title: Hydroxyurea induces the eNOS-cGMP pathway in endothelial cells.
abstract: Hydroxyurea is a cell-cycle-specific drug that has been used to treat myeloproliferative diseases and sickle cell anemia. We have recently shown that hydroxyurea, like nitric oxide (NO)-donor compounds, increased cGMP levels in human erythroid cells. We show now that hydroxyurea increases endothelial-cell production of NO; this induction of NO in human umbilical vein endothelial cells (HUVECs) and human bone marrow endothelial cell line (TrHBMEC) is blocked by competitive inhibitors of NO synthase (NOS), such as NG-nitro-L-arginine-methyl ester (L-NAME) and NG-nitro-L-arginine. It is dependent on cAMP-dependent protein kinase (PKA) and protein kinase B (PKB/Akt) activity. We found that hydroxyurea dose- and time-dependently induced rapid and transient phosphorylation of eNOS at Ser1177 in a PKA-dependent manner; inhibitors of PKB/Akt could partially abrogate this effect. In addition, hydroxyurea induced cAMP and cGMP levels in a dose-dependent manner, as well as levels of intracellular calcium in HUVECs. These studies established an additional mechanism by which rapid and sustained effects of hydroxyurea may affect cellular NO levels and perhaps enhance the effect of NO in myeloproliferative diseases.
authors.affiliation: Institute of Medical Research, and the Institute of Endocrinology, Diabetes and Digestive and Diseases of Metabolism, Belgrade, Serbia and Montenegro.
authors.forename: Vladan P
authors.initials: VP
authors.lastname: Cokic
authors.forename: Bojana B
authors.initials: BB
authors.lastname: Beleslin-Cokic
authors.forename: Melanija
authors.initials: M
authors.lastname: Tomic
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: D000730:Androstadienes / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002867:Chromones / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism*; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology*; D007546:Isoquinolines / Q000494:pharmacology; D009025:Morpholines / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013329:Structure-Activity Relationship; D013449:Sulfonamides / Q000494:pharmacology; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D002867:Chromones; D007546:Isoquinolines; D009025:Morpholines; D013449:Sulfonamides; D009569:Nitric Oxide; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D000242:Cyclic AMP; D019001:Nitric Oxide Synthase; D006152:Cyclic GMP; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D002118:Calcium; D006918:Hydroxyurea; D000077191:Wortmannin