Fig. 1

mRNA expression analysis of DNA damage response (DDR) regulator genes, and MGMT promoter methylation analysis in human GBM cell lines. A Basal mRNA expression levels of DDR regulator genes in GBM cell lines A172, LN18, LN229, T98G, U87-MG, U138-MG, and U251-MG as measured by qRT-PCR (ddCT method). Expression levels were normalized to a matrix of three reference genes (18S rRNA, β2-Microglobulin, and 5’-Aminolevulinate Synthase-1), and calibrated on the expression levels of astrocytes. Three replicates were analyzed per cell line. Expression values (log2-transformed) and samples were subjected to unsupervised hierarchical clustering. B Correlation of MGMT promoter methylation status and MGMT mRNA expression levels in the employed GBM cell lines as detected by methylome array and qRT-PCR, respectively. C Protein expression levels of MGMT in GBM cells as measured by western blot. Vinculin served as loading control