ-CCDC66 inhibited cervical cancer cell proliferation, migration, and invasion. Circ-CCDC66 was an efficient molecular sponge for miR-452-5p, and negatively regulated miR-452-5p expression. MiR-452-5p directly targeted to REXO1. Circ-CCDC66 regulated REXO1 expression to modulate cervical cancer progression via miR-452-5p. Moreover, downregulated circ-CCDC66 was found to suppress tumor growth in vivo.

Our results demonstrated the role of circ-CCDC66/miR-452-5p/REXO1 axis in cervical cancer progression, we might provide novel therapeutic targets for cervical cancer clinical intervention.