New perspective into mesenchymal stem cells: Molecular mechanisms regulating osteosarcoma

• The origin of osteosarcoma cells from osteoblasts and mesenchymal stem cells remains controversial. • Mesenchymal stem cells regulate the development of osteosarcoma by influencing the tumor microenvironment and mediating cell communication. • Mesenchymal stem cells and exosomes secreted by them can be used as good genes and drug carriers for the treatment of osteosarcoma. • Mesenchymal stem cells from different tissue sources have different regulatory effects on the development of osteosarcoma. Mesenchymal stem cells (MSCs) are multipotent stem cells with significant potential for regenerative medicine. The tumorigenesis of osteosarcoma is an intricate system and MSCs act as an indispensable part of this, interacting with the tumor microenvironment (TME) during the process. MSCs link to cells by acting on each component in the TME via autocrine or paracrine extracellular vesicles for cellular communication. Because of their unique characteristics, MSCs can be modified and processed into good biological carriers, loaded with drugs, and transfected with anticancer genes for the targeted treatment of osteosarcoma. Previous high-quality reviews have described the biological characteristics of MSCs; this review will discuss the effects of MSCs on the components of the TME and cellular communication and the prospects for clinical applications of MSCs.