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Bystander effect induced by counted high‐LET particles in confluent human fibroblasts: a mechanistic study
Author(s) -
Shao Chunlin,
Furusawa Yoshiya,
Kobayashi Yasuhiko,
Funayama Tomoo,
Wada Seiichi
Publication year - 2003
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.02-1115com
Subject(s) - bystander effect , cell culture , micronucleus test , reactive oxygen species , intracellular , chemistry , irradiation , biophysics , microbiology and biotechnology , microbeam , cell , biology , immunology , toxicity , biochemistry , genetics , medicine , physics , nuclear medicine , organic chemistry , nuclear physics
The possible mechanism of a radiation‐induced bystander response was investigated by using a high‐LET heavy particle microbeam, which allows selected cells to be individually hit with precise numbered particles. Even when only a single cell within the confluent culture was hit by one particle of 40 Ar (∼1260 keV/µm) or 20 Ne (∼380 keV/µ m), a 1.4‐fold increase of micronuclei (MN) was detected demonstrating a bystander response. When the number of targeted cells increased, the number of MN biphasically increased; however, the efficiency of MN induction per targeted cell markedly decreased. When 49 cells in the culture were individually hit by 1 to 4 particles, the production of MN in the irradiated cultures were ∼2‐fold higher than control levels but independent of the number and LET of the particles. MN induction in the irradiated‐culture was partly reduced by treatment with DMSO, a scavenger of reactive oxygen species (ROS), and was almost fully suppressed by the mixture of DMSO and PMA, an inhibitor of gap junctional intercellular communication (GJIC). Accordingly, both ROS and GJIC contribute to the above‐mentioned bystander response and GJIC may play an essential role by mediating the release of soluble biochemical factors from targeted cells.—Shao, C., Furusawa, Y., Kobayashi, Y., Funayama, T., Wada, S. Bystander effect induced by counted high‐LET particles in confluent human fibroblasts: a mechanistic study. FASEB J. 17, 1422–1427 (2003)