title: The effect of redox-related species of nitrogen monoxide on transferrin and iron uptake and cellular proliferation of erythroleukemia (K562) cells.
abstract: The iron-responsive element-binding protein (IRE-BP) modulates both ferritin mRNA translation and transferrin receptor (TfR) mRNA stability by binding to specific mRNA sequences called iron-responsive elements (IREs). The regulation of IRE-BP in situ could possibly occur either through its Fe-S cluster and/or via free cysteine sulphydryl groups such as cysteine 437 (Philpott et al, J Biol Chem 268:17655, 1993; and Hirling et al, EMBO J 13:453, 1994). Recently, nitrogen monoxide (NO) has been shown to have markedly different biologic effects depending on its redox state (Lipton et al, Nature 364:626, 1993). Considering this fact, it is conceivable that the NO group, as either the nitrosonium ion (NO+) or nitric oxide (NO+), may regulate IRE-BP activity by S-nitrosylation of key sulphydryl groups or via ligation of NO. to the Fe-S cluster, respectively. This hypothesis has been examined using the NO+ generator, sodium nitroprusside (SNP); the NO. generator, S-nitroso-N-acetylpenicillamine (SNAP); and the NO./peroxynitrite (ONOO-) generator, 3-morpholinosydnonimine hydrochloride (SIN-1). Treatment of K562 cells for 18 hours with SNP (1 mmol/L) resulted in a pronounced decrease in both the RNA-binding activity of IRE-BP and the level of TfR mRNA. In addition, Scatchard analysis showed a marked decrease in the number of specific Tf-binding sites, from 590,000/cell (control) to 170,000/cell (test), and there was also a distinct decrease in Fe uptake. Furthermore, SNP did not decrease cellular viability or proliferation. In contrast, the NO. generator, SNAP (1 mmol/L), increased RNA-binding activity of IRE-BP, the level of TfR mRNA, and the number of TfRs in K562 cells. Moreover, both SNAP (1 mmol/L) and SIN-1 (0.5 mmol/L) reduced cellular proliferation. The results are discussed in context of the possible physiologic role of redox-related species of NO in regulating iron metabolism.
authors.affiliation: Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada.
authors.forename: D R
authors.initials: DR
authors.lastname: Richardson
authors.forename: V
authors.initials: V
authors.lastname: Neumannova
authors.forename: E
authors.initials: E
authors.lastname: Nagy
authors.forename: P
authors.initials: P
authors.lastname: Ponka
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002455:Cell Division; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects; D006801:Humans; D007501:Iron / Q000378:metabolism*; D035925:Iron-Regulatory Proteins; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism* / Q000473:pathology; D046911:Macromolecular Substances; D008954:Models, Biological; D008981:Molsidomine / Q000031:analogs & derivatives / Q000494:pharmacology; D009363:Neoplasm Proteins / Q000378:metabolism*; D009569:Nitric Oxide / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology; D010084:Oxidation-Reduction; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D012323:RNA Processing, Post-Transcriptional / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D012334:RNA, Neoplasm / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011990:Receptors, Transferrin / Q000378:metabolism*; D026423:S-Nitroso-N-Acetylpenicillamine; D013438:Sulfhydryl Compounds / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000975:Antioxidants; D035925:Iron-Regulatory Proteins; D046911:Macromolecular Substances; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D016601:RNA-Binding Proteins; D011990:Receptors, Transferrin; D013438:Sulfhydryl Compounds; D014168:Transferrin; D009599:Nitroprusside; D009569:Nitric Oxide; C002385:linsidomine; D026423:S-Nitroso-N-Acetylpenicillamine; D008981:Molsidomine; D007501:Iron; D010396:Penicillamine