Bioinformatics analysis of exosome proteome derived from hepatic carcinoma HepG2 cells

Objective:The aim of this study was to analyze the exosome proteome derived from hepatic carcinoma HepG2 cells and normal hepatocytes HL-7702,and look for the key factors in carcinogenesis of hepatocellular carcinoma(HCC).Methods:HepG2 and HL-7702 cells were cultured,and exosome samples were obtained from the culture supernatant and verified.LTQ-Orbitrap Elite mass spectrometry was applied to analyze and identify the exosome proteome derived from the hepatic carcinoma cells and normal liver cells,which was for seeking hepatic carcinoma cells specifically expressed proteins.Furthermore,gene ontology(GO),protein-protein interaction(PPI)network,and pathway enrichment were constructed to analyze hepatic carcinoma cells specifically expressed proteins.Results:The exosomes of HL-7702 expressed 3,366proteins,and the exosomes of HepG2 expressed 2,874proteins,of which 1,224were expressed specifically in HepG2 exosomes.102 target proteins were selected and going on bioinformatics analysis under the condition that the unique peptide was≥1and PSMs≥10.GO analysis results showed that the target expression protein of HepG2 was concentrated on metabolism,proliferation,and localization adhesion function.76target proteins were chosen and formed a PPI network;combining with pathway analysis,ACTN1,FN1,RAC1and GSN were found to be involved in important signaling pathways of HCC.The 26target proteins which not in PPI network were analyzed pathway involved in,respectively.AKR1C2 and C5 were found to be involved in differently important signaling pathways of HCC.Conclusion:Exosomes proteomics provides the sources of specific protein derived from hepatic carcinoma cell;when it combines with bioinformatics analysis,they are able to reveal the important molecules that are related to carcinogenesis of HCC and provide new ideas for investigation of HCC biomarkers.

Abstract Objective：The aim of this study was to analyze the exosome proteome derived from hepatic carcinoma HepG2 cells and normal hepatocytes HL-7702, and look for the key factors in carcinogenesis of hepatoeellular carcinoma （HCC）. Methods：HepG2 and HL-7702 cells were cultured, and exo- some samples were obtained from the culture supernatant and verified. LTQ-Orbitrap Elite mass spectrometry was applied to analyze and identify the exosome proteome derivect from the hepatic carcinoma cells and normal liver cells, which was for seeking hepatic carcinoma cells specifically expressed pro- teins. Furthermore, gene ontology （GO）, protein-protein in- teraction （PPI） network, and pathway enrichment were con- structed to analyze hepatic carcinoma cells specifically ex- pressed proteins. Results： The exosomes of HL-7702 ex- pressed 3, 366 proteins, and the exosomes of HepG2 ex- pressed 2, 874 proteins, of which 1, 224 were expressed spe- cifically in HepG2 exosomes. 102 target proteins were select- ed and going on bioinformaties analysis under the condition that the unique peptide was ≥1 and PSMs ≥10. GO analysis results showed that the target expression protein of HepG2 was concentrated on metabolism, proliferation, and localiza- tion adhesion function. 76 target proteins were chosen and formed a PPI network; combining with pathway analysis, ACTN1, FN1, RAC1 and GSN were found to be involved in important signaling pathways of HCC. The 26 target proteins which not in PPI network were analyzed pathway involved in,respectively. AKRIC2 and C5 were found to be involved in differently important signaling pathways of HCC. Conclu- sion： Exosomes proteomics provides the sources of specific protein derived from hepatic carcinoma cell; when it com- bines with bioinformatics analysis, they are able to reveal the important molecules that are related to carcinogenesis of HCC and provide new ideas for investigation of HCC biomarkers.