重组人内皮抑素对肺鳞癌放射增敏作用的体外实验研究

目的 探讨国产重组人内皮抑素是否对肺鳞癌细胞系H-520具有放射增敏作用.方法 取指数生长期的人肺鳞癌细胞系H-520细胞,用成克隆实验检测内皮抑素的细胞毒性和各实验组的克隆形成能力,计算各组细胞存活分数,利用多靶单击模型拟合细胞存活曲线.流式细胞术检测细胞凋亡、细胞周期分布变化及活化的Caspase蛋白片段水平.结果 成克隆实验中内皮抑素联合照射组较照射组D0、Dq、D10、SF2值均低,放射增敏比为1.50(D0值之比).流式细胞术检测细胞凋亡示内皮抑素+照射组细胞凋亡率分别为22.38%±1.61%、35.01%±1.16%、46.83%±2.06%、64.08%±4.28%,照射组分别为4.27%±0.29%、14.3%±1.15%、28.49%±1.58%、54.79%±1.89%,两组凋亡率差异有统计学意义(t=19.17、17.79、25.64、3.44,P值均<0.05).内皮抑素可诱导H-520细胞G0+G1阻滞,而照射则诱导G2+M期阻滞.内皮抑素+照射组活化Caspase蛋白片段表达增加(62.7%±1.9%)较对照组(12.1%±0.1%)、内皮抑素组(54.6%±1.0%)和照射组(34.1%±1.2%)显著增高(t=46.69、6.55、22.54,P值均<0.05;).结论 内皮抑素可通过抑制H-520细胞牛长、促进凋亡、细胞周期重分布来达到放射增敏作用.

Radiosensitization of recombinant human endostatin in human lung squamous cancer cells in vitro

Objective To investigate the radiosensitising effect of recombinant human endostatin (endostar) on human lung squamous cancer cell line H-520 in vitro and its mechanism. Methods H-520 cells in exponential growing phase were treated with endostar alone, irradiation alone, or endostar plus irra-diation. Colony-forming assay was used to investigate the cytotoxicity and radiosensitising effects of endostar. Cell survival fractions of all groups were calculated and cell survival curves were fitted by single-hit multi-tar-get model. Cell apoptosis, cell cycle distribution and activated Caspase expression level were investigated by flow cytometry. Results The D0, Dq, D10 and SF2 values of combined treatment group were much lower than those of irradiation alone group. The sensitization enhancement ratio (SER) was 1.50 (ratio of D0 values). Endnstar induced H-520 cell apoptosis in a dose dependant manner. After administration of endostar, H-520 cell proliferation was inhibited, and cell apoptosis rate and apoptotic bodies were increased. After irradiation of 0 Gy, 2 Gy, 4 Gy and 8 Gy, the apoptosis rate of H-520 cells was 4.27% ±0.29%, 14.3% ±1.15%, 28.49% ± 1.58% and 54.79% ± 1.89% in the radiotherapy alone group, and 22.38% ± 1.61%, 35.01% ±1.16%, 46.83%±2.06% and 64.08%±4.28% in the combined treatment group, respective-ly. The difference between the two groups was significant (t = 19.17, 17.79, 25.64 and 3.44,all P < 0.05 ). Flow cytometric analysis showed that cell cycle distribution changed and G0 + G1 phase arrest oc-curred after endostar treatment, while irradiation induced G2 + M arrest. The expression level of activated Caspase in combination group (62.7% ±1.9% ) was higher compared to the control group ( 12.1%± 0. 1% ) , endostar alone group ( 54.6% ±1.0% ) and irradiation alone group ( 34.1%±1.2% ) ( t = 46.69, 6.55 and 22.54 ; all P < 0.05 ). Conclusion Endostar can enhance the radiosensitivity of H-520 ceils by inhibiting cell proliferation, promoting cell apoptosis and facilitating cell cycle redistribution.