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

Table 1

Summary of assay results.

Assay	Day	Radiation			TMZ			Rapamycin			Delta24-RGD
		U373	T98	DA	U373	T98	DA	U373	T98	DA	U373	T98	DA
Caspase 3/7	16 hr	0	0	0.9	0	0	1	0	0	1	0	0	0.9
CytoONE	5/6	0	+	1.1	0	0	0.6	0	0	0.4	ND	ND	ND
CytoGLO	5	+++++	+++++	2.7	+	0	44.7	0	0	0.5	++++	0	2
Clonogenic	10	++++	+++++	0.3	+++++	0	<0.1	++++	+++++	0.2	+++++	0	<0.1
WST-1	5/6	++	++++	0.2	++++	0	0.2	+++	0	2	+++++	0	0.1
CTG	5/6	++	++	1.2	+++	0	0.3	++	+++	0.8	+++	0	0.5
CTF	5/6	+	++	0.9	++++	0	0.3	+++	+++	0.8	+++++	++	0.1
ABa	5	++++	+++++	0.4	++++	0	0.2	++	+++	0.5	+++++	+++++	1.2
ABf	5	+++	++++	0.5	++++	0	0.3	+	+++	0.4	+++++	++++	0.5
CV	5	+++	+++++	0.6	+++++	0	0.2	+++	++++	0.5	++++	+++	0.2
IncuCyte	5	+++++	+++	0.5	+++++	++	0.2	++	++	0.4	+++++	++	<0.1

Results are expressed by 0 = no effect, + = ↑↓ 10–20%, ++ = ↑↓ 20–40%, +++ = ↑↓ 40–60%, ++++ = ↑↓ 60–80%, and +++++ = ↑↓ 80–100%. The discriminative ability (DA) was calculated by dividing the viability at the highest dose of the responder cell line by the viability of the nonresponder cell line. CytoONE = CytoTox ONE®, CytoGLO = CytoTox-GLO®, CTG = CellTiter-GLO®, CTF = CellTiter-FLUOR®, ABa = Alamar Blue®, absorbance, ABf = Alamar Blue®, fluorescent, CV = crystal violet.