Augmented drug resistance of osteosarcoma cells within decalcified bone matrix scaffold: The role of glutamine metabolism

Due to the lack of a precise in vitro model that can mimic the nature microenvironment in osteosarcoma, the understanding of its resistance to chemical drugs remains limited. Here, we report a novel three-dimensional model of osteosarcoma constructed by seeding tumor cells (MG-63 and MNNG/HOS Cl no. 5) within demineralized bone matrix scaffolds. Demineralized bone matrix scaffolds retain the original components of the natural bone matrix (hydroxyapatite and collagen type I), and possess good biocompatibility allowing osteosarcoma cells to proliferate and aggregate into clusters within the pores. Growing within the scaffold conferred elevated resistance to doxorubicin on MG-63 and MNNG/HOS Cl no. 5 cell lines as compared to two-dimensional cultures. Transcriptomic analysis showed an increased enrichment for drug resistance genes along with enhanced glutamine metabolism in osteosarcoma cells in demineralized bone matrix scaffolds. Inhibition of glutamine metabolism resulted in a decrease in drug resistance of osteosarcoma, which could be restored by alpha-ketoglutarate supplementation. Overall, our study suggests that microenvironmental cues in demineralized bone matrix scaffolds can enhance osteosarcoma drug responses and that targeting glutamine metabolism may be a strategy for treating osteosarcoma drug resistance. Osteosarcoma resistance to chemical drugs remains poorly understood. Here, the authors constructed a novel three-dimensional osteosarcoma model by seeding tumor cells within demineralized bone matrix scaffolds. Growing within the scaffold conferred elevated doxorubicin resistance to osteosarcoma cells when compared to two-dimensional cultures. Osteosarcoma cells in demineralized bone matrix scaffolds displayed an increased enrichment for drug resistance genes along with enhanced glutamine metabolism. This model could help better understand the complex cell-matrix interactions between osteosarcoma cells and surrounding native bone and potentially screen novel effective chemotherapies to treat osteosarcoma.image