丙戊酸对乳腺癌细胞放射敏感性的影响  

Effect of valproic acid on radiosensitivity to breast cancer cells

作　　者：赵锡鹏[1] 罗月[1] 董超[1] 张凤梅[1] 凤志慧[1] 

机构地区：[1]山东大学公共卫生学院环境与健康系,山东济南250012

出　　处：《中国药理学与毒理学杂志》2015年第2期247-252,共6页Chinese Journal of Pharmacology and Toxicology

基　　金：国家自然科学基金(81172527);国家自然科学基金项目(81472800);山东省科技发展计划(2013GGE27052)~~

摘　　要：目的探讨丙戊酸(VPA)对乳腺癌细胞MCF7放射敏感性的影响。方法 MCF7细胞用VPA临床安全剂量0.5 mmol·L-1和临界剂量1 mmol·L-1分别预处理0,24,48和72 h,8Gy电离辐射后6 h,免疫荧光染色法观察磷酸化组蛋白H2AX(γ-H2AX)焦点形成。对数生长期的MCF7细胞分别以VPA 0.5和1 mmol·L-1预处理72 h,4 Gy电离辐射后48 h,MTT法检测细胞存活率。MCF7细胞用VPA 0.5 mmol·L-1预处理24 h后,按照每皿接种细胞数分别给予电离辐射2 Gy(每皿500和1000),4 Gy(每皿2000和4000)和6 Gy(每皿8000和16000),计算克隆形成率。MCF7细胞分别用VPA 0.5和1 mmol·L-1预处理0,24,48和72 h,流式细胞仪检测细胞周期。结果与正常对照组相比,单独VPA 0.5 mmol·L-1处理0,24,48和72 h后,γ-H2AX焦点阳性率分别为(5.3±0.6)%,(10.8±1.0)%,(12.6±0.9)%和(17.8±1.1)%(r=0.985,P<0.05);VPA 1 mmol·L-1对γ-H2AX焦点形成有相同的影响趋势。单独照射组细胞核内γ-H2AX焦点阳性率为100%,其中表示DNA损伤较重的焦点较大且明亮的B类细胞所占比例为(16.5±1.8)%;与单独照射组相比,VPA 0.5 mmol·L-1预处理0,24,48和72 h后,B类细胞所占比例分别为(16.5±1.8)%,(28.9±1.0)%,(58.0±2.0)%和(70.8±0.9)%(r=0.986,P<0.05);VPA 1 mmol·L-1对辐射诱导的γ-H2AX焦点形成的影响有相同趋势。MTT和细胞克隆形成实验结果显示,与正常对照组相比,单独给予VPA0.5 mmol·L-1可显著降低细胞克隆形成率(P<0.05);与单独照射组相比,VPA预处理后接受电离辐射能显著降低细胞存活率(P<0.05)和细胞克隆形成率(P<0.05);VPA 0.5和1 mmol·L-1对细胞周期影响均无统计学差异。结论临床安全剂量和临界剂量VPA对肿瘤细胞具有放射增敏作用,且对肿瘤细胞生长具有抑制作用,其机制与增加电离辐射所致的DNA双链断裂损伤的蓄积有关。OBJECTIVE To study the effect of valproic acid （ VPA） on radiosensitivity to MCF7 breast cancer cells. METHODS MCF7 cells were pretreated with VPA 0.5 and 1 mmol.L-1 for 0, 24, 48 and 72 h respectively, irradiated with 8 Gy lR, and at 6 h post-lR, the γ-H2 AX foci formation in MCF7 cells was tested by immunofluorescence assay. MCF7 cells were pretreated with VPA 0.5 and 1 mmol.L-1 for 72 h, irradiated with 4 Gy lR, and at 48 h post-lR, the cell survival rate was detected by MTT assay. MCF7 cells were pretreated with VPA 0.5 mmol.L-1 for 24 h, and then irradiated according to the amount of cells： 2 Gy （500 and 1000 cells per plate）, 4 Gy （2000 and 4000 cells per plate）, 6 Gy （8000 and 16000 cells per plate）, and the cloning efficiency was calculated. MCF7 cells were pretreated with VPA 0.5 and 1 mmol.L-1 for 0, 24, 48 and 72 h respectively and the cell cycle profile was analyzed via flow cytometry. RESULTS After treatment with VPA alone for 24 h, MCF7 cells showed a significant increase in the amount of γ-H2 AX foci formation （ P 〈 0. 01）. lt was also found that VPA increased lR-induced γ-H2 AX foci formation, which obviously prolonged the pretreatment time of VPA（P〈0.01） in a time-dependent manner（r=0.98, P〈0.05）. VPA 0.5 and 1 mmol.L-1 had the same effect on γ-H2 AX foci formation. Furthermore, VPA was able to cause a significant decrease in lR-induced clonogenic survival but an increase in lR-induced cytotoxicity by MTT assay. Also, VPA alone decreased the plating efficiency of MCF7 cells. However, the cycle profile of MCF7 cells treated with both VPA 0.5 and 1 mmol.L-1 was not changed. CONCLUSION Without affecting the cell cycle profile, both the safe and critical dose of VPA used in clinical epilepsy treatment can significantly increase the accumulation of DNA double strand breaks in the cells and sensitize the cells to lR treatment, suggesting that VPA can induce radio-sensitization of breast cancer cells.

关 键 词：丙戊酸 乳腺癌 DNA损伤 放射增敏 细胞周期 

分 类 号：R96[医药卫生—药理学]