Identification of Proteins Associated With p53 in Nasopharyngeal Carcinoma Cell Line CNE2 by Proteomics and RNAi Techniques / 生物化学与生物物理进展

ABSTRACT

In order to elucidate the mechanisms of p53 overexpression in nasopharyngeal carcinoma (NPC) and detect proteins associated with the function of p53 in high throughout screening, p53 which knockdown human NPC CNE2 cell line (CNE2sip53) were successfully established by using stable RNA interference (RNAi). Two-dimensional gel electrophoresis (2-DE) was used to separate the total proteins of CNE2sip53 and its control cell line CNE2/pSUPER, and PDQuest software was applied to analyze 2-DE images. Twenty-two differential protein spots were identified by both MALDI-TOF-MS and ESI-Q-TOF-MS, some of which are known to be associated with the p53 function (HSP27, hnRNP K, 14-3-3? etc.) , and others may be novel proteins associated with p53 function (eIF4B, TPT1, hnRNP H3, SFRS1 etc.). Furthermore, the differential expression levels of the partial proteins (HSP27, 14-3-3?, GRP75) were confirmed by Western blot analysis and compared with CNE2 and CNE2 cells transfected with pcDNA3.1-FLAG, CNE2 cells transfected with pcDNA3.1-FLAG-p53 had obvious down-regulations of HSP27 and 14-3-3?, and an up-regulation of GRP75. The 22 differentially expressed proteins could be divided into five groups based on their functions signal transduction, chaperone, transcription and translation, metabolism and cytoskeleton, which were involved in cell cycle, the transcription regulation, cell adherence,cellular metabolism and so on. The data suggest that these differential proteins may be associated with the function of p53 in NPC, and will be valuable for further to study the mechanisms of p53 overexpression and inactivation in NPC.