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 γ-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-α, 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-α 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.

Periodontal and Serum Protein Profiles in Patients With Rheumatoid Arthritis Treated With Tumor Necrosis Factor Inhibitor Adalimumab

“…The protein concentration of each sample was measured by a commercially available kit §§ . After the samples were concentrated and desalted with a filter device, ‖‖ the first‐dimensional separation of proteins was carried out on immobilized pH gradient (IPG) strips, ¶¶ in accordance with published procedures 27,28 . Briefly, the protein samples (200 μg total protein) were applied overnight to IPG strips by in‐gel rehydration.…”

Low Concentration of Exogenous Carbon Monoxide Modulates Radiation-Induced Bystander Effect in Mammalian Cell Cluster Model

“…proved that a small fraction of irradiated cells (i.e., 5%) was good for a proteomic study of RIBE because the non-irradiated bystander cells were “contaminated” with only a very small number of irradiated cells [23]. Therefore, 1% irradiated cells in our mixed cell cluster would enable us to perform the western blot assay for the effect of CO on the protein expression in the bystander cells.…”

“…In the present study, RIBE and the effect of CO were investigated using the same cell-cluster model. Considering that Gerashchenko’s study [23] proved 5% irradiated cells did not affect the measurement of proteins in the bystander cells, the fraction of irradiated cells in our experiment should be less than 5%. When Eric Hall’s group adopted the mixed cell cluster model to assess the mutagenicity of bystander A L cells, they mixed the irradiated and bystander cells in a ratio of 1:5 to form the cluster and then separated the bystander A L cells with magnetic separation twice for the further mutagenicity analysis [5].…”

“…In the present paper, we further investigated the attenuation or inhibition of RIBE-induced cell proliferation and genetic damage in a model of mixed cell cluster (shown in Figure 1), which was developed by Eric Hall’s group for RIBE study [5] using low concentrations of exogenous CO. With sustained proliferation, gene mutations and chromosomal instability are considered to be risks for tumorigenesis [23]; our results will provide important information to protect normal tissues from RIBE hazards during radiotherapy procedures.…”

Proteomic overview and perspectives of the radiation-induced bystander effects

“…With a similar proteomic experimental strategy, the proliferative response of bystander rat liver cells was investigated in vitro using separated or co-cultures of un-irradiated and 5 Gy irradiated cells [62]. A confluent monolayer of rat liver cells were irradiated and mixed with a majority of un-irradiated cells (5/95) and cocultured for 24 h. Total extract of un-irradiated cells was compared with extracts from irradiated or co-cultured cells using 2DE.…”