Urokinase (uPA) Induces Endothelial Cell Survival Via the X-Linked Inhibitor of Apoptosis Protein (XIAP).

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3712-3712
Author(s):  
Gerald W. Prager ◽  
Patrick M. Brunner ◽  
Judit Mihaly ◽  
Yuri Koschelnick ◽  
Bernd R. Binder
Keyword(s):  
Endothelial Cells ◽  
Cell Migration ◽  
Endothelial Cell ◽  
Cell Survival ◽  
Pi3 Kinase ◽  
Endothelial Cell Migration ◽  
Inhibitor Of Apoptosis ◽  
Inhibitor Of Apoptosis Protein ◽  
Xiap Expression ◽  
Apoptosis Protein

Abstract uPA plays an important role in angiogenesis: Originally, the urokinase system has been implicated to assist the angiogenic process by it’s proteolytic properties. It is now becoming increasingly evident that uPA additionally elicits many pro-angiogenic responses like differentiation, proliferation and cell migration in a non-proteolytic fashion via induction of intracellular signal transduction. In this study we demonstrate that in endothelial cells uPA protects against apoptosis by transcriptional upregulation of inhibitor of apoptosis proteins (IAPs), among them most prominently the X-linked inhibitor of apoptosis protein (XIAP). In contrast to canonical growth factors, like vascular endothelial growth factor (VEGF), uPA elicits anti-apoptosis independently of the PI3-kinase pathway. uPA-induced cell survival is dependent on the type of extracellular matrix used indicating the involvement of integrin adhesion receptors. Thereby, uPA induces phosphorylation of the CDC42 downstream effector p21-activated kinase 1 (PAK1), which leads to IkappaB kinase alpha (IKKa) phosphorylation, a prerequisite for NFkappaB activation. Blocking NFkappaB by using the specific NFkappaB inhibitor BAY 11–7082 or by adenoviral-mediated overexpression of its inhibitor, IkB, inhibits uPA-induced XIAP expression as well as uPA-induced cell survival. Downregulating XIAP expression by small interfering RNA techniques significantly reduces cell survival efficiencies of uPA in endothelial cells. From these data we conclude that uPA activation, which is a main player in endothelial cell migration and invasion, provides an additional, PI3-kinase independent cell survival mechanism.

X-Linked Inhibitor of Apoptosis Protein (XIAP) Supports Urokinase (uPA)-Induced Endothelial Cell Survival

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5461-5461
Author(s):  
Gerald W Prager ◽  
Judit Mihaly ◽  
Patrick Brunner ◽  
Christoph Zielinski ◽  
Bernd Binder
Keyword(s):  
Endothelial Cells ◽  
Cell Migration ◽  
Endothelial Cell ◽  
Cell Survival ◽  
Endothelial Cell Migration ◽  
Migration And Invasion ◽  
Inhibitor Of Apoptosis ◽  
Inhibitor Of Apoptosis Protein ◽  
Endothelial Cell Survival ◽  
Apoptosis Protein

Abstract High uPA expressing tumors are associated with poor prognosis. While a direct effect on tumor cell behavior is described, uPA has especially been shown to mediate (tumor-) angiogenesis. Originally, the urokinase system has been implicated to assist the angiogenic process by it’s proteolytic activities. It is now becoming increasingly evident that uPA additionally elicits a whole array pro-angiogenic responses like differentiation, proliferation and cell migration, independent of its proteolytic activity by inducing intracellular signal transduction. Here we show that uPA induces upregulation of inhibitor of apoptosis proteins (IAPs), which protects endothelial cells against apoptosis. Thereby, uPA-induced endothelial cell survival is mediated by transcriptional upregulation the X-linked inhibitor of apoptosis protein (XIAP), because downregulation of XIAP by small interfering RNA techniques significantly reduces uPA mediated cell survival efficiencies of uPA in endothelial cells. The antiapoptotic activity of uPA was dependent on the presence of uPAR and LRP, but independent of the PI3kinase pathway, while VEGF-dependent antiapoptosis is mainly PI3kinase dependent. uPA-induced cell survival is dependent on the type of extracellular matrix on which cells are attached used indicating the involvement of integrin adhesion receptors. TherebyConsistently, uPA induces phosphorylation of the CDC42 downstream effector p21-activated kinase 1 (PAK1), which leads to IkappaB kinase alpha (IKKa) phosphorylation, a prerequisite for NFkappaB activation. As a consequence, p52/p50 but not p65 is are translocated into the nucleus. Blocking NFkappaB by using the specific NFkappaB inhibitor BAY 11–7082 or by adenoviral-mediated overexpression of its inhibitor, IkB, inhibits uPA-induced XIAP expression as well as uPA-induced cell survival. From these data we conclude that uPA, which is a main player in endothelial cell migration and invasion, provides an additional, PI3-kinase independent but NFkappaB dependent cell survival mechanism.

