Upregulation of PD-L1 by EML4-ALK fusion protein mediates the immune escape in ALK positive NSCLC: Implication for optional anti-PD-1/PD-L1 immune therapy for ALK-TKIs sensitive and resistant NSCLC patients
Upregulation of PD-L1 by EML4-ALK fusion protein mediates the immune escape in ALK positive NSCLC: Implication for optional anti-PD-1/PD-L1 immune therapy for ALK-TKIs sensitive and resistant NSCLC patients
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EML4-ALK 融合蛋白上调 PD-L1 介导 ALK 阳性 NSCLC 中的免疫逃逸：对 ALK-TKIs 敏感和耐药的 NSCLC 患者可选抗 PD-1/PD-L1 免疫治疗的意义
DOI：
10.1080/2162402x.2015.1094598
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发表时间：
2016-01-01
期刊：
影响因子：
7.2
通讯作者：
Zhang, Li
中科院分区：
文献类型：
--
作者：
Hong, Shaodong;Chen, Nan;Zhang, Li
据报道，驱动突变可上调程序性死亡配体1 （PD-L1）的表达。然而，ALK- tkis和抗pd -1/PD-L1治疗在ALK阳性非小细胞肺癌（NSCLC）中如何影响PD-L1表达和免疫功能仍然知之甚少。本研究采用western-blot、real-time PCR、流式细胞术、免疫荧光等方法探讨ALK融合蛋白对PD-L1的调控作用。ALK-TKIs和相关抑制剂被用来鉴定参与PD-L1调节的下游信号通路。采用细胞凋亡、细胞活力和Elisa法研究肿瘤细胞和DC-CIK细胞共培养体系中ALK活化对免疫的抑制作用以及ALK- tkis和/或PD-1阻断对免疫的再激活作用。我们发现，在NSCLC细胞系中，PD-L1表达与EGFR突变和ALK融合基因相关。ALK融合蛋白过表达增加PD-L1表达。ALK融合蛋白介导的PD-L1增加了肿瘤细胞和DC-CIK细胞共培养系统中T细胞的凋亡。通过敏感的TKIs抑制ALK可以促进IFNγ的产生。抗pd -1抗体对克唑替尼敏感和耐药的NSCLC细胞均有效。在共培养体系中，ALK-TKIs与抗pd -1抗体联合使用未观察到协同杀伤效果。ALK-TKIs不仅能直接抑制肿瘤存活，还能通过下调PD-L1间接增强抗肿瘤免疫。抗pd -1/PD-L1抗体可作为对克唑替尼敏感，特别是对克唑替尼耐药的ALK融合基因NSCLC患者的可选治疗。ALK- tkis联合抗pd -1/PD-L1抗体治疗ALK阳性NSCLC在进入临床实践之前需要更多的数据。
ABSTRACT Driver mutations were reported to upregulate programmed death-ligand 1 (PD-L1) expression. However, how PD-L1 expression and immune function was affected by ALK-TKIs and anti-PD-1/PD-L1 treatment in ALK positive non-small-cell lung cancer (NSCLC) remains poorly understood. In the present study, western-blot, real-time PCR, flow cytometry and immunofluorescence were employed to explore how PD-L1 was regulated by ALK fusion protein. ALK-TKIs and relevant inhibitors were used to identify the downstream signaling pathways involved in PD-L1 regulation. Cell apoptosis, viability and Elisa test were used to study the immune suppression by ALK activation and immune reactivation by ALK-TKIs and/or PD-1 blocking in tumor cells and DC-CIK cells co-culture system. We found that PD-L1 expression was associated with EGFR mutations and ALK fusion genes in NSCLC cell lines. Over-expression of ALK fusion protein increased PD-L1 expression. PD-L1 mediated by ALK fusion protein increased the apoptosis of T cells in tumor cells and DC-CIK cells co-culture system. Inhibiting ALK by sensitive TKIs could enhance the production of IFNγ. Anti-PD-1 antibody was effective in both crizotinib sensitive and resistant NSCLC cells. Synergistic tumor killing effects were not observed with ALK-TKIs and anti-PD-1 antibody combination in co-culture system. ALK-TKIs not only directly inhibited tumor viability but also indirectly enhanced the antitumor immunity via the downregulation of PD-L1. Anti-PD-1/PD-L1 antibodies could be an optional therapy for crizotinib sensitive, especially crizotinib resistant NSCLC patients with ALK fusion gene. Combination of ALK-TKIs and anti-PD-1/PD-L1 antibodies treatment for ALK positive NSCLC warrants more data before moving into clinical practice.