Role of activated protein C and its receptor in inhibition of tumor metastasis

Blood ◽  
2009 ◽  
Vol 113 (14) ◽  
pp. 3371-3374 ◽  
Author(s):  
Michael Bezuhly ◽  
Robyn Cullen ◽  
Charles T. Esmon ◽  
Steven F. Morris ◽  
Kenneth A. West ◽  
...  
Keyword(s):  
Protein C ◽  
Lung Metastases ◽  
Activated Protein C ◽  
Mrna Levels ◽  
Endothelial Protein C Receptor ◽  
Tumor Cell Adhesion ◽  
Similar Reduction ◽  
Tumor Endothelium

Abstract Engagement of endothelial protein C receptor (EPCR) by activated protein C (aPC) decreases expression of endothelial adhesion molecules implicated in tumor-endothelium interactions. We examined the role of the aPC/EPCR pathway on tumor migration and metastasis. In vitro, B16-F10 melanoma cells showed decreased adhesion to and transmigration through endothelium treated with recombinant human aPC (rhaPC). In murine B16-F10 metastasis models, transgenic EPCR overexpressing (Tie2-EPCR) mice exhibited marked reductions in liver (50%) and lung (92%) metastases compared with wild-type (WT) animals. Intravital imaging showed reduced B16-F10 entrapment within livers of Tie2-EPCR compared with WT mice. A similar reduction was observed in WT mice treated with rhaPC. Strikingly, rhaPC treatment resulted in a 44% reduction in lung metastases. This was associated with decreased lung P-selectin and TNF-α mRNA levels. These findings support an important role for the aPC/EPCR pathway in reducing metastasis via inhibition of tumor cell adhesion and transmigration.

Abstract 34: Endogenous Superoxide Dismutase Protects From Impaired Generation of Activated Protein C and Enhanced Susceptibility to Experimental Thrombosis in Mice

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Sanjana Dayal ◽  
Sean X Gu ◽  
Katinan M Wilson ◽  
Ryan Hutchins ◽  
Steven R Lentz
Keyword(s):  
Superoxide Dismutase ◽  
Protein C ◽  
Activated Protein C ◽  
Vena Cava ◽  
Oxidative Modification ◽  
Mrna Levels ◽  
Endothelial Protein C Receptor ◽  
Experimental Thrombosis

In vitro studies have suggested that reactive oxygen species such as superoxide can produce prothrombotic effects, including enhanced platelet activation, increased tissue factor (TF) expression, and an oxidative modification in thrombomodulin impairing its capacity to enhance the generation of activated protein C (APC) by thrombin. It is not known, however, if elevated levels of superoxide accelerate susceptibility to experimental thrombosis in vivo . We used mice genetically deficient in superoxide dismutase-1 (SOD1, an antioxidant enzyme that dismutates superoxide to hydrogen peroxide), to test the hypothesis that lack of SOD1 enhances susceptibility to thrombosis. Susceptibility to carotid artery thrombosis in a photochemical injury model demonstrated that Sod1-/- mice formed stable occlusions significantly faster than Sod1+/+ mice (P<0.05). In an inferior vena cava (IVC) stasis model Sod1- /- mice developed significantly larger thrombi 48 hours after IVC ligation (P<0.05 vs. Sod1+/+ mice). After activation with thrombin (0.5 U/ml) or convulxin (200 ng/ml), no differences in surface expression of P-selectin or binding of fibrinogen were observed between platelets from Sod1-/- and Sod1+/+ mice. The expression of TF mRNA in lung measured by real time qPCR showed similar levels in Sod1-/- and Sod1 +/+ mice. However, the activation of exogenous protein C by thrombin in lung homogenates was decreased in Sod1 -/- mice (P<0.05 vs. Sod1 +/+ mice). Further, in vivo generation of activated protein C in response to thrombin (40 U/Kg) infusion was significantly lower in Sod1-/- mice (P<0.05 vs. Sod1+/+ mice). No differences in mRNA levels for thrombomodulin or endothelial protein C receptor were detected in Sod1 -/- mice vs. Sod1 +/+ mice, suggesting that altered generation of activated protein C in Sod1-/- mice may be related to a direct oxidative effect on thrombomodulin. In accordance, thrombomodulin treated with xanthine/hypoxanthine showed 40% loss of ability to activate protein C that was overcome by addition of SOD and catalase (P<0.05). We conclude that endogenous SOD1 in mice protects from impaired generation of activated protein C and accelerated thrombosis.

