βIII-tubulin induces paclitaxel resistance in association with reduced effects on microtubule dynamic instability
βIII-tubulin induces paclitaxel resistance in association with reduced effects on microtubule dynamic instability
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DOI：
10.1074/jbc.m414477200
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发表时间：
2005-04-01
影响因子：
4.8
通讯作者：
Jordan, MA
中科院分区：
文献类型：
--
作者：
Kamath, K;Wilson, L;Jordan, MA
肿瘤对紫杉醇耐药性的发展是成功治疗的最重要障碍之一。β III-微管蛋白同种型的过表达与许多癌细胞系和肿瘤中的紫杉醇耐药相关，但耐药机制仍不清楚。紫杉醇通过与微管中微管蛋白的β亚基结合并抑制微管动态不稳定性来抑制癌细胞增殖，导致有丝分裂停滞和细胞死亡。我们假设β III-微管蛋白过度表达通过组成性增强耐药细胞中微管动力学不稳定性或通过使微管对紫杉醇动力学抑制不敏感来诱导对紫杉醇的耐药。使用中国仓鼠卵巢细胞，诱导过表达β I-或β III-微管蛋白，我们分析了微管动态不稳定性在间期通过显微注射罗丹明标记的微管蛋白和延时荧光显微镜。在没有紫杉醇的情况下，两种β-微管蛋白过表达细胞类型之间的动态不稳定性的任何方面都没有差异。然而，在存在150 nM紫杉醇的情况下，过表达β III-微管蛋白的细胞中动态不稳定性的抑制程度（仅抑制12%）显著低于过表达相似水平β I-微管蛋白的细胞（抑制47%）。结果表明，β III-微管蛋白的过度表达通过降低紫杉醇抑制微管动力学的能力而诱导紫杉醇耐药。结果还表明，微管动力学的内源性调节剂可能与个别微管蛋白同种型差异相互作用，支持微管蛋白同种型的差异表达在细胞中具有功能性后果的想法。
The development of resistance to paclitaxel in tumors is one of the most significant obstacles to successful therapy. Overexpression of the beta III-tubulin isotype has been associated with paclitaxel resistance in a number of cancer cell lines and in tumors, but the mechanism of resistance has remained unclear. Paclitaxel inhibits cancer cell proliferation by binding to the beta-subunit of tubulin in microtubules and suppressing microtubule dynamic instability, leading to mitotic arrest and cell death. We hypothesized that beta III-tubulin overexpression induces resistance to paclitaxel either by constitutively enhancing microtubule dynamic instability in resistant cells or by rendering the microtubules less sensitive to the suppression of dynamics by paclitaxel. Using Chinese hamster ovary cells that inducibly overexpress either beta I- or beta III-tubulin, we analyzed microtubule dynamic instability during interphase by microinjection of rhodamine-labeled tubulin and time-lapse fluorescence microscopy. In the absence of paclitaxel, there were no differences in any aspect of dynamic instability between the two beta-tubulin-overexpressing cell types. However, in the presence of 150 nM paclitaxel, dynamic instability was suppressed to a significantly lesser extent (suppressed only 12%) in cells overexpressing beta III-tubulin than in cells overexpressing similar levels of beta I-tubulin (suppressed 47%). The results suggest that overexpression of beta III-tubulin induces paclitaxel resistance by reducing the ability of paclitaxel to suppress microtubule dynamics. The results also suggest that endogenous regulators of microtubule dynamics may differentially interact with individual tubulin isotypes, supporting the idea that differential expression of tubulin isotypes has functional consequences in cells.