Combining proteomics, serum biomarkers and bioinformatics to discriminate between esophageal squamous cell carcinoma and pre-cancerous lesion

Objective: Biomarker assay is a noninvasive method for the early detection of esophageal squamous cellcarcinoma (ESCC). Searching for new biomarkers with high specificity and sensitivity is very important for the earlydetection of ESCC. Serum surface-enhanced laser desorption/ionization-time of flight mass spectrometry(SELDI-TOF-MS) is a high throughput technology for identifying cancer biomarkers using drops of sera. Methods: Inthis study, 185 serum samples were taken from ESCC patients in a high incidence area and screened by SELDI. Asupport vector machine (SVM) algorithm was adopted to analyze the samples. Results: The SVM patterns success-fully distinguished ESCC from pre-cancerous lesions (PCLs). Also, types of PCL, including dysplasia (DYS) and basalcell hyperplasia (BCH), and healthy controls (HC) were distinguished with an accuracy of 95.2% (DYS), 96.6% (BCH),and 93.8% (HC), respectively. A marker of 25.1 kDa was identified in the ESCC patterns whose peak intensity wasobserved to increase significantly during the development of esophageal carcinogenesis, and to decrease obviously after surgery. Conclusions: We selected five ESCC biomarkers to form a diagnostic pattern which can discriminateamong the different stages of esophageal carcinogenesis. This pattern can significantly improve the detection ofESCC.

Proteomic analysis of primary colon cancer-associated fibroblasts using the SELDI-ProteinChip platform

Objective: Cancer-associated fibroblasts (CAFs) are one of the hallmarks of the cancer microenvironment. Recent evidence has indicated that CAFs are more competent in enhancing cancer cell growth and migration than normal fibroblasts. However, the unique protein expression of CAFs has not been fully elucidated. This study aims to investigate the characterizations of colon CAFs by comparing the differential protein expression between CAFs and normal fibroblasts. Methods: Primary fibroblasts were isolated from surgical specimen of human colon cancer and matched normal colonic tissue. Purity of the cell population was verified through immunostain analysis. Total cell lysates and conditioned media from each group of cells were extracted, and protein expression analysis was conducted using the surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) ProteinChip platform. Results: Most primary cells showed typical fibroblast-like features after two weeks. Increased proportion of α-smooth muscle actin-positive myofibroblasts was detected within the CAFs in four of the six pairs of primary cells. Fibroblast activation protein was weakly expressed in most cells without differences. Using SELDI-TOF-MS ProteinChip platform, four protein peaks mass over charge ratio (m/z) 1142, 3011, 4035, and 4945 were detected in the total cell lysates, and two protein peaks m/z 1368 and 1389 were detected in the conditioned media. The potential candidate proteins found in the Swiss-Prot database include morphogenetic neuropeptides, FMRFamide-related peptides, insulin-like growth factor II, thymosin β-4-like protein 3, and tight junction-associated protein 1. Conclusions: Using the SELDI-ProteinChip platform, differential protein expressions were identified in colon CAFs compared with normal colonic stromal fibroblasts. The complex proteomic alternations in colon CAFs may play important roles related to the colon cancer microenvironment.