[癌症干细胞在喉鳞状细胞癌对缺氧介导的辐射抗性中起重要作用]

[Cancer stem cells play an important role in resistance of laryngeal squamous cancer to irradiation mediated by hypoxia].

作者信息

Wang Mao-xin, Li Xiao-ming, Zhao Yong, Lu Xiu-ying, Qu Yong-tao, Xu Ou, Sun Qing-jia

机构信息

Department of Otorhinolaryngology, Head and Neck Surgery, Chinese People Liberation Army General Hospital, Beijing, China.

出版信息

Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi. 2011 Dec;46(12):1024-9.

PMID:22336015

Abstract

OBJECTIVE

To study whether laryngeal cancer stem cells in hypoxia have the characteristic of resistance to irradiation and underlying mechanism.

METHODS

CD133(+) cells were separated from Hep-2 cells with flow cytometry (FCM) and the purity was 92.8%. The separated CD133(+) cells were cultured in serum-free medium in hypoxia in normoxia environment respectively, and hypoxia-inducible factor 1 alpha (HIF-1α) expression was detected by FCM. The cells were exposed respectively to X-rays emitted by linear accelerator with a dose of 0, 5, 10, 15 or 20 Gy for 24 hours, with additional time points of 12, 36, and 48 hours for the cells exposed to 10 Gy. Then the growth inhibition ratios of cells in hypoxia and normoxia groups were detected with MTT assay at different time points. Soft agar colony formation assay was used to detect colony formation ratios of cells in hypoxia and normoxia groups. DNA dependent protein kinase catalytic subunit (DNA-PKcs), ataxia telangiectasia mutate (ATM), Survivin and P53 were detected by FCM.

RESULTS

Growth inhibition ratio of CD133(+) cells in hypoxia group was lower than that in normoxia group (P < 0.05). Colony formation ratio of CD133(+) cells was higher than that of CD133(-) cells (P < 0.01) and the ratio of CD133(+) cells in hypoxia group was higher than that in normoxia group (P < 0.05). The ratio of hypoxia group was not affected by irradiation, while the ratio of normoxia group decreased significantly after irradiation (P < 0.05). The expressions of DNA-PKcs, ATM, Survivin and P53 in CD133(+) cells were higher than those in CD133(-) cells respectively (P < 0.01). In CD133(+) cells with radiation, the expressions of DNA-PKcs and Survivin of hypoxia group were higher those of normoxia group (P < 0.05), but no difference in the expression of ATM or P53 between the two groups.

CONCLUSIONS

Laryngeal cancer stem cells play an important role in radioresistance mediated by hypoxia.

摘要

目的

研究低氧环境下喉癌干细胞是否具有抗辐射特性及其潜在机制。

方法

采用流式细胞术从Hep-2细胞中分离出CD133(+)细胞，纯度为92.8%。将分离出的CD133(+)细胞分别在低氧和常氧环境的无血清培养基中培养，采用流式细胞术检测低氧诱导因子1α（HIF-1α）表达。细胞分别接受直线加速器发射的0、5、10、15或20 Gy X射线照射24小时，接受10 Gy照射的细胞另加12、36和48小时时间点。然后在不同时间点采用MTT法检测低氧组和常氧组细胞的生长抑制率。采用软琼脂集落形成试验检测低氧组和常氧组细胞的集落形成率。采用流式细胞术检测DNA依赖蛋白激酶催化亚基（DNA-PKcs）﹑共济失调毛细血管扩张突变基因（ATM）、生存素（Survivin）和P53。

结果

低氧组CD133(+)细胞的生长抑制率低于常氧组（P < 0.05）。CD133(+)细胞的集落形成率高于CD133(-)细胞（P < 0.01），且低氧组CD133(+)细胞的集落形成率高于常氧组（P < 0.05）。低氧组的集落形成率不受照射影响，而常氧组照射后集落形成率显著降低（P < 0.05）。CD133(+)细胞中DNA-PKcs、ATM、Survivin和P53的表达分别高于CD133(-)细胞（P < 0.01）。在接受辐射的CD133(+)细胞中，低氧组DNA-PKcs和Survivin的表达高于常氧组（P < 0.05），但两组间ATM或P53的表达无差异。