title: Induction of manganese superoxide dismutase by tumor necrosis factor in human breast cancer MCF-7 cell line and its TNF-resistant variant.
abstract: Tumor necrosis factor (TNF)-resistant variant of human mammary cancer MCF-7 cell line was isolated by stepwise selection. The final TNF-resistant variant Tnf-1000 showed more than 100-fold higher resistance than the parental MCF-7 cell. Saturation kinetics for 125I-TNF binding showed that TNF-1000 cells had similar TNF receptor numbers as MCF-7 cells, but of a lower affinity. Induction of superoxide dismutase (SOD) was compared between MCF-7 and Tnf-1000 cells treated with TNF: SOD scavenges potentially toxic superoxide radicals. TNF induced more mitochondrial manganese SOD (SODm) in MCF-7 than in Tnf-1000 whereas there appeared to be no significant induction of cytosolic copper/zinc SOD (SODc) by TNF in both MCF-7 and Tnf-1000 cell lines. Acquirement of TNF-resistance in MCF-7 cells might be correlated with expression of SODm.
authors.affiliation: Department of Biochemistry, Oita Medical School, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Asoh
authors.forename: Y
authors.initials: Y
authors.lastname: Watanabe
authors.forename: H
authors.initials: H
authors.lastname: Mizoguchi
authors.forename: M
authors.initials: M
authors.lastname: Mawatari
authors.forename: M
authors.initials: M
authors.lastname: Ono
authors.forename: K
authors.initials: K
authors.lastname: Kohno
authors.forename: M
authors.initials: M
authors.lastname: Kuwano
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology; D002455:Cell Division; D003513:Cycloheximide / Q000494:pharmacology; D003600:Cytosol / Q000201:enzymology; D003609:Dactinomycin / Q000494:pharmacology; D004351:Drug Resistance; D004790:Enzyme Induction; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D007700:Kinetics; D008345:Manganese; D008928:Mitochondria / Q000201:enzymology; D009154:Mutation; D011956:Receptors, Cell Surface / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor; D013482:Superoxide Dismutase / Q000096:biosynthesis*; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D007375:Interleukin-1; D011956:Receptors, Cell Surface; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D003609:Dactinomycin; D008345:Manganese; D003513:Cycloheximide; D013482:Superoxide Dismutase