Identification and Isolation of Slow-Dividing Cells in Human Glioblastoma Using Carboxy Fluorescein Succinimidyl Ester (CFSE)
Summary
This video protocol demonstrates the application of the fluorescent dye carboxyfluorescein succinimidyl ester (CFSE) for the identification and separation of different sub-populations of cells in human glioblastoma based on frequency of cell division.
Abstract
Tumor heterogeneity represents a fundamental feature supporting tumor robustness and presents a central obstacle to the development of therapeutic strategies1. To overcome the issue of tumor heterogeneity, it is essential to develop assays and tools enabling phenotypic, (epi)genetic and functional identification and characterization of tumor subpopulations that drive specific disease pathologies and represent clinically relevant targets. It is now well established that tumors exhibit distinct sub-fractions of cells with different frequencies of cell division, and that the functional criteria of being slow cycling is positively associated with tumor formation ability in several cancers including those of the brain, breast, skin and pancreas as well as leukemia2-8. The fluorescent dye carboxyfluorescein succinimidyl ester (CFSE) has been used for tracking the division frequency of cells in vitro and in vivo in blood-borne tumors and solid tumors such as glioblastoma2,7,8. The cell-permeant non-fluorescent pro-drug of CFSE is converted by intracellular esterases into a fluorescent compound, which is retained within cells by covalently binding to proteins through reaction of its succinimidyl moiety with intracellular amine groups to form stable amide bonds9. The fluorescent dye is equally distributed between daughter cells upon divisions, leading to the halving of the fluorescence intensity with every cell division. This enables tracking of cell cycle frequency up to eight to ten rounds of division10. CFSE retention capacity was used with brain tumor cells to identify and isolate a slow cycling subpopulation (top 5% dye-retaining cells) demonstrated to be enriched in cancer stem cell activity2.
This protocol describes the technique of staining cells with CFSE and the isolation of individual populations within a culture of human glioblastoma (GBM)-derived cells possessing differing division rates using flow cytometry2. The technique has served to identify and isolate a brain tumor slow-cycling population of cells by virtue of their ability to retain the CFSE labeling.
Protocol
Discussion
An increasing number of studies have demonstrated the importance of a slow-dividing sub-compartment of cells in cancer which contribute to tumor formation and treatment resistance2-8. Therefore it is critical to describe and standardize experimental methods enabling the study of this specific subpopulation of cells or more generally to compare subpopulations with different growth rates. Using CFSE to identify and isolate sub-fractions of cells based on their rate of cell division is a starting point to furthe…
Declarações
The authors have nothing to disclose.
Acknowledgements
This work was supported by the Florida Center for Brain Tumor Research, the Preston A. Wells Jr. Center for Brain Tumor Therapy and the National Institutes of Health (1R21CA141020-01).
Materials
| Name of the reagent | Tipo | Company | Catalogue number |
| NeuroCult NSC Basal Medium (Human) | Medium | Stem Cell Technologies | 05750 |
| NeuroCult NSC Proliferation Supplements (Human) | Medium supplement | Stem Cell Technologies | 05753 |
| %0.05 trypsin-EDTA | Reagent | Gibco | 25300-062 |
| Soybean trypsin inhibitor | Reagent | Sigma | T6522 |
| Penicillin/Streptomycin | Reagent | Gibco | 15140-122 |
| T25 flask | Culture ware | Nalge Nunc international | 136196 |
| T80 flask | Culture ware | Nalge Nunc international | 178905 |
| 15 ml tubes | Culture ware | BD Falcon | 352096 |
| 50 ml tubes | Culture ware | BD Falcon | 352070 |
| EGF | Growth factor | R&D | 2028-EG |
| CellTrace CFSE Cell Proliferation Kit | Fluorescent Cell Division Tracking Dye | Molecular Probes, Invitrogen | C34554 |
Referências
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