Department of Pathology, College of Basic Medical Sciences and First Affiliated Hospital of China Medical University, Shenyang, China.
Department of Pathology, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Shenyang, China.
J Thorac Oncol. 2019 Oct;14(10):1766-1783. doi: 10.1016/j.jtho.2019.06.014. Epub 2019 Jun 19.
The molecular mechanism underlying the induction of resistance to tyrosine kinase inhibitors (TKIs) via the membranous/cytoplasmic/nuclear translocation of EGFR has not yet been reported.
We performed immunohistochemistry to detect the distribution of EGFR in lung adenocarcinoma specimens after TKI treatment and analyzed the relationship between different EGFR locations and patient survival duration. Mass spectrometry analysis and immunoprecipitation were performed to show the interaction of cytosolic EGFR with YY1 associated protein 1 (YAP) and salt inducible kinase 2 (SIK2). Dual-luciferase assays, immunoblotting, real-time polymerase chain reaction, and functional experiments were used to elucidate the role of EGFR cytoplasmic/nuclear translocation in Hippo pathway dysregulation.
Patients with advanced lung adenocarcinoma with membranous mutant EGFR (19del or 21 L858R) showed significantly longer progression-free survival than those with cytoplasmic mutant EGFR after gefitinib treatment. The concentration that inhibits 50% in PC-9 with cytoplasmic EGFR was higher than that in hunman non-small cell lung cancer 827 with membranous EGFR. During first-generation TKI resistance induction, membrane EGFR translocated to the cytoplasm/nucleus, accompanied by the Hippo pathway inhibition. Cytoplasmic EGFR and SIK2 interaction inhibited large tumor suppressor kinase 1 (LATS1) and macrophage stimulating 1 (MST1) interaction, promoting YAP nuclear translocation. However, cells with osimertinib-induced resistance also showed EGFR translocation and lower phospho-EGF receptor but did not show Hippo pathway inhibition. Moreover, osimertinib and erlotinib could restore sensitivity to each other in resistant cells.
Plasma/nuclear translocation of EGFR and inhibition of the Hippo pathway are some of the important mechanisms underlying the resistance induced by first-generation TKIs. Membrane/plasma translocation of EGFR induced by osimertinib may be another resistance phenomenon besides MNNG HOS transforming gene (c-MET) amplification, C797S mutation, and ERK pathway inhibition.
表皮生长因子受体（EGFR）通过膜/细胞质/核转位诱导对酪氨酸激酶抑制剂（TKI）产生耐药的分子机制尚未报道。
我们通过免疫组织化学检测 TKI 治疗后肺腺癌标本中 EGFR 的分布，并分析不同 EGFR 位置与患者生存时间的关系。通过质谱分析和免疫沉淀显示细胞质 EGFR 与 YY1 相关蛋白 1（YAP）和盐诱导激酶 2（SIK2）的相互作用。双荧光素酶报告基因实验、免疫印迹、实时聚合酶链反应和功能实验用于阐明 EGFR 细胞质/核转位在 Hippo 通路失调中的作用。
与细胞质突变型 EGFR（19del 或 21 L858R）的晚期肺腺癌患者相比，接受吉非替尼治疗后，膜型突变型 EGFR 患者的无进展生存期明显更长。PC-9 中具有细胞质 EGFR 的抑制浓度比具有膜型 EGFR 的人非小细胞肺癌 827 更高。在第一代 TKI 耐药诱导过程中，膜型 EGFR 易位到细胞质/核，伴随着 Hippo 通路抑制。细胞质 EGFR 与 SIK2 的相互作用抑制了大肿瘤抑制激酶 1（LATS1）和巨噬细胞刺激素 1（MST1）的相互作用，促进 YAP 核转位。然而，具有奥希替尼诱导耐药的细胞也表现出 EGFR 易位和较低的磷酸化 EGFR，但没有表现出 Hippo 通路抑制。此外，奥希替尼和厄洛替尼在耐药细胞中可以相互恢复敏感性。
EGFR 的血浆/核转位和 Hippo 通路抑制是第一代 TKI 诱导耐药的重要机制之一。奥希替尼诱导的膜/血浆转位可能是 MNNG HOS 转化基因（c-MET）扩增、C797S 突变和 ERK 通路抑制以外的另一种耐药现象。
