CASP3 and cancer: For example, Liu et al. developed a light-up theranostic agent by tactfully linking a silole-based AIEgen, a cyclic RGD cancer cell-targeting peptide, a platinum Pt(iv) prodrug, and a stimulus responsive peptide together.17 The reductant of ascorbic acid in U87-MG cancer cells reduced the prodrug Pt(iv) to the active Pt(ii) drug, which triggered apoptosis by activating the pro-apoptotic enzyme caspase-3.