Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
J Thorac Oncol. 2013 Apr;8(4):415-22. doi: 10.1097/JTO.0b013e318283dcc0.
Anaplastic lymphoma kinase (ALK)-rearranged non-small-cell lung cancer (NSCLC) is markedly sensitive to the ALK inhibitor crizotinib. However, acquired resistance to crizotinib is inevitable through several mechanisms. Therefore, this study was conducted to identify genetic alterations associated with crizotinib resistance.
Tumor samples were derived from seven ALK-positive NSCLC patients who showed acquired resistance to crizotinib, and these patients were analyzed for ALK, EGFR, and KRAS mutations and ALK and EGFR gene amplifications. In vitro cytotoxicity of crizotinib and ALK downstream signals were compared between crizotinib-naive and -resistant NSCLC cells.
After a median duration of 6 months (range, 4-12 months), seven ALK-positive NSCLC patients developed acquired resistance to crizotinib. Three patients harbored secondary ALK mutations, including one patient with both mutations: L1196M (n = 2) and G1269A (n = 2). Of note, one patient displayed ALK gene copy number gain (4.1-fold increase compared with the pre-crizotinib specimen) and EGFR L858R mutation with high polysomy. The amphiregulin concentration was high in the supernatant fluid from five patients with malignant pleural effusion (116.4-18934.0 pg/ml). SNU-2535 cells derived from a patient who harbored the G1269 mutation were resistant to crizotinib treatment similar to H3122 CR1 cells. L1196M and G1269A mutant clones were less sensitive to crizotinib and ALK downstream signals were ineffectively suppressed in these clones.
Genetic changes associated with crizotinib resistance are heterogeneous in ALK-rearranged NSCLC patients who respond to crizotinib and subsequently develop resistance.
间变性淋巴瘤激酶（ALK）重排的非小细胞肺癌（NSCLC）对 ALK 抑制剂克唑替尼具有显著敏感性。然而，通过几种机制，对克唑替尼的获得性耐药是不可避免的。因此，本研究旨在鉴定与克唑替尼耐药相关的遗传改变。
从 7 名对克唑替尼耐药的 ALK 阳性 NSCLC 患者中获得肿瘤样本，对这些患者进行 ALK、EGFR 和 KRAS 突变以及 ALK 和 EGFR 基因扩增分析。比较克唑替尼敏感和耐药的 NSCLC 细胞对克唑替尼的体外细胞毒性和 ALK 下游信号。
在中位时间为 6 个月（范围为 4-12 个月）后，7 名 ALK 阳性 NSCLC 患者对克唑替尼产生了获得性耐药。3 名患者携带继发性 ALK 突变，包括 1 名同时携带 L1196M（n = 2）和 G1269A（n = 2）突变的患者。值得注意的是，1 名患者表现出 ALK 基因拷贝数增加（与克唑替尼治疗前标本相比增加了 4.1 倍）和 EGFR L858R 突变伴高多倍体。5 名恶性胸腔积液患者的上清液中 Amphiregulin 浓度较高（116.4-18934.0 pg/ml）。携带 G1269 突变的患者衍生的 SNU-2535 细胞对克唑替尼治疗耐药，与 H3122 CR1 细胞相似。L1196M 和 G1269A 突变克隆对克唑替尼的敏感性较低，并且这些克隆中 ALK 下游信号的抑制作用无效。
在对克唑替尼有反应并随后发生耐药的 ALK 重排 NSCLC 患者中，与克唑替尼耐药相关的遗传变化是异质性的。
