mA hypoxia/radiation dualª²sensitive promoter and its transcriptional activity

    WANG Weiª²Dong1, CHEN Zhengª²Tang1, LI Deª²Zhi1, LIU Xin2, DUAN Yuª²Zhong1

    1PLA Cancer Center, Third Military Medical University, Chongqing 400037, China, 2Department of Molecular Genetics, School of Basic Medicine, Third Military Medical University, Chongqing 400038, China

    ¡¾Abstract¡¿ AIM: To construct a hypoxia/radiation dualª²sensitive promoter and to elucidate its transcriptional characteristics. METHODS: An chimeric promoter HREª²Egr was generated by inserting the hypoxia response elements (HREs) from human vascular endothelium growth factor 5¡ä flanking sequence into the upstream of human early growth response geneª²1 (Egrª²1) promoter, which was transfected into human lung adenocarcinoma A549 cells by liposome. The expression of luciferase in transfected cells, exposed to 2, 4, 6, 8, 10 Gy irradiation combined with or without hypoxia (1, 5, 10, 25,5 0 mL/L oxygen concentrations), was detected. The dynamic changes of luciferase expression in transfected cells were observed following 6 Gy irradiation and 10 mL/L oxygen concentration. RESULTS: A hypoxia/radiation dualª²sensitive promoter HREª²Egr and its reporter vector were successfully constructed in the present study. HREª²Egr promoter transcriptional activity in the transfected cells demonstrated significant increment following irradiation, which displayed obvious doseª²dependent alteration. The luciferase expression in HREª²Egr transfected cells exposed to radiations combined with oxygen concentration below 2.5% showed markedly enhancement compared with that of Egrª²1 promoter transfected cells, which demonstrated remarkable decrease under the same conditions as above. The prolongation in radioª²inducible activity of HREª²Egr promoter was seen in transfected cells exposed to hypoxia. CONCLUSION: The HREª²Egr promoter generated in the present study possesses hypoxia/radiation dualª²sensitive identity, the transcriptional activity of which can be enhanced by hypoxia. ......