Genotoxicity in the eyes of bystander cells.
The controversial use of a linear, no threshold extrapolation model for low dose risk assessment has become even more so in light of the recent reports on the bystander phenomenon. The answer to the question as to which of the two phenomena, bystander versus adaptive response, is more important has practical implication in terms of low dose radiation risk assessment. In this review, genotoxicity is used as an endpoint to introduce the two phenomena, provide some insight into the mechanisms of bystander effect and to bridge the two low dose phenomena which operate in opposite directions: the bystander effect tends to exaggerate the effect at low doses, by communicating damage from hit to non-hit cells whereas the adaptive response confers resistance to a subsequent challenging dose by an initial low priming dose.
Hei
Tom K
TK
Center for Radiological Research, College of Physicians and Surgeons, Columbia University, Vanderbilt Clinic 11-205, 630 West 168th Street, New York, NY 10032, USA. tkh1@columbia.edu
Persaud
Rudranath
R
Zhou
Hongning
H
Suzuki
Masao
M
D000512:Alpha Particles; D000818:Animals; D024201:Bystander Effect / Q000235:genetics*; D018957:CD59 Antigens / Q000235:genetics / Q000528:radiation effects; D019457:Chromosome Breakage; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D006822:Hybrid Cells / Q000528:radiation effects; D016296:Mutagenesis; D009152:Mutagenicity Tests; D009154:Mutation; D011836:Radiation Tolerance; D011853:Radiobiology; D018570:Risk Assessment
D018957:CD59 Antigens