Cell Cycle Perturbations and Genotoxic Effects in Human Primary Fibroblasts Induced by Low-energy Protons and X/γ-rays
Cell Cycle Perturbations and Genotoxic Effects in Human Primary Fibroblasts Induced by Low-energy Protons and X/γ-rays
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DOI：
10.1269/jrr.09008
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发表时间：
2009-09-01
影响因子：
2
通讯作者：
Tanzarella, Caterina
中科院分区：
文献类型：
--
作者：
Antoccia, Antonio;Sgura, Antonella;Tanzarella, Caterina
在正常人成纤维细胞中，研究了梯度剂量高线性能量转移（LET）低能质子诱导周期扰动和基因毒性损伤的效果。此外，还将这种效应与低let辐射产生的效应进行了比较。HFFF2，人原代成纤维细胞暴露于质子（LET = 28.5 keV/mu m）或X/ γ射线，并分析了与细胞周期动力学和DNA损伤相关的终点。在两种类型的照射后，未同步的细胞在1-4 Gy剂量下受到抑制而无法进入s期，并在G(1)期停留数天。调节蛋白如TP53和CDKN1A的诱导水平显示出明显的let依赖性。通过对γ - h2ax焦点的评分测量DSB诱导和修复表明，相对于x射线，质子每Gy产生的DSB数量较低，其消失动力学较慢。这一结果与x照射后双核细胞中MN的诱导程度一致。用克隆实验观察两种类型的辐射之间没有显著差异，无论如何导致伽马射线曲线的斜率高于质子曲线。综上所述，在正常的人原代成纤维细胞中，细胞周期阻滞在G(1)/S转变可在照射后不久触发，并在质子和x射线照射后维持数小时。由质子产生的DNA损伤似乎不太容易修复，并可能以MN的形式转化为细胞遗传学损伤。
The effect of graded doses of high-linear energy transfer (LET) low-energy protons to induce cycle perturbations and genotoxic damage was investigated in normal human fibroblasts. Furthermore, such effects were compared with those produced by low-LET radiations. HFFF2, human primary fibroblasts were exposed to either protons (LET = 28.5 keV/mu m) or X/gamma-rays, and endpoints related to cell cycle kinetics and DNA damage analysed. Following both type of irradiations, unsynchronized cells suffered an inhibition to entry into S-phase for doses of 1-4 Gy and remained arrested in the G(1)-phase for several days. The levels of induction of regulator proteins, such as TP53 and CDKN1A showed a clear LET-dependence. DSB induction and repair as measured by scoring for gamma-H2AX foci indicated that protons, with respect to X-rays, yielded a lower number of DSBs per Gy, which showed a slower kinetics of disappearance. Such result was in agreement with the extent of MN induction in binucleated cells after X-irradiation. No significant differences between the two types of radiations were observed with the clonogenic assay, resulting anyway the slope of gamma-ray curve higher than that the proton one. In conclusion, in normal human primary fibroblasts cell cycle arrest at the G(1)/S transition can be triggered shortly after irradiation and maintained for several hours post-irradiation of both protons and X-rays. DNA damage produced by protons appears less amenable to be repaired and could be transformed in cytogenetic damage in the form of MN.