Mesenchymal Stem Cells as Regulators of the Bone Marrow and Bone Components

Abstract

Even though bone marrow mesenchymal stem cells and the “endosteal and vascular hematopoietic niche” have been an active area of study, the concept of the bone marrow/bone microenvironment harboring a niche for solid metastatic tumor cells was only recently considered. The hematopoietic stem cell niche that in some cases is thought to constitute the tumor niche shares many of the same structural and functional components, suggesting the possibility that the “hematopoietic and tumor niches” are one in the same. Mesenchymal stem cells, as well as the osteoblasts, are critical components for each of these niches and are important components for regulating cellular processes such as homing and migration, proliferation and survival, and quiescence and dormancy of tumor cells. Current understanding of mesenchymal stem cell properties may provide more insight to better defining the solid tumor niche, especially in the development of the bone marrow and bone “premetastatic niche.”