Analysis of the differential secretome of nasopharyngeal carcinoma cell lines CNE-2R and CNE-2.
Radioresistance is the major cause of poor prognosis in nasopharyngeal carcinoma (NPC). To identify and characterize the secretome associated with NPC radioresistance, we compared the conditioned serum-free medium of radioresistant CNE-2R cells with that of the parental radiosensitive CNE-2 cells using isobaric tags for relative and absolute quantitation (iTRAQ) with liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) quantitative proteomics. Before proceeding to quantitative proteomics, we investigated the survival curves of CNE-2R and CNE-2 cells by colony formation assay, and the CNE-2R survival curves were significantly higher than those for CNE-2. In total, 3,581 proteins were identified in the quantitative proteomics experiments, and 40 proteins exhibited significant differences between the CNE-2R and CNE-2 cells. Twenty-six of the 40 proteins were secreted by classical, non-classical, or exosomal secretion pathways. To verify the reliability of iTRAQ quantitative proteomics, we applied western blotting (WB) to study the secretory protein expression of fibrillin-2, CD166, sulfhydryl oxidase 1 and cofilin-2, which are involved in cell adhesion, migration and invasion. The WB results showed that fibrillin-2 (p=0.017) and sulfhydryl oxidase 1 (p=0.000) were highly expressed in the CNE-2 cells, while CD166 (p=0.012) and cofilin-2 (p=0.003) were highly expressed in the CNE-2R cells, which was in accordance with iTRAQ quantitative proteomics. Finally, a phenotypic subset of CD166-positive NPC cells was verified by immunocytochemistry. In summary, we defined a collection of secretory proteins that may be relevant to the radioresistance in NPC cells, and we determined that CD166, which is widely used as a positive marker of cancer stem cells, is expressed in NPC cells.
Department of Radiation Oncology, Cancer Hospital of Guangxi Medical University and Cancer Institute of Guangxi Zhuang Autonomous Region, Nanning, Guangxi 530021, P.R. China.
Ze-Tan
ZT
Chen
Department of Radiation Oncology, Cancer Hospital of Guangxi Medical University and Cancer Institute of Guangxi Zhuang Autonomous Region, Nanning, Guangxi 530021, P.R. China.
Ling
L
Li
Department of Radiation Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China.
Ya
Y
Guo
Department of Radiation Oncology, Cancer Hospital of Guangxi Medical University and Cancer Institute of Guangxi Zhuang Autonomous Region, Nanning, Guangxi 530021, P.R. China.
Song
S
Qu
Department of Radiation Oncology, Cancer Hospital of Guangxi Medical University and Cancer Institute of Guangxi Zhuang Autonomous Region, Nanning, Guangxi 530021, P.R. China.
Wei
W
Zhao
Department of Radiation Oncology, Cancer Hospital of Guangxi Medical University and Cancer Institute of Guangxi Zhuang Autonomous Region, Nanning, Guangxi 530021, P.R. China.
Hao
H
Chen
Department of Radiation Oncology, Cancer Hospital of Guangxi Medical University and Cancer Institute of Guangxi Zhuang Autonomous Region, Nanning, Guangxi 530021, P.R. China.
Fang
F
Su
Department of Radiation Oncology, Cancer Hospital of Guangxi Medical University and Cancer Institute of Guangxi Zhuang Autonomous Region, Nanning, Guangxi 530021, P.R. China.
Jun
J
Yin
Department of Radiation Oncology, Cancer Hospital of Guangxi Medical University and Cancer Institute of Guangxi Zhuang Autonomous Region, Nanning, Guangxi 530021, P.R. China.
Qi-Yan
QY
Mo
Department of Radiation Oncology, Cancer Hospital of Guangxi Medical University and Cancer Institute of Guangxi Zhuang Autonomous Region, Nanning, Guangxi 530021, P.R. China.
Xiao-Dong
XD
Zhu
D015703:Antigens, CD / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism; D002277:Carcinoma; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000528:radiation effects; D005326:Fetal Proteins / Q000378:metabolism; D006801:Humans; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000378:metabolism*; D014411:Neoplastic Stem Cells / Q000378:metabolism; D020543:Proteome / Q000378:metabolism*; D011836:Radiation Tolerance; D020410:Activated-Leukocyte Cell Adhesion Molecule
D015703:Antigens, CD; D014408:Biomarkers, Tumor; D015816:Cell Adhesion Molecules, Neuronal; D005326:Fetal Proteins; D020543:Proteome; C105613:ALCAM protein, human; D020410:Activated-Leukocyte Cell Adhesion Molecule