Radiation-inducible promoter mediated PUMA Gene in the the treatment of Tca8113

Abstract

Objective: The aim of this study is to explore the therapeutic effect of the PUMA gene mediated by radiation-inducible promoters in the treatment of tongue squamous cell carcinoma. Methods: Recombinant pcDNA3.1 (+)/E-PUMA was constructed, in which the PUMA gene was mediated by a synthetic radiation inducible promoter. The recombined plasmids were transfected into the Tca8113 cell and xenografts of human tongue squamous carcinoma in naked mice respectively. After 24 h, the tumors were treated with 3 Gy of irradiation to upregulate the PU-MA gene expression. PUMA mRNA was detected by RT-PCR. Proliferating cell nuclear antigen (PCNA) and apoptosis were detected by immunohistochemical method and in situ end-labeling (ISEL) respectively. The data were analyzed using the SPSS11.0 software package for chi-square test. Results: Compared with the control group, the comparative survival rate of Tca8113 cells in the PUMA/IR group was markedly decreased and the xenografts were signifycantly suppressed. Up-regulation of PUMA gene expression was observed in the Tca8113 cells and in the xenografts after irradiation. The apoptosis indices of the Tca-8113 cells and xenograft with irradiation were markedly higher than those without irradiation. At the same time, the proliferation indices of the Tca8113 cells and xenografts with irradiation were markedly lower than those without irradiation. Conclusions: radiation-inducible promoters can serve as molecular switches to improve the expression of PUMA gene in tongue squamous cell carcinoma both in vivo and in vitro. Low-dose induction radiation can significantly improve therapeutic efficiency.