title: The radiation-induced bystander effect for clonogenic survival.
abstract: It has long been accepted that the radiation-induced heritable effects in mammalian cells are the result of direct DNA damage. Recent evidence, however, suggests that when a cell population is exposed to a low dose of alpha particles, biological effects occur in a larger proportion of cells than are estimated to have been traversed by alpha particles. Experiments involving the Columbia University microbeam, which allows a known fraction of cells to be traversed by a defined number of alpha particles, have demonstrated a bystander effect for clonogenic survival and oncogenic transformation in C3H 10T(1/2) cells. When 1 to 16 alpha particles were passed through the nuclei of 10% of a C3H 10T(1/2) cell population, more cells were unable to form colonies than were actually traversed by alpha particles. Both hit and non-hit cells contributed to the outcome of the experiments. The present work was undertaken to assess the bystander effect of radiation in only non-hit cells. For this purpose, Chinese hamster V79 cells transfected with hygromycin- or neomycin-resistance genes were used. V79 cells stably transfected with a hygromycin resistance gene and stained with a nuclear dye were irradiated with the charged-particle microbeam in the presence of neomycin-resistant cells. The biological effect was studied in the neomycin-resistant V79 cells after selective removal of the hit cells with geneticin treatment.
authors.affiliation: Center for Radiological Research, Columbia University, New York, New York 10032, USA.
authors.forename: S G
authors.initials: SG
authors.lastname: Sawant
authors.forename: W
authors.initials: W
authors.lastname: Zheng
authors.forename: K M
authors.initials: KM
authors.lastname: Hopkins
authors.forename: G
authors.initials: G
authors.lastname: Randers-Pehrson
authors.forename: H B
authors.initials: HB
authors.lastname: Lieberman
authors.forename: E J
authors.initials: EJ
authors.lastname: Hall
mesh_terms: D000512:Alpha Particles; D000818:Animals; D024201:Bystander Effect / Q000235:genetics / Q000528:radiation effects*; D002460:Cell Line; D002467:Cell Nucleus / Q000235:genetics / Q000528:radiation effects*; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002999:Clone Cells / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D006224:Cricetinae; D004247:DNA / Q000235:genetics / Q000528:radiation effects; D004249:DNA Damage / Q000235:genetics / Q000528:radiation effects*; D004351:Drug Resistance / Q000235:genetics; D005839:Gentamicins / Q000494:pharmacology; D009355:Neomycin / Q000494:pharmacology; D014162:Transfection
chemical_list: D005839:Gentamicins; D004247:DNA; C010680:antibiotic G 418; D009355:Neomycin