Resistance to Taxol in lung cancer cells associated with increased microtubule dynamics
Resistance to Taxol in lung cancer cells associated with increased microtubule dynamics
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DOI：
10.1073/pnas.191388598
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发表时间：
2001-09-25
影响因子：
11.1
通讯作者：
Jordan, MA
中科院分区：
文献类型：
--
作者：
Gonçalves, A;Braguer, D;Jordan, MA
微管动力学对于有丝分裂纺锤体组装和染色体运动至关重要。紫杉醇对动力学的抑制似乎是该药物抑制有丝分裂和细胞增殖的强大能力的原因。尽管紫杉醇是一种重要的化疗药物，但耐药性的产生限制了其疗效。为了研究微管动力学在紫杉醇耐药性中的作用，我们测量了在对紫杉醇敏感和耐药的人活癌细胞中单个罗丹明标记的微管的动态不稳定性。从人肺癌细胞系A549中筛选出了对紫杉醇耐药的A549 - T12和 - T24细胞系。它们对紫杉醇的耐药性分别是9倍和17倍，并且需要低浓度的紫杉醇才能增殖。我们发现微管动态不稳定性在对紫杉醇耐药的细胞中显著增加。例如，在不添加紫杉醇的情况下，与A549细胞相比，A549 - T12细胞的微管动态性增加了57%。缩短偏移的长度和速率分别增加了75%和59%。这些参数在A549 - T24细胞中进一步增加，与亲本细胞相比，总体动态性增加了167%。因此，这些细胞对紫杉醇敏感性降低可以用其微管动力学增加来解释。在没有紫杉醇的情况下生长时，A549 - T12细胞在中期/后期转换时受阻，并显示出有未聚集染色体的异常有丝分裂纺锤体。在存在2 - 12 nM紫杉醇的情况下，细胞正常生长，这表明有丝分裂受阻是由于微管动力学过度。这些结果表明微管动力学在紫杉醇耐药性中起重要作用，并且过快的动力学和受抑制的动力学都会损害有丝分裂纺锤体功能并抑制增殖。
Microtubule dynamics are crucial for mitotic spindle assembly and chromosome movement. Suppression of dynamics by Taxol appears responsible for the drug's potent ability to inhibit mitosis and cell proliferation. Although Taxol is an important chemotherapeutic agent, development of resistance limits its efficacy. To examine the role of microtubule dynamics in Taxol resistance, we measured the dynamic instability of individual rhodamine-labeled microtubules in Taxol-sensitive and -resistant living human cancer cells. Taxol-resistant A549-T12 and -T24 cell lines were selected from a human lung carcinoma cell line, A549. They are, respectively, 9- and 17-fold resistant to Taxol and require low concentrations of Taxol for proliferation. We found that microtubule dynamic instability was significantly increased in the Taxol-resistant cells. For example, with A549-T12 cells in the absence of added Taxol, microtubule dynamicity increased 57% as compared with A549 cells. The length and rate of shortening excursions increased 75 and 59%, respectively. These parameters were further increased in A549-T24 cells, with overall dynamicity increasing by 167% compared with parental cells. Thus, the decreased Taxol-sensitivity of these cells can be explained by their increased microtubule dynamics. When grown without Taxol, A549-T12 cells were blocked at the metaphase/anaphase transition and displayed abnormal mitotic spindles with uncongressed chromosomes. In the presence of 2-12 nM Taxol, the cells grew normally, suggesting that mitotic block resulted from excessive microtubule dynamics. These results indicate that microtubule dynamics play an important role in Taxol resistance, and that both excessively rapid dynamics and suppressed dynamics impair mitotic spindle function and inhibit proliferation.