Urokinase mediates endothelial cell survival via induction of the X-linked inhibitor of apoptosis protein

Blood ◽  
2009 ◽  
Vol 113 (6) ◽  
pp. 1383-1390 ◽  
Author(s):  
Gerald W. Prager ◽  
Judit Mihaly ◽  
Patrick M. Brunner ◽  
Yuri Koshelnick ◽  
Gunilla Hoyer-Hansen ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Survival ◽  
Pi3 Kinase ◽  
Inhibitor Of Apoptosis ◽  
Inhibitor Of Apoptosis Protein ◽  
Mrna Stabilization ◽  
Endothelial Cell Survival ◽  
Iκb Kinase ◽  
Apoptosis Protein

AbstractUrokinase-type plasminogen activator (uPA) additionally elicits a whole array of pro-angiogenic responses, such as differentiation, proliferation, and migration. In this study, we demonstrate that in endothelial cells uPA also protects against apoptosis by transcriptional up-regulation and partially by mRNA stabilization of inhibitor of apoptosis proteins, most prominently the X-linked inhibitor of apoptosis protein (XIAP). The antiapoptotic activity of uPA was dependent on its protease activity, the presence of uPA receptor (uPAR) and low-density lipoprotein receptor-related protein (LRP), but independent of the phosphatidylinositol 3 (PI3) kinase pathway, whereas vascular endothelial growth factor (VEGF)–induced antiapoptosis was PI3 kinase dependent. uPA-induced cell survival involved phosphorylation of p21-activated kinase 1 (Pak1) and the IκB kinase α that leads to nuclear factor κB (NF-κB) p52 activation. Indeed, blocking NF-κB activation by using specific NF-κB inhibitors abolished uPA-induced cell survival as it blocked uPA-induced XIAP up-regulation. Furthermore, down-regulating XIAP expression by small interfering RNA (siRNA) significantly reduced uPA-dependent endothelial cell survival. This mechanism is also important for VEGF-induced antiapoptosis because VEGF-dependent up-regulation of XIAP was found defective in uPA−/− endothelial cells. This led us to conclude that uPA is part of a novel NF-κB–dependent cell survival pathway.

Vascular Endothelial Growth Factor (VEGF) Induces Cell Survival Via an Additional Urokinase (uPA)-Dependent Mechanism.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3919-3919
Author(s):  
Gerald W. Prager ◽  
Yuri Koshelnick ◽  
Judit Mihaly ◽  
Patrick Brunner ◽  
Bernd R. Binder
Keyword(s):  
Endothelial Cell ◽  
Growth Factor ◽  
Cell Survival ◽  
Pi3 Kinase ◽  
Endothelial Cell Migration ◽  
Inhibitor Of Apoptosis ◽  
Dependent Manner ◽  
Independent Manner ◽  
Apoptosis Protein ◽  
Nf Kappab

