LBPO.MCB02 · 分子与细胞生物学 · Late-Breaking
血小板来源的TGF-beta启动中性粒细胞HIF-1alpha/NETs正反馈环路，驱动骨肉瘤瘤内缺氧和肺转移
Platelet-derived TGF-beta initiates a neutrophil HIF-1alpha/NETs positive feedback loop driving osteosarcoma intratumoral hypoxia and lung metastasis
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摘要 Abstract
中文摘要
背景：骨肉瘤（OS）是儿童和青少年中最常见的原发性恶性骨肿瘤，30%-40%的病例会发生肺转移。瘤内缺氧是OS患者预后不良和肺转移的一个公认危险因素。此前，缺氧被认为在很大程度上是肿瘤生长超过营养供给的被动结果。这一在很大程度上被动的过程传统上被认为是不可靶向的。然而，最新证据显示它可以由动态细胞过程调控。因此，我们研究了驱动OS瘤内缺氧的机制。
实验设计：从OS患者中收集高转移性肿瘤瘤栓以及原发肿瘤样本（N=18）。对配对的肿瘤瘤栓和原发肿瘤样本进行单细胞RNA测序（scRNA-seq）。在体外和体内分析了血小板来源的TGF-beta、中性粒细胞HIF-1alpha和中性粒细胞胞外诱捕网（NETs）之间的相互作用。中性粒细胞相关实验使用来自健康供者的原代中性粒细胞和DMSO诱导的中性粒细胞样HL-60（dHL-60）细胞。收集临床OS数据进行验证。
结果：scRNA-seq显示，与原发肿瘤相比，肿瘤瘤栓中中性粒细胞浸润显著增加。与原发肿瘤中的中性粒细胞相比，肿瘤瘤栓中的中性粒细胞表现出明显升高的TGF-beta、HIF-1alpha和NETs信号。体内肺定植和转移模型证实中性粒细胞促进OS肺转移。体外实验证明，在常氧条件下，血小板来源的TGF-beta通过上调HIF-1alpha触发NET形成。在NETosis过程中，中性粒细胞消耗氧气，诱导瘤内缺氧并放大HIF-1alpha信号。因此，血小板来源的TGF-beta在常氧条件下启动中性粒细胞HIF-1alpha/NETs正反馈环路，驱动OS瘤内缺氧。靶向TGF-beta/HIF-1alpha/NETs轴在体内显著抑制肺转移并缓解瘤内缺氧。HIF-1alpha和NETs表达升高的患者预后明显较差。
结论：总之，这些发现为OS瘤内缺氧机制提供了新见解，强调缺氧并非被动过程，而是由血小板和中性粒细胞之间的TGF-beta/HIF-1alpha/NETs轴主动驱动的。
查看英文原文 English abstract
Background: Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents, with 30%-40% of cases developing lung metastasis. Intratumoral hypoxia is a well-established risk factor for poor prognosis and lung metastasis in OS patients. Previously, hypoxia was considered a largely passive consequence of tumor growth exceeding nutrient supply. This largely passive process has traditionally been considered non-targetable. However, recent evidence reveals it can be regulated by dynamic cellular processes. We therefore investigated the mechanism driving intratumoral hypoxia in OS.
Experimental design: High metastatic tumor thrombi from OS patients were collected alongside primary tumor samples (N=18). Single-cell RNA sequencing (scRNA-seq) was performed on paired tumor thrombus and primary tumor samples. The interplay between platelet-derived TGF-beta, neutrophil HIF-1alpha, and neutrophil extracellular traps (NETs) was analyzed in vitro and in vivo . Neutrophil related experiments used primary neutrophils from healthy donors and DMSO-induced neutrophil-like HL-60 (dHL-60) cells. Clinical OS data were collected for validation.
Results: scRNA-seq revealed significantly increased neutrophil infiltration in tumor thrombi compared with primary tumors. Neutrophils in tumor thrombi exhibited markedly elevated TGF-beta, HIF-1alpha, and NETs signalings compared to those in primary tumors. In vivo lung colonization and metastasis models confirmed neutrophils promote OS lung metastasis. In vitro experiments demonstrated that platelet-derived TGF-beta triggers NET formation via HIF-1alpha upregulation under normoxia. During NETosis, neutrophils consumed oxygen, inducing intratumoral hypoxia and amplifying HIF-1alpha signaling. Thus, platelet-derived TGF-beta initiates a neutrophil HIF-1alpha/NETs positive feedback loop that drives OS intratumoral hypoxia under normoxia. Targeting the TGF-beta/HIF-1alpha/NETs axis significantly suppressed lung metastasis and alleviated intratumoral hypoxia in vivo . Patients with elevated HIF-1alpha and NETs expression had significantly poorer prognosis.
Conclusions: Together, these findings provide novel insights into the mechanism of intratumoral hypoxia in OS, highlighting hypoxia is not a passive process but is actively driven by the TGF-beta/HIF-1alpha/NETs axis between platelets and neutrophils.
利益披露 Disclosure
Q. Shi, None..
T. Ji, None.