Epidermal growth factor receptors harboring kinase domain mutations associate with the heat shock protein 90 chaperone and are destabilized following exposure to geldanamycins
Epidermal growth factor receptors harboring kinase domain mutations associate with the heat shock protein 90 chaperone and are destabilized following exposure to geldanamycins
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DOI：
10.1158/0008-5472.can-05-0933
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发表时间：
2005-07-15
期刊：
影响因子：
11.2
通讯作者：
Shapiro, GI
中科院分区：
文献类型：
--
作者：
Shimamura, T;Lowell, AM;Shapiro, GI
表皮生长因子受体（EGFR）激酶结构域的体细胞突变，包括L 858 R和外显子19缺失，是非小细胞肺癌（NSCLC）对吉非替尼和厄洛替尼反应性的基础。在某些情况下，对这些酪氨酸激酶抑制剂的获得性耐药性由第二个突变T790 M介导。安莎霉素抗生素，如格尔德霉素，有效地抑制热休克蛋白90（HSP 90），促进泛素介导的致癌激酶的降解，需要伴侣蛋白进行正确的构象折叠。在这里，我们表明，L 858 R和缺失突变EGFR蛋白在NSCLC中发现的分子伴侣相互作用，并对Hsp 90抑制后的降解敏感。在表达野生型或突变型EGFR的NIH/3 T3细胞中，暴露于50 nmol/L格尔德霉素24小时后，L 85 SR和EGFR deIL 747-S752，P753 S的表达均减少，而野生型EGFR的部分减少需要至少200 nmol/L的药物。在时程实验中，突变型EGFR表达在暴露于1 μ mol/L格尔德霉素仅4小时后耗尽，而野生型EGFR的减少不太显著，仅在12小时后观察到。类似地，携带EGFR突变的NSCLC细胞系（包括NCI-H1650、NCI-H3255和NO-H1975）中的EGFR蛋白与野生型细胞中的蛋白相比，对格尔德霉素诱导的降解也更敏感。EGFR突变细胞系暴露于格尔德霉素诱导磷酸化Akt和细胞周期蛋白D1的显著耗竭以及细胞凋亡。这些数据表明EGFR的突变激活与稳定性对Hsp 90的依赖性相关，Hsp 90抑制可能代表EGFR突变型NSCLC治疗的新策略。
Somatic mutations in the kinase domain of the epidermal growth factor receptor (EGFR), including L858R and exon 19 deletions, underlie responsiveness to gefitinib and erlotinib in non-small cell lung cancer (NSCLC). Acquired resistance to these tyrosine kinase inhibitors is in some cases mediated by a second mutation, T790M. Ansamycin antibiotics, such as geldanamycin, potently inhibit heat shock protein 90 (Hsp90), promoting ubiquitin-mediated degradation of oncogenic kinases that require the chaperone for proper conformational folding. Here, we show that L858R and deletion mutant EGFR proteins found in NSCLC interact with the chaperone and are sensitive to degradation following Hsp90 inhibition. In NIH/3T3 cells expressing either wild-type or mutant EGFR, diminution of expression of both L85SR and EGFR deIL747-S752, P753S occurred following exposure to 50 nmol/L geldanamycin over 24 hours, whereas partial diminution of wild-type EGFR required a minimum of 200 nmol/L drug. In time course experiments, mutant EGFR expression was depleted after only 4 hours of exposure to 1 mu mol/L geldanamycin, whereas diminution of wild-type EGFR was less substantial and seen only following 12 hours. Similarly, EGFR proteins in NSCLC cell lines harboring EGFR mutations, including NCI-H1650, NCI-H3255, and NO-H1975, were also more sensitive to geldanamycin-induced degradation compared with the protein in wild-type cells. Exposure of EGFR-mutant cell lines to geldanamycin induced marked depletion of phospho-Akt and cyclin D1 as well as apoptosis. These data suggest mutational activation of EGFR is associated with dependence on Hsp90 for stability and that Hsp90 inhibition may represent a novel strategy for the treatment of EGFR-mutant NSCLC.