Abstract VEGF, the most important angiogenic growth factor, is known to induce cell-survival mainly via phosphorylation of the pro-apoptotic proteins BAD, PED/PEA-2 or pro-caspase-9 or inhibition of SAPKs (stress activated kinases). These mechanisms are all dependent on the PI3-kinase/Akt pathway. We could show recently that VEGF also induces pro-uPA activation via the PI3-kinase signaling pathway beside and independent of the transcriptional upregulation of uPA. Active uPA does not only contribute to angiogenesis via its proteolytic properties, but also effectuates itself pro-angiogenic signalling by the induction of endothelial cell migration, proliferation and differentiation. We were interested whether generation of uPA upon VEGF is inducing an additional effect on endothelial cell survival. First, we compared VEGF with urokinase in respect to cell survival in apoptosis assays and observed a pivotal anti-apoptotic effect of both stimuli, dose dependently and dependent on the type of matrix used. In addition, cell survival effects were additive, when both stimuli were added simultaneously. While VEGF-induced cell survival was PI3-kinase dependent, because it could be inhibited by the specific PI3-kinase inhibitor LY294002, the uPA-induced cell survival was PI3-kinase independent. Furthermore, uPA was able to rescue apoptosis induced by PI3-kinase inhibition in VEGF stimulated endothelial cells. From these data we conclude that uPA is indeed inducing an additional - PI3-kinase independent - cell survival mechanism. While VEGF led to a PI3-kinase dependent phosphorylation of Akt, which resulted in CDC42 activation, uPA activated CDC42 and its downstream effectors PAK leading to IKK-1 phosphorylation in a PI3-kinase/Akt independent manner. This indicates that the anti-apoptotic properties of uPA are not Akt, but NF-kappaB mediated. Indeed, when we used adenovirus overexpressing I-kappaB to block the NF-kappaB pathway, uPA was ineffective to support cell survival. In addition VEGF and uPA, both induced a transcriptional upregulation of inhibitor of apoptosis proteins (IAPs) in an NF-kappaB-dependent manner, among them most significantly the X-linked inhibitor of apoptosis protein (XIAP); again VEGF in a PI3-kinase dependent, uPA in a PI3-kinase independent manner. From these data we conclude that VEGF is inducing cell survival in a strictly PI3-kinase dependent manner, on the one hand via its known mitochondrial pathway, but also via the PI3-kinase dependent pro-uPA activation leading to an NFkappa B dependent upregulation of inhibitor of antiapoptosis proteins.

Constitutively activated Notch signaling is involved in survival and apoptosis resistance of B-CLL cells

Blood ◽  
2009 ◽  
Vol 113 (4) ◽  
pp. 856-865 ◽  
Author(s):  
Emanuela Rosati ◽  
Rita Sabatini ◽  
Giuliana Rampino ◽  
Antonio Tabilio ◽  
Mauro Di Ianni ◽  
...  
Keyword(s):  
Notch Signaling ◽  
Cell Survival ◽  
Ex Vivo ◽  
Critical Role ◽  
Lymphocytic Leukemia ◽  
Inhibitor Of Apoptosis ◽  
Apoptosis Resistance ◽  
Inhibitor Of Apoptosis Protein ◽  
Xiap Expression ◽  
Apoptosis Protein

Abstract Notch signaling is involved in tumorigenesis, but its role in B–chronic lymphocytic leukemia (B-CLL) pathogenesis is not completely defined. This study examined the expression and activation of Notch receptors in B-CLL cells and the role of Notch signaling in sustaining the survival of these cells. Our results show that B-CLL cells but not normal B cells constitutively express Notch1 and Notch2 proteins as well as their ligands Jagged1 and Jagged2. Notch signaling is constitutively activated in B-CLL cells, and its activation is further increased in B-CLL cells, which resist spontaneous apoptosis after 24-hour ex vivo culture. Notch stimulation by a soluble Jagged1 ligand increases B-CLL cell survival and is accompanied by increased nuclear factor–kappa B (NF-κB) activity and cellular inhibitor of apoptosis protein 2 (c-IAP2) and X-linked inhibitor of apoptosis protein (XIAP) expression. In contrast, Notch-signaling inhibition by the γ-secretase inhibitor I (GSI; z-Leu-Leu-Nle-CHO) and the specific Notch2 down-regulation by small-interfering RNA accelerate spontaneous B-CLL cell apoptosis. Apoptotic activity of GSI is accompanied by reduction of NF-κB activity and c-IAP2 and XIAP expression. Overall, our findings show that Notch signaling plays a critical role in B-CLL cell survival and apoptosis resistance and suggest that it could be a novel potential therapeutic target.

