Translational Cancer Research Center, Peking University First Hospital, Beijing 100034, China.
Division of General Surgery, Peking University First Hospital, Beijing 100034, China.
Cancer Biol Med. 2023 May 13;20(6):421-37. doi: 10.20892/j.issn.2095-3941.2023.0019.
Liver cancer is a deadly malignancy associated with high mortality and morbidity. Less than 20% of patients with advanced liver cancer respond to a single anti-PD-1 treatment. The high heterogeneity of neutrophils in the tumor immune microenvironment in liver cancer may contribute to resistance to immune checkpoint blockade (ICB). However, the underlying mechanism remains largely unknown.
We established an orthotopic liver cancer model by using transposable elements to integrate the oncogenes and into the genome in liver cells from conditional Trp53 null/null mice (pTMK/Trp53). Flow cytometry and immunohistochemistry were used to assess the changes in immune cells in the tumor microenvironment. An coculture assay was performed to test the inhibitory effects of tumor-associated neutrophils (TANs) on CD8 T cells. The roles of neutrophils, T cells, and NK cells were validated through antibody-mediated depletion. The efficacy of the combination of neutrophil depletion and ICB was evaluated.
Orthotropic pTMK/Trp53 mouse liver tumors displayed a moderate response to anti-Ly6G treatment but not PD-1 blockade. Depletion of neutrophils increased the infiltration of CD8 T cells and decreased the number of exhausted T cells in the tumor microenvironment. Furthermore, depletion of either CD8 T or NK cells abrogated the antitumor efficacy of anti-Ly6G treatment. Moreover, the combination of anti-Ly6G with anti-PD-L1 enhanced the infiltration of cytotoxic CD8 T cells and thereafter resulted in a significantly greater decrease in tumor burden.
Our data suggest that TANs may contribute to the resistance of liver cancer to ICB, and combining TAN depletion with T cell immunotherapy synergistically increases antitumor efficacy.
肝癌是一种致命的恶性肿瘤，死亡率和发病率都很高。不到 20%的晚期肝癌患者对单一的抗 PD-1 治疗有反应。肝癌肿瘤免疫微环境中中性粒细胞的高度异质性可能导致对免疫检查点阻断（ICB）的耐药性。然而，其潜在机制在很大程度上尚不清楚。
我们使用转座元件在条件性 Trp53 敲除/敲除小鼠（pTMK/Trp53）的肝细胞中将癌基因 和 整合到基因组中，建立了一个原位肝癌模型。流式细胞术和免疫组织化学用于评估肿瘤微环境中免疫细胞的变化。进行了 共培养实验以测试肿瘤相关中性粒细胞（TAN）对 CD8 T 细胞的抑制作用。通过抗体介导的耗竭验证中性粒细胞、T 细胞和 NK 细胞的作用。评估了中性粒细胞耗竭和 ICB 联合的疗效。
原位 pTMK/Trp53 小鼠肝癌对抗 Ly6G 治疗表现出中度反应，但对 PD-1 阻断无反应。中性粒细胞耗竭增加了 CD8 T 细胞在肿瘤微环境中的浸润，并减少了耗竭 T 细胞的数量。此外，耗竭 CD8 T 或 NK 细胞均可消除抗 Ly6G 治疗的抗肿瘤功效。此外，抗 Ly6G 与抗 PD-L1 的联合使用增强了细胞毒性 CD8 T 细胞的浸润，从而显著降低了肿瘤负担。
我们的数据表明 TAN 可能有助于肝癌对 ICB 的耐药性，并且 TAN 耗竭与 T 细胞免疫疗法联合使用可协同增强抗肿瘤疗效。
