Dose and time dependent apoptotic response in a human melanoma cell line exposed to accelerated boron ions at four different LET
Dose and time dependent apoptotic response in a human melanoma cell line exposed to accelerated boron ions at four different LET
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DOI：
10.1080/09553000500141215
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发表时间：
2005-04-01
影响因子：
2.6
通讯作者：
Edgren, MR
中科院分区：
文献类型：
--
作者：
Meijer, AE;Jernberg, ARM;Edgren, MR
目的是研究并比较线性能量转移 (LET)、剂量和时间对暴露于加速光硼 (B-10) 离子和光子的人类黑色素瘤细胞系细胞凋亡的影响。细胞在体外暴露于剂量高达6 Gy的加速硼离子（40、80、125和160 eV nm(-1)）和高达12 Gy的光子（0.2 eV nm(-1)）。使用凋亡细胞和细胞体的形态学特征，在照射后最多 9 天测量细胞凋亡的诱导。同时，通过 DNA 流式细胞术监测细胞周期分布，并根据克隆细胞存活测定进行细胞存活。此外，还研究了使用脉冲场凝胶电泳 (PFGE) 诱导和修复 DNA 双链断裂 (DSB)。与所有研究时间点的光子相比，加速硼离子诱导细胞凋亡显着增加。在 1-5 小时，辐射诱导的凋亡细胞的百分比随着剂量和 LET 的增加而增加。在后来的时间点（24-216小时），细胞凋亡反应更加复杂，并且不以严格依赖LET的方式增加。早期有丝分裂前凋亡细胞在暴露于最高LET（160 eV nm(-1)）后24小时消失。在释放剂量、时间和 LET 依赖性 G2/M 积累后，观察到有丝分裂后凋亡反应。克隆形成能力的丧失与剂量和 LET 相关，未重新连接的 DSB 比例随着 LET 的增加而增加。尽管存在 LET 依赖性克隆细胞杀伤作用，但仍无法定量测量 LET 依赖性细胞凋亡反应。这是由于凋亡细胞出现和消失的时间过程不同所致。
The aim was to investigate and compare the influence of linear energy transfer ( LET), dose and time on the induction of apoptosis in a human melanoma cell line exposed to accelerated light boron (B-10) ions and photons. Cells were exposed in vitro to doses up to 6 Gy accelerated boron ions ( 40, 80, 125 and 160 eV nm(-1)) and up to 12 Gy photons (0.2 eV nm(-1)). The induction of apoptosis was measured up to 9 days after irradiation using morphological characterization of apoptotic cells and bodies. In parallel, measurements of cell-cycle distribution, monitored by DNA flow cytometry, and cell survival based on the clonogenic cell survival assay, were performed. In addition, the induction and repair of DNA double-strand breaks (DSB), using pulsed-field gel electrophoresis (PFGE) were studied. Accelerated boron ions induced a significant increase in apoptosis as compared with photons at all time points studied. At 1 - 5 h the percentage of radiation-induced apoptotic cells increased with both dose and LET. At the later time points ( 24 - 216 h) the apoptotic response was more complex and did not increase in a strictly LET-dependent manner. The early premitotic apoptotic cells disappeared at 24 h following exposure to the highest LET (160 eV nm(-1)). A postmitotic apoptotic response was seen after release of the dose-, time- and LET-dependent G2/M accumulations. The loss of clonogenic ability was dose- and LET-dependent and the fraction of unrejoined DSB increased with increasing LET. Despite the LET-dependent clonogenic cell killing, it was not possible to measure quantitatively a LET-dependent apoptotic response. This was due to the different time course of appearance and disappearance of apoptotic cells.