Differences in bystander effect between Aldefluor positive and negative cells of fibrosarcoma using microbeam irradiation

Recently, the properties of cancer stem-like cells (CSCs) have been widely investigated, especially due to resistance against radiation exposure that becomes one of major concerns in radio-cancer therapy. . However, information is rare about their performance in indirect irradiation. Here, we sorted the Aldefluor-positive cells which have a CSC property in HT1080 cell line and proved the existence of radiation-induced bystander effect in these stem-like cells and their counterpart Aldefluor-negative cells. We found that the negative ones seemed to generate a more harmful bystander effect signal and were more vulnerable to such signals in terms of the DNA double strand break (DSB)foci number measured by 53BP1. In addition, the NO scavenger c-PTIO can effectively release the bystander effect in Aldefluor-negative cells but not in positive ones. Our results first shed light on the difference between CSCs and non stem-like cancer cells (NSCCs) in radiation-induced bystander effect (RIBE), and might contribute a further understanding of the property of CSCs in radiotherapy, especially in low dose and out-of-field effect assessment.第４回共用施設（PASTA&SPICE, NASBEE)共同研究成果報告