Preliminary study on proteomic technique in radiobiological characteristics in nasopharyngeal carcinoma cell line

Objective: To examine the variation of protein expression in nasopharyngeal carcinoma cell lines with different biological characteristics and to identify the radiobiological associated proteins. Methods: Biological characteristics of 5-8F and 6-10B were compared by flow cytometry assay after irradiation. The total proteins of 5-8F and 6-10B were separated by immobilized pH gradient(IPG) IEF-SDS two-dimensional gel eleetrophoresis technique. The differentially expressed proteins were cut from the gel and digested into peptides for MALDI-TOF MS and the Q-TOF mass spectrometric analysis. Identification of protein was made through searching in protein sequence database. Protein expressions were examined by western blot and immunohistochemistry method. Results: Nine most differentially expressed proteins between 5-8F cell and 6-10B cell were identified, p73 and CK19 expression examined by western blot were conformal with that by proteomic method, p73 expression in 5-8F cell was higher than in 6-10B cell. CK19 expression in 6- 10B cell was higher than in 5-8F cell. Conclusion: Differentially expression of proteins exist in nasopharyngeal carcinoma cell lines with different biological characteristics. These proteins may be associated with cell radiobiological characteristic with the p73 as a potential biomarker. (authors)