Recombinant human activated protein C upregulates cyclooxygenase-2 expression in endothelial cells via binding to endothelial cell protein C receptor and activation of protease-activated receptor-1

2005 ◽  
Vol 93 (04) ◽  
pp. 743-750 ◽  
Author(s):  
Sarah Horn ◽  
Siegfried Lang ◽  
Kenji Fukudome ◽  
Adriane Nahrup ◽  
Ursula Hoffmann ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Protein C ◽  
Activated Protein C ◽  
Cell Protein ◽  
Mrna Levels ◽  
Endothelial Protein C Receptor ◽  
Drotrecogin Alfa Activated ◽  
Cox 2 ◽  
Vitro Effect

SummaryProstacyclin (PGI2) has beneficial cytoprotective properties, is a potent inhibitor of platelet aggregation and has been reported to improve microcirculatory blood flow during sepsis. The formation of PGI2 in response to proinflammatory cytokines is catalysed by the inducible cyclooxygenase (COX) isoform COX-2. Recombinant human activated protein C (rhAPC, drotrecogin alfa (activated)) was shown to have multiple biological activities in vitro and to promote resolution of organ dysfunction in septic patients. Whether rhAPC exerts its beneficial effects by modulating prostanoid generation is unknown up to now. It was therefore the aim of the study to examine the in vitro effect of rhAPC on COX-2-mRNA-expression and PGI2 release from human umbilical vein endothelial cells (HUVEC). We found that rhAPC, at supra-therapeutical concentrations (500ng/ml-20μg/ ml), upregulated the amount of COX-2-mRNA in HUVEC at t=3–9h and caused a time- and dose-dependent release of 6-keto PGF1α, the stable hydrolysis product of prostacyclin. RhAPC further increased the stimulating effect of tumor necrosis factor-α (TNF-α) and thrombin on COX-2-mRNA-levels. Transcript levels of cyclooxygenase-1 (COX-1) and prostagland-in I2 synthase, however, were unaffected by the stimulation with rhAPC or thrombin. The upregulatory effect on COX2-mRNA levels was specific for rhAPC since the zymogen protein C in equimolar concentrations had no effect on COX-2-mRNA-levels or 6keto PGF1α-release. Western Blot analysis revealed an increase of COX-2-protein content in HUVEC after treatment with rhAPC. As shown by experiments using monoclonal antibodies against the thrombin receptor PAR-1 (mAb=ATAP2) and against the endothelial protein C receptor (EPCR; mAb=RCR-252), the effect of rhAPC on COX-2-mRNA up-regulation was mediated by binding to the EPCR-receptor and signaling via PAR-1. These results demonstrate that induction of COX-2-expression is an important response of HUVEC to stimulation with rhAPC and may represent a new molecular mechanism, by which rhAPC promotes upregulation of prostanoid production in human endothelium.

Activated protein C targets immune cells and rheumatoid synovial fibroblasts to prevent inflammatory arthritis in mice

Rheumatology ◽  
2019 ◽  
Vol 58 (10) ◽  
pp. 1850-1860 ◽  
Author(s):  
Meilang Xue ◽  
Suat Dervish ◽  
Kelly J McKelvey ◽  
Lyn March ◽  
Fang Wang ◽  
...  
Keyword(s):  
Protein C ◽  
Activated Protein C ◽  
Synovial Fibroblasts ◽  
Endothelial Protein C Receptor ◽  
Mouse Thymus ◽  
Tnf Α ◽  
Thymus Cells ◽  
Proliferation And Invasion

