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Regulation of gene expression in retrovirus vectors by X‐ray and proton beam radiation with artificially constructed promoters
Author(s) -
Ogawa Ryohei,
Morii Akihiro,
Watanabe Akihiko,
Cui ZhengGuo,
Kagiya Go,
Fukuda Shigekazu,
Kume Kyo,
Hasegawa Takashi,
Hatashita Masanori,
Izumi Hironori,
Ishimoto Tetsuya,
Feril Loreto B.
Publication year - 2012
Publication title -
the journal of gene medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.689
H-Index - 91
eISSN - 1521-2254
pISSN - 1099-498X
DOI - 10.1002/jgm.2625
Subject(s) - promoter , retrovirus , physics , beam (structure) , gene , gene expression , proton , biology , genetics , optics , nuclear physics
Background We previously obtained an X‐ray responsive promoter from 11 promoters that we constructed. In the present study, we aimed to determine the efficiency of our promoter construction method. In addition, the reactivity of the promoter to X‐rays in vivo is also investigated. Methods Promoters constructed by linking the TATA box to randomly combined binding sequences of transcription factors activated by radiation were cloned to prepare a promoter library. Combinations of promoters and various genes were stably‐transfected into HeLa cells to establish recombinant cell lines, which were then exposed to X‐rays or a proton beam to observe gene expression enhancement with or without anti‐oxidants. Tumors of luciferase‐expressing recombinant cells on mice were exposed to X‐rays and promoter activation was evaluated by detecting bioluminescence. As a model for in vitro suicide gene therapy, fcy::fur‐expressing recombinant cells were exposed to X‐rays before incubation with 5‐fluorocytosin. Cell viability was determined with WST‐8. Results Twenty‐five of the 62 promoters in the library enhanced luciferase activity over five‐fold, 6 h after receiving 10 Gy of X‐ray irradiation, suggesting the effectiveness of our method. Luciferase activity in recombinant cells was enhanced by X‐rays and, to a lesser extent, by a proton beam. Anti‐oxidants attenuated the enhancement, suggesting the involvement of oxidative stress. Promoters were less reactive to X‐rays in tumors on mice. In our suicide gene therapy model, survival of post‐irradiated cells decreased dose‐dependently with 5‐fluorocytosin. Conclusions Our method was efficient in generating radiation responsive promoters. Furthermore, we have successfully shown a potential therapeutic use for one of these promoters. Copyright © 2012 John Wiley & Sons, Ltd.