title: Hydroxyurea nitrosylates and activates soluble guanylyl cyclase in human erythroid cells.
abstract: Hydroxyurea, a drug widely used for treating myeloproliferative diseases, has also been approved for the treatment of sickle cell disease by raising fetal hemoglobin (HbF). We have shown that nitric oxide (NO) and the soluble guanylyl cyclase (sGC) pathways are involved in hydroxyurea induction of HbF levels in erythroid progenitor cells (EPCs). We demonstrate now that during erythroid differentiation, endothelial NO synthase mRNA and protein levels decline steadily, as does the production of NO derivatives and cyclic adenosine monophosphate (cAMP) levels, but guanosine 3',5'-cyclic monophosphate (cGMP) levels are stable. Hydroxyurea increased intracellular cGMP levels and cAMP levels in EPCs. The NO donor, DEANONOate, induced much higher cGMP levels, but reduced cAMP levels. Hydroxyurea (1 mM) induced production of approximately 45 pM cGMP/minute/ng of purified sGC, similar to induction by 1 muM DEANONOate. We found that hydroxyurea and ProliNONOate produced iron-nitrosyl derivatives of sGC. Thus, we confirm that hydroxyurea can directly interact with the deoxy-heme of sGC, presumably by a free-radical nitroxide pathway, and activate cGMP production. These data add to an expanding appreciation of the role of hydroxyurea as an inducer of the NO/cGMP pathway in EPCs. These mechanisms may also be involved in the cytostatic effects of hydroxyurea, as well as the induction of HbF.
authors.affiliation: Laboratory of Experimental Hematology, Institute for Medical Research, Belgrade, Serbia.
authors.forename: Vladan P
authors.initials: VP
authors.lastname: Cokic
authors.forename: Silvana A
authors.initials: SA
authors.lastname: Andric
authors.forename: Stanko S
authors.initials: SS
authors.lastname: Stojilkovic
authors.forename: Constance T
authors.initials: CT
authors.lastname: Noguchi
authors.forename: Alan N
authors.initials: AN
authors.lastname: Schechter
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D041905:Erythroid Cells / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006162:Guanylate Cyclase / Q000378:metabolism*; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism; D009608:Nitrous Acid / Q000494:pharmacology*; D009712:Nucleotides, Cyclic / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D000071756:Soluble Guanylyl Cyclase
chemical_list: D009712:Nucleotides, Cyclic; D018160:Receptors, Cytoplasmic and Nuclear; D019001:Nitric Oxide Synthase; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D009608:Nitrous Acid; D006918:Hydroxyurea