Low-dose reduction in transformation frequency compared to unirradiated controls: the role of hyper-radiosensitivity to cell death.
Calculations based on plausible parameters taken from the existing experimental database, and new measurements on the cell cycle dependence of low-dose hyper-radiosensitivity (HRS) of non-tumorigenic HeLa x skin fibroblast human hybrid cells, provide the first experimental evidence that the selective killing of a transformation-sensitive G(2)/M-phase subpopulation as a consequence of low-dose HRS could account in part for the observed reduction of induced transformation frequencies at low doses to values below that observed spontaneously. However, it is clear that other mechanisms associated with classical adaptive response, such as induced DNA repair, are also likely to be involved.
Redpath
J Leslie
JL
Department of Radiation Oncology, University of California Irvine, Irvine, California 92687, USA. jlredpat@uci.edu
Short
Susan C
SC
Woodcock
Michael
M
Johnston
Peter J
PJ
D016923:Cell Death; D002471:Cell Transformation, Neoplastic; D018920:Coculture Techniques; D004307:Dose-Response Relationship, Radiation; D005347:Fibroblasts / Q000166:cytology*; D016195:G2 Phase / Q000528:radiation effects; D006367:HeLa Cells; D006801:Humans; D006822:Hybrid Cells; D008938:Mitosis / Q000528:radiation effects; D011836:Radiation Tolerance; D012867:Skin / Q000166:cytology*