Analysis of Differentially Expressed Proteome in Urinary Exosome from Non-small Cell Lung Cancer Patients

Urine provides an alternative to blood plasma as a potential source of disease biomarkers. In this study, exosomes were separated by ultracentrifuge at 200000 × g in normal person's urine and non-small cell lung cancer (NSCLC) patients' urine. For proteomic analysis of urinary exosome, 1D sodium dodecylsulfonate-polyacrylate gel electrophoresis (SDS-PAGE) was carried out and the gel was cut at 31–20 kDa bands for normal group and disease group. These gel blocks were subjected to in-gel trypsinization, and the extracted peptides were analyzed using high performance liquid chromatography-chip-tandem mass spectrometry (HPLC-CHIP-MS/MS). Approximately 24 unique proteins were identified in the UniProtKB/SWISS-PORT. The difference expression proteins were found in urinary exosome of NSCLC patients, including three fragments of the immunoglobulin kappa, two types of Ras-related proteins, glutathione S-transferase A2, serum amyloid P-component precursor, and phosphatidylethanolamine-binding protein 1.