title: Se-methylselenocysteine induces apoptosis mediated by reactive oxygen species in HL-60 cells.
abstract: Recent studies have implicated apoptosis as one of the most plausible mechanisms of the chemopreventive effects of selenium compounds, and reactive oxygen species (ROS) as important mediators in apoptosis induced by various stimuli. In the present study, we demonstrate that Se-methylselenocysteine (MSC), one of the most effective selenium compounds at chemoprevention, induced apoptosis in HL-60 cells and that ROS plays a crucial role in MSC-induced apoptosis. The uptake of MSC by HL-60 cells occurred quite early, reaching the maximum within 1 h. The dose-dependent decrease in cell viability was observed by MSC treatment and was coincident with increased DNA fragmentation and sub-G(1) population. 50 microM of MSC was able to induce apoptosis in 48% of cell population at a 24 h time point. Moreover, the release of cytochrome c from mitochondria and the activation of caspase-3 and caspase-9 were also observed. The measurement of ROS by dichlorofluorescein fluorescence revealed that dose- and time-dependent increase in ROS was induced by MSC. N-acetylcysteine, glutathione, and deferoxamine blocked cell death, DNA fragmentation, and ROS generation induced by MSC. Moreover, N-acetylcysteine effectively blocked caspase-3 activation and the increase of the sub-G(1) population induced by MSC. These results imply that ROS is a critical mediator of the MSC-induced apoptosis in HL-60 cells.
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yusung-gu, Taejon, Republic of Korea.
authors.forename: U
authors.initials: U
authors.lastname: Jung
authors.forename: X
authors.initials: X
authors.lastname: Zheng
authors.forename: S O
authors.initials: SO
authors.lastname: Yoon
authors.forename: A S
authors.initials: AS
authors.lastname: Chung
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D003545:Cysteine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D003574:Cytochrome c Group / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005434:Flow Cytometry; D018922:HL-60 Cells / Q000187:drug effects* / Q000201:enzymology; D006367:HeLa Cells / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D008564:Membrane Potentials; D016566:Organoselenium Compounds / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017279:Selenocysteine / Q000031:analogs & derivatives
chemical_list: D016588:Anticarcinogenic Agents; D000975:Antioxidants; D003574:Cytochrome c Group; D016566:Organoselenium Compounds; D017382:Reactive Oxygen Species; D017279:Selenocysteine; D020169:Caspases; D003545:Cysteine; C002979:selenomethylselenocysteine; D000111:Acetylcysteine