Laboratory of Tumor Immunology, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.
Key Laboratory of Major Diseases in Children, Ministry of Education, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.
Front Immunol. 2024 Feb 29;15:1363454. doi: 10.3389/fimmu.2024.1363454. eCollection 2024.
Pediatric hepatoblastoma (HB) is the most common primary liver malignancy in infants and children. With great diversity and plasticity, tumor-infiltrating neutrophils were one of the most determining factors for poor prognosis in many malignant tumors. In this study, through bulk RNA sequencing for sorted blood and tumor-infiltrated neutrophils and comparison of neutrophils in tumor and para-tumor tissue by single-cell sequencing, we found that intratumoral neutrophils were composed of heterogenous functional populations at different development stages. Our study showed that terminally differentiated neutrophils with active ferroptosis prevailed in tumor tissue, whereas, in para-tumor, pre-fate naïve neutrophils were dominant and ferroptotic neutrophils dispersed in a broad spectrum of cell maturation. Gene profiling and T-cell coculture experiment confirmed that one of main functional intratumoral neutrophils was mainly immunosuppressive, which relied on the activation of ferroptosis. Combining the bulk RNA-seq, scRNA-seq data, and immunochemistry staining of tumor samples, CXCL12/CXCR4 chemotaxis pathway was suggested to mediate the migration of neutrophils in tumors as CXCR4 highly expressed by intratumoral neutrophils and its ligand CXCL12 expressed much higher level in tumor than that in para-tumor. Moreover, our study pinpointed that infiltrated CXCR4 neutrophils, regardless of their differential distribution of cell maturation status in HB tumor and para-tumor regions, were the genuine perpetrators for immune suppression. Our data characterized the ferroptosis-dependent immunosuppression energized by intratumoral CXCR4 expression neutrophils and suggest a potential cell target for cancer immunotherapies.
小儿肝母细胞瘤（HB）是婴儿和儿童中最常见的原发性肝脏恶性肿瘤。具有巨大的多样性和可塑性，肿瘤浸润中性粒细胞是许多恶性肿瘤预后不良的最决定性因素之一。在这项研究中，我们通过对分选的血液和肿瘤浸润中性粒细胞进行 bulk RNA 测序，并通过单细胞测序比较肿瘤和瘤旁组织中的中性粒细胞，发现肿瘤内中性粒细胞由不同发育阶段的异质功能群体组成。我们的研究表明，在肿瘤组织中，终末分化的具有活跃铁死亡的中性粒细胞占优势，而在瘤旁组织中，幼稚的前命运中性粒细胞占优势，铁死亡的中性粒细胞分布在广泛的细胞成熟谱中。基因谱分析和 T 细胞共培养实验证实，主要功能的肿瘤内中性粒细胞之一主要是免疫抑制性的，这依赖于铁死亡的激活。结合 bulk RNA-seq、scRNA-seq 数据和肿瘤样本的免疫化学染色，我们提出趋化因子 CXCL12/CXCR4 信号通路介导中性粒细胞在肿瘤中的迁移，因为肿瘤内中性粒细胞高表达 CXCR4，其配体 CXCL12 在肿瘤中的表达水平明显高于瘤旁组织。此外，我们的研究还指出，浸润的 CXCR4 中性粒细胞，无论其在 HB 肿瘤和瘤旁区域的细胞成熟状态的差异分布如何，都是免疫抑制的真正元凶。我们的数据描述了由肿瘤内 CXCR4 表达中性粒细胞驱动的铁死亡依赖性免疫抑制，并为癌症免疫治疗提供了一个潜在的细胞靶点。
