CircZDBF2 up-regulates RNF145 by ceRNA model and recruits CEBPB to accelerate oral squamous cell carcinoma progression via NFκB signaling pathway

Background Oral squamous cell carcinoma (OSCC), as one of the commonest malignancies showing poor prognosis, has been increasingly suggested to be modulated by circular RNAs (circRNAs). Through GEO (Gene Expression Omnibus) database, a circRNA derived from ZDBF2 (circZDBF2) was uncovered to be with high expression in OSCC tissues, while how it may function in OSCC remains unclear. Methods CircZDBF2 expression was firstly verified in OSCC cells via qRT-PCR. CCK-8, along with colony formation, wound healing, transwell and western blot assays was performed to assess the malignant cell behaviors in OSCC cells. Further, RNA pull down assay, RIP assay, as well as luciferase reporter assay was performed to testify the interaction between circZDBF2 and RNAs. Results CircZDBF2 expressed at a high level in OSCC cells and it accelerated OSCC cell proliferation, migration, invasion as well as EMT (epithelial-mesenchymal transition) process. Further, circZDBF2 sponged miR-362-5p and miR-500b-5p in OSCC cells to release their target ring finger protein 145 (RNF145). RNF145 expressed at a high level in OSCC cells and circZDBF2 facilitated RNF145 transcription by recruiting the transcription factor CCAAT enhancer binding protein beta (CEBPB). Moreover, RNF145 activated NFκB (nuclear factor kappa B) signaling pathway and regulated IL-8 (C-X-C motif chemokine ligand 8) transcription. Conclusion CircZDBF2 up-regulated RNF145 expression by sponging miR-362-5p and miR-500b-5p and recruiting CEBPB, thereby promoting OSCC progression via NFκB signaling pathway. The findings recommend circZDBF2 as a probable therapeutic target for OSCC. Graphical Abstract