Signaling and regulation of endothelial cell survival by angiopoietin-2

2006 ◽  
Vol 291 (4) ◽  
pp. H1635-H1645 ◽  
Author(s):  
Rania Harfouche ◽  
Sabah N. A. Hussain
Keyword(s):  
Cell Migration ◽  
Endothelial Cell ◽  
Cell Survival ◽  
Umbilical Vein ◽  
Biological Effects ◽  
Pi3 Kinase ◽  
Endothelial Cell Migration ◽  
Endothelial Cell Survival ◽  
Induced Apoptosis

Angiopoietins are ligands for endothelial cell-specific Tie-2 receptors. Whereas angiopoietin-1 (Ang-1) activates these receptors and promotes cell survival, migration, and sprouting, little information is available regarding how Ang-2 influences these cells. In this study, we evaluated signaling pathways and biological effects of physiological concentrations of Ang-2 in cultured human umbilical vein endothelial cells. Ang-2 at 150 and 300 ng/ml elicited a transient (reaching peak values within 15 min of exposure) increase in the phosphorylation of Tie-2 receptors, protein kinase B (Akt), ERK1/2, and p38 members of the mitogen-activated protein kinases. However, unlike Ang-1, Ang-2 significantly inhibited JNK/SAPK phosphorylation. When vascular endothelial growth factor (VEGF) was present along with Ang-2, ERK1/2 phosphorylation was inhibited, whereas augmentation of Ang-1-induced ERK1/2 phosphorylation was triggered by VEGF. Ang-2 treatment had no effect on cell migration and in vitro wound healing but significantly attenuated serum deprivation-induced apoptosis and promoted survival. These effects were completely reversed by phosphatidylinositol 3 (PI3)-kinase and ERK1/2 inhibitors but were augmented by an inhibitor of the p38 pathway. These results suggest that Ang-2 promotes endothelial cell survival through the ERK1/2 and PI3-kinase pathways and that this angiopoietin is not a strong promoter of endothelial cell migration. We also conclude that the nature of interactions in terms of ERK1/2 activation between Ang-2 and VEGF is different from that of Ang-1 and VEGF.

Reactive oxygen species mediate Rac-induced loss of cell-cell adhesion in primary human endothelial cells

2002 ◽  
Vol 115 (9) ◽  
pp. 1837-1846 ◽  
Author(s):  
Sandra van Wetering ◽  
Jaap D. van Buul ◽  
Safira Quik ◽  
Frederik P. J. Mul ◽  
Eloise C. Anthony ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Endothelial Cells ◽  
Cell Migration ◽  
Cell Adhesion ◽  
Endothelial Cell ◽  
Reactive Oxygen ◽  
Small Gtpases ◽  
Endothelial Cell Migration ◽  
Oxygen Species ◽  
Cell Cell

