RESUMEN
A subcellular proteomic method was applied to investigate the protein expression profiles of nasopharyngeal carcinoma (NPC) cell lines,CNE1 and CNE2,at various differentiation levels.Plasma membrane (PM) proteins were obtained by Percoll density grade centrifugation and subjected to twodimensional electrophoresis (2DE) followed by PDQuest software analysis.Nine proteins expressed with more than two folds difference were identified by MALDI-TOF-TOF,of which functions involved in cell differentiation,signal transduction,and metabolism.Half of these proteins,such as galectin-1 and annexin Ⅱ,were analyzed with real-time quantitative PCR or Westem blotting.We have tested a proteomic method to study differentiated NPCs at different levels and found several proteins that might be related to their biological characteristics.