Differential Expression of Immune-Regulatory Genes Associated with PD-L1 Display in Melanoma: Implications for PD-1 Pathway Blockade.
Differential Expression of Immune-Regulatory Genes Associated with PD-L1 Display in Melanoma: Implications for PD-1 Pathway Blockade.
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DOI：
10.1158/1078-0432.ccr-15-0244
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发表时间：
2015-09-01
期刊：
影响因子：
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通讯作者：
Topalian SL
中科院分区：
文献类型：
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作者：
Taube JM;Young GD;McMiller TL;Chen S;Salas JT;Pritchard TS;Xu H;Meeker AK;Fan J;Cheadle C;Berger AE;Pardoll DM;Topalian SL
阻断免疫抑制的PD-1/PD-L1通路在多种癌症类型中具有抗肿瘤活性，肿瘤细胞和浸润性髓系细胞上PD-L1的表达与应答的可能性有关。我们先前发现，在PD-L1+与PD-L1(−)黑色素瘤中，TIL过度表达干扰素-γ，通过促进PD-L1的显示而产生获得性免疫抵抗。目前的研究是为了确定PD-L1+黑色素瘤微环境中协同作用于免疫抑制的其他因素。采用免疫组织化学方法(IHC)检测经福尔马林固定、石蜡包埋的黑色素瘤标本中PD-L1蛋白在肿瘤细胞表面的表达。采用全基因组表达分析、定量(Q)RT-PCR法、免疫组织化学和体外功能验证研究来评估PD-L1+与PD-L1(−)黑色素瘤的差异表达因子。基于全基因组表达谱的功能注释聚类揭示了PD-L1+黑色素瘤中上调的途径，涉及免疫细胞激活、炎症以及抗原处理和呈递。QRT-PCR分析显示PD-L1+黑色素瘤中功能相关基因过度表达，参与CD8+T细胞活化(CD8A、IFNG、PRF1、CCL5)、抗原提呈(CD163、TLR3、CXCL1、LYZ)和免疫抑制[PDCD1(PD-1)、CD274(PD-L1)、LAG3、IL10]。功能研究表明，包括IL-10和IL-32-γ在内的某些因子可诱导单核细胞表达PD-L1，但不能诱导肿瘤细胞表达PD-L1。这些研究阐明了肿瘤微环境中免疫检查点调节的复杂性，确定了可能导致协同免疫抑制的多个因素。这些因素可能提供了抗PD-1/PD-L1治疗的肿瘤逃逸机制，在联合免疫调节治疗策略中应考虑共同靶向。
Blocking the immunosuppressive PD-1/PD-L1 pathway has anti-tumor activity in multiple cancer types, and PD-L1 expression on tumor cells and infiltrating myeloid cells correlates with the likelihood of response. We previously found that IFNG (interferon-gamma) was over-expressed by TILs in PD-L1+ vs. PD-L1(−) melanomas, creating adaptive immune resistance by promoting PD-L1 display. The current study was undertaken to identify additional factors in the PD-L1+ melanoma microenvironment coordinately contributing to immunosuppression. Archived, formalin-fixed paraffin-embedded melanoma specimens were assessed for PD-L1 protein expression at the tumor cell surface with immunohistochemistry (IHC). Whole genome expression analysis, quantitative (q)RT-PCR, immunohistochemistry, and functional in vitro validation studies were employed to assess factors differentially expressed in PD-L1+ versus PD-L1(−) melanomas. Functional annotation clustering based on whole genome expression profiling revealed pathways up-regulated in PD-L1+ melanomas, involving immune cell activation, inflammation, and antigen processing and presentation. Analysis by qRT-PCR demonstrated over-expression of functionally related genes in PD-L1+ melanomas, involved in CD8+ T cell activation (CD8A, IFNG, PRF1, CCL5), antigen presentation (CD163, TLR3, CXCL1, LYZ), and immunosuppression [PDCD1 (PD-1), CD274(PD-L1), LAG3, IL10]. Functional studies demonstrated that some factors, including IL-10 and IL-32-gamma, induced PD-L1 expression on monocytes but not tumor cells. These studies elucidate the complexity of immune checkpoint regulation in the tumor microenvironment, identifying multiple factors likely contributing to coordinated immunosuppression. These factors may provide tumor escape mechanisms from anti-PD-1/PD-L1 therapy, and should be considered for co-targeting in combinatorial immunomodulation treatment strategies.