CD133-

1. Supplementary Figure 1 G073 HUVECs 40 30 % PI + 20 CD133 + 10 E030 0 control TMZ 10μM TMZ 50μM TMZ 100μM CD133+ Isotype control CD31-PE CD105-PE G077 G408 100 20 80 15 60 % PI + % PI + 10 40 5 20 0 0 control control TMZ 10μM TMZ 50μM TMZ 100μM TMZ 10μM TMZ 50μM TMZ 100μM CD133- HUVECs E030 a CD133- Ki67 b Supplementary Figure 2 a b PE

2. Supplementary Figure 3 2000 1500 /5000 beads number of GBMs 1000 500 0 control 0Gy control 5Gy co-culture 5Gy co-culture 0Gy G008 G081 5000 4000 number of GBMs 3000 /5000 beads 2000 1000 0 control 5Gy control 0Gy co-culture 0Gy co-culture 5Gy G081 G008 G077 G008 G077 G081 60000 25000 60000 20000 40000 Co-culture 0Gy Control 0Gy Co-culture 5Gy Control 5Gy 40000 15000 CFSE MFI CFSE MFI CFSE MFI 10000 20000 20000 5000 0 0 0 control 5Gy control 0Gy control 5Gy control 0Gy control 0Gy control 5Gy co-culture 5Gy co-culture 5Gy co-culture 0Gy co-culture 0Gy co-culture 5Gy co-culture 0Gy a G077 1750 1500 1250 number of GBMs /5000 beads 1000 750 500 250 0 control 5Gy control 0Gy co-culture 5Gy co-culture 0Gy b CD133 - APC Isotype control - APC co-culture CD133-APC control CFSE-FITC c CFSE

3. Supplementary Figure 3 G077 G008 G081 35 55 15 50 30 45 40 G077 25 10 35 20 30 % specific cell death % specific cell death 3500 % specific cell death 25 15 20 5 3000 10 15 10 5 2500 5 0 0 0 2000 /5000 beads number of GBMs 1500 control 5Gy control 5Gy control 5Gy co-culture 5Gy co-culture 5Gy co-culture 5Gy 1000 500 0 control co-culture control 5Gy co-culture 5Gy control 100μM TMZ co-culture 100μM TMZ control 100μM TMZ 5Gy co-culture 100μM TMZ 5Gy d e

4. Supplementary Figure 4 0Gy 15Gy 5Gy HUVECs E030 100 3 G1 S 80 G2 2 60 % PI+ % of cells 40 1 20 0 0 0Gy 5Gy 15 Gy control 50μMTMZ 100μMTMZ E030 5Gy 0Gy 15Gy 7% 4% 1,5% PI 5Gy 15Gy 0Gy HUVECs 25 day 1 day 4 20 day 7 15 HUVECs % Pi + 10 5 5Gy 15Gy 0Gy 0 0Gy 5Gy 15Gy E023 E030 100 G1 S 80 G2 60 % of cells 40 20 0 50μMTMZ 100μMTMZ control a b c d SSC FSC e

5. G081 G008 G408 f Supplementary Figure 5