Microtubule Dynamics, Mitotic Arrest, and Apoptosis: Drug-Induced Differential Effects of βIII-Tubulin
Microtubule Dynamics, Mitotic Arrest, and Apoptosis: Drug-Induced Differential Effects of βIII-Tubulin
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DOI：
10.1158/1535-7163.mct-09-0679
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发表时间：
2010-05-01
影响因子：
5.7
通讯作者：
Kavallaris, Maria
中科院分区：
文献类型：
--
作者：
Gan, Pei Pei;McCarroll, Joshua A.;Kavallaris, Maria
β III-微管蛋白的过度表达与多种肿瘤类型对微管蛋白结合剂 (TBA) 的耐药性相关。我们之前表明，β III-微管蛋白表达的小干扰 RNA 沉默使非小细胞肺癌细胞对 TBA 过敏。为了确定β III-微管蛋白是否通过差异调节微管行为介导其对药物诱导的有丝分裂停滞和细胞死亡的影响，在稳定表达绿色荧光蛋白-β I-微管蛋白的H460非小细胞肺癌细胞中分析了β III-微管蛋白敲低对微管动力学的影响。在三种长春新碱和紫杉醇浓度下检查间期细胞，(a) 抑制细胞增殖，(b) 诱导 5% 至 10% 有丝分裂停滞，(c) 诱导 30% 至 40% 有丝分裂停滞。在没有任何一种药物存在的情况下，β III-微管蛋白敲低不会导致微管动态不稳定性发生显着变化。在 2 nmol/L 长春新碱 (IC50) 下，与对照组 (-6.5%) 相比，β III-微管蛋白敲低 (-31.2%) 中的整体微管动态显着受到抑制。使用紫杉醇也获得了类似的结果，表明β III-微管蛋白的敲低通过增强低药物浓度下微管动力学的稳定性来诱导超敏反应。与对照细胞相比，在较高的药物浓度（>= 40 nmol/L 长春新碱；>= 20 nmol/L 紫杉醇）下，β III-微管蛋白敲低导致对微管动态的抑制作用显着降低，而有丝分裂停滞几乎没有或没有进一步增加。重要的是，β III-微管蛋白敲低显着增加了细胞凋亡，而与微管动力学和有丝分裂停滞的进一步抑制无关。这些结果表明，β III-微管蛋白敲低通过两种机制增强了 TBA 的有效性：低药物浓度下抑制微管动力学，以及高药物浓度下独立于有丝分裂的细胞死亡机制。摩尔癌症治疗； 9(5)； 1339-48。 (C) 2010 AACR。
Overexpression of beta III-tubulin is associated with resistance to tubulin-binding agents (TBA) in a range of tumor types. We previously showed that small interfering RNA silencing of beta III-tubulin expression hypersensitized non-small cell lung cancer cells to TBAs. To determine whether beta III-tubulin mediates its effect on drug-induced mitotic arrest and cell death by differentially regulating microtubule behavior, the effects of beta III-tubulin knockdown on microtubule dynamics were analyzed in H460 non-small cell lung cancer cells stably expressing green fluorescent protein-beta I-tubulin. Interphase cells were examined at three vincristine and paclitaxel concentrations that (a) inhibited cell proliferation, (b) induced 5% to 10% mitotic arrest, and (c) induced 30% to 40% mitotic arrest. In the absence of either drug, beta III-tubulin knockdown caused no significant change in microtubule dynamic instability. At 2 nmol/L vincristine (IC50), overall microtubule dynamicity was significantly suppressed in beta III-tubulin knockdowns (-31.2%) compared with controls (-6.5%). Similar results were obtained with paclitaxel, suggesting that knockdown of beta III-tubulin induces hypersensitivity by enhancing stabilization of microtubule dynamics at low drug concentrations. At higher drug concentrations (>= 40 nmol/L vincristine; >= 20 nmol/L paclitaxel), beta III-tubulin knockdown resulted in significantly reduced suppressive effects on microtubule dynamicity with little or no further increase in mitotic arrest, compared with control cells. Importantly, apoptosis was markedly increased by beta III-tubulin knockdown independent of further suppression of microtubule dynamics and mitotic arrest. These results show that beta III-tubulin knockdown enhances the effectiveness of TBAs through two mechanisms: suppression of microtubule dynamics at low drug concentrations and a mitosis-independent mechanism of cell death at higher drug concentrations. Mol Cancer Ther; 9(5); 1339-48. (C) 2010 AACR.