title: Absence of radioadaptive responses in four cell-lines in vitro as determined by colony formation assay.
abstract: The purpose of this study was to investigate radioadaptive response in 4 cell-lines under identical conditions using a colony assay. First, 4 cell-lines (V79, HeLa S3, EMT6 and SCCVII) were exposed to 8 Gy at various intervals after pretreatment with an adapting dose of 50 mGy or without it. Second, V79 cells were exposed to 8 Gy at 4.5 hrs after an adapting dose of 0 to 400 mGy. Third, V79 cells were exposed to 2, 4 or 6 Gy at 6 hrs after an adapting dose of 0 or 50 mGy. In the last experiment, an adapting dose was given either immediately after cell plating or 24 hrs later. Cell survival was assessed by a standard colony assay. Adaptive response was not observed in any of the 4 lines tested. In V79 cells, no adaptive response was seen even by changing the adapting dose, challenging dose, and timing of adapting radiation after cell plating. Although radioadaptive response has been reported for the V79 cell-line, we could not reproduce the result. We also failed to demonstrate the phenomenon in the other 3 tumor cell-lines in culture.
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Miyamoto
authors.forename: Yuta
authors.initials: Y
authors.lastname: Shibamoto
authors.forename: Chikao
authors.initials: C
authors.lastname: Sugie
authors.forename: Masato
authors.initials: M
authors.lastname: Ito
authors.forename: Shiho
authors.initials: S
authors.lastname: Ayakawa
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects; D006224:Cricetinae; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D011836:Radiation Tolerance