Both microtubule-stabilizing and microtubule-destabilizing drugs inhibit hypoxia-inducible factor-1α accumulation and activity by disrupting microtubule function
Both microtubule-stabilizing and microtubule-destabilizing drugs inhibit hypoxia-inducible factor-1α accumulation and activity by disrupting microtubule function
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DOI：
10.1158/0008-5472.can-04-4095
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发表时间：
2005-10-01
期刊：
影响因子：
11.2
通讯作者：
Giannakakou, P
中科院分区：
文献类型：
--
作者：
Escuin, D;Kline, ER;Giannakakou, P
我们最近已经确定了一个机制之间的联系，通过缺氧诱导因子-1（HIF-1）途径破坏微管细胞骨架和抑制肿瘤血管生成。基于这个模型，我们假设其他微管靶向药物可能对HIF-1 α有类似的作用。为了验证这一假设，我们研究了不同的临床相关的微管破坏剂，包括泰索帝，埃博霉素B，discodermolide，长春新碱，2-甲氧基紫杉醇，秋水仙碱的影响。在所有情况下，HIF-1 α蛋白，而不是mRNA，下调药物剂量依赖性的方式。此外，HIF-1 α转录活性也被所有测试药物抑制。为了进一步研究这些作用是否依赖于微管网络的破坏，我们检测了埃坡霉素B在人卵巢癌细胞系1A 9及其β-微管蛋白突变体埃坡霉素抗性亚克隆1A 9/A8中抑制HIF-1 α蛋白的能力。我们的数据显示，埃坡霉素B处理下调了亲本1A 9细胞中的HIF-1 α蛋白，但对耐药1A 9/A8细胞没有影响。这些观察结果得到了共聚焦显微镜的证实，共聚焦显微镜显示在诱导广泛微管稳定的埃坡霉素B浓度下，亲代1A 9细胞中HIF-1 α的核积累受损。相比之下，埃坡霉素B处理对抗性1A 9/A8细胞中的微管或HIF-1 α核积累没有影响。此外，埃坡霉素B抑制HIF-1在1A 9细胞中的转录活性，如通过缺氧反应元件-荧光素酶报告基因测定所证明的，但对HIF-1在抗性1A 9/A8细胞中的活性没有影响。这些数据直接将β-微管蛋白药物结合与HIF-1 α蛋白抑制联系起来。我们的研究结果进一步提供了一个强有力的理由，测试紫杉烷和埃博霉素在临床试验中靶向HIF-1的癌症患者。
We have recently identified a mechanistic link between disruption of the microtubule cytoskeleton and inhibition of tumor angiogenesis via the hypoxia-inducible factor-1 (HIF-1) pathway. Based on this model, we hypothesized that other microtubule-targeting drugs may have a similar effect on HIF-1 alpha. To test that hypothesis, we studied the effects of different clinically relevant microtubule-disrupting agents, including taxotere, epothilone B, discodermolide, vincristine, 2-methoxyestradiol, and colchicine. In all cases, HIF-1 alpha protein, but not mRNA, was down-regulated in a drug dose-dependent manner. In addition, HIF-1 alpha transcriptional activity was also inhibited by all drugs tested. To further examine whether these effects were dependent on microtubule network disruption, we tested the ability of epothilone B to inhibit HIF-1 alpha protein in the human ovarian cancer cell line 1A9 and its beta-tubulin mutant epothilone-resistant subclone 1A9/A8. Our data showed that epothilone B treatment down-regulated HIF-1 alpha protein in the parental 1A9 cells but had no effect in the resistant 1A9/A8 cells. These observations were confirmed by confocal microscopy, which showed impaired nuclear accumulation of HIF-1 alpha in parental 1A9 cells at epothilone B concentrations that induced extensive microtubule stabilization. In contrast, epothilone B treatment had no effect on either microtubules or HIF-1 alpha nuclear accumulation in the resistant 1A9/A8 cells. Furthermore, epothilone B inhibited HIF-1 transcriptional activity in 1A9 cells, as evidenced by a hypoxia response element-luciferase reporter assay, but had no effect on HIF-1 activity in the resistant 1A9/A8 cells. These data directly link beta-tubulin drug binding with HIF-1 alpha protein inhibition. Our results further provide a strong rationale for testing taxanes and epothilones in clinical trials targeting HIF-1 in cancer patients.