| Background and Objective: Gastric cancer is one of the most common malignant tumors,and its morbidity and mortality are among the highest in the world.The morbidity and mortality of gastric cancer in our country is always high,and gastric cancer is seriously endangering people's health and even life.The reasons for the occurrence of gastric cancer are very complex,including environmental factors and genetic factors.With the development of bioinformatics and the development of microarray technology,gene chip has been widely used in the research of gastric cancer,and it also opens up a new way for the research of gastric cancer diagnosis.The purpose of this study is to through the analysis of a large number of gastric cancer microarray data,high-throughput screening out specific expression genes in gastric cancer,then constucting a gastric cancer diagnostic marker cluster.Meanwhile,we would like to take studies on HIF1 A in gastric cancer and have a better undersatanding of the key role that HIF1 A plays in the process of gastric cancer development,which may lay a foundation for the early diagnosis of gastric cancer as well as the molecular mechanism research in gastric cancer.Materials and Methods: The expression data sets of gastric cancer were retrived by GEO database,then we got the original data set.We used R language including GEOquery bag,Bioconductor bag,Affy bag,Meta QC bag and Meta DE bag to analyse the standardization,quality control and integration of microarray data,from which we can screen differentially expressed genes.We then applied DAVID online analysis tool for gene function annotation and pathway enrichment analysis of differentially expressed genes.Forther more,we put to use R language about Pearson correlation coefficient to do the research on differentially expressed genes,which was aimed at analysing the differentially expressed genes that have high correlation with HIF1 A,and the TRED database was utilized to find the downstream target gene of HIF1 A.Integrating the two analysis results we might obtain the genes that possibly regulated by HIF1 A.q RT-PCR was used to assess the relative expression of HIF1 A,TIMP1,EDN2,GPX3 and PFKFB2 in SGC7901 cells,GES-1 cells and SGC7901 cells into which the HIF1A-si RNA interference sequence was transfected,which was in order to analyse the regulatory function of HIF1 A for TIMP1,EDN2,GPX3 and PFKFB2 in gastric cancer.Results: A total of 520 differently expressed genes including 303 up-regulated genes and 217 down-regulated genes were screened in the study.From the analysis of gene functional annotation,we obtained 46 up-regulated GO-Trems and 21 down-regulated GO-Trems;pathway enrichment analysis showed that there was 16 up-regulated Pathways and 20 down-regulated Pathways.Through the feature analysis,we selected ATP4A?CNMK2N1?ESRRG?THBS2 to establish the diagnosis biomarker cluster of gastric cancer.According to the integration of Pearson correlation coefficient and TRED database we screened TIMP1,EDN2,GPX3 and PFKFB2 that may were regulated by HIF1 A in gastric cancer.We used q RT-PCR to verify the relative expression of HIF1 A,TIMP1,EDN2,GPX3 and PFKFB2 in gastric cancer tissues(adjacent tissues were control).The results showed that HIF1 A m RNA expression was up-regulated by 2.45±0.61 fold(P<0.05),while that of TIMP1,EDN2,GPX3 and PFKFB2 was up-regulated by 1.78±0.31(P<0.05),down-regulated by 0.47±0.15(P<0.05),0.34±0.17(P<0.05)and 0.49±0.18(P<0.05)times,respectively.And the trend was consistent with the microarray data analysis.Meanwhile,the relative expression of HIF1 A,TIMP1,EDN2,GPX3 and PFKFB2 in SGC7901 cells(control group GES-1 cells)was 2.55±0.51(P<0.05),1.58±0.35(P<0.05),0.51±0.18(P<0.05),0.42±0.15 and 0.57±0.19(P<0.05),respectively.And the results with the microarray data analysis results were in the same trend;In the SGC7901 cells(control group of normal SGC7901 cells)into which HIF1A-si RNA was transfected,HIF1 A and TIMP1 gene expression were up-regulated,EDN2,GPX3 and PFKFB2 gene expression were down-regulated,the relative expression of five genes was 0.35±0.07(P<0.05),0.57±0.13(P<0.05),1.59±0.37(P<0.05),1.87±0.51 and 1.64±0.49(P<0.05),respectively.Conclusion:1)A diagnositic marker cluster of gastric cancer was screened and constructed by ATP4A?CNMK2N1?ESRRG?THBS2;2)In gastric cancer,HIF1 A plays a positive role in regulating TIMP,and plays a negative role in regulating EDN2,GPX3 and PFKFB2. |
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