title: Proteome analysis of proliferative response of bystander cells adjacent to cells exposed to ionizing radiation.
abstract: Recently (Cytometry 2003, 56A, 71-80), we reported that direct cell-to-cell contact is required for stimulating proliferation of bystander rat liver cells (WB-F344) cocultured with irradiated cells, and neither functional gap junction intercellular communication nor long-range extracellular factors appear to be involved in this proliferative bystander response (PBR). The molecular basis for this response is unknown. Confluent monolayers of WB-F344 cells were exposed to 5-Gray (Gy) of gamma-rays. Irradiated cells were mixed with unirradiated cells and co-cultured for 24 h. Cells were harvested and protein expression was examined using 2-DE. Protein expression was also determined in cultures of unirradiated and 5-Gy irradiated cells. Proteins were identified by MS. Nucleophosmin (NPM)-1, a multifunctional nucleolar protein, was more highly expressed in bystander cells than in either unirradiated or 5-Gy irradiated cells. Enolase-alpha, a glycolytic enzyme, was present in acidic and basic variants in unirradiated cells. In bystander and 5-Gy irradiated cells, the basic variant was weakly expressed, whereas the acidic variant was overwhelmingly present. These data indicate that the presence of irradiated cells can affect NPM-1 and enolase-alpha in adjacent bystander cells. These proteins appear to participate in molecular events related to the PBR and suggest that this response may involve cellular defense, proliferation, and metabolism.
authors.affiliation: Department of Radiology, MSB F-451, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ, USA. bigerash@iupui.edu
authors.forename: Bogdan I
authors.initials: BI
authors.lastname: Gerashchenko
authors.forename: Akira
authors.initials: A
authors.lastname: Yamagata
authors.forename: Ken
authors.initials: K
authors.lastname: Oofusa
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Yoshizato
authors.forename: Sonia M
authors.initials: SM
authors.lastname: de Toledo
authors.forename: Roger W
authors.initials: RW
authors.lastname: Howell
mesh_terms: D000595:Amino Acid Sequence; D002450:Cell Communication / Q000187:drug effects*; D049109:Cell Proliferation; D002478:Cells, Cultured; D018920:Coculture Techniques; D015180:Electrophoresis, Gel, Two-Dimensional; D004847:Epithelial Cells / Q000378:metabolism; D005720:Gamma Rays / Q000009:adverse effects; D008969:Molecular Sequence Data; D020543:Proteome / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D020543:Proteome