Circular RNA HIPK3 plays a carcinogenic role in cervical cancer progression via regulating miR-485-3p/FGF2 axis.

Circular RNA (circRNA) is an endogenous RNA molecule with a stable closed-loop structure. The circular RNA HIPK3 (circHIPK3) is highly expressed in hepatocellular carcinoma and facilitates tumor growth. However, its role in cervical cancer (CC) and its regulatory mechanisms are not well-studied. This study aimed for investigating the function of circHIPK3 on proliferation and metastasis of CC cells. In this study, quantitative real-time PCR assay was adopted to delve into the circHIPK3 expression in CC cell lines. Cell counting kit-8 and colony formation assays were used to evaluate the influence of overexpression and knockdown of circHIPK3 on CC cell proliferation. Dual-luciferase reporter assay was employed to probe into the binding of miR-485-3p to circHIPK3 and miR-485-3p to the 3' untranslated region (UTR) of fibroblast growth factor 2 (FGF2), respectively. FGF2 protein expression was detected by western blot analysis. This study confirmed that circHIPK3 was highly expressed in CC tissues. Overexpressed circHIPK3 could remarkably expedite the proliferation, migration and invasion of SiHa cells, and knocking down circHIPK3 could significantly impede the proliferation, migration and invasion of HeLa cells. MiR-485-3p can directly bind to circHIPK3 and the 3'UTR of FGF2. Overexpression of circHIPK3 triggered the upregulation of FGF2 expression while knockdown of circHIPK3 reduced FGF2 expression in CC cells, and the transfection of miR-485-3p mimics reversed the upregulation of FGF2 expression and enhanced malignant phenotypes in CC cells with overexpressed circHIPK3.