scholarly journals Angiomotin

2001 ◽  
Vol 152 (6) ◽  
pp. 1247-1254 ◽  
Author(s):  
Boris Troyanovsky ◽  
Tetyana Levchenko ◽  
Göran Månsson ◽  
Olga Matvijenko ◽  
Lars Holmgren

Angiostatin, a circulating inhibitor of angiogenesis, was identified by its ability to maintain dormancy of established metastases in vivo. In vitro, angiostatin inhibits endothelial cell migration, proliferation, and tube formation, and induces apoptosis in a cell type–specific manner. We have used a construct encoding the kringle domains 1–4 of angiostatin to screen a placenta yeast two-hybrid cDNA library for angiostatin-binding peptides. Here we report the identification of angiomotin, a novel protein that mediates angiostatin inhibition of migration and tube formation of endothelial cells. In vivo, angiomotin is expressed in the endothelial cells of capillaries as well as larger vessels of the human placenta. Upon expression of angiomotin in HeLa cells, angiomotin bound and internalized fluorescein-labeled angiostatin. Transfected angiomotin as well as endogenous angiomotin protein were localized to the leading edge of migrating endothelial cells. Expression of angiomotin in endothelial cells resulted in increased cell migration, suggesting a stimulatory role of angiomotin in cell motility. However, treatment with angiostatin inhibited migration and tube formation in angiomotin-expressing cells but not in control cells. These findings indicate that angiostatin inhibits cell migration by interfering with angiomotin activity in endothelial cells.

Blood ◽  
2010 ◽  
Vol 115 (20) ◽  
pp. 4130-4137 ◽  
Author(s):  
Jinmin Gao ◽  
Lei Sun ◽  
Lihong Huo ◽  
Min Liu ◽  
Dengwen Li ◽  
...  

Cylindromatosis (CYLD) is a deubiquitinase that was initially identified as a tumor suppressor and has recently been implicated in diverse normal physiologic processes. In this study, we have investigated the involvement of CYLD in angiogenesis, the formation of new blood vessels from preexisting ones. We find that knockdown of CYLD expression significantly impairs angiogenesis in vitro in both matrigel-based tube formation assay and collagen-based 3-dimensional capillary sprouting assay. Disruption of CYLD also remarkably inhibits angiogenic response in vivo, as evidenced by diminished blood vessel growth into the angioreactors implanted in mice. Mechanistic studies show that CYLD regulates angiogenesis by mediating the spreading and migration of vascular endothelial cells. Silencing of CYLD dramatically decreases microtubule dynamics in endothelial cells and inhibits endothelial cell migration by blocking the polarization process. Furthermore, we identify Rac1 activation as an important factor contributing to the action of CYLD in regulating endothelial cell migration and angiogenesis. Our findings thus uncover a previously unrecognized role for CYLD in the angiogenic process and provide a novel mechanism for Rac1 activation during endothelial cell migration and angiogenesis.


2020 ◽  
Vol 21 (3) ◽  
pp. 755 ◽  
Author(s):  
Suyash Srivastava ◽  
Fatema Tuz Zahra ◽  
Nehal Gupta ◽  
Paul E. Tullar ◽  
Sanjay K. Srivastava ◽  
...  

Metastasis is considered a major burden in cancer, being responsible for more than 90% of cancer-related deaths. Tumor angiogenesis is one of the main processes that lead to tumor metastasis. Penfluridol is a classic and commonly used antipsychotic drug, which has a great ability to cross the blood–brain barrier. Recent studies have revealed that penfluridol has significant anti-cancer activity in diverse tumors, such as metastatic breast cancer and glioblastoma. Here, we aim to identify the effect of low doses of penfluridol on tumor microenvironment and compare it with its effect on tumor cells. Although low concentration of penfluridol was not toxic for endothelial cells, it blocked angiogenesis in vitro and in vivo. In vitro, penfluridol inhibited VEGF-induced primary endothelial cell migration and tube formation, and in vivo, it blocked VEGF- and FGF-induced angiogenesis in the matrigel plug assay. VEGF-induced VEGFR2 phosphorylation and the downstream p38 and ERK signaling pathways were not affected in endothelial cells, although VEGF-induced Src and Akt activation were abrogated by penfluridol treatment. When cancer cells were treated with the same low concentration of penfluridol, basal Src activation levels were mildly impaired, thus impacting their cell migration and wound healing efficiency. The potential of cancer-induced paracrine effect on endothelial cells was explored, although that did not seem to be a player for angiogenesis. Overall, our data demonstrates that low penfluridol levels, similar to the ones clinically used for anti-psychotic conditions, suppress angiogenic efficiency in the tumor microenvironment.


