Induction of cell killing by bystander effect with argon ion microbeam irradiation

Suzuki, Masao*; Autsavapromporn, N.*; Funayama, Tomoo; Yokota, Yuichiro; Muto, Yasuko*; Ikeda, Hiroko; Suzuki, Michiyo; Hattori, Yuya; Sakashita, Tetsuya; Kobayashi, Yasuhiko; Murakami, Takeshi*

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.