title: The proteasome is involved in angiogenesis.
abstract: The proteasome is a recently identified intracellular protease whose catalytic active site is a threonine residue and has been shown to play key roles in a variety of important intracellular events, including cell cycle progression, the antigen-presenting pathway, and apoptosis. However, its biological significance in multicellular organisms is still largely unknown because of lack of experimental systems for its study. Here we verified potential involvement of the proteasome in angiogenesis using lactacystin, a specific proteasome inhibitor. Lactacystin treatment resulted in almost complete prevention of in vivo neovascularization in the developing chick embryo chorioallantoic membrane. It also inhibited vascular endothelial tube formation on Matrigel, a model for in vitro angiogenesis, in a concentration-dependent fashion. Moreover, it prevented production of plasminogen activator, an important protease responsible for induction of angiogenesis, by endothelial cells, which correlated well with its suppression of intracellular proteasome activity. Our studies suggest that the proteasome operates in the process of angiogenesis, a phenomenon essential in important physiological and pathological settings.
authors.affiliation: Department of Cancer Therapeutics, Tokyo Metropolitan Institute of Medical Science, Rinshoken, Japan. oikawa@rinshoken.or.jp
authors.forename: T
authors.initials: T
authors.lastname: Oikawa
authors.forename: T
authors.initials: T
authors.lastname: Sasaki
authors.forename: M
authors.initials: M
authors.lastname: Nakamura
authors.forename: M
authors.initials: M
authors.lastname: Shimamura
authors.forename: N
authors.initials: N
authors.lastname: Tanahashi
authors.forename: S
authors.initials: S
authors.lastname: Omura
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D000482:Allantois / Q000098:blood supply / Q000187:drug effects; D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D002823:Chorion / Q000098:blood supply / Q000187:drug effects; D003546:Cysteine Endopeptidases / Q000502:physiology*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D006801:Humans; D009097:Multienzyme Complexes / Q000502:physiology*; D018919:Neovascularization, Physiologic / Q000187:drug effects; D010960:Plasminogen Activators / Q000096:biosynthesis; D046988:Proteasome Endopeptidase Complex
chemical_list: D015853:Cysteine Proteinase Inhibitors; D009097:Multienzyme Complexes; C067713:lactacystin; D010960:Plasminogen Activators; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D000111:Acetylcysteine