Circ_PGPEP1 Serves as a Sponge of miR-1297 to Promote Gastric Cancer Progression via Regulating E2F3

Background Circular RNA (circRNA) is a special kind of noncoding RNA that plays a vital function in the progression of gastric cancer (GC). However, the role of a new circRNA, circ_PGPEP1, in GC is unclear. Aims Exploring the role and mechanism of circ_PGPEP1 in GC progression. Methods The expression levels of circ_PGPEP1, miR-1297, and E2F transcription factor 3 (E2F3) were determined using quantitative real-time PCR. Flow cytometry, colony formation assay, MTT assay, and transwell assay were used to evaluate cell cycle, apoptosis, proliferation, migration, and invasion. The protein levels of apoptosis-related markers and E2F3 were measured by western blot analysis. The interaction between circ_PGPEP1 and miR-1297 or miR-1297 and E2F3 was confirmed by dual-luciferase reporter assay. In addition, animal experiments were performed to assess the effect of circ_PGPEP1 on GC tumor growth in vivo. Results Circ_PGPEP1 was a highly expressed circRNA in GC. Loss-of-function experiment indicated that circ_PGPEP1 silencing could induce cell cycle arrest and apoptosis, while inhibit proliferation, migration, and invasion in GC cells. MiR-1297 could be sponged by circ_PGPEP1, and its expression was downregulated in GC. MiR-1297 inhibitor could reverse the negatively regulation of circ_PGPEP1 knockdown on GC progression. Furthermore, we also found that E2F3 could be targeted by miR-1297, and its expression was positively regulated by circ_PGPEP1. Overexpression of E2F3 could invert the inhibitory effect of miR-1297 on GC progression. Animal experiments suggested that silenced circ_PGPEP1 could reduce GC tumor growth. Conclusion Our research showed that circ_PGPEP1 might serve as a potential biomarker for GC.