Patient-Derived Spheroid Culture Models Are Better Than Monolayer Models in Chondrosarcoma Research.

Purpose: Chondrosarcoma (CSA) are mesenchymal tissue-derived bone tumors. CSA mainly occurs in older people. CSA has demonstrated resistance to chemotherapy and radiation; complete surgical removal with negative margins is the only treatment option. In the case of metastatic CSA, the chance of survival is meager. Since the conventional two-dimensional cell culture models failed to retain tumor characteristics, developing preclinical models mimicking the disease with the highest fidelity is paramount for personalized treatments. Methods: In this study, we established spherical cultured cells as new models for CSA. First, we demonstrated that CSA cells could form spheroids when cultured in ultra-low attachment plates. Next, tissue samples from CSA patients were collected and processed into primary cells, which were subsequently cultured as primary spheroids. The growth rate of primary spheroids was monitored and the histology of mature spheroids were characterized. These primary spheroids were used in drug susceptibility studies where traditional doxorubicin therapy and our novel disulfiram-copper therapy were tested. Results: Compared with conventional monolayer cultures, spheroids better recapitulated the features of the in vivo tumor in the aspect of the formation of extracellular matrix. In the drug susceptibility study, spheroids demonstrated high resistance to the classic therapies, suggesting that monolayer cultures may give false positive results. Therefore, using spheroids for drug research and development in the CSA field should provide more accurate results. Conclusion: In summary, our study of primary CSA spheroids brought new insight into their chemoresistance and demonstrated its potential for personalized treatment of CSA in clinical medicine.