Ryan Lorna A, Seymour Colin B, Joiner Michael C, Mothersill Carmel E
Medical Physics and Applied Radiation Sciences Department, McMaster University, Hamilton, Ontario, Canada.
Int J Radiat Biol. 2009 Jan;85(1):87-95. doi: 10.1080/09553000802635062.
A previous study comparing the bystander effect and low-dose hypersensitivity found that they were inversely correlated. In the current study seven cell lines with established bystander effect and hyper-radiosensitivity/increased radioresistance (HRS/IRR) were further screened for the presence of an adaptive response.
Cell survival after exposure to direct radiation with or without a 0.1 Gy priming dose, was determined using the colony forming assay for seven human cell lines (HaCAT, HPV-G, SW48, T98G, U373, HGL21 and HT29). Furthermore, the impact of the bystander effect on cell survival after exposure to irradiated cell culture medium was measured concurrently.
An adaptive response was induced in four cell lines (U373, T98G, HGL21 and HT29) causing increased cell survival. In agreement with previous publications, a bystander effect was induced in three cell lines (HPV-G, HaCAT and SW48); while no bystander effect was seen in U373, T98G, HGL21 and HT29. An adaptive response was detected in cell lines known to produce hypersensitive response, and was inversely correlated with the bystander effect.
These results suggest that for the cell lines tested the ability to induce an adaptive response may be mutually exclusive to the bystander effect.
先前一项比较旁观者效应和低剂量超敏反应的研究发现，二者呈负相关。在本研究中，对七种已确定具有旁观者效应和高辐射敏感性/辐射抗性增加（HRS/IRR）的细胞系进一步筛选，以确定是否存在适应性反应。
使用集落形成试验，测定七种人类细胞系（HaCAT、HPV-G、SW48、T98G、U373、HGL21和HT29）在接受或不接受0.1 Gy预照射剂量的直接辐射后的细胞存活率。此外，同时测量旁观者效应对暴露于辐照细胞培养基后的细胞存活率的影响。
在四种细胞系（U373、T98G、HGL21和HT29）中诱导出适应性反应，导致细胞存活率增加。与先前的出版物一致，在三种细胞系（HPV-G、HaCAT和SW48）中诱导出旁观者效应；而在U373、T98G、HGL21和HT29中未观察到旁观者效应。在已知产生超敏反应的细胞系中检测到适应性反应，且与旁观者效应呈负相关。
这些结果表明，对于所测试的细胞系，诱导适应性反应的能力可能与旁观者效应相互排斥。
