CircRNA DNA methyltransferase 1 silence inhibits breast cancer development by regulating micoRNA-485-3p/zinc finger E-box binding homeobox 1 axis

Abstract

Background: Circular RNAs (circRNAs) are associated with tumorigenesis of breast cancer. Nevertheless, how and whether circRNA DNA methyltransferase 1 (circ-DNMT1) controls breast cancer development remains poorly understood.

Methods: The paired tumor and paracancer tissues (n = 41) were obtained from breast cancer patients. Circ-DNMT1, microRNA (miR)-485-3p, and zinc finger E-box binding homeobox 1 (ZEB1) abundances were measured by quantitative reverse transcription polymerase chain reaction and western blot. Cell colony formation, migration, invasion, and apoptosis were analyzed by colony formation analysis, transwell analysis, and flow cytometry. Target relationship was evaluated via dual-luciferase reporter analysis, RNA immunoprecipitation, and pull-down. The in vivo experiments were conducted using a xenograft model.

Results: Circ-DNMT1 and ZEB1 levels were upregulated in breast cancer, and miR-485-3p was downregulated. Circ-DNMT1 knockdown restrained cell colony formation, migration, and invasion and increased apoptosis. MiR-485-3p was negatively regulated by circ-DNMT1, and miR-485-3p knockdown mitigated the effect of circ-DNMT1 silence on breast cancer development. ZEB1 was targeted via miR-485-3p, miR-485-3p overexpression repressed cell colony formation, migration, and invasion and triggered apoptosis by decreasing ZEB1. Circ-DNMT1 silence reduced ZEB1 expression via regulating miR-485-3p. Circ-DNMT1 knockdown reduced xenograft tumor growth.

Conclusion: Circ-DNMT1 knockdown constrains breast cancer development via modulating miR-485-3p/ZEB1 axis.

Keywords: breast cancer; circ-DNMT1; miR-485-3p; zinc finger E-box binding homeobox 1.