title: Inhibition of programmed cell death impairs in vitro vascular-like structure formation and reduces in vivo angiogenesis.
abstract: Tissue remodeling during embryonic development and in the adult organism relies on a subtle balance between cell growth and apoptosis. As angiogenesis involves restructuring of preexisting endothelium, we examined the role of apoptosis in new vessel formation. We show that apoptosis occurs before capillary formation but not after vessels have assembled. Using the human umbilical vein endothelial cell (HUVEC) in vitro Matrigel angiogenesis model, we show that vascular-like structure formation requires apoptotic cell death through activation of a caspase-dependent mechanism and mitochondrial cytochrome c release. Vascular-like structure formation was further blocked by caspase inhibitors such as z-VAD or Ac-DEVD-CHO, using HUVEC and human lung microvascular endothelial cells. Overexpression of anti-apoptotic human Bcl-2 or baculovirus p35 genes in HUVEC altered endothelial cell rearrangement during in vitro angiogenesis, causing impaired vessel-like structure formation. Caspase inhibitors blocked VEGF- or bFGF-induced HUVEC angiogenesis on 2- or 3-D collagen gels, respectively, confirming that apoptosis was not the result of nonspecific cell death after seeding on the matrix. In an in vivo angiogenesis assay, caspase inhibitors blocked VEGF-dependent vascular formation at the alignment step, as demonstrated histologically. This evidence indicates that endothelial cell apoptosis may be relevant for precise vascular tissue rearrangement in in vitro and in vivo angiogenesis.
authors.affiliation: Department of Immunology and Oncology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid, Spain.
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Segura
authors.forename: Antonio
authors.initials: A
authors.lastname: Serrano
authors.forename: Gonzalo González
authors.initials: GG
authors.lastname: De Buitrago
authors.forename: Manuel A
authors.initials: MA
authors.lastname: González
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Abad
authors.forename: Cristina
authors.initials: C
authors.lastname: Clavería
authors.forename: Lucio
authors.initials: L
authors.lastname: Gómez
authors.forename: Antonio
authors.initials: A
authors.lastname: Bernad
authors.forename: Carlos
authors.initials: C
authors.lastname: Martínez-A
authors.forename: Hans H
authors.initials: HH
authors.lastname: Riese
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001808:Blood Vessels / Q000187:drug effects / Q000502:physiology; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D003094:Collagen; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003574:Cytochrome c Group / Q000378:metabolism; D004338:Drug Combinations; D016228:Endothelial Growth Factors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D019169:Jurkat Cells; D007797:Laminin; D008222:Lymphokines / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000502:physiology*; D009842:Oligopeptides / Q000494:pharmacology; D011509:Proteoglycans; D051381:Rats; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D003574:Cytochrome c Group; D004338:Drug Combinations; D016228:Endothelial Growth Factors; D007797:Laminin; D008222:Lymphokines; D009842:Oligopeptides; D011509:Proteoglycans; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C099158:acetyl-aspartyl-glutamyl-valyl-aspartal; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C059485:matrigel; D003094:Collagen; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases