Effect of doxorubicin and quercetin combined treatment on osteosarcoma model systems

Introduction Osteosarcoma (OS) is a highly aggressive bone tumor primarily affecting pediatric patients. Standard treatments include surgical resection, chemotherapy, and radiation for tumors that cannot be surgically removed. Although the 5–year survival rate is 65.5%, patients with metastases and recurrence have a significantly lower survival rate of ~30%. Despite this concerning statistic, the treatment for OS has remained largely unchanged over the past three decades. This stagnation in treatment innovation highlights the urgent need for further research and development in therapies tailored specifically for OS. Material and method We identified the DEGs between bone (7 samples) and OS (27 samples). To conduct in-depth study of the obtained upregulated DEGs, we constructed a PPI network and identified the most significant gene cluster. We investigated the effects of the combined treatment with doxorubicin and quercetin on SAOS-2 osteosarcoma cells in 2D condition and immobilized in alginate microbeads in 3D condition. We assessed the effects of treatments on cell viability using MTT and the expression of genes using qPCR. Result and discussion We have analysed DEGs between bone and human osteosarcoma samples and identified 630 upregulated genes. We extended the networks with information from DrugBank to identify potential therapeutics for osteosarcoma focusing on the top 10% of interconnected genes in cluster due to their important biological functions. The identified cluster had enrichment in biological processes connected to oxidative phosphorylation and we found quercetin as a promising candidate for treating OS. We analysed quercetin’s effect utilizing the Saos-2 in 2D and 3D on viability and gene expression, alone or in combination with doxorubicin. Following treatment, we assessed cell viability and the expression of genes. Our results have shown that the combined treatment statistically significantly decreased the viability of SAOS-2 cells cultured in 2D and 3D conditions compared to cells treated with doxorubicin. We analyzed the expression of genes associated with poor prognosis in patients such as pluripotency genes, an OS marker, and a resistance-related gene. Collectively our results show different responses to the combined treatment depending on the model system used. Conclusion The combined treatment substantially reduced cell viability in 2D and 3D models and decreased expression of genes associated with poor prognosis compared to doxorubicin alone in 3D models. We can hypothesize that microenvironment-based mechanisms modulate cell sensitivity to therapy and increase resistance to treatment of osteosarcoma cells cultured in 3D condition. Understanding the molecular mechanisms will significantly contribute to the development and enhancement of existing therapies, thereby facilitating advancements in the treatment of osteosarcoma.