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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 17:39 |
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Conference: Bucharest University Faculty of Physics 2014 Meeting
Section: Biophysics; Medical Physics
Title:
The study of bystander effects induced by X-rays and bleomycin in fibroblasts
Authors:
Ana MATEI (1), Mihaela TEMELIE(2), Doina GAZDARU (1), Diana SAVU(2)
Affiliation:
(1) University of Bucharest, Faculty of Physics, POBox MG-11, Bucharest, Magurele, Romania
(2) IFIN-HH - Horia Hulubei National Institute of Physics and Nuclear Engineering, DFVM -The Department of Life and Environmental Science, Magurele, Romania
E-mail
shalimar_2054@yahoo.com
Keywords:
Bystander effect, ionizing radiation, bleomycin, oxidative stress, micronuclei
Abstract:
Physical or chemical stress applied to a cell system triggers a signal cascade transmitted to the neighboring cell population known as bystander effect. The present study examines: (i) the bystander effects produced by X-rays and the chemotherapeutic agent, bleomycin, in two cell lines: L929 (mouse fibroblasts) and MEFs (mouse embryonic fibroblasts) by employing conditioned media transfer and co-culture methodologies; (ii) the role of reactive oxygen species (ROS) in mediating the bystander responses produced by bleomycin in MEFs.
The two cell lines were exposed to different doses (0.5 Gy - 2 Gy) of X-rays irradiation. The MEFs were treated with different concentrations (less than 60 µg/ml) of bleomycin. Bystander cells either received medium from treated cells (by exposure to bleomycin or irradiation) or were co-cultured with irradiated cells. The bystander effect was quantified using micronucleus (MN) assay. The role of ROS in mediating the bystander response in MEFs was explored by treating bystander cells with the free radical scavenger, dimethyl sulphoxide (DMSO).
This study showed that the direct treatments with X-rays and bleomycin leads to an increased level of micronuclei in both cell lines used, this increase being in dependence with the dose. Bystander responses were observed in both cell types used (L929 and MEFs) in case of both methodologies used (conditioned media transfer and co-culture). The DNA damage induced by BLM bystander medium in MEFs was reduced in the presence of DMSO. This result suggests that ROS could play a role in the appearance of the bystander effects.
X-ray irradiation and bleomycin induced bystander response is reflected in increased DNA damage. The bystander effect is independent of the irradiation dose and chemotherapeutic agent concentration. The bystander effects seemed to be mediated through transmission of certain biomolecules and/or molecular signals either by intercellular communication through gap-junctions or by release of soluble factors into the culture medium. The free radical species of oxygen contributed to the occurrence of bystander responses in MEFs after bleomycin treatment.
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