Department of Surgery, University of Washington, Seattle, Washington.
Department of Pathology, University of Washington, Seattle, Washington.
Clin Cancer Res. 2019 Jul 1;25(13):3934-3945. doi: 10.1158/1078-0432.CCR-19-0081. Epub 2019 Apr 2.
Pancreatic ductal adenocarcinoma (PDA) is rarely cured, and single-agent immune checkpoint inhibition has not demonstrated clinical benefit despite the presence of large numbers of CD8 T cells. We hypothesized that tumor-infiltrating CD8 T cells harbor latent antitumor activity that can be reactivated using combination immunotherapy.
Preserved human PDA specimens were analyzed using multiplex IHC (mIHC) and T-cell receptor (TCR) sequencing. Fresh tumor was treated in organotypic slice culture to test the effects of combination PD-1 and CXCR4 blockade. Slices were analyzed using IHC, flow cytometry, and live fluorescent microscopy to assess tumor kill, in addition to T-cell expansion and mobilization.
mIHC demonstrated fewer CD8 T cells in juxtatumoral stroma containing carcinoma cells than in stroma devoid of them. Using TCR sequencing, we found clonal expansion in each tumor; high-frequency clones had multiple DNA rearrangements coding for the same amino acid binding sequence, which suggests response to common tumor antigens. Treatment of fresh human PDA slices with combination PD-1 and CXCR4 blockade led to increased tumor cell death concomitant with lymphocyte expansion. Live microscopy after combination therapy demonstrated CD8 T-cell migration into the juxtatumoral compartment and rapid increase in tumor cell apoptosis.
Endogenous tumor-reactive T cells are present within the human PDA tumor microenvironment and can be reactivated by combined blockade of PD-1 and CXCR4. This provides a new basis for the rational selection of combination immunotherapy for PDA..
胰腺导管腺癌 (PDA) 很少能被治愈，尽管存在大量的 CD8 T 细胞，但单一的免疫检查点抑制并未显示出临床获益。我们假设肿瘤浸润的 CD8 T 细胞具有潜在的抗肿瘤活性，可以通过联合免疫疗法重新激活。
使用多重免疫组化 (mIHC) 和 T 细胞受体 (TCR) 测序分析保存的人 PDA 标本。使用器官型切片培养物处理新鲜肿瘤，以测试 PD-1 和 CXCR4 联合阻断的效果。通过免疫组化、流式细胞术和活荧光显微镜分析切片，以评估肿瘤杀伤，以及 T 细胞的扩增和动员。
mIHC 显示在含有癌细胞的肿瘤旁基质中 CD8 T 细胞比在没有它们的基质中更少。使用 TCR 测序，我们在每个肿瘤中都发现了克隆扩增；高频克隆具有多个编码相同氨基酸结合序列的 DNA 重排，这表明对共同肿瘤抗原的反应。用联合 PD-1 和 CXCR4 阻断治疗新鲜人 PDA 切片导致肿瘤细胞死亡增加，同时淋巴细胞扩增。联合治疗后的实时显微镜显示 CD8 T 细胞迁移到肿瘤旁区，并迅速增加肿瘤细胞凋亡。
内源性肿瘤反应性 T 细胞存在于人类 PDA 肿瘤微环境中，可以通过联合阻断 PD-1 和 CXCR4 来重新激活。这为 PDA 的联合免疫治疗的合理选择提供了新的依据。
