Irradiated glioma cells promote endothelial cell proliferation and migration. Caspase 3 in dying glioma cells mediates proangiogenic response. Proteolytic inactivation of caspase 3 reduces tumorigenicity. In silico analyses show positive relation between CASP3 and angiogenesis markers. NF-κB/COX-2/PGE2 and p-eIF4E/VEGF-A are downstream effectors of caspase 3.