CASP9 and cancer: Figure 7A shows that 0.5 μM of fascaplysin strongly decreased cell viability in the presence of TRAIL in HCT116 (colorectal), A375 (malignant melanoma), and H1975 (lung) cancer cells. Moreover, activation of caspase-9, -3, and PARP was further increased by a combination of fascaplysin and TRAIL (Figure 7B). Consistently, apoptotic cells were synergistically increased by the fascaplysin and TRAIL combination (Figure 7C and Figure S5).