DEPLETION OF SECURIN INDUCES SENESCENCE AFTER IRRADIATION AND ENHANCES RADIOSENSITIVITY IN HUMAN CANCER CELLS REGARDLESS OF FUNCTIONAL p53 EXPRESSION
DEPLETION OF SECURIN INDUCES SENESCENCE AFTER IRRADIATION AND ENHANCES RADIOSENSITIVITY IN HUMAN CANCER CELLS REGARDLESS OF FUNCTIONAL p53 EXPRESSION
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DOI：
10.1016/j.ijrobp.2009.12.013
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发表时间：
2010-06-01
影响因子：
7
通讯作者：
Chiu, Shu-Jun
中科院分区：
文献类型：
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作者：
Chen, Wen-Shu;Yu, Yi-Chu;Chiu, Shu-Jun
目的：放射治疗是肿瘤治疗的最佳选择之一。然而，各种肿瘤细胞表现出对辐射诱导的凋亡的抗性。因此，除了细胞凋亡外，开发新的策略来触发癌细胞死亡是必要的。本研究探讨了securin在辐射诱导的人癌细胞凋亡和衰老中的作用。Western印迹分析用于分析securin、半胱天冬酶-3、PARP、p53、p21、Rb、γ-H2 AX和磷酸化-Chk 2的水平。使用β-半乳糖苷酶染色测定分析衰老细胞。将securin表达载体（pcDNA-securin）稳定转染到securin缺失的HCT 116细胞中。结果：照射可诱导securin野生型HCT 116细胞凋亡，而securin缺失型HCT 116细胞衰老。securin的恢复减少衰老和增加照射后securin无效的HCT 116细胞的细胞存活。辐射诱导的γ-H2 AX和Chk 2磷酸化在securin野生型细胞中瞬时诱导，但在securin无效细胞中表现出持续的激活。Securin基因敲低开关辐射诱导的凋亡衰老的HCT 116 p53-null和MDA-MB-231 cells.Conclusions：我们的研究结果表明，securin的表达水平起着决定性的作用，在辐射敏感性和细胞的命运。securin的耗尽损害辐射后的DNA修复，增加DNA损伤，促进残留的存活细胞的衰老，而不管功能性p53的表达。敲低securin可能有助于一种新的放射治疗方案，用于治疗对辐射有抵抗力的人类癌细胞。(C)2010年爱思唯尔公司
Purpose: Radiotherapy is one of the best choices for cancer treatment. However, various tumor cells exhibit resistance to irradiation-induced apoptosis. The development of new strategies to trigger cancer cell death besides apoptosis is necessary. This study investigated the role of securin in radiation-induced apoptosis and senescence in human cancer cells.Methods and Materials: Cell survival was determined using clonogenic assays. Western blot analysis was used to analyze levels of securin, caspase-3, PARP, p53, p21, Rb, gamma-H2AX, and phospho-Chk2. Senescent cells were analyzed using a beta-galactosidase staining assay. A securin-expressed vector (pcDNA-securin) was stably transfected into securin-null HCT116 cells. Securin gene knockdown was performed by small interfering RNA and small hairpin RNA in HCT116 and MDA-MB-231 cells, respectively.Results: Radiation was found to induce apoptosis in securin wild type HCT116 cells but induced senescence in securin-null cells. Restoration of securin reduced senescence and increased cell survival in securin-null HCT116 cells after irradiation. Radiation-induced gamma-H2AX and Chk2 phosphorylation were induced transiently in securin-wild-type cells but exhibited sustained activation in securin-null cells. Securin gene knockdown switches irradiation-induced apoptosis to senescence in both HCT116 p53-null and MDA-MB-231 cells.Conclusions: Our results demonstrated that the level of securin expression plays a determining role in the radiosensitivity and fate of cells. Depletion of securin impairs DNA repair after irradiation, increasing DNA damage and promoting senescence in the residual surviving cells regardless of functional p53 expression. The knockdown of securin may contribute to a novel radiotherapy protocol for the treatment of human cancer cells that are resistant to irradiation. (C) 2010 Elsevier Inc.