Aberrant Activation of Wound Healing Programs within the Metastatic Niche Facilitates Lung Colonization by Osteosarcoma Cells

Lung metastasis is responsible for nearly all deaths caused by osteosarcoma, the most common pediatric bone tumor. How malignant bone cells coerce the lung microenvironment to support metastatic growth is unclear. This study delineates how osteosarcoma cells educate the lung microenvironment during metastatic progression.Using single-cell transcriptomics (scRNA-seq), we characterized genome– and tissue-wide molecular changes induced within lung tissues by disseminated osteosarcoma cells in both immunocompetent murine models of metastasis and patient samples. We confirmed transcriptomic findings at the protein level and determined spatial relationships with multi-parameter immunofluorescence. We evaluated the ability of nintedanib to impair metastatic colonization and prevent osteosarcoma-induced education of the lung microenvironment in both immunocompetent murine osteosarcoma and immunodeficient human xenograft models.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 that seen in other models of lung injury. Accordingly, metastasis-associated lung demonstrated marked fibrosis, likely due to the accumulation of pathogenic, pro-fibrotic, partially-differentiated epithelial intermediates. Inhibition of fibrotic pathways with nintedanib prevented metastatic progression in multiple murine and human xenograft models. Our work demonstrates that osteosarcoma cells co-opt fibrosis to promote metastatic outgrowth. When harmonized with data from adult epithelial cancers, our results support a generalized model wherein aberrant mesenchymal-epithelial interactions are critical for promoting lung metastasis. Adult epithelial carcinomas induce fibrotic pathways in normal lung fibroblasts, whereas osteosarcoma, a pediatric mesenchymal tumor, exhibits fibrotic reprogramming in response to the aberrant wound-healing behaviors of an otherwise normal lung epithelium, which are induced by tumor cell interactions.]]>
Inclusion Criteria:Subjects must meet one of the following criteria: Patients of any age group diagnosed with a malignant, intermediate or low grade solid tumors. Patients with newly diagnosed solid tumors who have imaging suggestive of a tumor with malignant potential who are undergoing tumor biopsy or resection. Patients previously diagnosed with a solid tumor that are undergoing a subsequent biopsy or resection of primary, metastatic or recurrent disease. Patients with a diagnosis of a solid tumor undergoing treatment. Patients with a diagnosis of a solid tumor who have completed treatment within the last 5 years. Subjects must be able to understand and sign the informed consent form directly or through an authorized representative. All existing enrollments on IRB#11-00478 will be rolled over to this study with continued specimen and data collection. There were no exclusion criteria.]]>