The Functional Roles And Clinical Significance Of Circ-DNMT1 In Gastric Cancer

Objective: Gastric cancer,also known as gastric adenocarcinoma,is the fifth most common cancer and third leading cause of cancer deaths in the world,and its incidence rate and mortality rate is second in China.Although much progress has been made in diagnosis and surgery,in recent years,the overall 5-year survival rate of gastric cancer patients in most countries is less than 30%.It is found that circRNA is closely related to the occurrence and development of many kinds of malignant tumors in researchs.At present,it has been found that circ-DNMT1 is highly expressed in breast cancer tissues and cells,promoting the growth and metastasis of breast cancer.However,its biological function and mechanism of action in gastric cancer are not clear,and need to be studied.Materials and Methods:(1)Expression of circ-DNMT1 in gastric cancer : In the early stage,we explored the experimental conditions and verified the primers through pre experiments.The expression levels of circ-DNMT1 in gastric cancer tissues and gastric cancer cells were detected by qRT-PCR(real-time fluorescence quantitative PCR).Then the data were collected and the clinicopathological parameters of the samples were counted to analyze whether the expression level of circ-DNMT1 was correlated with the pathological data,and whether circ-DNMT1 could be used as a biomarker for the diagnosis of gastric cancer.(2)The effect of circ-DNMT1 on the proliferation of gastric cancer cells: select the appropriate gastric cancer cells,carry out the growth curve measurement and clone formation experiment in vitro and nude mice experiment in vivo to study the effect of circ-DNMT1 on the proliferation of gastric cancer cells.Then flow cytometry,qRTPCR and Western blot were used to verify whether circ-DNMT1 can inhibit apoptosis and promote the proliferation of gastric cancer cells.(3)The migration and invasion of circ-DNMT1 in gastric cancer cells and the effect of EMT: firstly,Transwell migration and Transwell invasion experiments in vitro were used to study whether circ-DNMT1 affects the metastasis ability of gastric cancer cells.Secondly,qRT-PCR and Western blot were used to detect the expression level of genes and proteins related to epithelial mesenchymal transition(EMT).It was speculated whether circ-DNMT1 could affect the metastasis of gastric cancer through the EMT pathway.Results:(1)The expression of circ-DNMT1 in gastric cancer tissues was increased compared with that in normal gastric epithelial tissues.The content of circ-DNMT1 in gastric cells SGC-7901,MGC-803,HGC-27,BGC-823 and AGS was higher than that in normal gastric epithelial cells(GES-1).The analysis of relevant parameters in the clinicopathological data suggested that the expression level of circ-DNMT1 was related to lymph node metastasis.(2)Knockdown of circ-DNMT1 inhibited the proliferation of gastric cancer cells,but had no significant effect on apoptosis.Knockdown of circ-DNMT1 inhibited the growth of gastric cancer cells in nude mice.(3)Compared with the results of the control group,the knockdown of circ-DNMT1 showed that the knockdown of circ-DNMT1 could inhibit cell migration and metastasis.qRT-PCR and Western blot detection suggested that the knockdown of circ-DNMT1 could affect the changes of EMT related genes and proteins,so it was speculated that circ-DNMT1 might promote the metastasis of gastric cancer cells through EMT pathway.Conclusion: Circ-DNMT1 is highly expressed in gastric cancer tissues and cells,which not only promotes the proliferation of gastric cancer cells,but also promotes the migration and invasion of gastric cancer cells.At the same time,it may promote the occurrence and development of gastric cancer through EMT,which is expected to be of potential value in the diagnosis and treatment of gastric cancer.