Identification of tyrosine 806 as a molecular determinant of RET kinase sensitivity to ZD6474
Identification of tyrosine 806 as a molecular determinant of RET kinase sensitivity to ZD6474
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DOI：
10.1677/erc-08-0213
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发表时间：
2009-03-01
影响因子：
3.9
通讯作者：
Santoro, Massimo
中科院分区：
文献类型：
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作者：
Carlomagno, Francesca;Guida, Teresa;Santoro, Massimo
ZD6474(vandetanib，Zactima，Astra Zeneca)是一种苯胺喹唑啉，用于治疗家族性和散发性甲状腺癌(IC50：100 NM)。本研究的目的是确定RET对ZD6474敏感性的分子决定因素。在这里，我们发现RET酪氨酸806突变为半胱氨酸(Y806C)诱导了RET激酶对ZD6474(IC50：933 NM)的抗性。Y806定位在RET激酶核苷酸结合口袋的守门人位置附近。虽然酪氨酸806是一个RET自身磷酸化位点，但它对苯丙氨酸(Y806F)的取代并没有显著影响RET对ZD6474(IC50：87 nM)的敏感性，这表明Y806的磷酸化不是化合物结合所必需的。因此，引入拟磷残基(Y806E)也引起了对ZD6474的抗性，尽管程度低于半胱氨酸突变(IC50：512 nM)。Y806C/E RET突变体在胞内信号和AP1反应启动子的激活方面也对ZD6474具有抗性。我们得出结论：Y806是RET对ZD6474敏感的分子决定因素。Y806C是一种自然的RET突变，在一例2B型多发性内分泌肿瘤患者中被发现。基于其罕见的发生，Y806C不太可能成为ZD6474耐药的常见原因；然而，可以设想该位点的突变可以介导接受该化合物治疗的患者的继发性耐药形成。
ZD6474 (vandetanib, Zactima, Astra Zeneca) is an anilinoquinazoline used to target the receptor tyrosine kinase RET in familial and sporadic thyroid carcinoma (IC50: 100 nM). The aim of this study was to identify molecular determinants of RET sensitivity to ZD6474. Here, we show that mutation of RET tyrosine 806 to cysteine (Y806C) induced RET kinase resistance to ZD6474 (IC50: 933 nM). Y806 maps close to the gate-keeper position at the RET kinase nucleotide-binding pocket. Although tyrosine 806 is a RET auto-phosphorylation site, its substitution to phenylalanine (Y806F) did not markedly affect RET susceptibility to ZD6474 (IC50: 87 nM), suggesting that phosphorylation of Y806 is not required for compound binding. Accordingly, the introduction of a phosphomimetic residue (Y806E) also caused resistance to ZD6474, albeit of a lesser degree (IC50: 512 nM) than the cysteine mutation. Y806C/E RET mutants were also resistant to ZD6474 with respect to intracellular signalling and activation of an AP1-responsive promoter. We conclude that Y806 is a molecular determinant of RET sensitivity to ZD6474. Y806C is a natural RET mutation identified in a patient affected by multiple endocrine neoplasia type 2B. Based on its rare occurrence, it is unlikely that Y806C will be a frequent cause of refractoriness to ZD6474; however, it may be envisaged that mutations at this site can mediate secondary resistance formation in patients treated with the compound.