p55CDC/hCDC20 mutant induces mitotic catastrophe by inhibiting the MAD2-dependent spindle checkpoint activity in tumor cells
p55CDC/hCDC20 mutant induces mitotic catastrophe by inhibiting the MAD2-dependent spindle checkpoint activity in tumor cells
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DOI：
10.1016/s0304-3835(03)00465-8
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发表时间：
2003-11-25
期刊：
影响因子：
9.7
通讯作者：
Kima, SH
中科院分区：
文献类型：
--
作者：
Sihn, CR;Suh, EJ;Kima, SH
染色体的不分离导致哺乳动物细胞的非整倍体，导致基因组的不稳定。纺锤体检查点是维持基因组稳定性的监测系统之一，它防止染色体的错误分离，直到所有的动粒都与两极纺锤体正确连接。当不满足这一条件时，纺锤体检查点复合体的一个成分MAD2与p55CDC/hCDC20结合，以抑制后期促进复合体(APC)对底物的泛素化。在这项研究中，我们重点研究了p55CDC/hCDC20中MAD2结合域在维持基因组稳定性中的生物学作用。在前人研究的基础上，我们构建了一个截短的p55CDC/hCDC20突变体(172)，它只含有MAD2结合结构域。有趣的是，我们发现在酵母双杂交系统中，F2和MAD2的相互作用强于完整的p55CDC/hCDC20。我们还发现，在微管干扰药物诺康唑的存在下，表达p55CDC/hCDC20突变体的U2OS细胞绕过了有丝分裂停滞，并呈现出凋亡的形态，而单独携带载体的细胞则停滞在中期。特别是，在表达F2的细胞中，细胞的凋亡现象显著增强。这些有丝分裂灾难也发生在用其他微管干扰剂处理的细胞中，如紫杉醇和长春花碱。此外，突变细胞在有丝分裂过程中表现出染色体的错误分离，即使在没有诺康唑的情况下也是如此。综上所述，这些结果表明，阻断纺锤体检查点反应的药物可能会诱导肿瘤细胞对纺锤体毒药变得更加敏感，从而为改进化疗提供了一个强有力的工具。(C)2003爱思唯尔爱尔兰有限公司。保留所有权利。
Nondisjunction of chromosomes results in aneuploidy in mammalian cells causing genomic instability. The spindle checkpoint, one of the surveillance systems to maintain genomic stability, prevents missegregation of chromosomes until all the kinetochores are properly attached with bipolar spindles. When this condition is not met, MAD2, a component of the spindle checkpoint complex, associates with p55CDC/hCDC20 to inhibit ubiquitination of substrates by the anaphase-promoting complex (APC). In this study, we have focused on the biological role of the MAD2-binding domain in p55CDC/hCDC20 in the maintenance of genomic stability. Based on previous studies, we constructed a truncated p55CDC/hCDC20 mutant (172) that harbors only the MAD2-binding domain. Interestingly, we found that in the yeast two-hybrid system, the interaction of F2 and MAD2 was stronger than that of intact p55CDC/hCDC20. We also found that in the presence of the microtubule-disrupting drug, nocodazole, U2OS cells expressing p55CDC/hCDC20 mutants bypassed the mitotic arrest and showed apoptotic morphologies, whereas cells harboring vector alone arrested at metaphase. In particular, the apoptotic phenomena were dramatically enhanced in the F2-expressing cells. These mitotic catastrophes also occurred in cells treated with other microtubule disrupting agents, such as taxol and vinblastine. In addition, the mutant cells exhibited chromosomal missegregation during mitosis, even in the absence of nocodazole. Taken together, these results suggest that agents blocking the spindle checkpoint response may induce tumor cells to become more sensitive to spindle poison drugs, providing a powerful tool to improve chemotherapy. (C) 2003 Elsevier Ireland Ltd. All rights reserved.