RESUMEN
As human plasma is clinically valuable, reference data from healthy donors can be a useful source for serological biomarker studies. To make a reliable protein catalog of the Korean plasma proteome, various experimental methods, such as 1-D HPLC, 2-D LC, and narrow ranged 2-DE prior to MALDI-TOF and LC-MS/MS, were used to identify unique plasma proteins in this population. To compile candidates with high confidence, two different search engines were used to select proteins with a false discovery rate of less than or equal to 1%. From this rigorous selection process, we initially identified 494 distinct Korean plasma proteins. After multilevel stepwise filtrations with stringent, identification parameters were applied to acquire plasma protein list with the maximum confidence; a total 185 distinct plasma proteins were identified and integrated into our Korean human plasma proteome project database along with several bioinformatics analysis results, including gene ontology, biological pathways, tissue expression, and disease association. This is the first publicly available single ethnic group-specific plasma proteome database (http://proteomix.org/khppp/).
Asunto(s)
Proteínas Sanguíneas/química , Bases de Datos de Proteínas , Proteoma , Proteómica/métodos , Biomarcadores/análisis , Humanos , Corea (Geográfico) , Espectrometría de Masas/métodos , Motor de Búsqueda , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
To identify and characterize a serologic glycoprotein biomarker for hepatocellular carcinoma (HCC), multi-lectin affinity chromatography was used to isolate intracellular N-linked glycoprotein fractions from five paired non-tumor and tumor tissues. From the series of 2-D DIGE targeted differentially expressed N-linked glycoproteins, we identified human liver carboxylesterase 1 (hCE1), which was remarkably down-regulated in tumor tissues, a finding confirmed by Western blot, a quantitative real-time RT-PCR, and immunohistochemical staining of non-tumor and tumor tissues from total 58 HCC patients. To investigate whether hCE1 is also present in human plasma, we employed a magnetic bead-based immunoprecipitation followed by nano-LC-MS/MS analysis, and we found for the first time that hCE1 is present in human plasma as opposed to that in liver tissues. That is, from normalization of hCE1 signal by the immunoprecipitation and Western blot analysis, hCE1 levels were increased in plasma specimens from HCC patients than in plasma from other disease patient groups (e.g. liver cirrhosis, chronic hepatitis, cholangiocarcinoma, stomach cancer, and pancreatic cancer). From the receiver operating characteristic analysis in HCC, both sensitivity and specificity were shown to be greater than 70.0 and 85.0%, respectively. Thus, the high-resolution proteomic approach demonstrates that hCE1 is a good candidate for further validation as a serologic glycoprotein biomarker for HCC.