VTT Technical Research Centre of Finland, Medical Biotechnology, P.O. Box 106, Turku, Finland.
Exp Cell Res. 2012 Mar 10;318(5):578-92. doi: 10.1016/j.yexcr.2011.12.014. Epub 2011 Dec 29.
The spindle assembly checkpoint (SAC) is a conserved mechanism that ensures the fidelity of chromosome distribution in mitosis by preventing anaphase onset until the correct bipolar microtubule-kinetochore attachments are formed. Errors in SAC function may contribute to tumorigenesis by inducing numerical chromosome anomalies (aneuploidy). On the other hand, total disruption of SAC can lead to massive genomic imbalance followed by cell death, a phenomena that has therapeutic potency. We performed a cell-based high-throughput screen with a compound library of 2000 bioactives for novel SAC inhibitors and discovered a plant-derived phenolic compound eupatorin (3',5-dihydroxy-4',6,7-trimethoxyflavone) as an anti-mitotic flavonoid. The premature override of the microtubule drug-imposed mitotic arrest by eupatorin is dependent on microtubule-kinetochore attachments but not interkinetochore tension. Aurora B kinase activity, which is essential for maintenance of normal SAC signaling, is diminished by eupatorin in cells and in vitro providing a mechanistic explanation for the observed forced mitotic exit. Eupatorin likely has additional targets since eupatorin treatment of pre-mitotic cells causes spindle anomalies triggering a transient M phase delay followed by impaired cytokinesis and polyploidy. Finally, eupatorin potently induces apoptosis in multiple cancer cell lines and suppresses cancer cell proliferation in organotypic 3D cell culture model.
纺锤体组装检查点（SAC）是一种保守的机制，通过防止后期起始直到形成正确的双极微管-动粒附着，确保有丝分裂中染色体分配的保真度。SAC 功能的错误可能通过诱导数字染色体异常（非整倍体）导致肿瘤发生。另一方面，SAC 的完全破坏会导致大量基因组失衡，随后细胞死亡，这种现象具有治疗潜力。我们使用 2000 种生物活性化合物的化合物文库进行了基于细胞的高通量筛选，以寻找新型 SAC 抑制剂，并发现一种植物衍生的酚类化合物 eupatorin（3'，5-二羟基-4'，6，7-三甲氧基黄酮）作为一种抗有丝分裂的类黄酮。Eupatorin 对微管药物引起的有丝分裂阻滞的过早覆盖取决于微管-动粒附着，而不取决于动粒间张力。Aurora B 激酶活性对于维持正常 SAC 信号至关重要，eupatorin 在细胞中和体外都会降低其活性，为观察到的强制有丝分裂退出提供了机制解释。Eupatorin 可能还有其他靶点，因为 eupatorin 处理有丝分裂前期细胞会导致纺锤体异常，引发短暂的 M 期延迟，随后细胞分裂和多倍体受损。最后，eupatorin 能有效诱导多种癌细胞系凋亡，并抑制器官型 3D 细胞培养模型中的癌细胞增殖。
