二氯醋酸钠提高胶质母细胞瘤U251细胞的放疗敏感性

目的:探讨二氯醋酸钠(sodium dichloroacetate acid,DCA)预处理对胶质母细胞瘤U251细胞的放疗敏感性的影响,并研究其可能机制。方法:将U251细胞随机分4个实验组:空白对照(control)组、DCA组、高能X射线照射未经DCA预处理组(IR组)和高能X射线照射经DCA预处理组(DIR组)。用MTT法检测细胞的存活率,DHE染色检测细胞内活性氧簇(reactive oxygen species,ROS)水平,Western blot检测细胞内Bcl-2的表达变化,流式细胞术检测凋亡细胞百分比。结果:DCA组和control组相比细胞存活率无明显改变,IR组和DIR组较control组细胞存活率明显降低(P0.05),并且DIR组细胞存活率较IR组明显降低(P0.05);DIR组ROS阳性细胞百分数较IR组明显升高(P0.05);DIR组细胞内Bcl-2表达水平较IR组明显降低(P0.05)。DIR组凋亡细胞百分比较IR组明显升高(P0.05)。结论:DCA预处理提高了U251细胞对放疗的敏感性,取得了更好的抗肿瘤作用,具体机制可能与提高细胞内ROS含量从而降低Bcl-2蛋白的表达有关。

Sodium dichloroacetate improves radiosensitivity of U251 cells

AIM: To study the change of radiosensitivity of U251 cells after treated with sodium dichloroacetate (DCA) and further to explore the possible mechanism.METHODS: The U251 cells were divided into 4 groups: control group, DCA group, X-ray irradiation without DCA pretreatment (IR) group and X-ray irradiation with DCA pretreatment (DIR) group. MTT assay was applied to determine the cell viability. The intracellular reactive oxygen species (ROS) were detected by DHE fluorescence. The expression level of Bcl-2 was assessed by Western blot. The percentage of apoptosis of cells was determined by flow cytometry. RESULTS: No difference between control group and DCA group in cell viability (P>0.05) was observed. However, the cell viability of both IR group and DIR group was markedly reduced compared with control group (P<0.05). Furthermore, the viability of DIR group was significantly decreased compared with IR group (P<0.05). The percentage of ROS positive cells was obviously increased in DIR group compared with IR group (P<0.05). The expression level of Bcl-2 was sharply decreased in DIR group (P<0.05) and the percentage of apoptosis of cells was significantly elevated (P<0.05) in DIR group compared with IR group.CONCLUSION: The better antitumor effect was obtained by improving the radiosensitivity through pretreating the cells with DCA, and the possible mechanism was down-regulation of the Bcl-2 expression by developing the intracellular ROS.