[Inhibition of RBM5 expression by the interaction between hsa_circ_0006200 and EIF4A3 and its impact on cervical cancer progression].

Objective: To reveal the biological function and potential molecular mechanism of hsa_circ_0006200 in cervical cancer. Methods: Quantitative polymerase chain reaction (qPCR) was utilized to analyze the expression differences of hsa_circ_0006200 in cervical cancer cell lines versus normal cervical epithelial cells. 5-ethynyl-2'-deoxyuridine (EdU) method was applied for cell proliferation assessment, Transwell assays were for the detection of cell migration and invasion. RNA pull down assay and RNA immunoprecipitation (RIP) assay were applied to determine the interplay between hsa_circ_0006200 and eukaryotic translation initiation factor 4A3 (EIF4A3) and the binding between EIF4A3 and RNA binding motif protein 5 (RBM5). Western blot was carried out to determine protein expression levels of EIF4A3 and RBM5 in SiHa and HeLa cells. Results: In contrast to normal cervical epithelial cells, hsa_circ_0006200 expression was markedly upregulated in cervical cancer cell lines (P<0.001). In vitro, overexpression of hsa_circ_0006200 dramatically enhanced the proliferative, migratory and invasive capacities of cervical cancer cells (P<0.001), whereas hsa_circ_0006200 knockdown restrained the proliferation, migration, and invasion of cervical cancer cells (P<0.05). RNA pull down assay showed that hsa_circ_0006200 could bind to EIF4A3 in cervical cancer cells. RIP assay validated the interaction of EIF4A3 with both hsa_circ_0006200 and RBM5. Knockdown of hsa_circ_0006200 observably upregulated RBM5 protein expression in cervical cancer cells, whereas further EIF4A3 overexpression resulted in downregulated RBM5 protein expression (P<0.01). EdU method and Transwell assays demonstrated that RBM5 knockdown weakened the suppressive impacts of downregulating hsa_circ_0006200 on cervical cancer cell proliferation, migration and invasion (P<0.01). Conclusion: hsa_circ_0006200 expression is upregulated in cervical cancer cells, where it drives cancer cell proliferation, as well as migration and invasion, by repressing RBM5 expression through interaction with EIF4A3.