Supplementary Material for: Anti-Tumor Necrosis Factor Therapy Inhibits Lung Metastasis in an Osteosarcoma Cell Line

Background: Osteosarcoma is the most common primary malignancy of bone, and patients often develop pulmonary metastases. In a previous study, tumor necrosis factor (TNF)-α treatment of human osteosarcoma cells increases their metastatic ability in an animal model. TNF-α can act as a tumor necrosis factor and also as a tumor-promoting factor. In the present study, the effect of a TNF-α inhibitor on osteosarcoma aggressiveness and pulmonary metastases was investigated in vitro and in vivo. Methods: The effect of infliximab, a TNF-α inhibitor, on a metastatic osteosarcoma 143B cell growth and motility was investigated in vitro. An orthotopic xenograft model of 143B cell growth and spontaneous metastasis in SCID mice was used to assess the in vivo effect of infliximab. Results: Infliximab greatly reduced cell motility and pulmonary metastases in 143B cells. The mechanism of pulmonary metastasis inhibition involved decreased expression of CXC chemokine receptor 4 (CXCR4), Rho (small GTPase protein), and its effector. Conclusions: These results suggest a novel role for TNF-α inhibition in the reduction or prevention of pulmonary metastases of osteosarcoma in this animal model. TNF-α inhibition may become a preventive therapeutic option for the pulmonary metastases of osteosarcoma. © 2014 S. Karger AG, Basel