Background: Nova Circular RNA (circRNA) of non-coding RNA has gradually become an important regulatory factor, and it has made people attach great concern over the occurrence and development of many diseases, particularly carcinomas. circ_RPPH1 is a newly discovered circRNA. Gene Expression Omnibus (GEO) analysis showed that there are high contents of circ_RPPH1 in breast cancer (BC), but the mechanism of circRNA in BC remains unclear.

Methods: Real-time quantitative PCR (qRT-PCR) was applied to test the role of circ_RPPH1 in BC patients, and functional experiments were applied to test the role of circ_RPPH1 on BC tumor. Fluorescence in situ hybridization, double luciferase reporter gene analysis, RNA pull-down and RNA immunoprecipitation experiments were performed to explore the correlation of circ_RPPH1 with miR-146b-3p/E2F2 in BC.

Results: circ_RPPH1 was evidently enhanced in BC, and its content was related to the clinical stage and pathological grade. circ_RPPH1 can accelerate the proliferation, migration and invasion, and promote tumorigenesis and metastasis. Mechanism exploration indicated that circ_RPPH1 acted as ceRNA (competing endogenous RNA) of miR-146b-3p, so as to reduce the inhibitory role of miR-146b-3p on its target E2F2.

Conclusion: Circ_RPPH1/miR-146b-3p/E2F2 axis can promote the progression of BC, and it might be a latent therapeutic target for clinical BC.