Establishment and characterization of a novel human osteosarcoma cell line for spontaneous pulmonary metastasis research in vivo

Background: A large number of osteosarcoma patients are dying of pulmonary metastasis in spite of the recent progress achieved in treatment research. Therefore, there is an urgent need for an in vivo experiment, whose purpose is to investigate the growth and metastasis of human osteosarcoma tumor. In this study, a novel human osteosarcoma cell line was established and characterized for osteosarcoma metastatic research in vivo. Methods: Small pieces of parental primary osteosarcoma samples from a 16-year-old boy were xeno-transplanted into NOD/SCID mice. Then, osteosarcoma cells from the xeno-grafts were isolated and further passaged in vitro. Expression profiling was confirmed using HE staining and immunohistochemistry. The tumorigenic and metastatic ability of the established cell line was analyzed by cell scratch and CCK8 assay in vitro, and tumor transplantation in NOD/SCID mice. Results: Parental cells were pleomorphic and positive with ALP, SSEA-4, and CD44. Osteosarcoma cells, named Well5 cells, were successfully isolated and had the ability of adipogenesis and osteogenesis. Well5 cells were mostly positive for SSEA-4 protein, and possessed morphological characteristics such as osteoblastic nature during the cultivation and hetero transplantation. Cell scratch and CCK8 assay indicated Well5 cells obtained a better capacity for migration and proliferation than the MG63 cell line. In NOD/SCID mice, orthotopic tumors were established at the primary site, and spontaneous pulmonary metastases were developed. Conclusions: A novel human osteosarcoma cell line was successfully established, which may be helpful for spontaneous pulmonary metastasis research in vivo.