title: Are chromosomal instabilities induced by exposure of cultured normal human cells to low- or high-LET radiation?
abstract: Radiation-induced genomic instability has been proposed as a very early, if not an initiating, step in radiation carcinogenesis. Numerous studies have established the occurrence of radiation-induced chromosomal instability in various cells of both human and rodent origin. In many of these studies, however, the cells were not "normal" initially, and in many cases they involved tumor-derived cell lines. The phenomenon clearly would be of even greater interest if it were shown to occur generally in cells that are normal at the outset, rather than cells that may have been "selected" because of a pre-existing susceptibility to induced instability. As a test of the generality of the phenomenon, we studied low-passage normal diploid human fibroblasts (AG1521A) to determine whether they are susceptible to the induction of chromosomal instability in the progeny of surviving cells after exposure in G(0) to low- and high-LET radiation. Cytogenetic assays for instability were performed on both mixed populations of cells and clones of cells surviving exposure. We found no evidence for the induction of such instability as a result of radiation exposure, though we observed a senescence-related chromosomal instability in the progeny of both irradiated and unirradiated cell populations.
authors.affiliation: Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523, USA.
authors.forename: Lawrence C
authors.initials: LC
authors.lastname: Dugan
authors.forename: Joel S
authors.initials: JS
authors.lastname: Bedford
mesh_terms: D002453:Cell Cycle / Q000528:radiation effects*; D002455:Cell Division / Q000528:radiation effects; D002478:Cells, Cultured; D002588:Cesium Radioisotopes; D002869:Chromosome Aberrations; D002875:Chromosomes / Q000528:radiation effects*; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007091:Image Processing, Computer-Assisted; D017404:In Situ Hybridization, Fluorescence; D007501:Iron; D008677:Metaphase / Q000528:radiation effects; D008938:Mitosis; D011836:Radiation Tolerance; D016192:Resting Phase, Cell Cycle; D013997:Time Factors
chemical_list: D002588:Cesium Radioisotopes; D007501:Iron