Many human cancer cells contain more than two centrosomes, yet these cancer cells can form pseudo-bipolar spindles through the mechanism, called centrosome clustering, and survive, instead of committing lethal multipolar mitoses. Kinesin-14/HSET, a minus end-directed motor, plays a crucial role in centrosome clustering. Accordingly, HSET is deemed to be a promising chemotherapeutic target to selectively kill cancer cells. Recently, three HSET inhibitors (AZ82, CW069 and SR31527) have been reported, but their specificity and efficacy have not been evaluated rigorously. This downside partly stems from the lack of robust systems for the assessment of these drugs. Yeasts and filamentous fungi provide not only powerful models for basic and applied biology but also versatile tools for drug discovery and evaluation. Here we show that these three inhibitors on their own are cytotoxic to fission yeast, suggesting that they have off-targets in vivo except for kinesin-14. Nonetheless, intriguingly, AZ82 can neutralize otherwise toxic overproduced HSET; this includes a substantial reduction in the percentage of HSET-driven abnormal mitotic cells and partial suppression of its lethality. SR31527 also displays modest neutralizing activity, while we do not detect such activity in CW069. As an experimental proof-of-principle study, we have treated HSET-overproducing fission yeast cells with extracts prepared from various plant species and found activities that rescue HSET-driven lethality in those from Chamaecyparis pisifera and Toxicodendron trichocarpum. This methodology of protein overproduction in fission yeast, therefore, provides a convenient, functional assay system by which to screen for not only selective human kinesin-14 inhibitors but also those against other molecules of interest.

中文翻译：

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高产HSET / KIFC1的裂变酵母细胞为鉴定和评估人驱动蛋白14抑制剂提供了有用的工具。

许多人类癌细胞包含两个以上的中心体，但是这些癌细胞可以通过称为中心体聚类的机制形成伪双极纺锤体，并且可以生存，而不是致死致命的多极有丝分裂。Kinesin-14 / HSET，负向定向运动，在中心体簇中起关键作用。因此，HSET被认为是有选择地杀死癌细胞的有希望的化学治疗靶标。最近，已经报道了三种HSET抑制剂（AZ82，CW069和SR31527），但是尚未对其特异性和功效进行严格的评估。这种缺点部分是由于缺乏用于评估这些药物的强大系统。酵母和丝状真菌不仅为基础生物学和应用生物学提供了强大的模型，而且为药物发现和评估提供了多种工具。在这里，我们显示这三种抑制剂本身对裂变酵母具有细胞毒性，这表明除了驱动蛋白14之外，它们在体内的脱靶目标。有趣的是，AZ82可以中和原本有毒的过量生产的HSET。这包括显着降低HSET驱动的异常有丝分裂细胞的百分比，并部分抑制其杀伤力。SR31527还显示适度的中和活动，而我们在CW069中未检测到这种活动。作为一项实验性的原理验证研究，我们用从各种植物物种制备的提取物处理了过量生产HSET的裂变酵母细胞，并发现了可挽救Pisifera pisifera和Toxicodendron trichocarpum的HSET驱动的致死性的活性。因此，这种在裂变酵母中过量生产蛋白质的方法提供了一种方便的方法，