Tools to study neural and glioma stem cell quiescence.

Quiescence promotes resilience of neural stem cells to cellular stress and aging. Likewise, in glioma tumour/glioma stem cell populations, quiescent/slow-cycling states impart resistance to cellular stress and chemoradiation. Emerging evidence suggests that the molecular signatures of quiescent neural stem cells correlates with the molecular signatures of quiescent glioma stem cells. The few signals that have been experimentally interrogated, suggest these pathways are also functionally conserved. There are multiple challenges in identifying and tracking quiescent neural stem cells and glioma stem cells. Recent advances in methodologies such as intravital imaging, electroporation models of brain cancer and single-cell data tools are overcoming these challenges, which may accelerate the development of targeted therapeutics. Quiescence is a prolonged but reversible state of cell-cycle arrest that is an adaptive feature of most adult stem cell populations. In the brain, quiescence helps to protect adult neural stem cells from stress and supports lifelong neurogenesis. Unfortunately however, entry into a quiescent or a slow-cycling state is also a malignant feature of brain cancer stem cells. In glioblastoma, where the process has been best characterised, quiescent glioma stem cells preferentially survive chemoradiation, and after therapy, reactivate to regrow the tumour and drive recurrence. In this Review, we discuss the in vitro and in vivo models that have been developed for studying neural stem cell quiescence and how these tools may be used to deepen biological understanding and to develop novel therapies targeting quiescent glioma stem cells. [ABSTRACT FROM AUTHOR]