Circ-ATIC Serves as a Sponge of miR-326 to Accelerate Esophageal Squamous Cell Carcinoma Progression by Targeting ID1.

In the previous studies, circular RNA (circRNA) has been shown to be closely related to the occurrence and development of various cancers. However, the role and mechanism of circ-ATIC in the progression of esophageal squamous cell carcinoma (ESCC) is not yet clear. Quantitative real-time PCR was used to detect the expression levels of circ-ATIC, microRNA (miR)-326 and inhibitor of DNA binding 1 (ID1) in tissues (n = 50) and cells. Cell counting kit 8 assay, colony formation assay, flow cytometry, wound-healing assay and transwell assay were performed to measure the proliferation, apoptosis, migration, and invasion of cells. In addition, the oxidative stress of cells was evaluated by detecting the productions of superoxide dismutase and malondialdehyde. Animal studies were implied to explore the role of circ-ATIC in ESCC tumor growth. The relationship between circ-ATIC and miR-326 or ID1 was determined by dual-luciferase reporter assay and RNA immunoprecipitation assay. Additionally, the protein expression of ID1 was examined by western blot assay. Circ-ATIC was found to be upregulated in ESCC tissues and cells. Silenced circ-ATIC suppressed the proliferation, migration, invasion, promoted the apoptosis and oxidative stress of ESCC cells. The tumor growth of ESCC also was inhibited by circ-ATIC knockdown. Furthermore, we found that circ-ATIC could sponge miR-326, and miR-326 could target ID1. The rescue experiments revealed that miR-326 inhibitor could reverse the negative regulation of circ-ATIC silencing on ESCC progression, and ID1 overexpression also inverted the inhibitory effect of miR-326 on ESCC progression. In addition, we confirmed that the expression of ID1 was positively regulated by circ-ATIC. Our study showed that circ-ATIC facilitated the progression of ESCC by regulating the miR-326/ID1 axis, indicating that circ-ATIC might be a target for ESCC treatment.