Cathepsin L suppression increases the radiosensitivity of human glioma U251 cells via G2/M cell cycle arrest and DNA damage
Cathepsin L suppression increases the radiosensitivity of human glioma U251 cells via G2/M cell cycle arrest and DNA damage
复制标题
组织蛋白酶 L 抑制通过 G(2)/M 细胞周期停滞和 DNA 损伤增加人胶质瘤 U251 细胞的放射敏感性
DOI：
10.1038/aps.2015.36
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发表时间：
2015-09-01
影响因子：
8.2
通讯作者：
Liang, Zhong-qin
中科院分区：
文献类型：
--
作者：
Zhang, Qing-qing;Wang, Wen-juan;Liang, Zhong-qin
目的：组织蛋白酶L是一种溶酶体半胱氨酸蛋白酶，在肿瘤的发生、增殖和化疗耐药中起重要作用。本研究旨在探讨组织蛋白酶L（cathepsin L）在体外对人脑胶质瘤细胞放射敏感性的调节作用。方法：用X射线照射人脑胶质瘤U251细胞（携带突变型p53基因）和U87细胞（携带野生型p53基因）。用Western blot和免疫荧光法检测组织蛋白酶L的表达。分别使用克隆形成和彗星试验评价细胞存活和DNA损伤。流式细胞仪检测细胞周期分布。结果：照射后U251细胞胞浆和胞核内组织蛋白酶L的表达明显增加，而U87细胞胞浆和胞核内组织蛋白酶L的表达无明显变化。用组织蛋白酶L特异性抑制剂Z-FY-CHO（10 μ mol/L）处理或转染组织蛋白酶L shRNA可显著增加U251细胞的放射敏感性。抑制和敲低U251细胞中的组织蛋白酶L均增加辐射诱导的DNA损伤和G2/M期细胞周期阻滞。抑制或敲低U251细胞中的组织蛋白酶L也可增加放射诱导的凋亡，表现为Bax水平升高和Bcl-2水平降低。结论：组织蛋白酶L参与了体外人胶质瘤U251细胞（携带突变型p53基因）放射敏感性的调节。
Aim: Cathepsin L is a lysosomal cysteine protease that plays important roles in cancer tumorigenesis, proliferation and chemotherapy resistance. The aim of this study was to determine how cathepsin L regulated the radiosensitivity of human glioma cells in vitro.Methods: Human glioma U251 cells (harboring the mutant type p53 gene) and U87 cells (harboring the wide type p53 gene) were irradiated with X-rays. The expression of cathepsin L was analyzed using Western blot and immunofluorescence assays. Cell survival and DNA damage were evaluated using clonogenic and comet assays, respectively. Flow cytometry was used to detect the cell cycle distribution. Apoptotic cells were observed using Hoechst 33258 staining and fluorescence microscopy.Results: Irradiation significantly increased the cytoplasmic and nuclear levels of cathepsin L in U251 cells but not in U87 cells. Treatment with the specific cathepsin L inhibitor Z-FY-CHO (10 mu mol/L) or transfection with cathepsin L shRNA significantly increased the radiosensitivity of U251 cells. Both suppression and knockdown of cathepsin L in U251 cells increased irradiation-induced DNA damage and G2/M phase cell cycle arrest. Both suppression and knockdown of cathepsin L in U251 cells also increased irradiation-induced apoptosis, as shown by the increased levels of Bax and decreased levels of Bcl-2.Conclusion: Cathepsin L is involved in modulation of radiosensitivity in human glioma U251 cells (harboring the mutant type p53 gene) in vitro.