Microtubules are critical for a variety of cellular processes such as chromosome segregation, intracellular transport and cell shape. Drugs against microtubules have been widely used in cancer chemotherapies, though the acquisition of drug resistance has been a significant issue for their use. To identify novel small molecules that inhibit microtubule organization, we conducted sequential phenotypic screening of fission yeast and human cells. From a library of diverse 10 371 chemicals, we identified 11 compounds that inhibit proper mitotic progression both in fission yeast and in HeLa cells. An in vitro assay revealed that five of these compounds are strong inhibitors of tubulin polymerization. These compounds directly bind tubulin and destabilize the structures of tubulin dimers. We showed that one of the compounds, L1, binds to the colchicine-binding site of microtubules and exhibits a preferential potency against a panel of human breast cancer cell lines compared with a control non-cancer cell line. In addition, L1 overcomes cellular drug resistance mediated by βIII tubulin overexpression and has a strong synergistic effect when combined with the Plk1 inhibitor BI2536. Thus, we have established an economically effective drug screening strategy to target mitosis and microtubules, and have identified a candidate compound for cancer chemotherapy.

微管对于多种细胞过程至关重要，例如染色体分离、细胞内运输和细胞形状。针对微管的药物已广泛用于癌症化疗，尽管获得耐药性一直是其使用的一个重要问题。为了鉴定抑制微管组织的新型小分子，我们对裂殖酵母和人类细胞进行了顺序表型筛选。从包含 10 371 种不同化学物质的文库中，我们鉴定了 11 种化合物，它们可以抑制裂殖酵母和 HeLa 细胞中的正常有丝分裂进程。体外_化验表明，这些化合物中有五种是微管蛋白聚合的强抑制剂。这些化合物直接结合微管蛋白并破坏微管蛋白二聚体的结构。我们发现其中一种化合物 L1 与微管的秋水仙碱结合位点结合，并且与对照非癌细胞系相比，对一组人乳腺癌细胞系表现出优先效力。此外，L1 克服了 βIII 微管蛋白过表达介导的细胞耐药性，与 Plk1 抑制剂 BI2536 联合使用时具有很强的协同作用。因此，我们已经建立了一种经济有效的药物筛选策略来靶向有丝分裂和微管，并且已经确定了用于癌症化学疗法的候选化合物。