Smith John C, Husted Stefan, Pilrose Jay, Ems-McClung Stephanie C, Stout Jane R, Carpenter Richard L, Walczak Claire E
bioRxiv. 2023 Jun 1:2023.05.31.543118. doi: 10.1101/2023.05.31.543118.
Standard of care for triple negative breast cancer (TNBC) involves the use of microtubule poisons like paclitaxel, which are proposed to work by inducing lethal levels of aneuploidy in tumor cells. While these drugs are initially effective in treating cancer, dose-limiting peripheral neuropathies are common. Unfortunately, patients often relapse with drug resistant tumors. Identifying agents against targets that limit aneuploidy may be a valuable approach for therapeutic development. One potential target is the microtubule depolymerizing kinesin, MCAK, which limits aneuploidy by regulating microtubule dynamics during mitosis. Using publicly available datasets, we found that MCAK is upregulated in triple negative breast cancer and is associated with poorer prognoses. Knockdown of MCAK in tumor-derived cell lines caused a two- to five-fold reduction in the IC for paclitaxel, without affecting normal cells. Using FRET and image-based assays, we screened compounds from the ChemBridge 50k library and discovered three putative MCAK inhibitors. These compounds reproduced the aneuploidy-inducing phenotype of MCAK loss, reduced clonogenic survival of TNBC cells regardless of taxane-resistance, and the most potent of the three, C4, sensitized TNBC cells to paclitaxel. Collectively, our work shows promise that MCAK may serve as both a biomarker of prognosis and as a therapeutic target.
Triple negative breast cancer (TNBC) is the most lethal breast cancer subtype with few treatment options available. Standard of care for TNBC involves the use of taxanes, which are initially effective, but dose limiting toxicities are common, and patients often relapse with resistant tumors. Specific drugs that produce taxane-like effects may be able to improve patient quality of life and prognosis. In this study we identify three novel inhibitors of the Kinesin-13 MCAK. MCAK inhibition induces aneuploidy; similar to cells treated with taxanes. We demonstrate that MCAK is upregulated in TNBC and is associated with poorer prognoses. These MCAK inhibitors reduce the clonogenic survival of TNBC cells, and the most potent of the three inhibitors, C4, sensitizes TNBC cells to taxanes, similar to the effects of MCAK knockdown. This work will expand the field of precision medicine to include aneuploidy-inducing drugs that have the potential to improve patient outcomes.
三阴性乳腺癌（TNBC）的标准治疗方法包括使用微管毒物，如紫杉醇，据推测其作用机制是在肿瘤细胞中诱导致死水平的非整倍体。虽然这些药物最初对治疗癌症有效，但剂量限制性外周神经病变很常见。不幸的是，患者常因耐药肿瘤而复发。识别针对限制非整倍体的靶点的药物可能是治疗开发的一种有价值的方法。一个潜在的靶点是微管解聚驱动蛋白MCAK，它通过在有丝分裂期间调节微管动力学来限制非整倍体。利用公开可用的数据集，我们发现MCAK在三阴性乳腺癌中上调，且与较差的预后相关。在肿瘤衍生细胞系中敲低MCAK导致紫杉醇的半数抑制浓度（IC）降低两到五倍，而不影响正常细胞。使用荧光共振能量转移（FRET）和基于图像的分析方法，我们从ChemBridge 50k文库中筛选化合物，发现了三种假定的MCAK抑制剂。这些化合物重现了MCAK缺失导致的非整倍体诱导表型，降低了三阴性乳腺癌细胞的克隆形成存活率，无论其对紫杉烷是否耐药，且三种化合物中最有效的C4使三阴性乳腺癌细胞对紫杉醇敏感。总的来说，我们的研究表明MCAK有望作为预后生物标志物和治疗靶点。
三阴性乳腺癌（TNBC）是最致命的乳腺癌亚型，可用的治疗选择很少。TNBC的标准治疗方法包括使用紫杉烷，这些药物最初有效，但剂量限制性毒性很常见，且患者常因耐药肿瘤而复发。产生类似紫杉烷作用的特定药物可能能够改善患者的生活质量和预后。在这项研究中，我们鉴定出三种新型的驱动蛋白-13 MCAK抑制剂。抑制MCAK会诱导非整倍体，类似于用紫杉烷处理的细胞。我们证明MCAK在TNBC中上调，且与较差的预后相关。这些MCAK抑制剂降低了TNBC细胞的克隆形成存活率，三种抑制剂中最有效的C4使TNBC细胞对紫杉烷敏感，类似于敲低MCAK的效果。这项工作将扩大精准医学领域，纳入有可能改善患者预后的非整倍体诱导药物。
