title: Role of Ca(2+) in diallyl disulfide-induced apoptotic cell death of HCT-15 cells.
abstract: Diallyl disulfide (DADS) induced apoptosis through the caspase-3 dependent pathway in leukemia cells was earlier reported from this laboratory. In this study, we investigated the involvement of Ca(2+) in DADS-induced apoptotic cell death of HCT-15, human colon cancer cell line. DADS induced the elevation of cytosolic Ca(2+) by biphasic pattern; rapid Ca(2+) peak at 3 min and following slow and sustained elevation till 3 h after the addition of DADS. Production of H(2)O(2) was also observed with its peak value at 4 h. Apoptotic pathways including the sequence of caspase-3 activation, poly(ADP-ribose) polymerase cleavage, and DNA fragmentation by DADS were completely blocked by various inhibitors such as specific caspase-3 inhibitor, free radical scavenger, and intracellular Ca(2+) chelator. N-acetylcystein and catalase treatment prevented the accumulation of H2O2 and later caspase-3 dependent apoptotic pathway. However, these radical scavengers did not block the elevation of intracellular Ca(2+). Treatment of cells with 1, 2-bis (2-aminophenoxyethane)-N, N, N-tetraacetic acid tetrakis -acetoxymethyl ester (BAPTA-AM), cellular Ca(2+) chelator, resulted in a complete blockage of the caspase-3 dependent apoptotic pathway of HCT-15 cells. It abolished the elevation of intracellular Ca(2+), and furthermore, completely inhibited the production of H(2)O(2). These results indicate that cytosolic Ca(2+) elevation is an earlier signaling event in apoptosis of HCT-15 cells. Collectively, our data demonstrate that DADS can induce apoptosis in HCT-15 cells through the sequential mechanism of Ca(2+) homeostasis disruption, accumulation of H(2)O(2), and resulting caspase-3 activation.
authors.affiliation: Department of Biochemistry and Institute of Oral Bioscience, Dental School, Chonbuk National University, Chonju, Chonbuk 561-756, Korea.
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Park
authors.forename: Kang-Beom
authors.initials: KB
authors.lastname: Kwon
authors.forename: Kie-In
authors.initials: KI
authors.lastname: Park
authors.forename: Byung-Hyun
authors.initials: BH
authors.lastname: Park
authors.forename: Eun-Chung
authors.initials: EC
authors.lastname: Jhee
mesh_terms: D000498:Allyl Compounds / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D004220:Disulfides / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000498:Allyl Compounds; D004220:Disulfides; C028009:diallyl disulfide; D006861:Hydrogen Peroxide; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D002118:Calcium