Mesenchymal Stem Cells‐Derived Small Extracellular Vesicles and Their Validation as a Promising Treatment for Chondrosarcoma in a 3D Model in Vitro

Chondrosarcomas (CHS) constitute approximately 20% of all primary malignant bone tumors, characterized by a slow growth ratewith initial manifestation of few signs and symptoms. These malignant cartilaginous neoplasms, particularly those with dediffer-entiated histological subtypes, pose significant therapeutic challenges, as they exhibit high resistance to both radiation andchemotherapy. Ranging from relatively benign, low‐grade tumors (grade I) to aggressive high‐grade tumors with the potential forlung metastases and a grim prognosis, there is a critical need for innovative diagnostic and therapeutic approaches, particularly forpatients with more aggressive forms. Herein, small extracellular vesicles (sEVs) derived from mesenchymal stem cells are presentedas an efficient nanodelivery tool to enhance drug penetration in an in vitro 3D model of CHS. Employing high‐pressure homoge-nization (HPH), we achieved unprecedented encapsulation efficiency of doxorubicin (DXR) in sEVs derived from mesenchymal stemcells (MSC‐EVs). Subsequently, a comparative analysis between free DXR and MSC‐EVs encapsulated with DXR (DXR‐MSC‐EVs)was conducted to assess their penetration and uptake efficacy in the 3D model. The results unveiled a higher incidence of necroticcells and a more pronounced toxic effect with DXR‐MSC‐EVs compared to DXR alone. This underscores the remarkable ability ofMSC‐EVs to deliver drugs in complex environments, highlighting their potential application in the treatment of aggressive CHS.