| Research background and purpose:Gene expression microarray technology has produced a large number of gene chips and biological information.It is the challenge and goal of biological workers to use the data of gene chips in many laboratories and understand the biological meaning contained in them.The incidence rate of liver cancer is the fourth place in China,ranking seventh in the world,and is related to hepatitis B virus infection.The occurrence and development of liver cancer is a multi-factor,multi-step and multi gene process.The traditional method of studying the molecular mechanism of liver cancer is mainly single gene.However,gene chip research can express gene changes with high throughput,which has a great advantage in the study of the molecular mechanism of liver cancer.The purpose of this study is to analyze the bioinformatics data of liver cancer gene chip in geo database,screen out the differentially expressed genes,and then analyze the biological function of the differentially expressed genes,then explore the molecular mechanism of liver cancer,and carry out the corresponding preliminary functional test.Research methods:1.Download the gene chip data GSE19665 and GSE41804 from the GEO database,use the GEO2R analysis tool of the GEO website to analyze the gene chip data and screen the differentially expressed genes;process the PPI network map obtained by STRING with the software Cytoscape,and obtain the significant gene module after the processing of the MCODE plug-in,with a total of 25 significantly different genes.Further verify these 25 genes with the websites UALCAN and GEPIA,the expression difference of genes in patients with liver cancer and normal people finally got 20 significantly different genes.The expression of GO and KEGG of these 20 significantly different genes was queried by DAVID online database,and the results were analyzed.It was found that four significantly different genes were involved in each key signal pathway.GSEA analysis of these four genes further verified the previous inference;2?Of the 4 genes,PTTG1 was selected as the research object to construct the stable overexpression cell line Hep G2-PTTG1 and the stable interference cell lines MHCC 97H-PTTG1-shRNA1 and MHCC97H-PTTG1-shRNA2.Subsequently,MTT,plate cloning,softagar and Transwell experiments were carried out to detect the cell proliferation and invasion.It was found that PTTG1 has a certain relationship with hepatoma cells.Results:1.A total of 197 differentially expressed genes were screened out by geo database,of which 37 were up-regulated genes and 160 were down regulated genes.After screening by Cytoscape and mcode,25 differentially expressed genes were obtained,and 20 differentially expressed genes were obtained after validation.Then,the analysis of KEGG signaling pathway showed that the most influential signaling pathway in HCC was oocyte subtraction score Cleavage and cell cycle,followed by progesterone mediated oocyte maturation and p53 pathway,and the four genes,ccnb1,ccnb2,cdc25c and PTTG1,were obtained by crossing these four pathways.The hypomethylation of these gene promoters led to the up-regulation of their expression,thus promoting the occurrence and evolution of liver cancer;2.The overexpression of PTTG1 promoted the proliferation and migration of HCC cells,and the interference of PTTG1 inhibited the proliferation and migration of HCC cells.To investigate the relationship between PTTG1 gene copy number and methylation expression in hepatoma and hepatocarcinogenesis.Conclusion:(1)Oocyte meiosis,abnormal activation of cell cycle signaling pathway and up regulation of PTTG1,CCNB1,CCNB2 and CDC25C play an important role in the genesis and evolution of liver cancer;(2)The overexpression of PTTG1 related genes in meiosis and cell cycle signaling pathway of oocytes promotes the proliferation and migration of hepatoma cells,interferes with PTTG1 inhibiting the proliferation and migration of hepatoma cells,and its expression is regulated by gene copy number and methylation level. |
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