1. Supplementary figure 1A matrigel cell medium cells growing as spheroids in 3D cultures

2. Step 1- Wash 3x in PBS, add add 2x vols matrisperse. Gently scrape the matrigel/cells and transfer to universal container. Wash the well twice with x1 volume matrisperse and transfer to falcon tube. Step 2- Leave on ice for 30 minutes and spin @ 5000rpm for 5minutes. Step 3- Decant supernatant, re-suspend cells in 0.5ml trypsin and incubate at 37 0 c for 5min. Step 4- Add 1.5ml isotone and pass through 25G needle x 3 times. 3D Matrigel culture Experimental analysis Step 1Step 2Step 3Step 4 5000rpm 5min 37 0 C 5min Supplementary figure 1B

3. Control AKTi MEKi 116kDa PARP 85kDa PARP Control AKTi MEKi 2D3D controls - + BT474BT474 camptothecin 85kDa PARP Supplementary figure 2 MDAMB361 Control AKTi MEKi 116kDa PARP 85kDa PARP Control AKTi MEKi 2D3D controls - + camptothecin 85kDa PARP