Evidence for the involvement of double-strand breaks in heat-induced cell killing
Evidence for the involvement of double-strand breaks in heat-induced cell killing
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DOI：
10.1158/0008-5472.can-04-1876
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发表时间：
2004-12-15
期刊：
影响因子：
11.2
通讯作者：
Ohnishi, T
中科院分区：
文献类型：
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作者：
Takahashi, A;Matsumoto, H;Ohnishi, T
为了鉴定与热诱导的细胞杀伤相关的关键事件，我们检查了热处理细胞中γ H2AX（在丝氨酸139处磷酸化的组蛋白H2AX）的灶形成。已知该测定法非常灵敏，并且是双链断裂存在的特异性指示剂。我们发现，γ H2AX灶的数量迅速增加，并达到最大值后30分钟热处理，以及X射线照射后。当细胞在41.5 ℃至45.5 ℃加热时，我们观察到γ H2AX灶的数量随时间线性增加。根据Arrhenius图分析，在42.5 ℃处的拐点和拐点之上和之下的细胞杀伤和病灶形成的热活化能几乎相同。从这些结果，它表明，γ H2AX灶的数量与细胞杀伤的温度依赖性相关。在细胞暴露于热的时期期间，细胞杀伤的细胞周期依赖性模式与γ H2AX灶形成的细胞周期模式相同。我们还发现，热耐受性是由于在加热后形成的gammaH2AX灶的数量的抑郁症时，细胞通过热预处理。这些发现表明，细胞杀伤可能与通过蛋白质变性形成双链断裂有关。
To identify critical events associated with heat-induced cell killing, we examined foci formation of gammaH2AX (histone H2AX phosphorylated at serine 139) in heat-treated cells. This assay is known to be quite sensitive and a specific indicator for the presence of double-strand breaks. We found that the number of gammaH2AX foci increased rapidly and reached a maximum 30 minutes after heat treatment, as well as after X-ray irradiation. When cells were heated at 41.5degreesC to 45.5degreesC, we observed a linear increase with time in the number of gammaH2AX foci. An inflection point at 42.5degreesC and the thermal activation energies above and below the inflection point were almost the same for cell killing and foci formation according to Arrhenius plot analysis. From these results, it is suggested that the number of gammaH2AX foci is correlated with the temperature dependence of cell killing. During periods when cells were exposed to heat, the cell cycle-dependent pattern of cell killing was the same as the cell cycle pattern of gammaH2AX foci formation. We also found that thermotolerance was due to a depression in the number of gammaH2AX foci formed after heating when the cells were pre-treated by heat. These findings suggest that cell killing might be associated with double-strand break formation via protein denaturation.