National Human Diseases Animal Model Resource Center, The Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100021, China.
NHC Key Laboratory of Human Disease Comparative Medicine, Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Beijing, China.
J Transl Med. 2022 Oct 2;20(1):446. doi: 10.1186/s12967-022-03649-4.
Metastasis is the primary cause of cancer-related mortality. Metastasis involves a complex multistep process during which individual tumor cells spread primarily through destruction of the endothelial barrier, entering the circulatory system to colonize distant organs. However, the role of the endothelial barrier as the rate-limiting process in tumor metastasis and how these processes affect the regulation of the host microenvironment at the molecular level are poorly understood.
Here, we analyzed differentially expressed genes in breast cancer and lung adenocarcinoma, including metastatic and recurrent specimens, using TCGA dataset. The effects of EMCN on endothelial cells in vitro and in vivo were analyzed by assessing angiogenesis and vascular permeability, respectively. We established a syngeneic mouse model of endothelial cell-specific knockout of EMCN (EMCN) to study the role of EMCN in tumor growth and metastasis. Transcriptome sequencing, Western blotting, qPCR and immunofluorescence confirmed important factors in the premetastatic niche. A mouse model of allograft tumor resection with lung metastasis was established to confirm the therapeutic effect of a notch inhibitor combined with an anti-TGF-β antibody.
We found a strong correlation of EMCN deficiency with tumor recurrence and metastasis. Comparative experiments in WT and EMCN mice revealed that endothelial EMCN deficiency did not affect primary tumor growth significantly but strongly promoted spontaneous metastasis. EMCN deficiency was associated with gene profiles that regulate cell junctions in vitro and enhance vascular permeability in vivo. Mechanistically, EMCN deficiency mainly affected the host microenvironment and led to the formation of a lung premetastatic niche by recruiting Ly6G neutrophils and upregulating MMP9, S100A8/A9 and TGF-β expression. Anti-TGF-β antibody effectively eliminated TGF-β-induced neutrophil polarization, thereby reducing lung metastasis. Notably, the combination of a Notch inhibitor and an anti-TGF-β antibody effectively inhibited tumor growth and lung metastasis and prolonged the survival time of mice.
We present a new translational strategy of EMCN as a new key player in tumor lung metastasis by affecting the host microenvironment. These findings could provide a sound theoretical basis for clinical treatment.
转移是癌症相关死亡的主要原因。转移涉及一个复杂的多步骤过程，在此过程中，单个肿瘤细胞主要通过破坏内皮屏障扩散，进入循环系统在远处器官定植。然而，内皮屏障作为肿瘤转移的限速过程的作用，以及这些过程如何在分子水平上影响宿主微环境的调节，目前了解甚少。
在这里，我们使用 TCGA 数据集分析了包括转移性和复发性标本在内的乳腺癌和肺腺癌中的差异表达基因。通过评估血管生成和血管通透性，分别分析 EMCN 对体外和体内内皮细胞的影响。我们建立了内皮细胞特异性敲除 EMCN（EMCN）的同基因小鼠模型，以研究 EMCN 在肿瘤生长和转移中的作用。转录组测序、Western blotting、qPCR 和免疫荧光证实了前转移龛中的重要因素。建立了同种异体肿瘤切除伴肺转移的小鼠模型，以证实 Notch 抑制剂联合抗 TGF-β 抗体的治疗效果。
我们发现 EMCN 缺陷与肿瘤复发和转移有很强的相关性。WT 和 EMCN 小鼠的比较实验表明，内皮细胞 EMCN 缺陷对原发性肿瘤生长没有明显影响，但强烈促进自发性转移。EMCN 缺陷与体外调节细胞连接和体内增强血管通透性的基因谱相关。从机制上讲，EMCN 缺陷主要影响宿主微环境，并通过募集 Ly6G 中性粒细胞和上调 MMP9、S100A8/A9 和 TGF-β 表达来形成肺前转移龛。抗 TGF-β 抗体可有效消除 TGF-β 诱导的中性粒细胞极化，从而减少肺转移。值得注意的是，Notch 抑制剂和抗 TGF-β 抗体的联合使用可有效抑制肿瘤生长和肺转移，并延长小鼠的生存时间。
我们提出了一种新的转移策略，即 EMCN 通过影响宿主微环境成为肿瘤肺转移的新关键因素。这些发现为临床治疗提供了坚实的理论基础。
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