Targeted regulation of miR-154-5p/Cullin2 pathway by hsa_circ_TRIM22 in promoting human papillomavirus 16 positive cervical cancer progression.

Tripartite motif-containing 22 (TRIM22) is characterized by a canonical RING domain with ubiquitin E3 ligase activity and is closely associated with tumorigenesis. As a product of TRIM22 transcription, whether hsa_circ_TRIM22 has a function of regulating tumorigenesis is unclear. Thus, we aimed to explore the role and mechanism of hsa_circ_TRIM22 in human papillomavirus (HPV) 16 positive cervical cancer (CC). We collected HPV16-positive cervical tissues including chronic cervicitis, high-grade squamous intraepithelial lesions (HSIL), low-grade squamous intraepithelial lesions (LSIL), and CC, and along with CC cell lines to detect the hsa_circ_TRIM22 level using real-time fluorescence quantitative polymerase chain reaction (RT-qPCR). Hsa_circ_TRIM22 was silenced using specific short hairpin ribonucleic acid (shRNA) in CC cell lines and functional assays were performed thereafter. Mechanistically, the targeting and regulatory relationship between hsa_circ_TRIM22 and miR-154-5p were confirmed using the luciferase report assay and rescue experiments. We found hsa_circ_TRIM22 expression level was significantly higher in CC cells and tissues. Further, hsa_circ_TRIM22 knockdown inhibited migration, proliferation, invasiveness, enhanced apoptosis, and slowed the cell cycle. Mechanistically, hsa_circ_TRIM22 could bind miR-154-5p and prevent miR-154-5p from reducing the levels of Cullin2 (CUL2). Notably, the application of miR-154-5p inhibitor significantly rescued hsa_circ_TRIM22-mediated tumorigenesis. Our observations suggest hsa_circ_TRIM22 is upregulated in HPV16-positive CC and promotes CC progression by regulating the miR-154-5p/CUL2 axis, thereby serving as a promising candidate for diagnosis and treatments of CC.