Figure 1.
Contralateral normal and tumor tissue samples were irradiated (MRT) or not (untreated) in 2 experimental sessions (S1 and S2). The transcriptomic data were compared in order to determine contralateral normal and tumor tissue responses to MRT (Δ normal tissue or Δ tumor tissue).
Table 1.
Validation gene set.
Figure 2.
Kaplan-Meier representation of tumor-bearing rat survival.
Intracerebral 9-irradiated (solid black line) or not (dashed grey line). MRT significantly increased the Median Survival Time of animals compared with untreated rats (33 days versus 19 days, log rank test: p<0.0001).
Figure 3.
Influence of MRT on gene expression in tumor and contralateral brain tissues.
a, b- Heat map showing either significant decrease or increase in mRNA expression after MRT in tumor and normal brain tissues. Colors indicate expression levels above (red) or below (green) the median value for each gene. Vertical columns indicate individual arrays and horizontal rows indicate genes. c- Venn diagrams showing the numbers of significantly increased (red) or decreased (green) genes after MRT in both tissues.
Figure 4.
Validation of microarray analysis by quantitative RT-PCR on tumor tissue samples.
Data were first normalized to the expression of Arpc1 and Atp5b housekeeping genes. The fold changes (±SEM) in each gene expression was calculated using the mean expression in treated (n = 6 for microarray and n = 8 to 9 for RT-qPCR) versus untreated (n = 5 for microarray and n = 7 to 10 for RT-qPCR) tumors 6 h after MRT. Fold changes are indicated below the histograms (several fold changes were available for microarray because of the presence of several probesets). All tested genes presented a significant difference between treated and untreated tissues (p<0.05; permutation t-test).
Figure 5.
Molecular and cellular functions constituting the MRT response.
Genes with a significantly modified expression in brain or tumor 6-values (−log(p-value)) are illustrated for each function. The p-values associated with brain (dark blue) and tumor (light blue) are represented using histogram in the right-hand column. The p-values were calculated using the right-tailed Fisher's exact test in IPA.