ABSTRACT

Differences in biological response of breast and lung cancer cells to 62 MeV/u therapeutic protons and carbon ions are investigated on MCF-7 and HTB177 cells. Hydroxyl radical scavenger, dimethyl sulfoxide (DMSO) is applied to reduce indirect effects of irradiation, while serum deprivation provided uniformity of cell population. Survival, immunocytochemical, and cell-cycle analysis, changes in protein expression involved in repair and apoptosis are followed. Radiobiological parameters, Bax/Bcl-2 ratio, and increased subG1 fraction show that carbon ions are more efficient in cellular killing than protons. No significant difference in the number of γH2AX foci are found between protons and carbon ions. According to SF2 values, MCF-7 cells are more radioresistant to both ion species compared to HTB177 cells. Cell-cycle analysis and expression of relevant protein markers further confirm somewhat higher radiosensitivity of HTB177 cells compared to MCF-7. DMSO leads to the rise of cell survival and decreases the number of γH2AX foci. Even though there are no significant changes in the number of γH2AX foci after used irradiation types, lesions induced by carbon ions are probably more complex than those produced by protons. DMSO minimizes indirect DNA damage to achieve experimental conditions needed for comparisons of obtained results with numerical simulations.

摘要

在MCF-7和HTB177细胞上研究了乳腺癌和肺癌细胞对62 MeV / u治疗性质子和碳离子的生物学反应差异。羟基自由基清除剂二甲基亚砜（DMSO）用于减少辐射的间接影响，而血清剥夺则可提供均匀的细胞群。进行存活，免疫细胞化学和细胞周期分析，追踪参与修复和凋亡的蛋白质表达的变化。放射生物学参数，Bax / Bcl-2比和增加的subG1分数表明，碳离子比质子更有效地杀死细胞。质子和碳离子之间的γH2AX焦点数量没有显着差异。根据SF2值，与HTB177细胞相比，MCF-7细胞对这两种离子的辐射耐受性更高。细胞周期分析和相关蛋白质标志物的表达进一步证实，与MCF-7相比，HTB177细胞具有更高的放射敏感性。DMSO导致细胞存活率上升，并减少γH2AX灶的数量。即使使用过的辐射类型后γH2AX病灶的数量没有明显变化，但碳离子诱导的损伤可能比质子产生的损伤更为复杂。DMSO可以最大程度地减少间接DNA损伤，从而达到将获得的结果与数值模拟进行比较所需的实验条件。由碳离子引起的损伤可能比由质子产生的损伤更为复杂。DMSO可以最大程度地减少间接DNA损伤，从而达到将获得的结果与数值模拟进行比较所需的实验条件。由碳离子引起的损伤可能比由质子产生的损伤更为复杂。DMSO可以最大程度地减少间接DNA损伤，从而达到将获得的结果与数值模拟进行比较所需的实验条件。