cAMP inhibits TGFbeta1-induced in vitro angiogenesis.
Transforming growth factor-beta (TGFbeta1) is a proangiogenic factor both, in vitro and in vivo, that is mainly involved in the later phases of angiogenesis. In an attempt to identify genes that participate in this effect, we found that TGFbeta1 down-regulates expression of adenylate cyclase VI. In addition, cAMP analogs (8-Bromo-cAMP) and forskolin (an adenylate cyclase activator) also reduced TGFbeta1-induced in vitro angiogenesis in mouse endothelial cell lines and in primary cultures of human umbilical vein endothelial cells on collagen gels. Induction of Ets-1 and plasminogen activator inhibitor-1 (PAI-1) by TGFbeta1 was blocked by these cAMP agonists and activators, in the absence of effects on endothelial cell viability. Moreover, the signal transduction pathways stimulated by TGFbeta1 were unaffected. Thus, Smad2 was normally phosphorylated and translocated to the nucleus in the presence of forskolin. In contrast, transfection studies using the PAI-1-promoter indicated that these cAMP analogues inhibit transcriptional stimulation by TGFbeta1. Electrophoretic mobility shift assay showed that Smad2/3 were bound normally to a TGFbeta1-response region in the presence of the cAMP analogs. In all, these data suggest that the cAMP pathway inhibits the transcriptional activity of Smads, that could be responsible for the block of the TGFbeta1-induced in vitro angiogenesis caused by this second messenger.
del Valle-Pérez
Beatriz
B
Unitat de Bioquímica i Biologia Molecular, Departament de Ciències Fiològiques II, Campus de Bellvitge, Universitat de Barcelona, C/ Feixa Llarga s/n, E-08907 L'Hospitalet de Llobregat, Spain.
Martínez-Estrada
Ofelia Maria
OM
Vilaró
Senén
S
Ventura
Francesc
F
Viñals
Francesc
F
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology*; D000818:Animals; D002196:Capillaries / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D000242:Cyclic AMP / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D051379:Mice; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1; D014471:Umbilical Veins / Q000187:drug effects / Q000502:physiology
D011994:Recombinant Proteins; C508960:TGFB1 protein, human; C508961:Tgfb1 protein, mouse; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D015124:8-Bromo Cyclic Adenosine Monophosphate; D000242:Cyclic AMP