1. A B Supplementary Figure 1
Buhl et al. “The SASP mediates OIS in pediatric PA” A B
6.0 PA
nr.1 NB
5.5 **
5.0
log2 (mRNA expression)
4.5
200µm
4.0
nr.2
3.5
3.0
Cdkn2a
200µm
Supplementary figure 1. Markers of OIS are detectable in the PA mouse model A) Boxplot of log2 mRNA expression of the senescence marker CDKN2A in PA mice (n=8) versus normal brain (NB) of healthy control mice (n=8). Depicted are median (black bar), quartiles (box), median +/- 1.5 IQR (interquartile range) (whiskers), and outliers (circles). Significant differences are indicated as ** p<0.01 (Student´s t-Test). B) Bright field image of senescence-associated ß-galactosidase (SA-ß-Gal) staining of cell derived from two PA mouse tumors. Induction of Sa-ß-Gal activity, indicated by blue staining, is observed in the tumor-derived cells.

2. treatment duration (days)
Supplementary Figure 2
rIL1B (pg/ml)
100 15
100
500
10000
viability (%) 50 5 10 15 20
treatment duration (days)
Supplementary figure 2. rIL1B treatment does not affect viability of DKFZ-BT66 cells. Viability, determined by automated trypan blue exclusion staining, of proliferating DKFZ-BT66 cells under rIL1B treatment in the concentrations indicated for 20 days. Depicted are mean +/- SD of three independent experiments.

3. log10 (concentration (pg/ml))
Supplementary Figure 3 4 PA
Normal brain 3 2
log10 (concentration (pg/ml)) 1 -1 -2
FGF2
IL15
CSF3
VEGFA
IL17A
CCL2
CXCL8
CCL3
IFNG
IL6
IL13
CCL11
IL1B
CSF2
Supplementary figure 3. SASP factors are detectable on protein level in pediatric PAs. Multiplex assay including 14 SASP factors, conducted in n=22 fresh frozen primary PA samples and one normal brain sample showing presence of all 14 SASP factors in every PA sample. VEGFA is not expressed to a detectable level in the normal brain sample.

4. A B C D E F G H I J Supplementary Figure 4 DKFZ-BT66 OIS
DKFZ-BT66 proliferation
Human astrocytes A B C
1.5
1.5
1.5
1.0
1.0
1.0
0.5
IC50:
0,04 µM
0,28 µM
1,16 µM
0.5
IC50:
0,14 µM
0,60 µM
1,98 µM
0.5
IC50:
6,36 µM
5,22 µM
16,20 µM
0.0
0.0
0.0
10-4
10-3
10-2
10-1
100
101
102
10-4
10-3
10-2
10-1
100
101
102
10-3
10-2
10-1
100
101
102
103
Navitoclax (µM)
ABT-737 (µM)
Dasatinib + Quercetin (µM) D E
1.5
2.5
2.0
1.0
1.5
(fraction of solvent control)
metabolic activity
1.0
0.5
IC50:
20,78 µM
0,17 µM
2,80 µM
IC50: NA
0.5
0.0
0.0
10-4
10-3
10-2
10-1
100
101
102
10-5
10-4
10-3
10-2
10-1
100
101
Vincristine (µM)
Trametinib (µM) F G
1.5
2.0
1.5
1.0
1.0
0.5
0.5
0.0
0.0
10-4
10-3
10-2
10-1
100
101
102
10-4
10-3
10-2
10-1
100
101
102
Navitoclax + Vincristine (µM)
Navitoclax + Trametinib (µM) H I J
1.5
1.5
1.5
1.0
1.0
1.0
(fraction of solvent control)
metabolic activity
0.5
0.5
0.5
0.0
0.0
0.0
10-4
10-3
10-2
10-1
100
101
102
10-4
10-3
10-2
10-1
100
101
102
10-4
10-3
10-2
10-1
100
101
102
ABT Carboplatin (µM)
ABT Vincristine (µM)
ABT Trametinib (µM)

5. Supplementary figure 4. Single and combination treatments in human astrocytes and combination treatments of ABT-737 with standard of care chemotherapeutic agents and targeted therapy for PAs in DKFZ-BT66 cells. A - G) Assessment of metabolic activity by CellTiter-Glo of senescent (red) or proliferating (blue) DKFZ-BT66 cells and primary human astrocytes (black) treated for 72 hours with navitoclax (A), ABT-737 (B), dasatinib plus quercetin (C), vincristine (D), trametinib (E), navitoclax plus vincristine (F) and navitoclax plus trametinib (G) in the indicated concentrations. Depicted are mean +/- SD of three technical replicates. H – J) Assessment of metabolic activity by CellTiter-Glo of senescent (red) or proliferating (blue) DKFZ-BT66 cells treated for 72 hours with ABT-737 in combination with carboplatin (H), vincristine (I) and trametinib (J) in the indicated concentrations. Shown are mean +/- SD of three technical replicates.