Figure 2

UW228 medulloblastoma cells surviving 10 Gy radiation show elevated expression of c-Myc and several ABC transporters. Pair-matched live non-apoptotic cell populations, from 0 Gy (control) and 10 Gy treated (surviving) cells in multiple independent experiments, were isolated using FACS. Analysis by qRT-PCR showed (A) c-Myc, (B) ABCG2 and (D) ABCA1 are elevated in surviving cells. Bars show relative gene expression derived from the mean ΔCt of quadruplicate multiplex assays. To clearly display variation between experiments (both in terms of magnitudes of expression and the difference between control and resistant cells), independent experiments are shown individually. The fold-change value for each pair-matched experiment is also indicated (being the relative expression for surviving cells divided by that for control cells, or 2^-ΔΔCt). Error bars (asymmetric on gene expression scale) represent symmetric +/− 1 SD in the Ct space. When surviving cells are compared with control cells over all pooled biological experiments, p-values are <0.05 for all three genes. (C) ABCG2 was also elevated at the protein level when assessed by flow cytometry.