The integrity of the endothelium is dependent on cell-cell adhesion, which is mediated by vascular-endothelial (VE)-cadherin. Proper VE-cadherin-mediated homotypic adhesion is, in turn, dependent on the connection between VE-cadherin and the cortical actin cytoskeleton. Rho-like small GTPases are key molecular switches that control cytoskeletal dynamics and cadherin function in epithelial as well as endothelial cells. We show here that a cell-penetrating, constitutively active form of Rac (Tat-RacV12) induces a rapid loss of VE-cadherin-mediated cell-cell adhesion in endothelial cells from primary human umbilical veins (pHUVEC). This effect is accompanied by the formation of actin stress fibers and is dependent on Rho activity. However,transduction of pHUVEC with Tat-RhoV14, which induces pronounced stress fiber and focal adhesion formation, did not result in a redistribution of VE-cadherin or an overall loss of cell-cell adhesion. In line with this observation, endothelial permeability was more efficiently increased by Tat-RacV12 than by Tat-RhoV14. The loss of cell-cell adhesion, which is induced by Tat-RacV12, occurred in parallel to and was dependent upon the intracellular production of reactive oxygen species (ROS). Moreover, Tat-RacV12 induced an increase in tyrosine phosphorylation of a component the VE-cadherin-catenin complex, which was identified as α-catenin. The functional relevance of this signaling pathway was further underscored by the observation that endothelial cell migration, which requires a transient reduction of cell-cell adhesion, was blocked when signaling through ROS was inhibited. In conclusion, Rac-mediated production of ROS represents a previously unrecognized means of regulating VE-cadherin function and may play an important role in the (patho)physiology associated with inflammation and endothelial damage as well as with endothelial cell migration and angiogenesis.

scholarly journals miR-122 Targets X-Linked Inhibitor of Apoptosis Protein to Sensitize Oxaliplatin-Resistant Colorectal Cancer Cells to Oxaliplatin-Mediated Cytotoxicity

2018 ◽  
Vol 51 (5) ◽  
pp. 2148-2159 ◽  
Author(s):  
Yongqiang Hua ◽  
Yaodong Zhu ◽  
Jijie Zhang ◽  
Zhenfeng Zhu ◽  
Zhouyu Ning ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Acquired Resistance ◽  
Cellular Protein ◽  
Cell Counting ◽  
Inhibitor Of Apoptosis ◽  
Acquired Drug Resistance ◽  
Inhibitor Of Apoptosis Protein ◽  
Ht29 Cells ◽  
Xiap Expression ◽  
Apoptosis Protein

Background/Aims: Although oxaliplatin is one of the most effective chemotherapeutic drugs used to treat colorectal cancer (CRC), long-term administration usually induces acquired drug resistance during the course of treatment. Thus, there is an urgent need to explore novel strategies to improve the efficiency of cancer therapy. The aim of this study was to explore the effect of microRNA-122 (miR-122) on reversing oxaliplatin resistance in CRC. Methods: The expression of miR-122 in CRC cells was examined by quantitative reverse transcriptase real-time PCR. The cytotoxicity of oxaliplatin against CRC cells was evaluated by Cell Counting Kit-8 assays. Mitochondrial membrane potentials and cell apoptotic rates were measured by flow cytometry. Cellular protein expression and interactions were detected by western blot and co-immunoprecipitation. Results: Established oxaliplatin-resistant SW480 and HT29 cells (SW480/OR and HT29/OR) expressed significantly higher levels of X-linked inhibitor of apoptosis protein (XIAP) and lower levels of miR-122 compared with normal SW480 and HT29 cells, respectively. Our results showed that the downregulation of miR-122 was responsible for the overexpression of XIAP in these oxaliplatin-resistant CRC cells. We then found that the recovery of miR-122 expression can sensitize SW480/OR and HT29/OR cells to oxaliplatin-mediated apoptosis through the inhibition of XIAP expression. Conclusion: Upregulation of XIAP in CRC cells is responsible for the acquired resistance to oxaliplatin. Furthermore, miR-122 reversed oxaliplatin resistance in CRC by targeting XIAP.

scholarly journals CRIF1 deficiency suppresses endothelial cell migration via upregulation of RhoGDI2

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256646
Author(s):  
Harsha Nagar ◽  
Seonhee Kim ◽  
Ikjun Lee ◽  
Su-Jeong Choi ◽  
Shuyu Piao ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Migration ◽  
Endothelial Cell ◽  
Signaling Pathway ◽  
Umbilical Vein ◽  
Vascular Endothelial Cell ◽  
Cellular Migration ◽  
Endothelial Cell Migration ◽  
Migration And Invasion ◽  
Mitochondrial Functions

