Numerous solid tumors and hematologic malignancies acquire resistance to apoptosis-inducing chemotherapeutic drugs by downregulating the key effector caspase-3. These cells rely on caspase-7 to execute the apoptotic program, yet binding with XIAP constitutively inhibits active caspase-7 (p19/p12-CASP7). In this issue, Lin et al. describe how a newly synthesized drug is able to disrupt the XIAP:p19/p12-CASP7 complex and induce apoptosis in caspase-3–deficient cancer cells in vitro and in vivo. As this compound appears to exhibit minimal toxicity on normal tissues, it may represent a promising therapeutic agent to help treat caspase-3–deficient tumors.
Maria Eugenia Guicciardi, Gregory J. Gores
Both extrinsic and intrinsic apoptotic pathways result in activation of effector caspases.