Induction of a bystander mutagenic effect of alpha particles in mammalian cells
AUTOR(ES)
Zhou, Hongning
FONTE
The National Academy of Sciences
RESUMO
Ever since the discovery of X-rays was made by Röntgen more than a hundred years ago, it has always been accepted that the deleterious effects of ionizing radiation such as mutation and carcinogenesis are attributable mainly to direct damage to DNA. Although evidence based on microdosimetric estimation in support of a bystander effect appears to be consistent, direct proof of such extranuclear/extracellular effects are limited. Using a precision charged particle microbeam, we show here that irradiation of 20% of randomly selected AL cells with 20 alpha particles each results in a mutant fraction that is 3-fold higher than expected, assuming no bystander modulation effect. Furthermore, analysis by multiplex PCR shows that the types of mutants induced are significantly different from those of spontaneous origin. Pretreatment of cells with the radical scavenger DMSO had no effect on the mutagenic incidence. In contrast, cells pretreated with a 40 μM dose of lindane, which inhibits cell–cell communication, significantly decreased the mutant yield. The doses of DMSO and lindane used in these experiments are nontoxic and nonmutagenic. We further examined the mutagenic yield when 5–10% of randomly selected cells were irradiated with 20 alpha particles each. Results showed, likewise, a higher mutant yield than expected assuming no bystander effects. Our studies provide clear evidence that irradiated cells can induce a bystander mutagenic response in neighboring cells not directly traversed by alpha particles and that cell–cell communication process play a critical role in mediating the bystander phenomenon.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=15760Documentos Relacionados
- Mutagenic effects of a single and an exact number of α particles in mammalian cells
- Targeted cytoplasmic irradiation with alpha particles induces mutations in mammalian cells
- Identification of mutagenic metabolites of benzo(a)pyrene in mammalian cells.
- Bystander effect produced by radiolabeled tumor cells in vivo
- UV light-induced cyclobutane pyrimidine dimers are mutagenic in mammalian cells.