Abstract 6170: Development and characterization of 3D osteosarcoma models recapitulating tumor heterogeneity and bone microenvironment

Abstract Introduction: Osteosarcoma is the most common primary bone cancer in adolescents and young adults. It is characterized by high heterogeneity and a hostile bone microenvironment shaped by osteoclasts, endothelial cells, and immunosuppressive myeloid populations, underscoring the need for innovative models to evaluate novel therapeutic strategies. Objective: This study aims to develop and characterize novel three-dimensional (3D) culture models that recapitulate the complexity and the microenvironment of osteosarcoma. Methods: Tumor samples from patient-derived xenografts (PDXs) established from patients with osteosarcoma at relapse or treatment failure were processed to generate 3D tumor cultures. Tumor tissues were mechanically and enzymatically dissociated into single-cell suspensions and seeded into round-bottom plates with very low adhesion to promote spontaneous formation of 3D tumoroids. Culture conditions were optimized using medium supplemented with specific growth factors to support cell viability and proliferation. Morphology and growth of the tumoroids were monitored over time. The resulting 3D models were characterized by histology (H Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6170.