Shogaols at proapoptotic concentrations induce G2/M arrest and aberrant mitotic cell death associated with tubulin aggregation
Shogaols at proapoptotic concentrations induce G2/M arrest and aberrant mitotic cell death associated with tubulin aggregation
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DOI：
10.1007/s10495-011-0611-3
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发表时间：
2011-08-01
期刊：
影响因子：
7.2
通讯作者：
Chew, Eng-Hui
中科院分区：
文献类型：
--
作者：
Gan, Fei-Fei;Nagle, Amrita A.;Chew, Eng-Hui
此前已报道姜烯酚通过多种机制诱导癌细胞死亡，其中一种类似物6-姜烯酚据报道可通过与微管蛋白中的巯基发生特异性反应而引起微管损伤。在本研究中，合成了一系列具有不同侧链长度的姜烯酚（4-、6-、8-和10-姜烯酚），并评估了 HCT 116 结肠癌和 SH-SY5Y 神经母细胞瘤细胞的抗增殖活性。 4-和6-姜烯酚被鉴定为具有最强抗增殖活性的先导化合物。在软琼脂测定中，先导姜烯酚在不依赖贴壁的条件下对癌细胞集落形成显示出剂量依赖性抑制作用。使用 HCT 116 作为选定的癌细胞系，研究了姜烯酚诱导的 G(2)/M 细胞周期停滞与以 caspase 3 和 PARP 裂解为特征的细胞凋亡之间的分子事件。在亚致死浓度下，G(2)/M 期的停滞随着时间的推移而减轻，细胞得以存活。相反，促凋亡浓度的4-和6-姜烯酚诱导不可逆的G(2)/M阻滞，这至少部分与细胞周期检查点蛋白cdk1、cyclin B和cdc25C以及纺锤体组装检查点蛋白mad2、cdc20和survivin的下调相关。细胞裂解物不溶性部分中不溶性微管蛋白的剂量和时间依赖性积累提供了G(2)检查点故障导致微管周转破坏的证据。总之，我们的结果得出结论，姜烯酚至少通过细胞周期和纺锤体组装检查点蛋白的减弱诱导异常有丝分裂，从而引起细胞凋亡。
Shogaols have been previously reported to induce cancer cell death via multiple mechanisms, among which one analog 6-shogaol has been reported to cause microtubule damage through specific reaction with sulfhydryl groups in tubulin. In this study, a series of shogaols with different side chain lengths (4-, 6-, 8- and 10-shogaol) was synthesized and evaluated for antiproliferative activity in HCT 116 colon carcinoma and SH-SY5Y neuroblastoma cells. 4- and 6-shogaol were identified as lead compounds possessing the strongest antiproliferative activity. In the soft agar assay, the lead shogaols displayed dose-dependent inhibition on cancer cell colony formation under anchorage-independent conditions. Using HCT 116 as the selected cancer cell line, the molecular events linking shogaols-induced G(2)/M cell cycle arrest to apoptosis characterized by caspase 3 and PARP cleavage were investigated. At sublethal concentrations, the halt at G(2)/M phase was alleviated along time and cells survived. Conversely, proapoptotic concentrations of 4- and 6-shogaol induced irreversible G(2)/M arrest that was at least in part associated with down-regulation of cell cycle checkpoint proteins cdk1, cyclin B and cdc25C, as well as spindle assembly checkpoint proteins mad2, cdc20 and survivin. A dose- and time-dependent accumulation of insoluble tubulin in the insoluble fractions of cell lysates provided evidence that G(2) checkpoint failure led to disruption of microtubule turnover. In summary, our results conclude that shogaols cause apoptosis by inducing aberrant mitosis at least through the attenuation of cell cycle and spindle assembly checkpoint proteins.