Engineering a metastatic stroma directs the osteosarcoma tumour transcriptome in a spatially specific manner

The biological behaviour of the cancer cell is in part controlled by its microenvironment and in part by underlying genetics. The interaction of cancer cells with the surrounding stroma directs cancer progression. The most common primary malignant tumour of the bone, osteosarcoma, is a highly complex disease in terms of its progression, invasion, and metastasis. To better understand disease characteristics and develop accurate therapies for osteosarcoma, novel tissue models have been developed to systematically understand how facets of the tumour microenvironment (TME) can influence cancer cell behaviour. This study aims to understand how osteosarcoma invasion and metastasis is influenced by different types of stromal cells in the TME. The engineering of complex tumouroids, which segregate the tumour and stromal cells in specific 3D compartments, allows for the study of tumour-stroma interaction and invasion of cells between different compartments. Complex tumouroids comprised a central osteosarcoma tumour mass with different engineered stromal compartments, representative of the primary bone or metastatic lung. Spatial Transcriptomics (ST) unveiled that osteosarcoma cells upregulated metastatic genes such as IFI27 in the presence of a lung stromal compartment, whereas a bone stromal compartment resulted in the upregulated of oncogenes and drug resistance genes such as DUSP1 and HIF1A within the osteosarcoma compartment. Engineering a primary stromal cell compartment compared to a metastatic stromal cell compartment unveiled how the regulation of cell proliferation, invasion, extracellular matrix (ECM) remodelling, metastasis markers and tumour suppressor markers was altered in the osteosarcoma transcriptome.