CircVPRBP Is Down-regulated In Gastric Cancer And Inhibits Cell Growth,migration And Invasion

Objective: Even today,despite the development of science and technology,cancer is still a difficult problem for many clinicians.Gastric cancer is one of the most common malignant tumors with high morbidity and mortality in the world.Because of the occult in the early stage of gastric cancer,patients are often in the late stage and accompanied by malignant metastasis when diagnosed,thus missing the optimal treatment period,leading to poor prognosis.Therefore,it is of great significance to search for molecular markers for early diagnosis and establish new therapeutic targets for improving the prognosis of gastric cancer patients.CircRNAs are a newly discovered class of endogenous non-coding RNAs,which have covalent closed-loop structures rather than the traditional 5 ’to 3’ polyadenylate tails,making them more stable than linear RNA and more likely to serve as biomarkers for diagnosis or prognosis in multiple tumors.To date,a variety of circRNAs have been shown to be involved in tumor development and have the potential as molecular markers for the early diagnosis of gastric cancer.Therefore,it is necessary to explore the role of circRNAs in gastric cancer and its regulatory mechanism.Methods: We collected gastric cancer tissue and adjacent non-cancerous tissue from71 pairs of gastric cancer patients who underwent surgery at the first affiliated hospital of China medical university.All specimens were placed in liquid nitrogen within half an hour after surgery and frozen at-80℃ until RNA extraction.All patients in this study signed the informed consent form.The project was approved by the ethics committee of the first affiliated hospital of China medical university.Real-time quantitative PCR was used to detect the expression of circVPRBP in gastric cancer.Mann-Whitney test and Kruskall-Wallis test analyzed the correlation between the relative expression level of circVPRBP and the clinicopathological data.CCK8 assay and colony formation assay were used to detect the effect of circVPRBP on proliferation of gastric cancer cells.Transwell test and scratch test were used to detect the effect of circVPRBP on invasion of gastric cancer cells.The cell cycle/apoptosis detection kit of NanJing KaiJi biological company was used to identify the effect ofcircVPRBP on the cell cycle distribution and apoptosis of gastric cancer cells.All statistical analyses were performed using SPSS 19.0 software package,and P<0.05 was considered statistically significant.Results: Real-time quantitative PCR analysis showed that circVPRBP was significantly lower expressed in gastric cancer tissues and has diagnostic efficiency.However,we did not find a significant correlation between the relative expression level of circVPRBP and the clinicopathological data of the patients by non-parametric test.In addition,we found that compared with the control group,overexpression of circVPRBP could significantly inhibit proliferation and invasion of gastric cancer cells.Cell cycle experiment results also showed that overexpression of circVPRBP could induce cell cycle arrest in G0/G1 phase.In addition,we also detected the expression of MMPs after the overexpression of circVPRBP.Western blotting results showed that overexpression of circVPRBP inhibited the protein expression levels of MMP2 and MMP9.Furthermore,based on the target gene prediction tool and sequencing results of 30 pairs of gastric cancer tissues,we speculated that circVPRBP might play an anti-tumor role in the development of gastric cancer by up-regulating HPGD via competitive binding hsa-mi R-146b-3p.Conclusion: CircVPRBP is mainly expressed in cytoplasm and significantly low in gastric cancer tissues.During the development of gastric cancer,it can significantly inhibit the proliferation and invasion of gastric cancer cells,and may exert the anti-tumor effect through the circVPRBP/ hsa-miR-146b-3p /HPGD axis,which makes circVPRBP a potential therapeutic target for gastric cancer.