中性粒细胞的表型和功能是动态变化的，其受微环境的影响而发生改变，例如肿瘤微环境（TME）内的N1抗肿瘤和N2促肿瘤状态。但它的调节仍未确定。在这里，我们研究了转化生长因子β1/Smad3信号在非小细胞肺癌（NSCLC）患者的肿瘤相关中性粒细胞（TAN）中的作用。Smad3在N2 TAN中的激活与N1人群和患者生存率呈负相关。在实验性肺癌中，TAN从野生型小鼠的主要N2状态转变为Smad3-KO小鼠中的N1状态，与增强的中性粒细胞浸润和肿瘤消退相关。中性粒细胞消减使Smad3-KO小鼠的N1抗癌表型消失，而移植Smad3-KO中性粒细胞则可在野生型小鼠中重现保护作用。单细胞分析揭示了在Smad3-KO TME中表现成熟N1表型的TAN亚群，而野生型TAN主要保留未成熟的N2状态，这是由于Smad3所致。机械上，TME诱导的Smad3靶基因与细胞命运决定相关，以保持TAN的N2状态。重要的是，Smad3的基因敲除和药物抑制通过促进N1成熟增强中性粒细胞对NSCLC的抗癌能力。因此，我们的工作表明，中性粒细胞中的Smad3信号可能代表着癌症免疫治疗的治疗靶点。©2023年作者。

Neutrophils are dynamic with their phenotype and function shaped by the microenvironment, such as the N1 antitumor and N2 pro-tumor states within the tumor microenvironment (TME), but its regulation remains undefined. Here we examine TGF-β1/Smad3 signaling in tumor-associated neutrophils (TANs) in non-small cell lung carcinoma (NSCLC) patients. Smad3 activation in N2 TANs is negatively correlate with the N1 population and patient survival. In experimental lung carcinoma, TANs switch from a predominant N2 state in wild-type mice to an N1 state in Smad3-KO mice which associate with enhanced neutrophil infiltration and tumor regression. Neutrophil depletion abrogates the N1 anticancer phenotype in Smad3-KO mice, while adoptive transfer of Smad3-KO neutrophils reproduces this protective effect in wild-type mice. Single-cell analysis uncovers a TAN subset showing a mature N1 phenotype in Smad3-KO TME, whereas wild-type TANs mainly retain an immature N2 state due to Smad3. Mechanistically, TME-induced Smad3 target genes related to cell fate determination to preserve the N2 state of TAN. Importantly, genetic deletion and pharmaceutical inhibition of Smad3 enhance the anticancer capacity of neutrophils against NSCLC via promoting their N1 maturation. Thus, our work suggests that Smad3 signaling in neutrophils may represent a therapeutic target for cancer immunotherapy.© 2023. The Author(s).