摘要
目的 观察Stattic对乏氧人食管癌ECA109细胞的体外放射增敏作用，并探讨其可能机制。方法 应用四甲基偶氮唑盐比色法（MTT）检测Stattic对食管癌ECA109细胞的毒性，细胞克隆形成法确定1.0 μmol Stattic对ECA细胞放疗敏感性的影响，流式细胞法检测细胞的凋亡率，γ-H2AX免疫荧光染色法检测不同时间点下ECA109细胞中双键断裂情况，Western blot检测Stattic照射前后STAT3、pSTAT3、HIF-1α、VEGF蛋白的表达。结果 Stattic对ECA109细胞具有毒性，24 h IC50为5.499 μmol/L，克隆形成实验通过单击多靶模型拟合细胞的存活曲线，计算出1.0 μmol/L Stattic的放射增敏比SERDo分别为1.20（常氧）和1.28（乏氧），γ-H2AX荧光染色提示Stattic能增加双键断裂情况，尤其是在照射之后0.5 h最为明显。照射联合给药组的乏氧细胞凋亡率较单独乏氧照射组的细胞凋亡增加（t=7.33，P 〈 0.05），Western blot显示乏氧食管癌细胞株pSTAT3、乏氧诱导因子1α（HIF-1α）、血管内皮生长因子（VEGF）蛋白的表达升高，Stattic作用24 h表达显著下调。结论 Stattic对乏氧人食管癌细胞株ECA109细胞的毒性呈剂量依赖性，放射增敏作用明显，随药物剂量的增加而增强，其机制可能与抑制pSTAT3、HIF-1α和VEGF蛋白表达有关。
Objective To investigate the radiosensitivity of ESCC by signal transducer and activator of transcription 3 （STAT3） inhibitor Stattic, since the radioresistance of esophageal squamous cell carcinoma（ESCC） remains an obstacle for the effective radiotherapy of ESCC. Methods ECA109 cell line was exposed to hypoxia and treated with Stattic or radiation, alone or in combination. Cell proliferation,colony formation, apoptosis, and double-stranded DNA breaks （DSBs） were examined. The levels of STAT3, pSTAT3, hypoxiainduciblefactor1α（HIF-1α）, and vascular endothelial growthfactor （VEGF） in ESCC cells were detected by Western blot. Results Stattic efficiently inhibited the proliferation of ECA109 cells in time-dependent and dose-dependent fashions with an IC50 of 5.499 μmol/ L. Clonogenic survival assay showed that stattic （1.0 μmol/L） sensitized ECA109 cells to ionizing radiation and its SERDo was 1.20（in normoxia） or 1.28（in hypoxia）. Under hypoxic condition, stattic combined with IR disrupted the repair of DSBs and increased the apoptosis（t=7.33,P 〈 0.05） in ESCC cells compared to that of radiation treatment alone. Moreover, Western blot assay showed that stattic inhibited STAT3 activation and downregulated the expression level of pSTAT3 and HIF-1α and VEGF. Conclusions Stattic confers radiosensitivity in ESCC cells in vitro and is a potential adjuvant for the radiotherapy of ESCC in the clinical setting.
出处
《中华放射医学与防护杂志》
CAS
CSCD
北大核心
2016年第7期491-495,共5页
Chinese Journal of Radiological Medicine and Protection
