Osteosarcoma 3D patient derived cultures to test genome-informed personalized treatment options: a feasibility study.

Background: Improving osteosarcoma treatment beyond conventional (neo)adjuvant chemotherapy and resection remains challenging. An urgent need for novel therapeutic options, particularly personalized and targeted approaches, has emerged due to high inter-patient molecular heterogeneity. A lack of representative Methods: Tumour cells from seven osteosarcoma patients were propagated in monolayer or collagen hydrogels, while whole-exome sequencing of corresponding primary tumour tissue was performed to identify potential drug targets. Established cultures were subsequently used to assess efficacy of the identified personalized treatment options. Results: Three out of seven hydrogel cultures harbored the same genetic alterations as the corresponding primary tumours, but only one culture (L6565) showed viable cells after cryopreservation in combination with long term expansion. Our findings demonstrate feasibility of establishing long-term patient-derived osteosarcoma cultures with a success rate of 14%. This single patient line was used to evaluate genome-informed therapy and to compare cell culture models of increasing complexity. L6565 exhibited homozygous CDKN2A loss with retained Rb expression, rendering tumour cells sensitive to CDK4/CDK6 inhibition via palbociclib. Tumour heterogeneity was reflected in advanced culture methods producing more variability in treatment response. Conclusion: These results highlight the potential of genome-informed therapies in osteosarcoma and the importance of refining culture techniques to enhance translational research and therapeutic outcomes.