Mycotoxin Citrinin Induced Cell Cycle G2/M Arrest and Numerical Chromosomal Aberration Associated with Disruption of Microtubule Formation in Human Cells
Mycotoxin Citrinin Induced Cell Cycle G2/M Arrest and Numerical Chromosomal Aberration Associated with Disruption of Microtubule Formation in Human Cells
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DOI：
10.1093/toxsci/kfq309
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发表时间：
2011-01-01
影响因子：
3.8
通讯作者：
Liu, Biing-Hui
中科院分区：
文献类型：
--
作者：
Chang, Chia-Hao;Yu, Feng-Yih;Liu, Biing-Hui
桔霉素(CTN)是一种肾毒性真菌毒素，可污染多种食品和动物饲料。本研究以人胚胎肾(HEK293)细胞为模型，研究了CTN对细胞周期停滞和微管形成的影响。CTN可使HEK293细胞G2/M期停滞，并呈浓度依赖性增加。给予CTN后，P53和p21蛋白表达水平升高，而磷酸化细胞分裂周期2(CDC2)信号减弱。此外，用CTN处理HEK293细胞后，细胞分裂指数和抗体有丝分裂蛋白2识别的细胞数均增加，提示CTN诱导的细胞周期停滞主要发生在有丝分裂期。在α-微管蛋白免疫细胞染色的辅助下，CTN被发现在细胞周期间期破坏稳定的微管骨架，并在有丝分裂过程中干扰有丝分裂纺锤体的完整性。此外，无论是在体内还是体外实验中，CTN都以浓度依赖的方式有效地抑制微管蛋白聚合。人外周血单个核细胞暴露于CTN后，染色体数目改变的细胞百分率较赋形剂处理组增加4.3倍。这项研究的结果表明，CTN激活的G2/M期停滞主要是由于抑制了微管蛋白聚合和相关的有丝分裂纺锤体的形成。此外，CTN对微管组织的破坏也是诱发人类细胞染色体数目异常的原因之一。
As a nephrotoxic mycotoxin, citrinin (CTN) contaminates various foodstuffs and animal feed commodities. In the present study, the effects of CTN on cell cycle arrest and microtubule formation were investigated by applying human embryonic kidney (HEK293) cells as a model. Exposure of HEK293 cells to CTN resulted in an arrest of cell cycle G2/M in a concentration-dependent increase. Administrating CTN elevated the expression levels of p53 and p21 proteins, yet attenuated the signals of phosphorylated cell division cycle 2 (cdc2). Furthermore, treating HEK293 with CTN increased both the value of mitotic index and the population of cells recognized by antibody mitotic protein monoclonal 2, suggesting that arrest of CTN-induced cell cycle occurred mainly during the mitotic phase. With the assistance of immunocytostaining of alpha-tubulin, CTN was found to disrupt the stable microtubule skeleton during the interphase of cell cycle and also interfere with the mitotic spindle integrity during mitosis. Additionally, for either in vivo or in vitro assays, CTN effectively inhibited tubulin polymerization in a concentration-dependent manner. When human peripheral blood mononuclear cells were exposed to CTN, the percentage of cells with numerical chromosome changes was increased by 4.3-fold over that of vehicle-treated group. Results of this study suggest that CTN-activated G2/M arrest primarily arises from the inhibition of tubulin polymerization and associated mitotic spindle formation. Additionally, disruption of microtubule organization by CTN also contributes to the induction of numerical chromosome aberration in human cells.