Osteogenic and Adipogenic Differentiation of Osteosarcoma Cells

Abstract

Osteosarcomas are the most common primary, non-hematologic malignant tumors in childhood and adolescence, comprising almost 60% of all bone sarcomas. Although these tumors are osteoblastic in nature, the characteristics of the specific tumor-initiating cells are unclear. Osteosarcomas contain highly proliferative undifferentiated malignant cells with a disrupted bone differentiation program. Cancer stem cells (CSCs) that have tumor-initiating properties and capacity of symmetric and asymmetric division have now been described in many solid tumors. For osteosarcomas, the CSC hypothesis has received support from recently reported findings that both human and murine osteosarcomas contain a sub-population of multipotent cells that that express various mesenchymal stem cell surface markers and are capable of undergoing differentiation in multiple mesenchymal lineages such as osteoblasts and adipocytes. Differentiation into these different lineages can be easily assessed by growing cells in specific medium and assaying for differentiation markers.