Abstract
Endosialin/CD248/tumor endothelial marker 1 is classified as a C-type lectin-like transmembrane receptor, found on the plasma membrane of activated mesenchymal cells, which binds to fibronectin. Although endosialin is expressed at high levels in stem-like cells of sarcomas, its role has not been fully uncovered. The present study aimed to determine whether endosialin expression is associated with tumor progression and metastasis, and whether endosialin has the potential to act as a novel therapeutic target in osteosarcoma (OS) using MORAb-004/ontuxizumab, a humanized monoclonal antibody, which targets the type C lectin domain of endosialin. The results demonstrated that endosialin was highly expressed in OSs with metastatic disease. Furthermore, MORAb-004 had no cytostatic effect on OS cells in vitro and did not change the expression of stem cells and differentiation markers; however, it inhibited migration of OS cells. Taken together, these results suggest that endosialin may play a role in migration, and may be involved in the metastatic process of OSs. Furthermore, MORAb-004 reduces the motility of OS cells, and suppresses invasion and the development of metastatic lesions.