KRAS and EGFR Amplifications Mediate Resistance to Rociletinib and Osimertinib in Acquired Afatinib-Resistant NSCLC Harboring Exon 19 Deletion/T790M in EGFR
KRAS and EGFR Amplifications Mediate Resistance to Rociletinib and Osimertinib in Acquired Afatinib-Resistant NSCLC Harboring Exon 19 Deletion/T790M in EGFR
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DOI：
10.1158/1535-7163.mct-18-0591
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发表时间：
2019-01-01
影响因子：
5.7
通讯作者：
Ohmori, Tohru
中科院分区：
文献类型：
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作者：
Nakatani, Kaori;Yamaoka, Toshimitsu;Ohmori, Tohru
EGFR中关键的T790M突变介导对第一代和第二代EGFR酪氨酸激酶抑制剂（TKI；吉非替尼、厄洛替尼和阿法替尼）的耐药性，促进了第三代突变选择性EGFR TKIs（罗西莱替尼和奥西替尼）的发展。我们之前报道了异质的阿法替尼耐药机制，包括T790M-EGFR的出现，以及对第三代EGFR TKIs的反应。在这里，我们使用了抗阿法替尼肺腺癌细胞[AfaR（以前的AFR3）细胞]，在EGFR中携带19外显子缺失/T790M。为了确定阿法替尼治疗后新的耐药机制，分别使用增加浓度的罗西替尼和奥西替尼建立RocR1/RocR2和OsiR1/OsiR2细胞。两种罗西替尼耐药细胞均证实外显子19缺失和T790M的衰减；此外，在RocR1和RocR2中分别观察到EGFR和KRAS的扩增。在奥西替尼耐药细胞系中观察到显著的KRAS扩增，表明OsiR1和OsiR2细胞中随着奥西替尼浓度的增加，KRAS呈线性和可逆的增加。停用奥西替尼2个月后，OsiR1细胞维持了对奥西替尼的耐药性，KRAS扩增。OsiR2细胞表现出KRAS衰减，奥西替尼敏感性完全恢复。在持续KRAS激活的OsiR1细胞中，发现Phospho-EGFR （Y1068）和生长因子受体结合蛋白2 (GRB2)/son of sevenless homolog 1 （SOS1）复合物介导了奥希替尼耐药性。停药2个月后，该复合物被解离，EGFR信号被激活，但GRB2/SOS1信号未被激活。同时抑制MAPK激酶和EGFR可克服奥希替尼耐药。因此，我们确定了第三代EGFR TKIs的异质获得性耐药机制，为开发新的治疗策略提供了见解。
The critical T790M mutation in EGFR, which mediates resistance to first- and second-generation EGFR tyrosine kinase inhibitors (TKI; gefitinib, erlotinib, and afatinib), has facilitated the development of third-generation mutation-selective EGFR TKIs (rociletinib and osimertinib). We previously reported heterogeneous afatinib-resistant mechanisms, including emergence of T790M-EGFR, and responses to third-generation EGFR TKIs. Here, we used afatinib-resistant lung adenocarcinoma cells [AfaR (formerly AFR3) cells], carrying exon 19 deletion/T790M in EGFR. To identify the novel resistance mechanisms in post-afatinib treatment, RocR1/RocR2 and OsiR1/OsiR2 cells were established using increasing concentrations of rociletinib and osimertinib, respectively. Attenuation of exon 19 deletion and T790M was confirmed in both rociletinib-resistant cells; in addition, EGFR and KRAS amplification was observed in RocR1 and RocR2, respectively. Significant KRAS amplification was observed in the osimerti-nib-resistant cell lines, indicating a linear and reversible increase with increased osimertinib concentrations in OsiR1 and OsiR2 cells. OsiR1 cells maintained osimertinib resistance with KRAS amplification after osimertinib withdrawal for 2 months. OsiR2 cells exhibited KRAS attenuation, and osimertinib sensitivity was entirely recovered. Phospho-EGFR (Y1068) and growth factor receptor-bound protein 2 (GRB2)/son of sevenless homolog 1 (SOS1) complex was found to mediate osimertinib resistance in OsiR1 cells with sustained KRAS activation. After 2 months of osimertinib withdrawal, this complex was dissociated, and the EGFR signal, but not the GRB2/SOS1 signal, was activated. Concomitant inhibition of MAPK kinase and EGFR could over-come osimertinib resistance. Thus, we identified a heterogeneous acquired resistance mechanism for third-generation EGFR TKIs, providing insights into the development of novel treatment strategies.