Fig. 2

Clonogenic survival of GBM cells upon treatment with X-ray IR, TMZ, and the combination thereof. A Clonogenic survival of A172, T98G, LN229, LN18, U251-MG, M138-MG, and U87-MG cells after single-shot IR (0–10 Gy), fractionated IR (0–5 fractions of 2 Gy each), TMZ treatment (0–500 μM for 24 h), and combination of 5 µM TMZ (24 h) and single-shot IR (0–10 Gy) as determined by colony formation assays. Results of at least three independent experiments are depicted. Super-imposed fitting functions are linear-quadratic in case of radiation experiments and logistic in case of TMZ treatment. B Z-transformed survival data are depicted as unsupervised hierarchical clustering. Principal component analysis (PCA)-derived resistance scores (scores of PC1 as described in [21]) are shown