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Autsavapromporn, N.*; Plante, I.*; Liu, C.*; Konishi, Teruaki*; Usami, Noriko*; Funayama, Tomoo; Azzam, E.*; Murakami, Takeshi*; Suzuki, Masao*
International Journal of Radiation Biology, 91(1), p.62 - 70, 2015/01
Times Cited Count:31 Percentile:92.67(Biology)Radiation-induced bystander effects have important implications in radiotherapy. Their persistence in normal cells may contribute to risk of health hazards, including cancer. This study investigates the role of radiation quality and gap junction intercellular communication (GJIC) in the propagation of harmful effects in progeny of bystander cells. Confluent human skin fibroblasts were exposed to microbeam radiations with different linear energy transfer (LET) by which 0.0360.4% of the cells were directly targeted by radiation. Following 20 population doublings, the cells were harvested and assayed for micronucleus formation, gene mutation and protein oxidation. The results showed that expression of stressful effects in the progeny of bystander cells is dependent on LET.
Suzuki, Masao*; Autsavapromporn, N.*; Usami, Noriko*; Funayama, Tomoo; Plante, I.*; Yokota, Yuichiro; Muto, Yasuko*; Suzuki, Michiyo; Ikeda, Hiroko; Hattori, Yuya; et al.
Journal of Radiation Research, 55(Suppl.1), P. i54, 2014/03
Autsavapromporn, N.*; Suzuki, Masao*; Funayama, Tomoo; Usami, Noriko*; Plante, I.*; Yokota, Yuichiro; Muto, Yasuko*; Ikeda, Hiroko; Kobayashi, Katsumi*; Kobayashi, Yasuhiko; et al.
Radiation Research, 180(4), p.367 - 375, 2013/10
Times Cited Count:60 Percentile:89.43(Biology)We investigated the role of gapjunction intercellular communication (GJIC) in the propagation of stressful effects in confluent normal human fibroblast cultures wherein only 0.036-0.144% of cells in the population were traversed by primary radiation tracks. Confluent cells were exposed to graded doses from X ray, carbon ion, neon ion or argon ion microbeams in the presence or absence of an inhibitor of GJIC. After 4 h incubation, the cells were assayed for micronucleus (MN) formation. Micronuclei were induced in a greater fraction of cells than expected based on the fraction of cells targeted by primary radiation, and the effect occurred in a dose-dependent manner with any of the radiation sources. Interestingly, the inhibition of GJIC depressed the enhancement of MN formation in bystander cells from cultures exposed to high-LET radiation but not low-LET radiation. The results highlight the important role of radiation quality and dose in the observed effects.
Autsavapromporn, N.*; Plante, I.*; Liu, C.*; Konishi, Teruaki*; Usami, Noriko*; Funayama, Tomoo; Azzam, E.*; Murakami, Takeshi*; Suzuki, Masao*
no journal, ,
Confluent human skin fibroblasts (NB1RGB) were exposed to various types of microbeam with a different linear energy transfer (LET) at mean absorbed doses 0.4 Gy, wherein 0.036-0.4% of the cells were targeted by IR. Following 20 populations post-irradiation, the cells were harvested and assayed for micronucleus formation, mutation assay and protein oxidation. The progeny of bystander cells exposed to X rays and protons showed the persistence of oxidative stress, and correlate with the increased micronucleus formation and mutant fraction. However, such effects were not observed after irradiation by carbon ions. Interestingly, inhibition of GJIC mitigated the damaging effects in the progeny of bystander cells exposed to protons and carbon ions but not X rays. These data show carbon ions can reduce cancer risk after microbeam irradiation compared with X rays or protons, and GJIC may be a critical mediator in the observed effect.
Suzuki, Masao*; Autsavapromporn, N.*; Funayama, Tomoo; Yokota, Yuichiro; Muto, Yasuko*; Ikeda, Hiroko; Suzuki, Michiyo; Hattori, Yuya; Sakashita, Tetsuya; Kobayashi, Yasuhiko; et al.
no journal, ,
To determine signal transduction factors that are expected to be secreted from microbeam-irradiated cells, the time course analysis of cell killing effect in microbeam irradiated cell population was carried out. To irradiate cell with heavy-ion microbeam, a collimating heavy-ion microbeam system of JAEA-Takasaki was used. After microbeam irradiation, the samples were incubated for 0.5, 3, 24 hours respectively, and the cell killing effect of the microbeam irradiation were measured by colony formation assay. The result suggested that some factors, which induces bystander cell killing, were secreted after argon-ion microbeam, and the factor can be inhibited by the addition of gap-junction inhibitor and DMSO, but not by the ascorbic acid.