骨肉瘤（OS）是最常见的恶性骨肿瘤，儿童和青少年的发病率较高。肿瘤的频繁转移和术后复发是OS最常见的挑战。然而，其详细机制仍然不为人知。我们通过免疫组化（IHC）染色检查了OS组织芯片中CD248的表达，并研究了CD248在OS细胞增殖、侵袭和迁移中的生物学功能，包括CCK8实验、Transwell和伤口愈合实验等。我们还研究了其在OS转移中的功能。最后，我们使用RNA-seq、Western blot、免疫荧光染色和共同免疫沉淀，利用CD248敲除OS细胞，探索了CD248如何促进OS转移的潜在机制。CD248在OS组织中高度表达，其高表达与OS的肺转移有关。CD248在OS细胞中的敲除明显抑制了细胞迁移、侵袭和转移，而对细胞增殖没有明显影响。当CD248被敲除时，裸鼠的肺转移明显受到抑制。从机制上讲，我们发现CD248可以促进ITGB1与细胞外基质（ECM）蛋白如CYR61和FN之间的相互作用，从而激活FAK-paxillin通路，促进成像焦点的形成和OS的转移。我们的数据表明，高CD248表达与OS的转移潜力相关联。CD248可能通过增强ITGB1与某些ECM蛋白之间的相互作用来促进迁移和转移。因此，CD248是转移性OS的诊断潜在标志物和有效靶点。 ©2023年，作者。

Osteosarcoma (OS) is the most common malignant bone tumor with a high incidence in children and adolescents. Frequent tumor metastasis and high postoperative recurrence are the most common challenges in OS. However, detailed mechanism is largely unknown.We examined the expression of CD248 in OS tissue microarrays by immunohistochemistry (IHC) staining. We studied the biological function of CD248 in cell proliferation, invasion and migration of OS cells by CCK8 assay, transwell and wound healing assay. We also studied its function in the metastasis of OS in vivo. At last, we explored the potential mechanism how CD248 promotes OS metastasis by using RNA-seq, western blot, immunofluorescence staining and co-immunoprecipitation using CD248 knockdown OS cells.CD248 was highly expressed in OS tissues and its high expression was correlated with pulmonary metastasis of OS. Knockdown of CD248 in OS cells significantly inhibited cell migration, invasion and metastasis, while had no obvious effect on cell proliferation. Lung metastasis in nude mice was significantly inhibited when CD248 was knocked down. Mechanistically, we found that CD248 could promote the interaction between ITGB1 and extracellular matrix (ECM) proteins like CYR61 and FN, which activated the FAK-paxillin pathway to promote the formation of focal adhesion and metastasis of OS.Our data showed that high CD248 expression is correlated with the metastatic potential of OS. CD248 may promote migration and metastasis through enhancing the interaction between ITGB1 and certain ECM proteins. Therefore, CD248 is a potential marker for diagnosis and effective target for the treatment of metastatic OS.© 2023. The Author(s).