title: In vitro and in vivo anti-angiogenic effects of hydroxyurea.
abstract: Hydroxyurea (HU), or hydroxycarbamide, is used for the treatment of some myeloproliferative and neoplastic diseases, and is currently the only drug approved by the FDA for use in sickle cell disease (SCD). Despite the relative success of HU therapy for SCD, a genetic disorder of the hemoglobin β chain that results in red-cell sickling, hemolysis, vascular inflammation and recurrent vasoocclusion, the exact mechanisms by which HU actuates remain unclear. We hypothesized that HU may modulate endothelial angiogenic processes, with important consequences for vascular inflammation. The effects of HU (50-200 μM; 17-24 h) on endothelial cell functions associated with key steps of angiogenesis were evaluated using human umbilical vein endothelial cell (HUVEC) cultures. Expression profiles of the HIF1A gene and the miRNAs 221 and 222, involved in endothelial function, were also determined in HUVECs following HU administration and the direct in vivo antiangiogenic effects of HU were assessed using a mouse Matrigel-plug neovascularization assay. Following incubation with HU, HUVECs exhibited high cell viability, but displayed a significant 75% inhibition in the rate of capillary-like-structure formation, and significant decreases in proliferative and invasive capacities. Furthermore, HU significantly decreased HIF1A expression, and induced the expression of miRNA 221, while downregulating miRNA 222. In vivo, HU reduced vascular endothelial growth factor (VEGF)-induced vascular development in Matrigel implants over 7 days. Findings indicate that HU is able to inhibit vessel assembly, a crucial angiogenic process, both in vitro and in vivo, and suggest that some of HU's therapeutic effects may occur through novel vascular mechanisms.
authors.affiliation: INCT de Sangue, Hematology and Hemotherapy Center, School of Medical Sciences, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil.
authors.forename: Flávia Cristine Mascia
authors.initials: FC
authors.lastname: Lopes
authors.affiliation: INCT de Sangue, Hematology and Hemotherapy Center, School of Medical Sciences, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil.
authors.forename: Regiane
authors.initials: R
authors.lastname: Ferreira
authors.affiliation: INCT de Sangue, Hematology and Hemotherapy Center, School of Medical Sciences, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil.
authors.forename: Dulcinéia Martins
authors.initials: DM
authors.lastname: Albuquerque
authors.affiliation: INCT de Sangue, Hematology and Hemotherapy Center, School of Medical Sciences, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil.
authors.forename: Angélica A Antoniellis
authors.initials: AA
authors.lastname: Silveira
authors.affiliation: Department of Biochemistry (U38-FCT), Faculty of Medicine, University of Porto, Porto, Portugal.
authors.forename: Raquel
authors.initials: R
authors.lastname: Costa
authors.affiliation: Department of Biochemistry (U38-FCT), Faculty of Medicine, University of Porto, Porto, Portugal.
authors.forename: Raquel
authors.initials: R
authors.lastname: Soares
authors.affiliation: INCT de Sangue, Hematology and Hemotherapy Center, School of Medical Sciences, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil.
authors.forename: Fernando Ferreira
authors.initials: FF
authors.lastname: Costa
authors.affiliation: INCT de Sangue, Hematology and Hemotherapy Center, School of Medical Sciences, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil. Electronic address: conran@unicamp.br.
authors.forename: Nicola
authors.initials: N
authors.lastname: Conran
mesh_terms: D000755:Anemia, Sickle Cell / Q000188:drug therapy*; D020533:Angiogenesis Inhibitors / Q000737:chemistry*; D000818:Animals; D002465:Cell Movement; D049109:Cell Proliferation; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D006918:Hydroxyurea / Q000737:chemistry*; D000860:Hypoxia / Q000188:drug therapy; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D020287:In Situ Nick-End Labeling; D007249:Inflammation / Q000188:drug therapy; D007871:Leg Ulcer / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000378:metabolism; D009196:Myeloproliferative Disorders / Q000188:drug therapy; D009389:Neovascularization, Pathologic; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D020533:Angiogenesis Inhibitors; D006918:Hydroxyurea; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D035683:MicroRNAs; D042461:Vascular Endothelial Growth Factor A; C497442:HIF1A protein, human; C534451:MIRN20a microRNA, human; C525709:MIR221, human
keywords: Angiogenesis; Capillary formation; Endothelial cells; Hydroxyurea; Hypoxia; Inflammation; Leg ulcer; Myeloproliferative diseases; Sickle cell disease; miRNA