Fig. 5

H3K27M-expressing cells increase hypoxanthine-derived salvage and maintain high guanine salvage following RT. A and B Immunoblots of (A) IMPDH1 and (B) HGPRT expression before and after 4Gy RT in DIPGXIII cells. Densitometric analysis was performed using ImageJ software and expression values were normalized to No-RT controls. Values are listed below the blot images. C FC in the ion abundances of ¹⁵N-labeled GMP in DIPGXIII H3K27M-isogenic cell lines before (gray bars) and 3hrs after 4Gy RT (red bars). Data are normalized to untreated control samples. D FC in the ion abundances of 1D-labeled GMP in DIPGXIII H3K27M-isogenic cell lines before (gray bars) and 3hrs after 4Gy RT (red bars). Data are normalized to untreated control samples. E Ratio of ¹⁵N-Gln:2D-Hpx label incorporation into GMP after 3 hours in DIPGXIII cells that were either untreated or treated with 4Gy RT. Data is normalized to untreated control. F Total abundance of ¹³C₈-labeled GMP in H3K27M-isogenic cells. G FC in the ion abundances of ¹³C₈-labeled GMP in DIPGXIII H3K27M-isogenic cell lines before (gray bars) and 3hrs after 4Gy RT (red bars). H Percent relative abundances of 1D-labeled GMP (light blue bars) and ¹³C₈-labeled GMP (red bars) in H3K27M-isogenic cells before and after 3hrs 4Gy RT. Statistical analyses were performed using two-tailed t-tests in GraphPad Prism 10.0