Long-term maintenance of brain tumor stem cell properties under at non-adherent and adherent culture conditions.

There is increasing evidence for the presence of cancer stem-like progenitors in malignant brain tumors. This subpopulation of progenitor cells, the so-called "cancer stem cells (CSCs)", may play a pivotal role in brain tumor initiation, growth, and recurrence. Here we describe the establishment of one permanent brain tumor stem cell line that able to form new spheres after culture under adherent monolayer conditions and to recapitulate the properties of the original tumor upon transplantation into immunodeficient mice. Re-formed spheres retained their stem cell properties and isolated single CSCs from these spheres formed spheres/tumors even after long-term cultures (over 2 years). These data suggested that a small population of CSCs preserved its stem cell properties even after serial passages under non-adherent/adherent culture conditions. Evaluation of underlying metabolic events and assessment of the biological features of these viable cell lines will yield useful knowledge on the in situ behavior of brain tumors.