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目的探讨姜黄素对放射诱导产生的鼻咽癌抗拒株CNE-2R的放射增敏作用及其机制。方法通过MTT实验筛选姜黄素的最佳浓度;对克隆生存实验结果进行L-Q拟合和单机多靶拟合,计算相关放射生物学参数;再通过流式细胞术检测细胞周期的改变;最后通过RT-qPCR实验检测细胞周期及DNA损伤修复相关基因的表达情况。结果浓度在10μmol·L~(-1)的姜黄素对CNE-2R细胞无明显抑制作用。给药后抗拒株CNE-2R的α/β值从6.56增加到1 596;SF2从1.93 Gy减少到0.361 Gy;N值从1.60减少到1.06;D0值从3.27减少到2.12;Dq值从1.53减少到0.12。细胞周期G2期明显增多,G1期稍微减少,S期明显减少。CDK4基因的表达明显上调,GADD45 g、BRCA1基因的表达明显下调。结论姜黄素通过调控GADD45 g、CDK4、BRCA1基因的表达,改变CNE-2R的细胞周期和影响DNA损伤修复,发生G2期阻滞,从而增加了抗拒株的放射敏感性。
Objective To investigate the radiosensitization effect of curcumin on CNE-2R induced by radiation and its mechanism. Methods The optimal concentrations of curcumin were screened by MTT assay. The results of clonal survival experiments were fitted by LQ fitting and single multi-target fitting, and the relevant radiobiological parameters were calculated. The changes of cell cycle were detected by flow cytometry. Finally, -qPCR assay was used to detect the expression of cell cycle and DNA damage related genes. Results Curcumin at the concentration of 10μmol·L -1 had no obvious inhibitory effect on CNE-2R cells. The α / β value of CNE-2R increased from 6.56 to 1 596 after administration; the SF2 decreased from 1.93 Gy to 0.361 Gy; the N value decreased from 1.60 to 1.06; the D0 value decreased from 3.27 to 2.12; the Dq value decreased from 1.53 To 0.12. Cell cycle G2 increased significantly, G1 decreased slightly, S decreased significantly. CDK4 gene expression was significantly increased, GADD45 g, BRCA1 gene expression was significantly down-regulated. Conclusion Curcumin increases the radiosensitivity of resistant plants by regulating the expression of GADD45 g, CDK4 and BRCA1, changing the cell cycle of CNE-2R and affecting the DNA damage repair, resulting in G2 arrest.