Sphere Formation (Osteosphere/Sarcopshere) Assay

Abstract

Self-renewing cells from adult tissue (such as bone) that represent a progenitor population can be grown in suspension cultures in the presence of defined serum-free medium. Progenitor cells can be identified by this property of anchorage-independent growth in suspension cultures. These spherical clusters of progenitor bone cells growing under non-adherent conditions are called osteospheres. Such progenitor populations often possess characteristics of multipotency and can differentiate into multiple mesenchymal lineages. Cancer cells capable of growing in suspension have also been reported in osteosarcomas, tumors of the bone tissue. These spherical colonies formed from single cells (clonal) in non-adherent conditions are generally considered to represent self-renewing, stem-like cells and can be employed for other assays such as multipotency and limiting dilution analysis (LDA).