Comparative proteomic analysis of secreted proteins from nasopharyngeal carcinoma-associated stromal fibroblasts and normal fibroblasts.

Since the concept of the secretome (ensemble of proteins secreted and/or shed from cells) was proposed, it has become an attractive and challenging proteomic technology in recent years. However, secretome analysis still faces some difficulties mainly related to sample collection and preparation. In the present study, we established a reliable method for extracting secreted proteins by ultrafiltration centrifugation and conducting secretomic analysis. Accumulating evidence suggests that carcinoma-associated stromal fibroblasts (CAFs) play an important role in cancer initiation and progression. To investigate the expression patterns of secreted proteins from fibroblasts and to identify the secreted proteins involved in nasopharyngeal carcinoma (NPC) carcinogenesis, we conducted comparative secretome analysis between CAFs and normal fibroblasts. After two-dimensional gel electrophoresis (2-D PAGE), 11 significant spots were differentially expressed and identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). These proteins may take part in the regulation of the tumor micro-environment through different processes. The expression level of galectin-1 in the CAF supernatant was also determined by ELISA. This study provides useful information and new clues for the further understanding of the regulatory mechanisms of CAFs in the NPC microenvironment.