Diallyl disulfide causes caspase-dependent apoptosis in human cancer cells through a Bax-triggered mitochondrial pathway.

Diallyl disulfide (DADS), an important component of garlic (Allium sativum) derivative, has been demonstrated to exert a potential molecular target against human cancers. We investigated DADS-induced expressions of Apaf1, cystatin B, caspase-3 and FADD (fas-associated protein with death domain) in breast, prostate and lung cancer cells. These showed coincident data when further examined by quantitative reverse transcription-polymerase chain reaction and Western blot analysis. Furthermore, DADS induced a marked amount of Bax translocation, cytochrome c release and activation of caspase-3 and caspase-9. DADS-treated tumor cells triggered mitochondria-mediated signaling pathways that led to a significant increase in apoptosis induction. Further studies with caspase-3 and caspase-9 inhibitors (zDEVD-fmk and zLEHD-fmk, respectively) proved that DADS induces apoptosis through a caspase-3-dependent pathway. DADS is only an agent used in the study. The molecular mechanism presented therefore provides strong additional support to the hypothesis that DADS is a strong inducer of apoptosis through a Bax-triggered mitochondria-mediated and caspase-3-dependent pathway. This study shows clearly that DADS causes caspase-dependent apoptosis in human cancer cells through a Bax-triggered mitochondrial pathway. Therefore, the mitochondrial pathway might be the target for cancer chemoprevention and/or chemotherapy by DADS.