Abstract Objectives To investigate whether activated protein C (APC), a physiological anticoagulant can inhibit the inflammatory/invasive properties of immune cells and rheumatoid arthritis synovial fibroblasts (RASFs) in vitro and prevent inflammatory arthritis in murine antigen-induced arthritis (AIA) and CIA models. Methods RASFs isolated from synovial tissues of patients with RA, human peripheral blood mononuclear cells (PBMCs) and mouse thymus cells were treated with APC or TNF-α/IL-17 and the following assays were performed: RASF proliferation and invasion by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and cell invasion assays, respectively; cytokines and signalling molecules using ELISA or western blot; Th1 and Th17 phenotypes in human PBMCs or mouse thymus cells by flow cytometry. The in vivo effect of APC was evaluated in AIA and CIA models. Results In vitro, APC inhibited IL-1β, IL-17 and TNF-α production, IL-17-stimulated cell proliferation and invasion and p21 and nuclear factor κB activation in RASFs. In mouse thymus cells and human PBMCs, APC suppressed Th1 and Th17 phenotypes. In vivo, APC inhibited pannus formation, cartilage destruction and arthritis incidence/severity in both CIA and AIA models. In CIA, serum levels of IL-1β, IL-6, IL-17, TNF-α and soluble endothelial protein C receptor were significantly reduced by APC treatment. Blocking endothelial protein C receptor, the specific receptor for APC, abolished the early or preventative effect of APC in AIA. Conclusion APC prevents the onset and development of arthritis in CIA and AIA models via suppressing inflammation, Th1/Th17 phenotypes and RASF invasion, which is likely mediated via endothelial protein C receptor.

scholarly journals Hyperantithrombotic, noncytoprotective Glu149Ala-activated protein C mutant

Blood ◽  
2009 ◽  
Vol 113 (23) ◽  
pp. 5970-5978 ◽  
Author(s):  
Laurent O. Mosnier ◽  
Antonella Zampolli ◽  
Edward J. Kerschen ◽  
Reto A. Schuepbach ◽  
Yajnavalka Banerjee ◽  
...  
Keyword(s):  
Protein C ◽  
Anticoagulant Activity ◽  
Activated Protein C ◽  
Bleeding Risk ◽  
Endothelial Protein C Receptor ◽  
Antithrombotic Activity ◽  
Cytoprotective Activity ◽  
Protease Activated Receptor 1

Abstract Activated protein C (APC) reduces mortality in severe sepsis patients. APC exerts anticoagulant activities via inactivation of factors Va and VIIIa and cytoprotective activities via endothelial protein C receptor and protease-activated receptor-1. APC mutants with selectively altered and opposite activity profiles, that is, greatly reduced anticoagulant activity or greatly reduced cytoprotective activities, are compared here. Glu149Ala-APC exhibited enhanced in vitro anticoagulant and in vivo antithrombotic activity, but greatly diminished in vitro cytoprotective effects and in vivo reduction of endotoxin-induced murine mortality. Thus, residue Glu149 and the C-terminal region of APC's light chain are identified as functionally important for expression of multiple APC activities. In contrast to Glu149Ala-APC, 5A-APC (Lys191-193Ala + Arg229/230Ala) with protease domain mutations lacked in vivo antithrombotic activity, although it was potent in reducing endotoxin-induced mortality, as previously shown. These data imply that APC molecular species with potent antithrombotic activity, but without robust cytoprotective activity, are not sufficient to reduce mortality in endotoxemia, emphasizing the need for APC's cytoprotective actions, but not anticoagulant actions, to reduce endotoxin-induced mortality. Protein engineering can provide APC mutants that permit definitive mechanism of action studies for APC's multiple activities, and may also provide safer and more effective second-generation APC mutants with reduced bleeding risk.

Activated protein C induces the release of microparticle-associated endothelial protein C receptor

Blood ◽  
2005 ◽  
Vol 105 (4) ◽  
pp. 1515-1522 ◽  
Author(s):  
Margarita Pérez-Casal ◽  
Colin Downey ◽  
Kenji Fukudome ◽  
Gernot Marx ◽  
Cheng Hock Toh
Keyword(s):  
Endothelial Cells ◽  
Protein C ◽  
Umbilical Vein ◽  
Activated Protein C ◽  
Enzyme Linked Immunosorbent Assay ◽  
Factor V ◽  
Endothelial Protein C Receptor ◽  
Microparticle Formation ◽  
Umbilical Vein Endothelial Cells

