Mutagenic adaptive response to high-LET radiation in human lymphoblastoid cells exposed to X-rays.
The ability of cells to adapt low-dose or low-dose rate radiation is well known. High-LET radiation has unique characteristics, and the data concerning low doses effects and high-LET radiation remain fragmented. In this study, we assessed in vitro the ability of low doses of X-rays to induce an adaptive response (AR) to a subsequent challenging dose of heavy-ion radiation. Lymphoblastoid cells (TK6, AHH-1, NH32) were exposed to priming 0.02-0.1Gy X-rays, followed 6h later by challenging 1Gy heavy-ion radiation (carbon-ion: 20 and 40keV/μm, neon-ion: 150keV/μm). Pre-exposure of p53-competent cells resulted in decreased mutation frequencies at hypoxanthine-guanine phosphoribosyl transferase locus and different H2AX phosphorylation kinetics, as compared to cells exposed to challenging radiation alone. This phenomenon did not seem to be linked with cell cycle effects or radiation-induced apoptosis. Taken together, our results suggested the existence of an AR to mutagenic effects of heavy-ion radiation in lymphoblastoid cells and the involvement of double-strand break repair mechanisms.
National Institute of Radiological Sciences, Anagawa 4-9-1, Inage-ku, Chiba, Japan. vares@nirs.go.jp
Guillaume
G
Varès
Bing
B
Wang
Kaoru
K
Tanaka
Ayana
A
Kakimoto
Kyomi
K
Eguchi-Kasai
Mitsuru
M
Nenoi
D000222:Adaptation, Physiological / Q000528:radiation effects*; D017209:Apoptosis / Q000528:radiation effects; D002453:Cell Cycle / Q000528:radiation effects; D002460:Cell Line; D004307:Dose-Response Relationship, Radiation; D006657:Histones / Q000378:metabolism; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D007700:Kinetics; D018499:Linear Energy Transfer; D008214:Lymphocytes / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D009154:Mutation / Q000528:radiation effects*; D010766:Phosphorylation / Q000528:radiation effects; D011836:Radiation Tolerance / Q000528:radiation effects; D013997:Time Factors
C468783:H2AX protein, human; D006657:Histones; D007041:Hypoxanthine Phosphoribosyltransferase