免疫检查点阻断（ICB）能够在多种晚期癌症中诱导持久的免疫反应，并对肿瘤学领域产生了革命性影响。然而，只有一部分患者能够获得长期的临床益处。肿瘤相关巨噬细胞（TAMs）通常分泌免疫抑制细胞因子，并导致ICB治疗失败。因此，机械调控肿瘤微环境（TME）中TAMs的数量和功能至关重要，从而为改善ICB在癌症患者中的临床反应效果提供有希望的分子基础。本研究旨在调查免疫抑制微环境中的TAMs，以确定新的治疗靶点，改善临床免疫治疗的预测和指导能力，并开发肺肿瘤免疫治疗的新策略。拟采用路易斯肺癌（LLC）移植小鼠模型，分析黄连中药在体内的抗肿瘤活性。采用系统药理学策略预测黄连和M2巨噬细胞的相关性。通过流式细胞术分析小鼠样本中M2巨噬细胞的数量变化。采用Western blot技术分析收获的肺癌组织中白三烯A4水解酶（LTA4H）和白三烯B4受体1（BLT1）的表达水平。通过体外和体内实验评估黄连阻断白三烯B4（LTB4）信号对M2巨噬细胞招募的影响。通过Transwell迁移实验明确阻断LTB4对巨噬细胞迁移的抑制作用。采用Lta4h基因敲除小鼠（Lta4h-/-小鼠）研究阻断LTB4信号对肺癌免疫治疗敏感性的影响。在这里，我们报告了来自毛茛科植物家族的黄连通过抑制TAMs的招募和免疫抑制功能，使肺癌对ICB治疗产生敏感性。首先，我们提出了一种系统药理学策略，以系统生物学的视角，从药物-靶点-通路-肿瘤微环境表型的角度寻找ICB治疗的联合药物。我们预测并验证了黄连显著抑制LLC肿瘤小鼠中肿瘤生长和M2-TAMs对TME的浸润。然后，我们证实黄连通过阻断LTB4信号抑制巨噬细胞对肿瘤TME的招募，并抑制免疫抑制因子（IL-10、TGF-β和VEGF）的表达。结果，黄连使CD8+ T细胞在TME内保持其增殖和浸润能力。最终，这些事件促进了细胞毒性T细胞介导的肿瘤细胞清除，进一步通过抗PD-L1治疗的添加而得到增强。此外，我们采用了LTA4H基因敲除小鼠（Lta4h-/-小鼠）评估抗肿瘤效果，结果显示，由于LTB4信号阻断和ICB抑制的协同作用，免疫治疗的功效得到增强，显著抑制了肺腺癌模型小鼠的肿瘤生长。总而言之，这些发现表明黄连增强了抗肿瘤免疫力，为将黄连与免疫治疗联合应用作为潜在的抗癌治疗策略提供了理论基础。版权所有© 2023 Elsevier GmbH。保留所有权利。

Immune checkpoint blockade (ICB) induces durable immune responses across a spectrum of advanced cancers and revolutionizes the oncology field. However, only a subset of patients achieves long-lasting clinical benefits. Tumor-associated macrophages (TAMs) usually secrete immunosuppressive cytokines and contribute to the failure of ICB therapy. Therefore, it is crucial to mechanically manipulate the abundance and function of TAMs in the tumor microenvironment (TME), which can offer a promising molecular basis to improve the clinical response efficacy of ICB in cancer patients.This study aims to investigate TAMs in the immunosuppressive microenvironment to identify new therapeutic targets, improve the ability to predict and guide responses to clinical immunotherapy, and develop new strategies for immunotherapy of lung tumors.Lewis lung carcinoma (LLC) xenograft-bearing mouse models were established to analyze the antitumor activity of Rhizoma Coptidis (RC) in vivo. A systems pharmacology strategy was used to predict the correlation between RC and M2 macrophages. The effect of RC on the abundance of M2 macrophages was analyzed by flow cytometry of murine samples. Western blot was performed to analyze the expression of Leukotriene A4 hydrolase (LTA4H) and LTB4 receptor 1 (BLT1) in harvested lung cancer tissues. The impact of blocking leukotriene B4 (LTB4) signaling by RC on the recruitment of M2 macrophages was assessed in vitro and in vivo. Transwell migration assays were conducted to clarify the inhibition of macrophage migration by blocking LTB4. Lta4h-/- mice were used to investigate the sensitivity of immunotherapy to lung cancer by blocking the LTB4 signaling.Here, we report that RC, an herbal medicine from the family Ranunculaceae, suppresses the recruitment and immunosuppressive function of TAMs, which in turn sensitizes lung cancer to ICB therapy. Firstly, a systems pharmacology strategy was proposed to identify combinatorial drugs for ICB therapy with a systems biology perspective of drug-target-pathway-TME phenotype. We predicted and verified that RC significantly inhibits tumor growth and the infiltration of M2-TAMs into TME of LLC tumor-bearing mice. Then, RC inhibits the recruitment of macrophages to the tumor TME via blocking LTB4 signaling, and suppresses the expression of immunosuppressive factors (IL-10, TGF-β and VEGF). As a result, RC enables CD8+ T cells to retain their proliferative and infiltrative abilities within the TME. Ultimately, these events promote cytotoxic T-cell-mediated clearance of tumor cells, which is further enhanced by the addition of anti-PD-L1 therapy. Furthermore, we employed LTA4H deficient mice (Lta4h-/- mice) to evaluate the antitumor efficiency, the results showed that the efficacy of immunotherapy was enhanced due to the synergistic effect of LTB4 signaling blockage and ICB inhibition, leading to remarkable inhibition of tumor growth in a mouse model of lung adenocarcinoma.Taken together, these findings suggest that RC enhances antitumor immunity, providing a rationale for combining RC with immunotherapies as a potential anti-cancer treatment strategy.Copyright © 2023 Elsevier GmbH. All rights reserved.