Chopra Avijeet, Bond Michael J, Bleiler Marina, Yeagley Michelle, Wright Dennis, Giardina Charles
Department of Molecular and Cell Biology, University of Connecticut, 91 N Eagleville Rd, Storrs, Connecticut, United States of America.
School of Pharmacy, University of Connecticut, 69 N Eagleville Rd, Storrs, Connecticut, United States of America.
PLoS One. 2016 Apr 20;11(4):e0153818. doi: 10.1371/journal.pone.0153818. eCollection 2016.
Mitotic inhibitors are widely utilized chemotherapeutic agents that take advantage of mitotic defects in cancer cells. We have identified a novel class of piperazine-based mitotic inhibitors, of which AK301 is the most potent derivative identified to date (EC50 < 200 nM). Colon cancer cells arrested in mitosis with AK301 readily underwent a p53-dependent apoptosis following compound withdrawal and arrest release. This apoptotic response was significantly higher for AK301 than for other mitotic inhibitors tested (colchicine, vincristine, and BI 2536). AK301-treated cells exhibited a robust mitosis-associated DNA damage response, including ATM activation, γH2AX phosphorylation and p53 stabilization. The association between mitotic signaling and the DNA damage response was supported by the finding that Aurora B inhibition reduced the level of γH2AX staining. Confocal imaging of AK301-treated cells revealed multiple γ-tubulin microtubule organizing centers attached to microtubules, but with limited centrosome migration, raising the possibility that aberrant microtubule pulling may underlie DNA breakage. AK301 selectively targeted APC-mutant colonocytes and promoted TNF-induced apoptosis in p53-mutant colon cancer cells. Our findings indicate that AK301 induces a mitotic arrest state with a highly active DNA damage response. Together with a reversible arrest state, AK301 is a potent promoter of a mitosis-to-apoptosis transition that can target cancer cells with mitotic defects.
有丝分裂抑制剂是广泛应用的化疗药物，它们利用癌细胞中的有丝分裂缺陷发挥作用。我们已经鉴定出一类新型的基于哌嗪的有丝分裂抑制剂，其中AK301是迄今为止鉴定出的最有效的衍生物（EC50 < 200 nM）。用AK301使结肠癌细胞停滞在有丝分裂期，在撤除化合物并解除停滞状态后，这些细胞很容易发生p53依赖的凋亡。AK301引起的这种凋亡反应明显高于其他测试的有丝分裂抑制剂（秋水仙碱、长春新碱和BI 2536）。经AK301处理的细胞表现出强烈的与有丝分裂相关的DNA损伤反应，包括ATM激活、γH2AX磷酸化和p53稳定。有丝分裂信号与DNA损伤反应之间的关联得到了以下发现的支持：抑制极光激酶B可降低γH2AX染色水平。对经AK301处理的细胞进行共聚焦成像显示，多个γ-微管蛋白微管组织中心附着于微管，但中心体迁移有限，这增加了异常微管牵拉可能是DNA断裂基础的可能性。AK301选择性靶向APC突变的结肠细胞，并促进p53突变的结肠癌细胞中TNF诱导的凋亡。我们的研究结果表明，AK301诱导一种具有高度活跃DNA损伤反应的有丝分裂停滞状态。连同可逆的停滞状态，AK301是有丝分裂向凋亡转变的有力促进剂，可靶向具有有丝分裂缺陷的癌细胞。
