CircTSN promotes the proliferation and metastasis of gastric cancer through the miR-1825/SLC38A2 signaling axis.

Background: Comprehensive treatment of gastric cancer (GC) is progressing, but the rapid proliferation and metastasis of GC remains a cause of high recurrence and mortality rates. In this study we investigated GC-associated circRNA tending to yield more insight into the mechanisms of gastric cancer development.

Methods: We detected the expression levels of circTSN in GC tissues and cell lines using qRT-PCR. The circular structure of circTSN was confirmed by Sanger sequencing, agarose gel electrophoresis and RNase R. A series of cell functional experiments were employed to investigate the implication of circTSN aberrant expression on the proliferation and metastasis of GC cells. The predicted binding domain between circTSN and miR-1825 was analyzed by luciferase reporter gene analysis. Meanwhile, subcutaneous tumor xenografts in nude mice were used to validate the role of circTSN in vivo.

Results: It was found that RNA levels of circTSN were significantly elevated in GC tissues and cell lines, which was also confirmed to contain a closed-loop structure. CCK8, clone formation, EdU, transwell and in vivo experiments indicated that the highly expressed circTSN was involved in the proliferation and metastasis process of GC. In addition, circTSN modulates the expression of SLC38A2 by sequence-specific binding to miR-1825.

Conclusion: This study identified that circTSN, which is highly expressed in GC, was able to contribute to the proliferation and metastasis of GC cell through miR-1825/SLC38A2 axis and this might provide a new candidate target for the precision treatment of GC.