Establishment and Characterization of OS-MET-R-092: A Novel Patient-Derived Cell Culture from an Osteosarcoma Bone Metastasis.

Bone metastases from osteosarcoma occur in only 10% of patients, and related preclinical models are lacking. A patient diagnosed with pelvic osteosarcoma developed a metachronous scapular metastasis and was treated with multi-agent chemotherapy and surgery. Patient-derived tissue fragments (PDTFs) were obtained from leftover material after diagnosis and biobanking. PDTFs were grown on chick chorioallantoic membrane, establishing an in vivo-like predictive model. Additionally, we obtained a patient-derived cell culture, OS-MET-R-092, which has been maintained in vitro for nearly one year. OS-MET-R-092 cells were authenticated based on short tandem repeats and on their morphology when grown on commercial 3D scaffolds. Using U-2 OS and SaOS-2 as controls, we characterized growth, clonogenic potential, ability to form spheroids, migration, osteogenic differentiation, and expression of related genes. OS-MET-R-092 cells showed a low proliferation rate, impaired differentiation potential, and migratory abilities comparable to SaOS-2, while expressing higher levels of some MMPs and CD44. Functionally, OS-MET-R-092 cells demonstrated a resistant phenotype to doxorubicin, cisplatin, gemcitabine, and docetaxel, corroborated by higher expression of chemo-resistance-related genes. Collectively, OS-MET-R-092 represents a valuable tool for studying bone metastasis from osteosarcoma across various experimental settings and serves as the foundational building block for composite and translatable 3D models.