title: Decline of superoxide dismutase activity during antioxidant-induced apoptosis in HL-60 cells.
abstract: Possible changes in Mn-containing superoxide dismutase (MnSOD) and Cu- and Zn-containing superoxide dismutase (CuZnSOD) activity during the apoptosis of human promyelocytic leukemia HL-60 cells, induced by three antioxidants, were investigated. Agarose gel electrophoresis of the DNA isolated from cells treated with sodium ascorbate, gallic acid or epigallocatechin gallate (EGCG) showed the internucleosomal DNA fragmentation, a biochemical hallmark of apoptosis. The optimum concentration for induction of DNA fragmentation was narrow and higher concentrations were rather inhibitory. Their effects were detected after 3 hours and reached a maximum level at 6 hours. Polyacrylamide gel electrophoresis and activity staining demonstrated that both MnSOD and CuZnSOD activities were significantly reduced at cytotoxic concentrations of all these compounds. Incubation of an intracellular MnSOD-enriched fraction with apoptosis-inducing concentrations of sodium ascorbate, gallic acid or EGCG did not significantly reduce the MnSOD activity, suggesting that their actions might be cell-mediated. These data suggest the mitochondrial dysfunction at the early stages of apoptosis.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Peking University School of Stomatology, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Ken
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Guang-Yan
authors.initials: GY
authors.lastname: Yu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakagami
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001205:Ascorbic Acid / Q000494:pharmacology; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology; D003593:Cytoplasm / Q000201:enzymology; D005707:Gallic Acid / Q000494:pharmacology; D018922:HL-60 Cells / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D008928:Mitochondria / Q000201:enzymology; D013482:Superoxide Dismutase / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005707:Gallic Acid; D002392:Catechin; C045651:epigallocatechin gallate; D013482:Superoxide Dismutase; D001205:Ascorbic Acid