CircUSP36 promotes FBXO5 expression to accelerate cervical cancer progression by targeting miR-520d-5p.

CircRNAs are associated with the progression of various tumors. This study aims to explore the regulation of circUSP36 on cervical cancer progression and the mechanism behind. Human cervical cancer cell lines HeLa and SiHa were cultured for RT-qPCR detection of circUSP36, miR-520d-5p, and FBXO5 mRNA and western blotting detection of FBXO5 protein. After transfection, HeLa and SiHa cells were subjected to CCK-8, transwell, scratch, and flow cytometry assays to measure their proliferation, invasion, migration, and apoptosis. Luciferase reporters were used to detect the binding of miR-520d-5p to circUSP36 and FBXO5. CircUSP36 and FBXO5 were highly expressed in HeLa and SiHa while miR-520d-5p was expressed at low levels. CircUSP36 or FBXO5 knockdown or miR-520d-5p overexpression reduced proliferation, invasion, and migration and increased apoptosis in cervical cancer cell lines. CircUSP36 targeted miR-520d-5p and inhibited its expression. miR-520d-5p negatively regulated FBXO5 expression by binding to FBXO5. miR-520d-5p inhibition or FBXO5 overexpression reversed the tumor-suppressive effect of circUSP36 knockdown. CircUSP36 promotes FBXO5 expression by targeting and inhibiting miR-520d-5p, thereby driving cervical cancer cell proliferation, invasion, and migration. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10616-025-00852-1.