@misc{oai:repo.qst.go.jp:00071707, author = {Lui, Yu and Kobayashi, Alisa and Maeda, Takeshi and Fu, Qibin and Oikawa, Masakazu and Yang, Gen and Konishi, Teruaki and Uchihori, Yukio and K., Hei Tom and Wang, Yugang and 前田 武 and 及川 将一 and 小西 輝昭 and 内堀 幸夫}, month = {May}, note = {Tumors are heterogeneous in nature and consist of multiple cell types. Among them, cancer stem-like cells (CSCs) are suggested to be the principal cause of tumor metastasis, resistance and recurrence. Therefore, understanding the behavior of CSCs in direct and indirect irradiations is crucial for clinical radiotherapy. Here, the CSCs and their counterpart non stem-like cancer cells (NSCCs) in HT1080 fibrosarcoma cell line were sorted and labelled, then the two subtypes were mixed together and chosen separately to be irradiated via proton microbeam. The results showed there was a radiation-induced bystander effect (RIBE) between the CSCs and NSCCs measured as an increase of 53BP1 foci, a widely used indicator for DNA double strand break (DSB). In addition, CSCs were found to be less susceptible than NSCCs in both the generation and the response of bystander signals. Interestingly, the NO scavenger c-PTIO can effectively alleviate the bystander effect in bystander NSCCs but not in bystander CSCs, indicating a difference of the two subtypes in NO signal responding. To our knowledge, this is the first report shedding light on the RIBE between CSCs and NSCCs, which might contribute a further understanding of the out-of-field effect in cancer radiotherapy., The 12th International Workshop on Microbeam Probes of Cellular Radiation Response}, title = {Target irradiation induced bystander effects between stem-like}, year = {2015} }