A Systematic Comparison Identifies an ATP-Based Viability Assay as Most Suitable Read-Out for Drug Screening in Glioma Stem-Like Cells

Figure 1

The clonogenic assay detects treatment effects in cell lines but not in GSCs. U373 cells (white bars) or T98 cells (black bars) were treated with radiation (a), TMZ (b), rapamycin (c), and Delta-24RGD (d) at different doses (-axis). After 10 days clones were stained and counted by hand and the surviving fraction was calculated. Error bars indicate standard deviation, . Microscopic pictures of clones (e) treated with 100 nM rapamycin (right images) and nontreated clones (left images) of U373 cells (top row) and T98 cells (bottom row). Magnification ×10. Three primary GSCs (f) were tested for their ability to form clones over a 10-day period. Cells were plated at densities of 500, 1000, or 2000 cells/T25 flask. Magnification ×10.

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