High-throughput sequencing reveals circular RNA hsa_circ_0000592 as a novel player in the carcinogenesis of gastric carcinoma

Abstract

Background/Aim: Gastric cancer is one of the most common malignant tumors, and its complex pathogenesis has not been fully elucidated. Circular RNAs (circRNAs) are involved in various biological processes and human diseases. However, their exact functional roles and mechanisms of action remain largely unclear. We previously discovered the differential expression of non-coding RNAs (ncRNAs) during the malignant transformation of human gastric epithelial cells. In this study, we investigated the functional roles of a significantly up-regulated circRNA (hsa_circ_0000592) in gastric cancer. Methods:N-methyl-N′-nitro-N-nitrosoguanidine (MNNG)-induced malignant-transformed gastric epithelial cells (GES-1-T) and normal gastric epithelial cells (GES-1-N) were analyzed by high-throughput circRNA sequencing. The top 15 up-regulated circRNAs in high-throughput sequencing results were further confirmed by qRT-PCR in different gastric epithelial cell lines. The function of the most significant circRNA (hsa_circ_0000592) was investigated by using RNA interference (RNAi) assays, fluorescence in situ hybridization analysis (FISH), and bioinformatics prediction methods. Results: A total of 1509 genes were up-regulated and 3142 genes were down-regulated in GES-1-T cells when compared with GES-1-N cells. When compared with GES-1-N cells, hsa_circ_0000592 was obviously up-regulated in GES-1-T cells, as well as in other gastric cancer cell lines. The silencing of hsa_circ_0000592 mRNA led to a decrease in cell proliferation, cell cycle arrest at the G0/G1 phase, an increased rate of apoptosis, and a reduction in cell migration. Furthermore, FISH showed that hsa_circ_0000592 was mainly located in the cytoplasm, and a bioinformatics analysis suggested that hsa_circ_0000592 might function by sponging multiple miRNAs, and most notably four conserved miRNAs, including miR-139-3p, miR-200, miR-367-3p, and miR-33a-3p. Conclusion: This study is the first to identify hsa_circ_0000592 as a novel circRNA with a critical role in MNNG-induced gastric cancer. Due to the essential role of hsa_circ_0000592 in gastric carcinoma cells, it may be considered as a potential biomarker for use in diagnosing gastric carcinoma. Our findings provide a new insight into the function of circRNAs in environmental carcinogen-induced gastric cancer.

Long Non-Coding RNA LINC00518 Induces Radioresistance by Regulating Glycolysis Through An miR-33a-3p/HIF-1α Negative Feedback Loop in Melanoma

“…Next, we veri ed whether LINC00518 and HIF-1α could speci cally inhibit miR-33a-3p expression. In some studies, miR-33a-3p is a recognized antioncogene that suppresses a malignant phenotype by inhibiting the expression of pre-B-cell leukaemia homeobox in hepatocellular cancer [49], and increased miR-33a-3p expression can promote the malignant phenotype of gastric carcinoma [50].…”

Circular RNAs as New Regulators in Gastric Cancer: Diagnosis and Cancer Therapy

“…As significant attention has been received in recent years regarding the role of circRNAs in GC diagnosis and treatment, many papers report high-throughput sequencing or microarray results that describes the differential circRNAs expression profiles in GC patients and healthy donors (20,21). These identified circRNAs are down-regulated or up-regulated during carcinogenesis, and therefore serve as tumor suppressors or oncogenes in GC, which make possible that circRNAs become diagnosis biomarkers and prognosis predictors.…”

Circular RNA hsa_circ_0001829 Promotes Gastric Cancer Progression through miR-155-5p/SMAD2 Axis

“…High-throughput sequencing was performed and data was analyzed as we previously described (12,20,21). CircRNAs were subjected to further analysis including annotation, sequence prediction, and the calculated expression levels.…”

“…RNA extraction, nuclear-cytoplasmic fractionation and qRT-PCR assay were performed as previously described (20).GAPDH or U6 acted as internal standards. The 2 −ΔΔCt method was used to analyze relative expression levels.…”

“…Recently, it has been reported that circRNAs harbor abundant conserved miRNA response elements (MREs) and serve as miRNA sponge to regulate gene expression, which is involved in tumor initiation and progression (19). Although our previous studies have demonstrated that hsa_circ_006100 and hsa_circ_0000592 were involved in the regulation of MNNG induced gastric tumorigenesis (20,21), the role of circRNAs in the occurrence and development of GC induced by environmental carcinogens has been poorly elucidated and more studies are needed.…”