衰老中性粒细胞通过线粒体转位-胞外捕获网构建乳腺癌肺转移前微环境的新机制

Breast cancer is one of the most common malignant tumor in women, and distant metastasis is the main cause of death. Pre-metastatic niche formation is a critical stage of tumor metastasis. We found that aged neutrophils are closely related to it: in the early stages of breast cancer progression, aged neutrophils are recruited in lung tissue and form pre-metastatic niche by forming vital neutrophil extracellular traps (NETs). Further studies have found that NETs are associated with mitochondrial trafficking and decreased membrane potential. At present, there are no reports on the biological functions of aged neutrophils associated with tumor metastasis and the formation mechanism of vital NETs. Therefore, we propose a hypothesis that neutrophil aging- ROS injury- mitochondrial trafficking- vital NETs formation- lung pre-metastatic niche formation and finallly promote breast cancer lung metastasis. We use a variety of breast cancer animal models to systematically explore the characteristics and functions of aged neutrophils in the formation of breast cancer lung pre-metastatic niche through transcriptome sequencing, energy metabolism detection, and live tracing techniques; Mechanisms of vital NETs; evaluation of potential applications of targeted interventions for aged neutrophils and NETs-related mechanisms. The completion of the project can enrich the relevant theory of pre-metastatic niche and provide a new target for prevention and treatment of tumor metastasis.

乳腺癌是女性最常见的恶性肿瘤，远处转移是死亡主因。转移前微环境形成是肿瘤转移的关键阶段。我们发现衰老中性粒细胞与其密切相关：乳腺癌进展早期，衰老中性粒细胞于肺组织募集并通过形成非致死性胞外捕获网（NETs）营造转移前微环境。进一步研究发现衰老中性粒细胞NETs与其线粒体转位和膜电位下降有关。目前对肿瘤转移相关衰老中性细胞的生物学功能、非致死性NETs的形成机制尚不清楚。由此我们提出“中性粒细胞衰老—ROS损伤—线粒体转位—非致死性NETs形成—肺转移前微环境建立”进而促进乳腺癌肺转移的假说。为此我们利用多种乳腺癌小鼠模型，通过转录组测序、能量代谢检测、活体示踪等技术，系统探索衰老中性粒细胞在肺转移前微环境形成中的特征与功能；阐明线粒体参与形成非致死性NETs的机制；评价靶向干预衰老中性粒细胞及NETs相关机制的潜在应用价值。项目的完成可丰富转移前微环境相关理论，为防治肿瘤转移提供新靶点。

乳腺癌是女性最常见恶性肿瘤，远处转移是其主要死因。其中三阴性乳腺癌是恶性程度最高、最易发生肺转移的乳腺癌亚型，是目前临床治疗的难点和热点。既往研究提示肿瘤转移发生与转移前免疫微环境形成密切相关，且免疫细胞参与其中，但机制尚不清。申请人前期发现一群新型衰老中性粒细胞亚群在三阴性乳腺癌转移中具有关键调控作用。基于此，申请人以三阴性乳腺癌转移前微环境为核心，围绕衰老中性粒细胞生物学功能，通过流式细胞分选、高通量转录组测序、能量代谢检测、活细胞体内示踪、扫描电镜、透射电镜等技术，开展以下工作：1）系统性检测了肺转移前微环境中免疫细胞构成，发现了衰老中性粒细胞是调控转移前免疫微环境的主导细胞；2）阐明了衰老中性粒细胞通过胞外捕获网促进乳腺癌肺转移的生物学特性；3）分析了肺转移前微环境中中性粒细胞异质性差异，明确了衰老中性粒细胞通过SIRT1形成非致死性NETs的关键机制；4）通过动物体内靶向干预治疗进一步揭示了衰老中性粒细胞促进三阴性乳腺癌肺转移的重要意义，并提出“衰老中性粒细胞通过非致死性线粒体胞外捕获网形成肿瘤转移前微环境进而促进乳腺癌肺转移”科学假说，临床转化提供了新的方向。.在本项目的资助下，申请人围绕“乳腺癌转移前微环境”开展系列性研究，并发表相关SCI论文5篇，其中一区高质量SCI论文2篇；并获得国家发明专利1项。.