Dual kinase inhibition of EGFR and HER2 overcomes resistance to cetuximab in a novel in vivo model of acquired cetuximab resistance.
Dual kinase inhibition of EGFR and HER2 overcomes resistance to cetuximab in a novel in vivo model of acquired cetuximab resistance.
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DOI：
10.1158/1078-0432.ccr-11-0370
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发表时间：
2011-09-15
期刊：
影响因子：
--
通讯作者：
Grandis JR
中科院分区：
文献类型：
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作者：
Quesnelle KM;Grandis JR
对西妥昔单抗（一种嵌合 EGFR 靶向单克隆抗体）的获得性耐药是实体瘤治疗中的一个普遍问题。临床前模型的缺乏限制了确定获得性治疗耐药机制的研究，从而限制了有效治疗的开发。本研究的目的是在体内产生西妥昔单抗耐药肿瘤，以表征获得性耐药机制。我们通过将西妥昔单抗敏感的异种移植物暴露于浓度不断增加的西妥昔单抗，然后使用侵袭测定在体内和体外验证耐药表型，从体内西妥昔单抗敏感的膀胱癌细胞系产生西妥昔单抗耐药克隆。基于候选的方法用于检查 HER2 在体外和体内介导西妥昔单抗耐药性中的作用。我们建立了一种新的西妥昔单抗耐药模型，并且首次在 EGFR 抑制剂耐药的背景下，我们发现了西妥昔单抗耐药细胞中 HER2 C 末端片段 (611-CTF) 的磷酸化增加。阿法替尼 (BIBW-2992) 是一种针对 EGFR 和 HER2 的不可逆激酶抑制剂，在体外成功抑制西妥昔单抗耐药细胞的生长。当阿法替尼与西妥昔单抗在体内联合使用时，我们观察到对西妥昔单抗耐药的异种移植物具有附加的生长抑制作用。这些数据表明，使用双重 EGFR-HER2 激酶抑制剂可以增强对西妥昔单抗的反应，部分原因可能是 611-CTF 的下调。这项新型体内模型研究为正在进行的使用这种联合治疗方式的 I 期临床试验提供了机制原理。
Acquired resistance to cetuximab, a chimeric EGFR-targeting monoclonal antibody, is a widespread problem in the treatment of solid tumors. The paucity of preclinical models has limited investigations to determine the mechanism of acquired therapeutic resistance thereby limiting the development of effective treatments. The purpose of this study was to generate cetuximab-resistant tumors in vivo to characterize mechanisms of acquired resistance. We generated cetuximab-resistant clones from a cetuximab-sensitive bladder cancer cell line in vivo by exposing cetuximab-sensitive xenografts to increasing concentrations of cetuximab followed by validation of the resistant phenotype in vivo and in vitro using invasion assays. A candidate-based approach was used to examine the role of HER2 on mediating cetuximab resistance both in vitro and in vivo. We generated a novel model of cetuximab resistance and, for the first time in the context of EGFR-inhibitor resistance, we identified increased phosphorylation of a c-terminal fragment of HER2 (611-CTF) in cetuximab-resistant cells. Afatinib (BIBW-2992), an irreversible kinase inhibitor targeting EGFR and HER2, successfully inhibited growth of the cetuximab-resistant cells in vitro. When afatinib was combined with cetuximab in vivo, we observed an additive growth inhibitory effect in cetuximab-resistant xenografts. These data suggest that the use of dual EGFR-HER2 kinase inhibitors can enhance responses to cetuximab, perhaps in part due to downregulation of 611-CTF. This study in a novel in vivo model provides a mechanistic rationale for ongoing phase I clinical trials using this combination treatment modality.