Establishment of experimental systems for analyzing bystander effects induced by heavy-ion irradiation between normal and cancer cells

Ikeda, Hiroko; Yokota, Yuichiro; Funayama, Tomoo; Kanai, Tatsuaki*; Kobayashi, Yasuhiko

The purpose of this study is to make clear the bystander effect between cancer cells and normal cells and to establish a new approach using microbeam for elucidating its molecular mechanism. When irradiated cells and non-irradiated cells were co-cultured without physical contact, it was found that clonogenic abilities of non-irradiated bystander cells increased between different type cells but decrease between same type cells. This suggests that bystander responses were greatly different between the same type cells and different type cells. However, we could detect only the medium-mediated bystander response in the co-culture experiment. Since there is another pathway that induces bystander response via gap junction intercellular communications, we planned to irradiate the mixed culture of different type cells using the heavy-ion microbeam system for elucidating its molecular mechanism. Now, we are constructing the new experimental approach and will report the latest findings.