Blood ◽  
2012 ◽  
Vol 119 (5) ◽  
pp. 1302-1313 ◽  
Author(s):  
Cheng-Hsiang Kuo ◽  
Po-Ku Chen ◽  
Bi-Ing Chang ◽  
Meng-Chen Sung ◽  
Chung-Sheng Shi ◽  
...  

AbstractLewis Y Ag (LeY) is a cell-surface tetrasaccharide that participates in angiogenesis. Recently, we demonstrated that LeY is a specific ligand of the recombinant lectin-like domain of thrombomodulin (TM). However, the biologic function of interaction between LeY and TM in endothelial cells has never been investigated. Therefore, the role of LeY in tube formation and the role of the recombinant lectin-like domain of TM—TM domain 1 (rTMD1)—in antiangiogenesis were investigated. The recombinant TM ectodomain exhibited lower angiogenic activity than did the recombinant TM domains 2 and 3. rTMD1 interacted with soluble LeY and membrane-bound LeY and inhibited soluble LeY-mediated chemotaxis of endothelial cells. LeY was highly expressed on membrane ruffles and protrusions during tube formation on Matrigel. Blockade of LeY with rTMD1 or Ab against LeY inhibited endothelial tube formation in vitro. Epidermal growth factor (EGF) receptor in HUVECs was LeY modified. rTMD1 inhibited EGF receptor signaling, chemotaxis, and tube formation in vitro, and EGF-mediated angiogenesis and tumor angiogenesis in vivo. We concluded that LeY is involved in vascular endothelial tube formation and rTMD1 inhibits angiogenesis via interaction with LeY. Administration of rTMD1 or recombinant adeno-associated virus vector carrying TMD1 could be a promising antiangiogenesis strategy.


2000 ◽  
Vol 113 (1) ◽  
pp. 59-69 ◽  
Author(s):  
M.F. Carlevaro ◽  
S. Cermelli ◽  
R. Cancedda ◽  
F. Descalzi Cancedda

Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) induces endothelial cell migration and proliferation in culture and is strongly angiogenic in vivo. VEGF synthesis has been shown to occur in both normal and transformed cells. The receptors for the factor have been shown to be localized mainly in endothelial cells, however, the presence of VEGF synthesis and the VEGF receptor in cells other than endothelial cells has been demonstrated. Neoangiogenesis in cartilage growth plate plays a fundamental role in endochondral ossification. We have shown that, in an avian in vitro system for chondrocyte differentiation, VEGF was produced and localized in cell clusters totally resembling in vivo cartilage. The factor was synthesized by hypertrophic chondrocytes and was released into their conditioned medium, which is highly chemotactic for endothelial cells. Antibodies against VEGF inhibited endothelial cell migration induced by chondrocyte conditioned media. Similarly, endothelial cell migration was inhibited also by antibodies directed against the VEGF receptor 2/Flk1 (VEGFR2). In avian and mammalian embryo long bones, immediately before vascular invasion, VEGF was distinctly localized in growth plate hypertrophic chondrocytes. In contrast, VEGF was not observed in quiescent and proliferating chondrocytes earlier in development. VEGF receptor 2 colocalized with the factor both in hypertrophic cartilage in vivo and hypertrophic cartilage engineered in vitro, suggesting an autocrine loop in chondrocytes at the time of their maturation to hypertrophic cells and of cartilage erosion. Regardless of cell exposure to exogenous VEGF, VEGFR-2 phosphorylation was recognized in cultured hypertrophic chondrocytes, supporting the idea of an autocrine functional activation of signal transduction in this non-endothelial cell type as a consequence of the endogenous VEGF production. In summary we propose that VEGF is actively responsible for hypertrophic cartilage neovascularization through a paracrine release by chondrocytes, with invading endothelial cells as a target. Furthermore, VEGF receptor localization and signal transduction in chondrocytes strongly support the hypothesis of a VEGF autocrine activity also in morphogenesis and differentiation of a mesoderm derived cell.


