| Summary: | 博士 === 長庚大學 === 基礎醫學研究所 === 93 === Advances in proteomic technologies have provided researchers new tools for identifying tumor markers systematically. Nasopharyngeal carcinoma (NPC), endemic in southern China and Taiwan, is commonly diagnosed late due to its deep location and vague symptoms. Therefore, it is important to identify biomarkers for early diagnosis. For this purpose, we analyzed the secreted proteomes of two NPC cell lines (NPC-TW02 and 04), and selected the proteins identified in both cell lines for further characterization as potential NPC biomarkers. Secreted proteins in the NPC cell-line cultured media were identified by SDS-PAGE combined with matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry. Thirty-three proteins were detected in NPC-TW02 cultured medium, and 36 proteins in NPC-TW04. Twenty-three secreted proteins were identified both in NPC-TW02 and 04 cultured media. Four cell mobility-related proteins fibronectin, Mac-2 binding protein (Mac-2 BP), fascin, and plasminogen activator inhibitor 1 (PAI-1) identified in this study were further confirmed by Western blot analysis.
Among the proteins secreted from both NPC cell lines, 15 proteins have been reported previously to be highly expressed or dysregulated in certain types of tumor. In addition, 14 of them could be detected in serum in previous reports, and 7 of the 14 proteins were considered as potential serum tumor markers. Most of these proteins have not been described previously to be secreted by NPC cell lines.
The 3 proteins fibronectin, Mac-2 BP, and PAI-1 were highly expressed in NPC biopsies, but weakly or not expressed in normal nasopharyngeal tissues. To detect serum level of the 3 proteins, sandwich ELISA were developed. The serum levels of the three proteins were significantly higher in NPC patients (n = 46) than in normal controls (n = 47) (p < 0.0001). Nude mice bearing NPC tumors derived from NPC-TW02 cells (n = 9) also showed elevated serum levels of Mac-2 BP and PAI-1 when compared with tumor-free mice (n = 9) (p < 0.01).
Our work shows that fibronectin, Mac-2 BP, and PAI-1 may be potential markers for diagnosis of NPC. Systematic analysis of cancer cell-secreted proteomes in conjunction with work in animal tumor models can be a feasible, convenient strategy for searching multiple potential tumor markers.
|
|---|
