Purpose: Lung metastasis is responsible for most deaths caused by osteosarcoma. How malignant bone cells coerce the lung microenvironment to support metastatic growth remains unclear. We sought to identify metastasis-specific therapeutic vulnerabilities by delineating the cellular and molecular mechanisms essential to metastatic niche formation in the lung. Experimental design: We used single-cell transcriptomics (scRNA-seq) to characterize molecular changes induced within lung tissues by disseminated osteosarcoma cells. We then evaluated the ability of nintedanib to reverse metastasis-specific changes in both immunocompetent mouse and immunodeficient xenograft models. Molecular pharmacodynamic studies used single-nucleus and spatial transcriptomics to define the tumor-intrinsic and -extrinsic changes induced by the drug. Results: Osteosarcoma cells induced acute alveolar epithelial injury upon lung dissemination. scRNA-seq demonstrated that the surrounding lung stroma adopts a chronic, non-resolving wound-healing phenotype similar to diseases associated with lung injury. Accordingly, metastasis-associated lung demonstrated marked fibrosis, likely due to the accumulation of pathogenic, pro-fibrotic, partially differentiated epithelial intermediates and macrophages. Our data suggested that nintedanib prevented metastatic progression in multiple murine and human xenograft models by inhibiting osteosarcoma-induced fibrosis. Conclusions: Fibrosis is essential to osteosarcoma lung metastasis and represents a targetable vulnerability. Our data support a model where interactions between osteosarcoma and epithelial cells induce the deposition of extracellular matrix proteins—a reaction disrupted by the anti-fibrotic TKI nintedanib. Our data shed light on the non-cell autonomous effects of TKIs on metastasis and provide a roadmap for using single-cell and spatial transcriptomics to define the mechanism of action of TKIs on metastases in animal models.

中文翻译：

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转移性生态位内伤口愈合程序的异常激活促进了骨肉瘤细胞的肺定植


目的：肺转移是导致骨肉瘤导致的大多数死亡的原因。恶性骨细胞如何胁迫肺微环境以支持转移性生长仍不清楚。我们试图通过描述对肺部转移性生态位形成至关重要的细胞和分子机制来识别转移特异性治疗脆弱性。实验设计： 我们使用单细胞转录组学 （scRNA-seq） 来表征播散性骨肉瘤细胞在肺组织内诱导的分子变化。然后，我们评估了尼达尼布在免疫功能正常的小鼠和免疫缺陷异种移植模型中逆转转移特异性变化的能力。分子药效学研究使用单核和空间转录组学来定义药物诱导的肿瘤内在和外在变化。结果： 骨肉瘤细胞在肺播散时诱导急性肺泡上皮损伤。scRNA-seq 证明，周围的肺基质采用类似于肺损伤相关疾病的慢性、不解决性伤口愈合表型。因此，转移相关肺表现出明显的纤维化，这可能是由于致病性、促纤维化、部分分化的上皮中间体和巨噬细胞的积累。我们的数据表明，尼达尼布通过抑制骨肉瘤诱导的纤维化来阻止多种小鼠和人异种移植模型的转移进展。结论： 纤维化是骨肉瘤肺转移的必要条件，是一种可靶向的脆弱性。我们的数据支持一个模型，其中骨肉瘤和上皮细胞之间的相互作用诱导细胞外基质蛋白的沉积——这种反应被抗纤维化 TKI 尼达尼布破坏。 我们的数据阐明了 TKIs 对转移的非细胞自主作用，并为使用单细胞和空间转录组学来确定 TKIs 对动物模型中转移的作用机制提供了路线图。