Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University, Hněvotínská 5, 77900 Olomouc, Czech Republic.
Schools of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand.
Biochim Biophys Acta Gen Subj. 2017 Jul;1861(7):1833-1843. doi: 10.1016/j.bbagen.2017.03.023. Epub 2017 Mar 31.
Hypoxia is a prominent feature of solid tumors, dramatically remodeling microtubule structures and cellular pathways and contributing to paclitaxel resistance. Peloruside A (PLA), a microtubule-targeting agent, has shown promising anti-tumor effects in preclinical studies. Although it has a similar mode of action to paclitaxel, it binds to a distinct site on β-tubulin that differs from the classical taxane site. In this study, we examined the unexplored effects of PLA in hypoxia-conditioned colorectal HCT116 cancer cells.
Cytotoxicity of PLA was determined by cell proliferation assay. The effects of a pre-exposure to hypoxia on PLA-induced cell cycle alterations and apoptosis were examined by flow cytometry, time-lapse imaging, and western blot analysis of selected markers. The hypoxia effect on stabilization of microtubules by PLA was monitored by an intracellular tubulin polymerization assay.
Our findings show that the cytotoxicity of PLA is not altered in hypoxia-conditioned cells compared to paclitaxel and vincristine. Furthermore, hypoxia does not alter PLA-induced microtubule stabilization nor the multinucleation of cells. PLA causes cyclin B1 and G2/M accumulation followed by apoptosis.
The cellular and molecular effects of PLA have been determined in normoxic conditions, but there are no reports of PLA effects in hypoxic cells. Our findings reveal that hypoxia preconditioning does not alter the sensitivity of HCT116 to PLA.
These data report on the cellular and molecular effects of PLA in hypoxia-conditioned cells for the first time, and will encourage further exploration of PLA as a promising anti-tumor agent.
缺氧是实体瘤的一个显著特征，它显著重塑微管结构和细胞途径，并导致紫杉醇耐药。Peloruside A（PLA）是一种微管靶向药物，在临床前研究中显示出有希望的抗肿瘤作用。尽管它与紫杉醇具有相似的作用模式，但它与β-微管蛋白的不同结合位点结合，与经典的紫杉烷位点不同。在这项研究中，我们研究了 PLA 在缺氧条件下培养的结直肠 HCT116 癌细胞中的未知作用。
通过细胞增殖测定法测定 PLA 的细胞毒性。通过流式细胞术、延时成像和选定标记物的 Western blot 分析，研究了预先暴露于缺氧对 PLA 诱导的细胞周期改变和凋亡的影响。通过细胞内微管聚合测定法监测 PLA 对微管稳定的缺氧作用。
我们的研究结果表明，与紫杉醇和长春新碱相比，缺氧条件下培养的细胞中 PLA 的细胞毒性没有改变。此外，缺氧不会改变 PLA 诱导的微管稳定，也不会改变细胞的多核化。PLA 导致细胞周期蛋白 B1 和 G2/M 积累，随后发生凋亡。
在常氧条件下已经确定了 PLA 的细胞和分子作用，但尚无 PLA 在缺氧细胞中作用的报道。我们的研究结果表明，缺氧预处理不会改变 HCT116 对 PLA 的敏感性。
这些数据首次报道了 PLA 在缺氧条件下培养的细胞中的细胞和分子作用，并将鼓励进一步探索 PLA 作为一种有前途的抗肿瘤药物。
