Circ_0000419 acts as a tumor suppressor in gastric cancer development via regulating miR-300/RGMB axis.

Objective: Dysregulated circular RNAs (circRNAs) have been verified to function in the development of gastric cancer (GC). The current study was designed to investigate the role of circ_0000419 in GC progression, and the potential mechanistic pathway.

Methods: Relative expression of circ_0000419, microRNA-300 (miR-300) and Repulsive Guidance Molecule B (RGMB) was analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assay. Cell metastasis, including migration and invasion, was assessed by wound healing and Transwell assays. Glucose consumption and lactate production were examined using kits. The association between miR-300 and circ_0000419 or RGMB was validated by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assays. Role of circ_0000419 in vivo was determined by xenograft experiment.

Results: Circ_0000419 and RGMB were downregulated, while miR-300 was upregulated in GC tissues and cells. Gain of circ_0000419 inhibited migration, invasion and glycolysis in GC cells, which was attenuated by introduction of miR-300 or silencing of RGMB. Circ_0000419 sponged miR-300, and RGMB was direct target of miR-300. Circ_0000419 overexpression could block GC tumor growth in vivo.

Conclusion: Circ_0000419 inhibited GC cell migration, invasion and glycolysis through regulation of miR-300/RGMB axis, at least in part, affording a molecular target for GC treatment.