title: Matrix metalloproteinase-14 (MT1-MMP)-mediated endoglin shedding inhibits tumor angiogenesis.
abstract: Endoglin is a transforming growth factor-beta coreceptor with a crucial role in angiogenesis. A soluble form of endoglin is present in the circulation, but the role of soluble endoglin (sEndoglin) is poorly understood. In addition, the endoglin shedding mechanism is not known. Therefore, we examined the role of sEndoglin in tumor angiogenesis and the mechanism by which the extracellular domain of endoglin is released from the membrane.In colorectal cancer specimens, we observed high endothelial endoglin protein expression, accompanied with slightly lower sEndoglin levels in the circulation, compared with healthy controls. In vitro analysis using endothelial sprouting assays revealed that sEndoglin reduced spontaneous and vascular endothelial growth factor-induced endothelial sprouting. Human umbilical vascular endothelial cells were found to secrete high levels of sEndoglin. Endoglin shedding was inhibited by matrix metalloproteinase (MMP) inhibitors and MMP-14 short hairpin RNA, indicating MMP-14 as the major endoglin shedding protease. Coexpression of endoglin and membrane-bound MMP-14 led to a strong increase in sEndoglin levels. Endoglin shedding required a direct interaction between endoglin and membrane-localized MMP-14. Using cleavage site mutants, we determined that MMP-14 cleaved endoglin at a site in close proximity to the transmembrane domain. Taken together, this study shows that MMP-14 mediates endoglin shedding, which may regulate the angiogenic potential of endothelial cells in the (colorectal) tumor microenvironment.
authors.affiliation: Departmentsof Molecular Cell Biology, Centre for Biomedical Genetics, Gastroenterology-Hepatology, and Surgery, Leiden University Medical Center, Leiden, the Netherlands. L.J.A.C.Hawinkels@LUMC.nl
authors.forename: Lukas J A C
authors.initials: LJ
authors.lastname: Hawinkels
authors.forename: Patricia
authors.initials: P
authors.lastname: Kuiper
authors.forename: Eliza
authors.initials: E
authors.lastname: Wiercinska
authors.forename: Hein W
authors.initials: HW
authors.lastname: Verspaget
authors.forename: Zhen
authors.initials: Z
authors.lastname: Liu
authors.forename: Evangelia
authors.initials: E
authors.lastname: Pardali
authors.forename: Cornelis F M
authors.initials: CF
authors.lastname: Sier
authors.forename: Peter
authors.initials: P
authors.lastname: ten Dijke
mesh_terms: D000236:Adenoma / Q000098:blood supply* / Q000378:metabolism / Q000517:prevention & control; D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003106:Colon / Q000166:cytology / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000098:blood supply* / Q000378:metabolism / Q000517:prevention & control; D000071063:Endoglin; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007124:Immunoenzyme Techniques; D053511:Matrix Metalloproteinase 14 / Q000235:genetics / Q000378:metabolism*; D061965:Matrix Metalloproteinase Inhibitors; D009389:Neovascularization, Pathologic / Q000517:prevention & control*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D012007:Rectum / Q000166:cytology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014471:Umbilical Veins / Q000166:cytology / Q000378:metabolism
chemical_list: D015703:Antigens, CD; C064206:ENG protein, human; D000071063:Endoglin; D061965:Matrix Metalloproteinase Inhibitors; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface; C507086:MMP14 protein, human; D053511:Matrix Metalloproteinase 14