A Novel Orthotopic Mouse Model of Lung Metastasis Using Fluorescent Patient-derived Osteosarcoma Cells

Background: A mouse model of metastatic osteosarcoma is imperative to identify effective agents for metastatic osteosarcoma, which is a recalcitrant disease. In the present study, we established osteosarcoma patient-derived cells (OS-PDCs) and transfected them with green fluorescent protein (GFP). Materials and Methods: The OS-PDCs were transfected with GFP-lentivirus. GFP-expressing OS-PDCs (2.0×10⁵) were then injected into the tibia of nude mice to establish the patient-derived orthotopic cell (PDOC) model (n=3). Six weeks after injection, the primary tumor and each organ were resected and imaged. Results: Primary orthotopic tumors were established in two out of three mice. The GFP-expressing OS-PDCs in the PDOC model were visualized. Multiple GFP-expressing lung metastases were detected in one of the two mice with primary tumor. Conclusion: The present study proves the concept that a GFP-expressing PDOC model can mimic clinical lung-metastatic osteosarcoma. This model can serve as a paradigm to screen for effective drugs for osteosarcoma lung metastasis.