Similarly, caspase 3 and caspase 9 were activated (Supplementary Figure S3D) in the GBM cells treated with PBI-05204 and RT and the subG1 phase of U87MG cell population was four-fold higher following treatment with of PBI-05204 and RT compared to that of the RT only group (Supplementary Figure S3E). Here, CASP9 is linked to glioblastoma.