Purification of p53-associated Proteins from Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a common cancer in southeast China that is closely associated with Epstein-Barr virus. We investigated the potential interaction between p53 and viral or cellular proteins in NPC tumor leading to the accumulation of p53 protein, by using immunoaffinity purification of p53 protein in NPC tumor specimens. Two immunoaffinity columns, each with monoclonal antibodies against p53, pAb1801 and pAb240 were used for the p53 protein purification, respectively. The p53 binding proteins were purified from metastasized lymph node tumors of NPC. p53 protein was highly purified with either of the two columns, as indicated by silver staining and Western blot analysis. In addition, two other protein bands could be visualized of 74 and 26 kD. The 26 kD band was detected by anti-p53 antibodies. The 74 kD protein bound to p53 protein by secondary bonds in NPC cells and weakly reacted with NPC patien's serum.