Study ON The Relationship Between The Anaphase-promoting Complex( APC) And The Radiosensitivity Of Nasopharyngeal Carcinoma CNE-1 Cells

Objective The Anaphase-Promoting Complex APC is closely associated with the expression of CDH1 protein and plays an important role in cell proliferation, differentiation and apoptosis. The aim of this study was to investigate the possibility of CDH1 as a potential therapeutic target in the radiosensitivity of nasopharyngeal carcinoma cell CNE-1 and explained the role and the molecular mechanism of APC subunits after the silence of CDH1 combined with radiotherapy. The results would provide a theoretical basis for the target to enhance the sensitization of Nasopharyngeal Carcinoma in radiotherapy.Methods Take silence of CDH1 gene high-differentiated nasopharyngeal carcinoma CNE-1 cells(1184 cells) and containing empty lentiviral vector NC cells as research objects,expression of CDH1, APC3,CDC20 and Cyclin B1 after cells treated with 2Gy was detected by Western Blot.Cell cycle and apoptosis were detected by Annexin-V-FITC/PE and flow cytometry. The expression of DNA repair gene KU70 / KU80 was detected by real-time PCR. Colony forming experiment tested whether silence CDH1 gene alters the sensitization in radiotherapy. The growth curve of two kinds of cells, growth inhibition caused by radiation and platinum drugs sensitization were determined by MTT assay.Result(1) The expression of CDH1, APC3 and CDC20 were decreased in 1184 cells compared with NC cells, while the expression of Cyclin B1 was clearly increased. After treated with 2Gy, the expression of CDC20 was up-regulated and the level of CDH1 and APC3 were decreased more obviously in 1184 cells compared with NC cells(P<0.01).(2) The 1184 cells grew more quickly than NC cells.The double time of 1184 and NC cells was(35.04±0.03)h and(40.10±0.77)h, respectively.There is significantly different between two groups(F=28.409,P=0.006).(3) The sensitization enhancement ration(SER) of 1184 cells was 1.74. We found that 1184 cells occurred G2 / M phase arrest and significantly increased the apoptosis rates compared with NC cells. Compared with NC cells, the expression of KU70 /KU80 significantly reduced after the silence of CDH1 and combined with radiation.(4) Sensitization index(SI) was used to evaluate the sensitization to platinum drugs, our result suggested that sh-CDH1 CNE-1 cells had lower SI than vector control. The SI of DDP, CDP and oxaliplatin was 2.87,1.77 and 1.33 respectively.Conclusion Silence of CDH1 gene may closely associate with inhibition of AnaphasePromoting Complex APC activation,up-regulated Cyclin B1 expression and induced G2 / M phase arrest. What’s more, silence of CDH1 not only increased the radiation sensitivity of CNE-1 cells, but also increased the sensitivity to platinum-based drugs effectively. We assume that CDH1 is a potential target to radiation sensitization.