In vitro and in vivo anti-angiogenic effects of hydroxyurea

Flávia Cristine Mascia Lopes, Regiane Ferreira, Dulcinéia Martins Albuquerque, Angélica A.Antoniellis Silveira, Raquel Costa, Raquel Soares, Fernando Ferreira Costa, Nicola Conran*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)106-113
Number of pages8
JournalMicrovascular Research
Publication statusPublished - Jul 2014
Externally publishedYes


  • Angiogenesis
  • Capillary formation
  • Endothelial cells
  • Hydroxyurea
  • Hypoxia
  • Inflammation
  • Leg ulcer
  • MiRNA
  • Myeloproliferative diseases
  • Sickle cell disease


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