CircRNA_0005075 suppresses carcinogenesis via regulating miR‐431/p53/epithelial‐mesenchymal transition axis in gastric cancer

This study was aimed to explore the expression and biological function of circRNA_0005075 in gastric cancer (GC) progression and its underlying mechanism. First, the expression level of circRNA_0005075 and microRNA-431 (miR-431) in GC tissues were detected with the quantitative real-time polymerase chain reaction. In addition, after down-regulated the circRNA_0005075 expression by plasmid transfection in GC cells, the Cell Counting Kit-8 (CCK-8), EDU, transwell assay were conducted to evaluate the function of circRNA_0005075 or miR-431 on cell proliferation, metastasis in vitro. Moreover, p53 and Epithelial-mesenchymal transition (EMT) pathway related proteins were also measured with western blotting. Then, our data revealed that CircRNA_0005075 was found to be significantly up-regulated in GC tissues as well as GC cell lines, and the GC patients with higher CircRNA_0005075 expression were more likely to have poor outcomes. Down-regulation of CircRNA_0005075 could significantly suppress the GC cell proliferation and cell metastasis ability, while the addition of miR-431 inhibitors could counteract this effect. Importantly, we discovered that the silencing of circRNA_0005075 could weaken the micro-RNA sponge function for miR-431, and then upregulate the expression of p53 and forbid the EMT signalling pathway, and finally suppress the tumourigenesis of GC. To sum up, CircRNA_0005075 could inhibit cell growth and metastasis of GC through regulating the miR-431/p53/EMT axis. SIGNIFICANCE OF THE STUDY: The research clearly elucidated the potential role and relative regulatory mechanism of circRNA_0005075 in gastric cancer (GC) progression. Briefly, circRNA_0005075 could directly inhibit the expression level of miR-431, then regulate the p53/Epithelial-mesenchymal transition axis, and finally inhibit cell growth and metastasis in GC. Consequently, circRNA_0005075 might act as an oncogene in the GC procession, which provides a promising way for the treatment of GC.