title: Development of a therapeutically important radiation induced promoter.
abstract: Radio-genetic therapy is a combination of radiation therapy and gene therapy that may solve some of the problems associated with conventional radiotherapy. A promoter responsive to radiation was obtained from a promoter library composed of DNA fragments created by linking the TATA box signal to randomly combined binding sequences of transcription factors that are reactive to radiation. Each promoter connected to the luciferase gene, was evaluated by luciferase expression enhancement in transfected cells after X-ray irradiation. The reactivity of the best promoter was improved by the random introduction of point mutations and the resultant promoter showed more than a 20-fold enhancement of the luciferase expression after X-ray irradiation at 10 Gy. The expression of downstream genes was also enhanced in stably transfected cells not only by X-rays but also by proton beam irradiation; and either enhancement was attenuated when an anti-oxidant was added, thus suggesting the involvement of oxidative stress in the promoter activation. Constructed promoters were also activated in tumors grown in mice. In addition, cell killing with the fcy::fur gene (a suicide gene converting 5-fluorocytosin to highly toxic 5-fluorouracil) increased dose-dependently with 5-fluorocytosin only after X-ray irradiation in vitro. These results suggest that promoters obtained through this method could be used for possible clinical applications.
authors.affiliation: Department of Radiological Sciences; Graduate School of Medicine and Pharmaceutical Sciences; University of Toyama; Toyama, Japan. ogawa@med.u-toyama.ac.jp
authors.forename: Ryohei
authors.initials: R
authors.lastname: Ogawa
authors.forename: Akihiro
authors.initials: A
authors.lastname: Morii
authors.forename: Akihiko
authors.initials: A
authors.lastname: Watanabe
authors.forename: Zheng-Guo
authors.initials: ZG
authors.lastname: Cui
authors.forename: Go
authors.initials: G
authors.lastname: Kagiya
authors.forename: Shigekazu
authors.initials: S
authors.lastname: Fukuda
authors.forename: Kyo
authors.initials: K
authors.lastname: Kume
authors.forename: Takashi
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Masanori
authors.initials: M
authors.lastname: Hatashita
authors.forename: Hironori
authors.initials: H
authors.lastname: Izumi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ishimoto
authors.forename: Loreto B
authors.initials: LB
authors.lastname: Feril
mesh_terms: D000818:Animals; D004194:Disease / Q000235:genetics; D041722:Genes, Transgenic, Suicide; D015316:Genetic Therapy; D006801:Humans; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D011401:Promoter Regions, Genetic; D011878:Radiotherapy; D014162:Transfection
chemical_list: D008156:Luciferases