Schwartz J L, Jordan R, Sedita B A, Swenningson M J, Banáth J P, Olive P L
Center for Mechanistic Biology and Biotechnology, Argonne National Laboratory, IL 60439-4833, USA.
Mutagenesis. 1995 May;10(3):227-33. doi: 10.1093/mutage/10.3.227.
The gamma-ray sensitivity of two human lymphoblastoid cell lines, TK6 and WI-L2-NS, was studied; both cell lines are derived from the same parent, WI-L2. TK6 was more sensitive to the cytotoxic effects of gamma rays, but showed fewer induced chromosome aberrations. There was no difference between the two cell lines in their capacity to rejoin DNA double-strand breaks or in the kinetics of the rejoining process. The kinetics of cell cycle progression following radiation exposure was also similar in TK6 and WI-L2-NS. However, while TK6 cells were very sensitive to apoptosis induction, showing high levels of apoptotic cells within 24 h of exposure, no evidence for any significant levels of apoptosis was found for WI-L2-NS within 30 h of irradiation, when chromosome aberration frequency was determined. Evidence of apotosis were seen at later times in WI-L2-NS cells, but the levels were significantly lower than comparably treated TK6 cells. The results support a hypothesis that the lower survival and induced aberration frequencies in TK6 cells are due to selective removal of damaged cells by apoptotic processes prior to analysis of chromosome aberration frequencies in mitosis.
研究了两个人类淋巴母细胞系TK6和WI-L2-NS对γ射线的敏感性；这两个细胞系均源自同一亲本WI-L2。TK6对γ射线的细胞毒性作用更敏感，但诱导的染色体畸变较少。在重新连接DNA双链断裂的能力或重新连接过程的动力学方面，这两个细胞系之间没有差异。辐射暴露后细胞周期进程的动力学在TK6和WI-L2-NS中也相似。然而，虽然TK6细胞对凋亡诱导非常敏感，在暴露后24小时内显示出高水平的凋亡细胞，但在照射后30小时内测定染色体畸变频率时，未发现WI-L2-NS有任何显著水平凋亡的证据。在WI-L2-NS细胞中，在较晚时间观察到凋亡证据，但水平明显低于经相同处理的TK6细胞。这些结果支持了一个假设，即TK6细胞中较低的存活率和诱导的畸变频率是由于在有丝分裂中分析染色体畸变频率之前，通过凋亡过程选择性地清除了受损细胞。
