Screening Differentially Expressed Proteins With Itraq And Orbitrap Ms/MS In Nasopharyngeal Carcinoma Xenograft Tumor Tissue By10Gy X-ray Irradiation

Background and ObjectiveNasopharyngeal Carcinoma(NPC), a malignant turmor with regionalpopulation distribution claims many lives in Southern China. As the clinicapplication of intensity modulated radiation therapy and comprehensivetreatment for the locally advanced NPC, the curative effect has beensignificantly improved. But local residue, recurrence and distant metastasisemerged after a minority of patients’ treatment, an important factor is due tocancer cells to radiation resistance. Investigating radiation resistance mechanismwill provide theoretical guidance for the sensitization to clinical radiotherapy ofNPC.This study applied the multidimensional protein identification technologyof proteomics research methods with tumor xenograft tissue protein after receiving high-dose radiation.Differentially expressed proteins were classified asbiological functions in Gene Ontology. It was designed to consider theirtolerance to radiation and further explore the radiotherapy resistance mechanismof NPC.Method1.CNE-2group and CNE-2R group of tumor xenograft in nude mice wereestablished. Xenograft tumor tissue proteins were extracted.2.Tissue proteins were digested into peptides, and labeled by iTRAQ kit. Thepeptides mixture were separated by2D-HPLC system, then identified andscreened by LTQ-Orbitrap mass spectrometry.3.The differentially expressed proteins were classified according to GeneOntology(GO).Results2762kinds of tissue proteins were identified by mass spectrometry analysisof nasopharyngeal carcinoma xenografts after10Gy irradiation. Among them,61differential expressed proteins were identified:17up-regulated,44down-regulated. Among these proteins, GO analysis showed that differentialprotein are mainly involved in biological processes such as cell cycle regulation,catabolism, signaling pathways regulation, pressure stress reaction and redoxreaction. Annexin2、PDIA3、Ubiquitin、CKAP4、HSPA8、14-3-3δ/ζ、NLRC4which were involved in these biological processes.ConclusionSeven important differentially expressed proteins（Annexin2、PDIA3、 Ubiquitin、CKAP4、HSPA8、14-3-3δ/ζ、NLRC4）are potential radiation sensitiveindexes by MudPIT.