Structure and function of the solid tumor niche

Abstract

Although the hematopoietic stem cell (HSC) niche has been an active area of study, the concept of the bone marrow microenvironment (BMM) harboring a niche for solid metastatic tumor cells has only recently been considered. The HSC niche and microenvironment that is thought to constitute the solid tumor niche share many of the same structural and functional components, suggesting the possibility that the HSC and tumor niche are one in the same. The osteoblast is a critical component for each of these niches, and is important for regulating cellular processes such homing and migration, growth and survival, and quiescence and dormancy. Current understanding of the HSC niche may provide more insight to better defining the solid tumor niche. As role of the niche in regulating these processes is better understood, new insights to the role of the BMM in metastatic disease may be gained, and provide more potential targets for therapy.

Figure 1

refer to figure1.gif. The hematopoietic stem cell niche and the solid tumor niche in marrow. The hematopoietic stem cell (HSC) niche provides insight to the structure and function of the solid tumor niche. The HSC niche regulates homing, self-renewal and quiescence to preserve the multipotency of the HSCs. Likewise, the solid tumor niche probably regulates invasion, survival, and dormancy to allow a metastatic cell to acclimate to the bone marrow microenvironment (BMM). In both cases, adhesion to the osteoblasts is critical.