Abstract:

Objective  To observe the therapeutic effect of CDglyTK gene mediated by synthetic radiation-inducible promoter in the treatment of Tca8113 cells. Methods  CDglyTK gene in pCEA-CDglyTK was subcloned into pcDNA3.1（+） to construct plasmid pcDNA3.1（+）-CDglyTK, and then the synthetic radiation-inducible promoter in pMD18-T-E was inserted into pcDNA3.1（+）-CDglyTK to construct plasmid pcDNA3.1（+）/E-CDglyTK. The recombinant plasmid was transfected into Tca8113 cells by lipofectamine, and then exposed to 3 Gy irradiation. Cytotoxicity was evaluated by MTT. The expression of CDglyTK gene was detected by RT-PCR. The apoptosis and proliferation were examined by flow cytomtery. Results  The plasmid pcDNA3.1（+）/E-CDglyTK was constructed successfully. The comparative survival rate of Tca8113 cells was markedly decreased by induction irradiation. Up-regulation of CDglyTK expression was found in Tca8113 cells exposed to irradiation. The apoptosis index（AI） of  Tca8113 cells exposed to irradiation was higher than that of Tca8113 cells without irradiation, the other way round, the proliferation index（PI） of Tca8113 cells exposed to irradiation was lower than that of Tca8113 cells without irradiation. Conclusion  The synthetic radiation-inducible promoter can be served as a molecular switch to improve the expression of CDglyTK gene in Tca8113 cells, and low dose induction radiation can significantly improve the therapeutic efficiency.

Key words: radiation-inducible promoter, radiation therapy, tongue squamous cell carcinoma