Cancers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 237 ◽  
Author(s):  
Takayuki Okamoto ◽  
Haruki Usuda ◽  
Tetsuya Tanaka ◽  
Koichiro Wada ◽  
Motomu Shimaoka

Angiogenesis—the sprouting and growth of new blood vessels from the existing vasculature—is an important contributor to tumor development, since it facilitates the supply of oxygen and nutrients to cancer cells. Endothelial cells are critically affected during the angiogenic process as their proliferation, motility, and morphology are modulated by pro-angiogenic and environmental factors associated with tumor tissues and cancer cells. Recent in vivo and in vitro studies have revealed that the gap junctions of endothelial cells also participate in the promotion of angiogenesis. Pro-angiogenic factors modulate gap junction function and connexin expression in endothelial cells, whereas endothelial connexins are involved in angiogenic tube formation and in the cell migration of endothelial cells. Several mechanisms, including gap junction function-dependent or -independent pathways, have been proposed. In particular, connexins might have the potential to regulate cell mechanics such as cell morphology, cell migration, and cellular stiffness that are dynamically changed during the angiogenic processes. Here, we review the implication for endothelial gap junctions and cellular mechanics in vascular angiogenesis.


Cells ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 349
Author(s):  
Devandir A. de Souza Junior ◽  
Carolina Santana ◽  
Gabriel V. Vieira ◽  
Constance Oliver ◽  
Maria Celia Jamur

Previous studies from our laboratory have shown that during angiogenesis in vitro, rmMCP-7 (recombinant mouse mast cell protease-7) stimulates endothelial cell spreading and induces their penetration into the matrix. The ability of rmMCP-7 to induce angiogenesis in vivo was assessed in the present study using a directed in vivo angiogenesis assay (DIVAA™). Vessel invasion of the angioreactor was observed in the presence of rmMCP-7 but was not seen in the control. Since integrins are involved in endothelial cell migration, the relationship between rmMCP-7 and integrins during angiogenesis was investigated. Incubation with rmMCP-7 resulted in a reduction in the levels of integrin subunits αv and β1 on SVEC4-10 endothelial cells during angiogenesis in vitro. Furthermore, the degradation of integrin subunits occurs both through the direct action of rmMCP-7 and indirectly via the ubiquitin/proteasome system. Even in the presence of a proteasome inhibitor, incubation of endothelial cells with rmMCP-7 induced cell migration and tube formation as well as the beginning of loop formation. These data indicate that the direct degradation of the integrin subunits by rmMCP-7 is sufficient to initiate angiogenesis. The results demonstrate, for the first time, that mMCP-7 acts in angiogenesis through integrin degradation.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 846-846
Author(s):  
Gerald W. Prager ◽  
Johannes M. Breuss4 ◽  
Patrick Brunner4 ◽  
Bernd R. Binder4

Abstract VEGF activates endothelial cells to migrate and invade surrounding tissues, an initial event in the angiogenic process. For invasion, the coordinated localized formation of a proteolytic repertoir is necessary. Focusing the urokinase receptor towards the leading edge of migrating cells provides such armor and inhibition of uPA binding to its receptor inhibits invasion of endothelial cells. In addition integrins continuously have to form focal contacts at the leading edge. Thus the spatial proximity between the localized proteases and the matrix seems to be essential for matrix degradation. In order to allow cell locomotion integrins have to release their ligands when they reach the trailing end and are subsequently endocytosed and redistributed to newly formed focal adhesions in a repetitive process. We here describe a new role of uPAR in regulating integrin redistribution. We have previously reported that stimulation of human endothelial cells by VEGF (50ng/ml) via its receptor flk-1 induces pro-uPA activation, when bound to uPAR. Subsequently a uPA/PAI-1/uPAR-complex is formed, which thereafter is endocytosed via a LDL-R family member. We now show that by this process beta-1 integrins are co-internalized in clathrin coated vesicles via a uPAR dependent mechanism. Subsequently, endocytosed uPAR recycles to focal adhesions where it co-localizes with integrin alpha-v/beta-3. Disrupting this chain of events, either by (1) RAP - a specific inhibitor of the LDL-R family - or by (2) uPAR depletion (using uPAR−/− cells or cleaving the GPI-anchor of uPAR by PI-PLC), beta-1 integrins are no longer internalized after VEGF stimulation. Under the same circumstances the migratory response of endothelial cells toward VEGF is impaired in vitro as shown by video-based migration assays and in vivo as demonstrated by matrigel angiogenesis assays. Next, we generated synthetic peptides interfering with uPAR/integrin interaction, which inhibit not only VEGF-induced integrin redistribution, but also diminish VEGF-induced endothelial cell migration, significantly. These data suggest that in VEGF-induced cell migration uPAR plays a central role not only in focusing proteolytic activity, but also in initial integrin redistribution. Interference with this process could be a therapeutic target for diseases depending on VEGF-induced angiogenesis.


Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3531
Author(s):  
Kate Connor ◽  
David W. Murray ◽  
Monika A. Jarzabek ◽  
Nhan L. Tran ◽  
Kieron White ◽  
...  

Glioblastoma (GBM), a highly invasive and vascular malignancy is shown to rapidly develop resistance and evolve to a more invasive phenotype following bevacizumab (Bev) therapy. Rho Guanine Nucleotide Exchange Factor proteins (RhoGEFs) are mediators of key components in Bev resistance pathways, GBM and Bev-induced invasion. To identify GEFs with enhanced mRNA expression in the leading edge of GBM tumours, a cohort of GEFs was assessed using a clinical dataset. The GEF βPix/COOL-1 was identified, and the functional effect of gene depletion assessed using 3D-boyden chamber, proliferation, and colony formation assays in GBM cells. Anti-angiogenic effects were assessed in endothelial cells using tube formation and wound healing assays. In vivo effects of βPix/COOL-1-siRNA delivered via RGD-Nanoparticle in combination with Bev was studied in an invasive model of GBM. We found that siRNA-mediated knockdown of βPix/COOL-1 in vitro decreased cell invasion, proliferation and increased apoptosis in GBM cell lines. Moreover βPix/COOL-1 mediated endothelial cell migration in vitro. Mice treated with βPix/COOL-1 siRNA-loaded RGD-Nanoparticle and Bev demonstrated a trend towards improved median survival compared with Bev monotherapy. Our hypothesis generating study suggests that the RhoGEF βPix/COOL-1 may represent a target of vulnerability in GBM, in particular to improve Bev efficacy.


2009 ◽  
Vol 37 (6) ◽  
pp. 1214-1217 ◽  
Author(s):  
Ana Raquel Verissimo ◽  
John M.J. Herbert ◽  
Victoria L. Heath ◽  
John A. Legg ◽  
Helen Sheldon ◽  
...  

We have applied search algorithms to expression databases to identify genes whose expression is restricted to the endothelial cell. Such genes frequently play a critical role in endothelial biology and angiogenesis. Two such genes are the roundabout receptor Robo4 and the ECSCR (endothelial-cell-specific chemotaxis regulator). Endothelial cells express both Robo1 and Robo4, which we have knocked down using siRNA (small interfering RNA) and then studied the effect in a variety of in vitro assays. Both Robo4 and Robo1 knockdown inhibited in vitro tube formation on Matrigel™. Transfection of Robo4 into endothelial cells increased the number of filopodial extensions from the cell, but failed to do so in Robo1-knockdown cells. Separate immunoprecipitation studies showed that Robo1 and Robo4 heterodimerize. We conclude from this and other work that a heteroduplex of Robo1 and Robo4 signals through WASP (Wiskott–Aldrich syndrome protein) and other actin nucleation-promoting factors to increase the number of filopodia and cell migration. Knockdown of the transmembrane ECSCR protein in endothelial cells also reduced chemotaxis and impaired tube formation on Matrigel™. Yeast two-hybrid analysis and immunoprecipitation studies showed that, in contrast with the roundabouts, ECSCR binds to the actin-modulatory filamin A. We conclude that all three of these genes are critical for effective endothelial cell migration and, in turn, angiogenesis.


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