Expression Of ATAD2 In Human Gastric Adenocarcinoma And Its Effect On Cell Proliferation In Vitro

Objective To determine the expression of ATAD2 in human gastic adenocarcinoma,and investigate the effects of ATAD2 on proliferation,colony formation,cell cycle and apoptosis of gastric adenocarcinoma cells,to explore the significance of ATAD2 in the occurrence and development of gastric adenocarcinoma.Methods Collected twelve pairs of fresh gastric adenocarcinoma and corresponding normal tissues,and real-time fluorescence quantitative PCR(qRT-PCR)and Western blot were used to detect mRNA and protein levels of ATAD2.121 cases of gastric adenocarcinoma and corresponding normal tissue were collected for tissue microarray.Immunohistochemistry were used to detect the expression of ATAD2 in tissue microarray,78 cases of chronic superficial gastritis,43 cases of chronic atrophic gastritis,16 cases of low grade intraepithelial neoplasia and 13 cases of low grade intraepithelial neoplasia,and statistical analysis was used to analyze the relationship between the expression of ATAD2 and clinical pathological characteristics,the postoperative survival time of gastric adenocarcinoma.Construct small interfering RNA(siRNA)to interfere with the expression of ATAD2 in gastric adenocarcinoma cell line SCG-7901 and MGC-803 cells.The effect of ATAD2 on the proliferation and colony forming ability of gastric adenocarcinoma cells was detected by MTT and plate colony formation assay,the effect of ATAD2 on cell cycle and apoptosis was detected by flow cytometer.Results The qRT-PCR and Western blot results showed that ATAD2 mRNA and protein levels both increased in 12 fresh gastric adenocarcinoma tissues increased(t=4.624~4.664,P<0.01).ATAD2 was not expressed in nontumorigenic gastric tissues;it was higher in gastric adenocarcinoma tissues than in corresponding normal tissues(z=-12.588,P<0.01);The expression in gastric adenocarcinoma and high-grade intraepithelial neoplasia were higher than that in low-grade intraepithelial neoplasia(z=-2.531~-2.285,P<0.05);and it was higher in low grade intraepithelial neoplasia than chronic atrophic gastritis and chronic superficial gastritis(z=-4.935~-6.489,P<0.01);there were no differences between gastric adenocarcinoma and high-grade intraepithelial neoplasia,chronic atrophic gastritis and chronic superficial gastritis(P>0.05).The expression of ATAD2 in gastric adenocarcinoma was related to tumor size and differentiation(?~2=5.506~8.412,P<0.05),but not with age,sex,lymph node metastasis,TNM stage,and depth of invasion(P>0.05).Kaplan-Meier analysis showed that,patients with lower expression of ATAD2 in gastric adenocarcinoma had longer postoperative overall survival time(P=0.003)and disease-free survival time(P=0.002)than patients with higher expression;The patients with poorly differentiated gastric adenocarcinoma,had shorter overall survival time(P=0.028)and disease-free survival time(P=0.011)han those with lower expression of ATAD2;Cox multivariate analysis showed that ATAD2 was an independent prognostic factor of postoperative overall survival time and disease-free survival time in patients who with gastric adenocarcinoma(P<0.05).After knockdown of ATAD2,the proliferation ability and colony formation rates both decreased(t=5.356~52.410,P<0.05)of gastric adenocarcinoma cell line SGC-7901and MGC-803,as for cell cycle,the proportion of cells in G1 phase increased,and the proportion of cells in S phase decreased significantly(t=2.514~47.956,P<0.05);By apoptosis assay,ATAD2 promoted the apoptosis of gastric adenocarcinoma cell line SGC-7901 and MGC-803 cells(t=2.690~6.215,P<0.05).Conclusion ATAD2 may be involved in the occurrence and development of gastric adenocarcinoma and may be one of the valuable indicators for determining the nature of gastric mucosal lesions.The expression of ATAD2 is correlated with the survival time of patients with gastric adenocarcinoma,suggesting that ATAD2 can be used as a marker for the diagnosis of gastric adenocarcinoma;ATAD2 can affect the cell cycle through the regulation of cell G1/S phase transition and inhibit cell apoptosis,and promote the proliferation and colony formation ability of gastric adenocarcinoma cell lines SGC-7901 and MGC-803.