title: The effect and mechanism of celecoxib in hypoxia-induced survivin up-regulation in HUVECs.
abstract: OBJECTIVE
  To investigate the roles of hypoxia-inducible factor 1α (HIF-1α), cyclooxygenase-2 (Cox-2) and its product, Prostaglandin E2 (PGE2), in the mechanisms underlying hypoxia-induced survivin expression in human umbilical vein endothelial cells (HUVECs) and to examine the effect of celecoxib, a selective Cox-2 inhibitor, on survivin expression.
  
  
  METHODS
  HUVECs were exposed to a normal (95% O2) or hypoxic (3% O2) environment for 24 hrs. We observed the localized expression of survivin, Cox-2 and HIF-1α in HUVECs using immunocytochemistry and detected the inhibitory effects of celecoxib on the growth of HUVECs using an MTT assay. mRNA and protein levels of Cox-2, HIF-1α and survivin were determined by real-time PCR and Western blot analysis under hypoxic conditions for 0, 6, 12, or 24 hrs. The time course changes of HIF-1α and survivin protein expression induced by cobalt chloride (CoCl2) were studied using Western blot analysis. We then treated HUVECs under hypoxia for 24 hrs with celecoxib (a Cox-2 selective inhibitor), genistein (a HIF-1α inhibitor) or exogenous PGE2 to further investigate the changes in hypoxia-induced survivin expression.
  
  
  RESULTS
  Following 24 hrs of hypoxic treatment, cells exhibited strongly positive survivin, HIF-1α and Cox-2 cytoplasmic staining. Celecoxib (65 μM) effectively inhibited cell proliferation under hypoxic conditions. The protein and mRNA levels of Cox-2, HIF-1α and survivin were increased under hypoxia. The patterns of HIF-1α and survivin expression induced by CoCl2 were similar to those induced by exposure to hypoxia. Genistein partially blocked survivin expression. Celecoxib reversed the hypoxia-induced survivin expression, whereas the addition of PGE2 partially restored this effect.
  
  
  CONCLUSIONS
  Hypoxia-induced survivin expression in HUVECs may be mediated by dual interdependent mechanisms directly involving HIF-1α and indirectly involving the Cox-2/PGE2 pathways. Celecoxib may offset hypoxia-induced survivin expression.
authors.affiliation: The Department of Ophthalmology, the First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China.
authors.forename: Ning-Ning
authors.initials: NN
authors.lastname: Liu
authors.forename: Ning
authors.initials: N
authors.lastname: Zhao
authors.forename: Na
authors.initials: N
authors.lastname: Cai
mesh_terms: D000068579:Celecoxib / Q000494:pharmacology*; D015687:Cell Hypoxia; D049109:Cell Proliferation / Q000187:drug effects; D003035:Cobalt / Q000494:pharmacology; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology*; D015232:Dinoprostone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D019833:Genistein / Q000494:pharmacology; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics / Q000378:metabolism*; D000077022:Survivin; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: C107489:BIRC5 protein, human; D052246:Cyclooxygenase 2 Inhibitors; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D051034:Inhibitor of Apoptosis Proteins; D000077022:Survivin; D003035:Cobalt; D019833:Genistein; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; C018021:cobaltous chloride; D000068579:Celecoxib; D015232:Dinoprostone