Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.
Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
Cancer Res Treat. 2019 Jul;51(3):1231-1240. doi: 10.4143/crt.2018.486. Epub 2018 Dec 31.
The purpose of this study was to evaluate the relationships between the resistance of anaplastic lymphoma kinase (ALK)‒positive non-small cell lung cancer (NSCLC) to ALK inhibitors and the programmed cell death-1/programmed cell death-ligand 1 (PD-L1) pathway, we evaluated alterations in PD-L1 following acquisition of resistance to ALK inhibitors in ALK-positive lung cancer.
We established ALK inhibitor-resistant cell lines (H3122CR1, LR1, and CH1) by exposing the parental H3122 ALK-translocated NSCLC cell line to ALK inhibitors. Then, the double-resistant cell lines H3122CR1LR1 and CR1CH1 were developed by exposing the H3122CR1 to other ALK inhibitors. We compared the alterations in PD-L1 expression levels using western blotting, flow cytometry, and quantitative polymerase chain reaction. We also investigated gene expression using RNA sequencing. The expression of PD-L1 in the tumors from 26 ALK-positive metastatic NSCLC patients (11 ALK inhibitor-naïve and 15 ALK inhibitor-resistant patients) was assessed by immunohistochemistry and analyzed.
PD-L1 was expressed at higher levels in ALK inhibitor-resistant cell lines than in the ALK inhibitor-naïve parental cell line at the total protein, surface protein, and mRNA levels. Furthermore, PD-L1 expression in the double-resistant cell lines was much higher than that in the single resistant cell lines. RNA sequencing demonstrated that expression of immune-related genes were largely involved in ALK inhibitor resistance. The mean value of the PD-L1 H-score was 6.5 pre-treatment and 35.0 post-treatment, and the fold difference was 5.42 (p=0.163).
PD-L1 expression increased following acquisition of ALK inhibitor resistance in ALK-positive NSCLC cell lines and tumors.
本研究旨在评估间变性淋巴瘤激酶（ALK）阳性非小细胞肺癌（NSCLC）对 ALK 抑制剂的耐药性与程序性细胞死亡蛋白-1/程序性死亡配体 1（PD-L1）通路之间的关系，我们评估了 ALK 阳性肺癌对 ALK 抑制剂获得性耐药后 PD-L1 的改变。
我们通过暴露于 ALK 抑制剂来建立 ALK 抑制剂耐药细胞系（H3122CR1、LR1 和 CH1），然后通过暴露于其他 ALK 抑制剂来建立 H3122CR1LR1 和 CR1CH1 双耐药细胞系。我们使用 Western blot、流式细胞术和定量聚合酶链反应比较 PD-L1 表达水平的变化。我们还使用 RNA 测序研究基因表达。通过免疫组织化学评估并分析 26 例 ALK 阳性转移性 NSCLC 患者（11 例 ALK 抑制剂初治和 15 例 ALK 抑制剂耐药患者）肿瘤中 PD-L1 的表达。
与 ALK 抑制剂初治亲本细胞系相比，ALK 抑制剂耐药细胞系在总蛋白、表面蛋白和 mRNA 水平上表达更高水平的 PD-L1。此外，双耐药细胞系中的 PD-L1 表达水平明显高于单耐药细胞系。RNA 测序表明，免疫相关基因的表达在很大程度上参与了 ALK 抑制剂耐药。PD-L1 H 评分的平均值为治疗前 6.5，治疗后 35.0，倍数差异为 5.42（p=0.163）。
ALK 阳性 NSCLC 细胞系和肿瘤对 ALK 抑制剂获得性耐药后 PD-L1 表达增加。
