CircRNA Coiled-Coil Domain Containing 66 Up-Regulates LIM-Homeodomain Gene 2 to Promote Gastric Cancer Progression via Sponing miR-129-5p

The death rate from gastric cancer (GC) is increasing while the methods of early diagnosis and treatment of GC are still limited. CircRNAs have ability to bind with miRNA to exert therapeutic action on kinds of cancers. The purpose of this study was to explore the action mechanism of circ-CCDC66 in GC. CCDC66, miR-129-5p and LHX2 mRNA and protein expression were examine by qRT-PCR and Western blot. Flow cytometry and Western blot were used to identify cells apoptosis. Dual-luciferase reporter assay was applied to verified the binding site that miR-129-5p and CCDC66 or LHX2. Transwell assay and cell account kit 8 (CCK-8) were used to examined cells proliferation ability, migration or invasion ability. Compared with normal tissues, CCDC66 expression was obviously higher and miR-129-5p expression was significantly lower in GC tissues. Knockdown circ-CCDC66 changed malignant behavior of GC cells. MiR-129-5p inhibitor changed the effect of down-regulated circ-CCDC66 on malignant behavior of gastric cancer cells. LHX2 was bond with miR-129-5p, and circ-CCDC66 regulated LHX2 expression to participated in GC progression via miR-129-5p. All the findings suggested that CCDC66 could adjust LHX2 expression to promote GC progression through restraining miR-129-5p, which may provide a key strategy for GC therapy.