title: MT1-MMP controls tumor-induced angiogenesis through the release of semaphorin 4D.
abstract: The semaphorins are a family of proteins originally identified as regulators of axon growth that recently have been implicated in blood vessel development. The plexins are high affinity receptors for the semaphorins and are responsible for initiation of signaling upon ligation. Emerging evidence indicates that many human cancers overexpress Semaphorin 4D, which promotes neovascularization upon stimulating its receptor, Plexin-B1, on endothelial cells. However, to exert its pro-angiogenic functions, Semaphorin 4D must be processed and released from its membrane bound form to act in a paracrine manner on endothelial cells. Here we show that Semaphorin 4D is a novel target for the membrane-tethered collagenase membrane type 1-matrix metalloproteinase. We demonstrate that this metalloproteinase, which is not expressed in normal or immortal but non-tumorigenic epithelial cell lines, was present in several head and neck squamous cell carcinoma cell lines and was required for processing and release of Semaphorin 4D into its soluble form from these cells, thereby inducing endothelial cell chemotaxis in vitro and blood vessel growth in vivo. These results suggest that the proteolytic cleavage of Semaphorin 4D may provide a novel molecular mechanism by which membrane type 1-matrix metalloproteinase controls tumor-induced angiogenesis.
authors.affiliation: Oral and Pharyngeal Cancer Branch and Matrix Metalloproteinase Unit, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, USA. jbasile@mail.nih.gov
authors.forename: John R
authors.initials: JR
authors.lastname: Basile
authors.forename: Kenn
authors.initials: K
authors.lastname: Holmbeck
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Bugge
authors.forename: J Silvio
authors.initials: JS
authors.lastname: Gutkind
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D045744:Cell Line, Tumor; D002633:Chemotaxis; D042783:Endothelial Cells; D053511:Matrix Metalloproteinase 14 / Q000502:physiology*; D051379:Mice; D009369:Neoplasms / Q000098:blood supply; D009389:Neovascularization, Pathologic; D019899:Paracrine Communication; D039961:Semaphorins / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; C093224:CD100 antigen; C507096:Mmp14 protein, mouse; D039961:Semaphorins; D053511:Matrix Metalloproteinase 14