Acting mechanism and clinical significance of hsa_circ_0005927 in the invasion and metastasis of gastric cancer.

An increasing number of studies have demonstrated that differentially expressed circular RNAs (circRNAs) play critical roles in carcinogenesis. However, the biological function and clinical significance of hsa_circ_0005927 during gastric carcinogenesis remain unclear. The aim of this study was to investigate the acting mechanism and clinical significance of hsa_circ_0005927 in the invasion and metastasis of gastric cancer (GC). Hsa_circ_0005927 was detected in GC tissues, plasma and gastric juice from patients with GC, and its correlations with clinicopathological parameters were investigated. Receiver operating characteristic curves, Kaplan-Meier survival curves and a prognostic nomogram model were generated to analyze the diagnostic and prognostic value. Real-time cell analyzer, plate colony formation, and Transwell migration and invasion assays were utilized to assess GC cell proliferation, migration and invasion, respectively. Nucleoplasmic separation was applied to determine the distribution of hsa_circ_0005927 in cells. TargetScan and miRanda software were used for target microRNA (miRNA) prediction. Transcriptome sequencing and bioinformatics analysis were performed to annotate the functions of hsa_circ_0005927 in gastric carcinogenesis and metastasis from an RNomic perspective. Key target genes and immune cell infiltrations were analysed. Hsa_circ_0005927 was found downregulated in high-grade intraepithelial neoplasia (HGIEN) tissues and GC tissues. Hsa_circ_0005927 levels in GC tissues were negatively correlated not only with lymphatic metastasis and distal metastasis but also with overall survival and disease-free survival. As a screening biomarker for GC, plasma hsa_circ_0005927 levels significantly increased in the early stages of GC, with a sensitivity and specificity of 52.38% and 76.19%, respectively. Hsa_circ_0005927 was mainly distributed in the cytoplasm, and structurally, it possesses multiple miRNA response elements (MREs) that interact with five miRNAs. A total of 421 downstream target genes of hsa_circ_0005927 were identified by transcriptome sequencing; and bioinformatics analysis suggested that these genes were involved mainly in the negative regulation of the T-cell apoptotic process, the interleukin-27-mediated signaling pathway, growth factor activity, guanylate cyclase activity, transcriptional misregulation in cancer, the cGMP-PKG signaling pathway, and the GnRH signaling pathway during gastric carcinogenesis and metastasis. GUCY1A2 and STK32A are key target genes significantly associated with immune infiltration. Our study revealed that hsa_circ_0005927 is a new player related to the invasion and metastasis of GC and is a potential indicator for early GC screening.