Personalized Bone Tumour Models With a Humanized Bone Niche for Enhanced in Vitro Studies

Malignant primary bone tumours are associated with substantial health burdens for individual patients, often adolescents or young adults. To improve the treatment of these patients in the future, innovative preclinical models are needed to better understand the patient-specific and entity-specific pathomechanisms and conduct future drug trials on a personalized level. The development of cutting-edge personalized preclinical models, particularly those that incorporate patient-derived tissue and address the bone microenvironment, is a promising strategy to make research more relevant to actual patient conditions and help bridge the gap to successful clinical applications. However, there remains a lack of models incorporating both a (human) bone microenvironment and a patient-specific tumour component. Therefore, a bone tumour model consisting of fresh patient-derived tumour tissue combined with a tissue-engineered humanized bone niche was established in this study to enhance the understanding of these diseases and to support more effective drug testing in the future. Our model consists of tumour tissue (n=4 osteosarcoma, n=2 Ewing-Sarcoma, n=2 chondrosarcoma; consent given) combined with a tissue-engineered bone construct (TEBC). The TEBC is created by seeding osteoprogenitor cells onto 3D-printed mPCL scaffolds coated with calcium phosphate (CaP). The tumour tissue and TEBC are bonded together using fibrin glue, forming a “tumour-TEBC” construct. As a control, tumour tissue was combined with non-cellular CaP-scaffolds. After a 3-week in vitro culture period, we assessed the co-constructs using live-dead fluorescence imaging, micro-CT, and histological analysis. The TEBCs serve as an in vitro model for human bone by replicating important bone characteristics, such as mineralization driven by osteoblasts and the presence of bone extracellular matrix. The combined tumour-TEBC model survives during in vitro co-culture and the tumour component successfully proliferates as well as retains its original tumour characteristics. Histological analysis revealed tissue interactions at the contact points between the tumour and TEBC, as evidenced by the merging of the two tissues through the extracellular matrix. In conclusion, an advanced bone tumour model integrating both patient-specific tumour tissue and a human bone model component was established. This novel model has the potential to improve the reliability of in vitro drug testing and provide valuable insights into the personalized care of bone tumour patients.