携带 EGFR 突变的非小细胞肺癌 (NSCLC) 患者对免疫检查点抑制剂 (ICI) 单药治疗表现出不良反应，其肿瘤微环境 (TME) 通常受到免疫抑制。 TGF-β在免疫抑制中发挥重要作用；然而，TGF-β对TME的影响以及抗PD-1免疫疗法对EGFR突变肿瘤的疗效仍不清楚。相应的体外研究使用了TCGA数据库、临床标本和自建的带有EGFR的小鼠细胞系突变。我们利用携带 EGFR 突变 NSCLC 的 C57BL/6N 和人源化 M-NSG 小鼠模型来研究 TGF-β 对 TME 的影响以及 TGF-β 阻断和抗 PD-1 治疗的联合疗效。通过流式细胞术监测免疫细胞的变化。 TGF-β 与 EGFR 突变 NSCLC 免疫治疗结果之间的相关性已通过临床样本得到验证。我们发现 EGFR 突变 NSCLC 中 TGF-β 通过 EGFR 激活和随后的 ERK1/2-p90RSK 磷酸化而上调。 TGF-β在体外和体内均直接抑制CD8 T细胞浸润、增殖和细胞毒性，但阻断TGF-β并不能抑制体内EGFR突变肿瘤的生长。抗TGF-β抗体联合抗PD-1抗体显着抑制C57BL/6N小鼠重组EGFR突变肿瘤的增殖，优于其单一疗法。从机制上讲，抗TGF-β和抗PD-1抗体的组合显着增加了CD8 T细胞的浸润，增强了CD8 T细胞的抗肿瘤功能。此外，我们发现EGFR-TKI耐药细胞系中TGF-β1的表达显着高于亲本细胞系。抗TGF-β和纳武单抗联合显着抑制人源化M-NSG小鼠中EGFR-TKI耐药肿瘤的增殖并延长其生存期。我们的结果表明，EGFR突变的NSCLC中TGF-β表达通过EGFR-TKI表达上调。 ERK1/2-p90RSK 信号通路。 TGF-β的高表达抑制CD8 T细胞的浸润和抗肿瘤功能，导致EGFR突变肿瘤的“冷”TME。阻断 TGF-β 可以重塑 TME，增强抗 PD-1 对 EGFR 突变肿瘤的治疗效果，这为 EGFR 突变的晚期 NSCLC 患者提供了潜在的联合免疫治疗策略。© 2024。作者。

Non-small cell lung cancer (NSCLC) patients with EGFR mutations exhibit an unfavorable response to immune checkpoint inhibitor (ICI) monotherapy, and their tumor microenvironment (TME) is usually immunosuppressed. TGF-β plays an important role in immunosuppression; however, the effects of TGF-β on the TME and the efficacy of anti-PD-1 immunotherapy against EGFR-mutated tumors remain unclear.Corresponding in vitro studies used the TCGA database, clinical specimens, and self-constructed mouse cell lines with EGFR mutations. We utilized C57BL/6N and humanized M-NSG mouse models bearing EGFR-mutated NSCLC to investigate the effects of TGF-β on the TME and the combined efficacy of TGF-β blockade and anti-PD-1 therapy. The changes in immune cells were monitored by flow cytometry. The correlation between TGF-β and immunotherapy outcomes of EGFR-mutated NSCLC was verified by clinical samples.We identified that TGF-β was upregulated in EGFR-mutated NSCLC by EGFR activation and subsequent ERK1/2-p90RSK phosphorylation. TGF-β directly inhibited CD8+ T cell infiltration, proliferation, and cytotoxicity both in vitro and in vivo, but blocking TGF-β did not suppress the growth of EGFR-mutated tumors in vivo. Anti-TGF-β antibody combined with anti-PD-1 antibody significantly inhibited the proliferation of recombinant EGFR-mutated tumors in C57BL/6N mice, which was superior to their monotherapy. Mechanistically, the combination of anti-TGF-β and anti-PD-1 antibodies significantly increased the infiltration of CD8+ T cells and enhanced the anti-tumor function of CD8+ T cells. Moreover, we found that the expression of TGF-β1 in EGFR-TKI resistant cell lines was significantly higher than that in parental cell lines. The combination of anti-TGF-β and nivolumab significantly inhibited the proliferation of EGFR-TKI resistant tumors in humanized M-NSG mice and prolonged their survival.Our results reveal that TGF-β expression is upregulated in NSCLC with EGFR mutations through the EGFR-ERK1/2-p90RSK signaling pathway. High TGF-β expression inhibits the infiltration and anti-tumor function of CD8+ T cells, contributing to the "cold" TME of EGFR-mutated tumors. Blocking TGF-β can reshape the TME and enhance the therapeutic efficacy of anti-PD-1 in EGFR-mutated tumors, which provides a potential combination immunotherapy strategy for advanced NSCLC patients with EGFR mutations.© 2024. The Author(s).