ABSTRACT
Differential protein expression profiles in the serum samples from patients with lung adenocarcinoma may be associated with glycosylation during cancer development. In this study, we used various glycoproteomic approaches to investigate the different glycoproteomic profiles of human normal and lung adenocarcinoma serum samples and to investigate putative altered glycoprotein biomarkers. In our preliminary screening, FITC-labeled lectin staining was used for the detection of specific glycoprotein profiles. wheat germ agglutinin (WGA) lectin had the highest level of specific binding to glycoproteins in both samples. We enriched for glycoproteins in the serum samples using WGA lectin affinity and then performed co-immunoprecipitation with anti-haptoglobin and 2-DE, 2-D difference in-gel electrophoresis and MS analyses. From these analyses, we identified 39 differentially expressed proteins, including 27 up-regulated proteins and 12 down-regulated proteins. Bioinformatics tools were used to search for protein ontology, category classifications and prediction of glycosylation sites. In addition, three up-regulated glycoproteins (adiponectin, cerulolasmin and glycosylphosphatidyl-inositol-80) and two down-regulated glycoproteins (cyclin H and Fyn) that were found to be correlated with lung cancer development were validated by Western blot analysis. We suggest that these altered glycoproteins may be useful as biomarkers for lung cancer development and progression.
Subject(s)
Adenocarcinoma/diagnosis , Glycoproteins/blood , Lung Neoplasms/diagnosis , Proteome/analysis , Proteomics/methods , Wheat Germ Agglutinins/metabolism , Adenocarcinoma/genetics , Adenocarcinoma/metabolism , Aged , Biomarkers, Tumor/blood , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Blotting, Western , Computational Biology , Electrophoresis, Gel, Two-Dimensional/methods , Electrophoresis, Polyacrylamide Gel/methods , Fluorescein-5-isothiocyanate/chemistry , Gene Expression Regulation, Neoplastic , Glycoproteins/genetics , Glycoproteins/metabolism , Humans , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Protein Binding , Proteome/genetics , Proteome/metabolism , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Wheat Germ Agglutinins/chemistryABSTRACT
Lung cancer is the leading cause of cancer deaths worldwide and is often diagnosed in the advanced or late stages. The discovery of candidate biomarkers in human lung cancer materials holds clinical potential as well as a significant challenge. Due to a large number of proteins in human materials that form the protein complexity and post-translational modifications (PTMs) of proteins, proteomic analysis of lung cancer biomarkers remains a difficult task. Many proteomic approaches have been used to investigate the biomarkers in human lung cancer materials. In this review, we summarize the current proteomic approaches employed for analysis of proteome profiles in human lung cancer materials and some PTMs causing different proteome profiles and expression levels of biomarkers in lung cancer. In addition, bioinformatic tools for PTMs are useful for prediction of glycosylation and phosphorylation sites in proteins, which can help us further understand the correlation of PTMs and tumor development. However, it is necessary that proteome analysis of lung cancer materials be incorporated with new strategies and technologies to improve the efficiency of the analysis and to investigate novel biomarkers that would be very useful for further diagnostic and therapeutic applications.