Rho GDP-dissociation inhibitor (RhoGDI), a downregulator of Rho family GTPases, prevents nucleotide exchange and membrane association. It is responsible for the activation of Rho GTPases, which regulate a variety of cellular processes, such as migration. Although RhoGDI2 has been identified as a tumor suppressor gene involved in cellular migration and invasion, little is known about its role in vascular endothelial cell (EC) migration. CR6-interacting factor 1 (CRIF1) is a CR6/GADD45-interacting protein with important mitochondrial functions and regulation of cell growth. We examined the expression of RhoGDI2 in CRIF1-deficient human umbilical vein endothelial cells (HUVECs) and its role in cell migration. Expression of RhoGDI2 was found to be considerably higher in CRIF1-deficient HUVECs along with suppression of cell migration. Moreover, the phosphorylation levels of Akt and CREB were decreased in CRIF1-silenced cells. The Akt-CREB signaling pathway was implicated in the changes in endothelial cell migration caused by CRIF1 downregulation. In addition to RhoGDI2, we identified another factor that promotes migration and invasion of ECs. Adrenomedullin2 (ADM2) is an autocrine/paracrine factor that regulates vascular tone and other vascular functions. Endogenous ADM2 levels were elevated in CRIF1-silenced HUVECs with no effect on cell migration. However, siRNA-mediated depletion of RhoGDI2 or exogenous ADM2 administration significantly restored cell migration via the Akt-CREB signaling pathway. In conclusion, RhoGDI2 and ADM2 play important roles in the migration of CRIF1-deficient endothelial cells.

scholarly journals Skeletal muscle-endothelial cell cross talk through angiotensin II

2010 ◽  
Vol 299 (6) ◽  
pp. C1402-C1408 ◽  
Author(s):  
Leeann M. Bellamy ◽  
Adam P. W. Johnston ◽  
Michael De Lisio ◽  
Gianni Parise
Keyword(s):  
Skeletal Muscle ◽  
Endothelial Cells ◽  
Cell Migration ◽  
Endothelial Cell ◽  
Angiotensin Ii ◽  
Branch Point ◽  
Endothelial Cell Migration ◽  
Tube Length ◽  
Ang Ii

The role of angiotensin II (ANG II) in postnatal vasculogenesis and angiogenesis during skeletal muscle (SKM) regeneration is unknown. We examined the capacity of ANG II to stimulate capillary formation and growth during cardiotoxin-induced muscle regeneration in ACE inhibitor-treated ANG II type 1a receptor knockout (AT1a−/−) and C57Bl/6 control mice. Analysis of tibialis anterior (TA) cross-sections revealed 17% and 23% reductions in capillarization in AT1a−/− and captopril treated mice, respectively, when compared with controls, 21 days postinjury. Conversely, no differences in capillarization were detected at early time points (7 and 10 days). These results identify ANG II as a regulator of angiogenesis but not vasculogenesis in vivo. In vitro angiogenesis assays of human umbilical vein endothelial cells (HUVECs) further confirmed ANG II as proangiogeneic as 71% and 124% increases in tube length and branch point number were observed following ANG II treatment. Importantly, treatment of HUVECs with conditioned media from differentiated muscle cells resulted in an 84% and 203% increase in tube length and branch point number compared with controls, which was abolished following pretreatment of the cells with an angiotensin-converting enzyme inhibitor. The pro-angiogenic effect of ANG II can be attributed to an enhanced endothelial cell migration because both transwell and under agarose migration assays revealed a 37% and 101% increase in cell motility, respectively. Collectively, these data highlight ANG II as a proangiogenic regulator during SKM regeneration in vivo and more importantly demonstrates that ANG II released from SKM can signal endothelial cells and regulate angiogenesis through the induction of endothelial cell migration.

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