In vitro characterization of OSA-424 and OSA-55: new canine models for osteosarcoma research.

Canine osteosarcoma (OSA) represents a highly aggressive malignancy known for its high rates of recurrence and metastatic potential. This study establishes and characterizes two novel OSA cell lines, OSA-424 and OSA-55, derived from osteoblastic and chondroblastic subtypes, respectively. We conducted a comparative analysis against the established canine chondrosarcoma line Mango. Comprehensive characterization included primary tumor imaging using computed tomography (CT) and magnetic resonance imaging (MRI), as well as histopathological evaluation and immunohistochemical (IHC) profiling. In vitro, functional analyses assessed cellular morphology, karyotypic stability, proliferative capacity, extracellular matrix (ECM) composition, proteomic profiling, migratory potential, invasive behavior, and in vivo tumorigenicity. Both cell lines demonstrated stable propagation beyond 40 passages while maintaining subtype-specific characteristics, with distinct ECM protein expression patterns identified. These validated cellular models provide essential resources for investigating the OSA heterogeneity and advancing the development of subtype-targeted therapeutics.