title: Sensitivities of NIH/3T3-derived clonal cell lines to ionizing radiation: significance for gene transfer studies.
abstract: Rodent cells are frequently used as recipients in experiments involving gene transfer, isolation, and characterization. The present studies were designed to investigate the clonal responses to ionizing radiation of NIH/3T3 cells subjected to DNA-mediated gene transfer. Radiation sensitivity (D0) values were determined for the parental NIH/3T3 cell strain, six clonal cell lines transfected with DNA from radiation-resistant human tumor cells, and six nontransfected clonal cell lines. The radiation sensitivities of four transfected and two nontransfected clonal cell lines differed significantly from parental NIH/3T3 cells (P less than 0.05). Detailed karyotype analysis of two nontransfected clonal cell lines with differing radiation sensitivities showed variation in chromosomal composition. Specifically, a minute chromosome was observed to segregate consistently (in 49 of 50 metaphases) with the genome of one NIH/3T3 clone (D0 2.07 Gy) and was completely absent (from 50 metaphases) in another NIH/3T3 clone (D0 1.06 Gy). In the parental NIH/3T3 strain (D0 2.02 Gy) 10% of cells (3 of 30 metaphases) had such minute chromosomes. These findings demonstrate that the clonal cellular heterogeneity of NIH/3T3 cells is characterized by genotypic and phenotypic variations which must be considered in the experimental design involving gene transfer and expression.
authors.affiliation: Department of Radiation Medicine, Georgetown University School of Medicine, Vincent T. Lombardi Comprehensive Cancer Research Center, Washington, DC 20007.
authors.forename: U N
authors.initials: UN
authors.lastname: Kasid
authors.forename: R R
authors.initials: RR
authors.lastname: Weichselbaum
authors.forename: T
authors.initials: T
authors.lastname: Brennan
authors.forename: G E
authors.initials: GE
authors.lastname: Mark
authors.forename: A
authors.initials: A
authors.lastname: Dritschilo
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects*; D002999:Clone Cells; D004307:Dose-Response Relationship, Radiation; D005814:Genes, Viral; D007621:Karyotyping; D051379:Mice; D008815:Mice, Inbred Strains; D009693:Nucleic Acid Hybridization; D011519:Proto-Oncogenes; D014162:Transfection; D014407:Tumor Cells, Cultured