Using Carboxy Fluorescein Succinimidyl Ester (CFSE) to Identify Quiescent Glioblastoma Stem-Like Cells.

Tumor resistance to conventional therapies is a major challenge toward the eradication of cancer, a life-threatening disease. This resistance mainly results from tumor heterogeneity and more specifically from the existence of "stem-like" cells that remain in a quiescent state for long periods of time and thus escape commonly used anti-cancer drugs resulting in treatment failure. Therefore, targeting this subpopulation would present a viable strategy to overcome tumor burden. This daunting task requires a deep and thorough understanding of the biology of the quiescent stem-cell population, their interaction with tumor microenvironments, and mechanisms used to sustain themselves despite aggressive therapies. In this chapter, we describe detailed technical procedures for the isolation of quiescent or infrequently dividing stem-like cells in cultured glioblastoma tumor cells using carboxy fluorescein succinimidyl ester (CFSE) staining and flow cytometric analysis. Quiescent glioblastoma cells with stem-like features are characterized and subsequently isolated based on their ability to retain the CFSE labeling.