title: All-trans retinoic acid induces in vitro angiogenesis via retinoic acid receptor: possible involvement of paracrine effects of endogenous vascular endothelial growth factor signaling.
abstract: A natural retinoid all-trans retinoic acid (ATRA) regulates a variety of important cellular functions via retinoic acid receptor (RAR). ATRA has therapeutically been used against various malignancies including acute promyelocytic leukemia. Recently ATRA has also been recognized to be beneficial against atherosclerotic vascular disorders. However, its effects on angiogenesis remain controversial. We therefore examined ATRA effects on in vitro angiogenesis in terms of capillary-like tube formation using human umbilical vein endothelial cells (HUVECs)/normal human dermal fibroblast (NHDF) coculture. ATRA as well as RAR agonist Am80 significantly induced capillary-like tube formation. The ATRA-induced tube formation was inhibited by coincubation with RAR antagonist LE540/LE135. HUVEC proliferation, but not its migration, was also induced by ATRA. The ATRA-induced tube formation was completely abolished by coincubation with vascular endothelial growth factor (VEGF) neutralizing antibody or with VEGF receptor (VEGFR)-2 (KDR) neutralizing antibody, but not VEGFR-1 (Flt-1) neutralizing antibody. ATRA and Am80 induced VEGF secretion in the coculture as well as VEGF secretion/mRNA expression in NHDFs. Transcription activity of human VEGF gene promoter in NHDFs was stimulated by ATRA, which was augmented by RAR overexpression. ATRA also induced VDGFR-2/KDR mRNA expression in HUVECs. Moreover, ATRA-induced secretion of hepatocyte growth factor as well as angiopoietin-2 in the coculture. Taken together, ATRA may have induced angiogenesis via RAR mainly by stimulation of HUVEC proliferation and enhancement of endogenous VEGF signaling and in part by induction of hepatocyte growth factor and angiopoietin-2 production. Retinoids may therefore be potential candidates for therapeutic angiogenesis against ischemic vascular disorders.
authors.affiliation: Department of Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-cho, Aoba-ku, Sendai 980-8574, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Saito
authors.forename: Akira
authors.initials: A
authors.lastname: Sugawara
authors.forename: Akira
authors.initials: A
authors.lastname: Uruno
authors.forename: Masataka
authors.initials: M
authors.lastname: Kudo
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kagechika
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Sato
authors.forename: Yuji
authors.initials: Y
authors.lastname: Owada
authors.forename: Hisatake
authors.initials: H
authors.lastname: Kondo
authors.forename: Mayumi
authors.initials: M
authors.lastname: Sato
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kurabayashi
authors.forename: Masue
authors.initials: M
authors.lastname: Imaizumi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Tsuchiya
authors.forename: Sadayoshi
authors.initials: S
authors.lastname: Ito
mesh_terms: D042702:Angiopoietin-2 / Q000378:metabolism; D002196:Capillaries / Q000187:drug effects / Q000254:growth & development; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D004305:Dose-Response Relationship, Drug; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D006801:Humans; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D019899:Paracrine Communication / Q000502:physiology*; D018168:Receptors, Retinoic Acid / Q000378:metabolism*; D015398:Signal Transduction; D014212:Tretinoin / Q000494:pharmacology*; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism
chemical_list: D042702:Angiopoietin-2; D018168:Receptors, Retinoic Acid; D042461:Vascular Endothelial Growth Factor A; D014212:Tretinoin; D017228:Hepatocyte Growth Factor; D040301:Vascular Endothelial Growth Factor Receptor-2