Abstract Activated protein C (APC) treatment is now used for patients with severe sepsis. We investigated its effect in vitro on primary, physiologically relevant cells and demonstrate a novel mechanism of endothelial protein C receptor (EPCR) release that is not inhibited by metalloproteinase inhibitors. Exposure of human umbilical vein endothelial cells or monocytes to APC (6.25-100 nM) results in the release of EPCR-containing microparticles, as demonstrated by confocal microscopy and characterized through flow cytometry, enzyme-linked immunosorbent assay quantitation of isolated microparticles, and Western blotting. The phenomenon is time- and concentration-dependent and requires the APC active site, EPCR, and protease activated receptor 1 (PAR1) on endothelial cells. Neither protein C nor boiled or d-Phe-Pro-Arg-chloromethylketone–blocked APC can induce microparticle formation and antibody blockade of EPCR or PAR1 cleavage and activation abrogates this APC action. Coincubation with hirudin does not alter the APC effect. The released microparticle bound is full-length EPCR (49 kDa) and APC retains factor V–inactivating activity. Although tumor necrosis factor-α (10 ng/mL) can also induce microparticle-associated EPCR release to a similar extent as APC (100 nM), it is only APC-induced microparticles that contain bound APC. This novel observation could provide new insights into the consequences of APC therapy in the septic patient.

Deficiency of Superoxide Dismutase Impairs Generation of Activated Protein C and Enhances Susceptibility to Experimental Thrombosis in Mice

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 535-535
Author(s):  
Sanjana Dayal ◽  
Katina M Wilson ◽  
Ryan Hutchins ◽  
Steven R. Lentz
Keyword(s):  
Superoxide Dismutase ◽  
Protein C ◽  
Conflicts Of Interest ◽  
Activated Protein C ◽  
Oxidative Modification ◽  
Mrna Levels ◽  
Endothelial Protein C Receptor ◽  
Experimental Thrombosis ◽  
Increased Susceptibility

Abstract Abstract 535 In vitro studies have suggested that reactive oxygen species such as superoxide can produce several potentially prothrombotic effects, including enhanced platelet activation, increased tissue factor (TF) expression, and an oxidative modification in thrombomodulin that impairs its capacity to enhance the generation of activated protein C (APC) by thrombin. It is not known, however, if elevated levels of superoxide accelerate susceptibility to experimental thrombosis in vivo. Using a murine model that is genetically deficient in superoxide dismutase-1 (SOD1, an antioxidant enzyme that dismutates superoxide to hydrogen peroxide), we tested the hypothesis that lack of superoxide dismutase enhances susceptibility to thrombosis. Additionally, we investigated the mechanisms of superoxide-enhanced thrombosis. First, we examined the susceptibility to carotid artery thrombosis in a photochemical injury model. We found that Sod1−/− mice formed stable occlusions significantly faster than Sod1+/+ or Sod1+/− mice (P<0.05). Further, using an inferior vena cava (IVC) stasis method we observed that Sod1−/− mice developed significantly larger thrombi 48 hours after IVC ligation (P<0.05 compared with Sod1+/+ or Sod1+/− mice). These findings suggest that deficiency of SOD1 leads to increased susceptibility to both arterial and venous thrombosis in mice. To address the mechanism of accelerated thrombosis, we first examined activation of platelets in response to multiple agonists using flow cytometry. After activation by thrombin (0.5 U/ml) and convulxin (200 ng/ml), no differences in surface expression of P-selectin or binding of fibrinogen to activated platelets were observed between Sod1−/−, Sod1+/+, or Sod1+/− mice, suggesting that increased susceptibility to thrombosis in Sod1−/− mice is not platelet mediated. Next, we measured expression of TF mRNA in lung by real time qPCR. TF mRNA levels in Sod1−/− mice were similar to those in Sod1+/+ mice, suggesting that deficiency of SOD1 does not influence TF expression in mice. Finally, we measured the activation of protein C in vivo in response to infusion of thrombin (40 U/Kg). Generation of activated protein C was significantly lower in Sod1−/− mice compared with Sod1+/+ mice (P<0.05). No differences in mRNA levels for thrombomodulin or endothelial protein C receptor were detected in Sod1−/− mice compared with Sod1+/+ mice (P=0.4 and 0.6 respectively), suggesting that altered generation of activated protein C in Sod1−/− mice may be related to a direct oxidative effect on thrombomodulin rather than to decreased expression of thrombomodulin or EPCR. We conclude that lack of SOD1 in mice accelerates thrombosis and impairs the protein C anticoagulant response to thrombin. Disclosures: No relevant conflicts of interest to declare.

The endothelial protein C receptor and activated protein C play a limited role in host defense during experimental tuberculosis

2013 ◽  
Vol 109 (04) ◽  
pp. 726-737 ◽  
Author(s):  
Joris J. T. H. Roelofs ◽  
Alex F. de Vos ◽  
Catharina W. Wieland ◽  
Marcel Schouten ◽  
Joost C. M. Meijers ◽  
...  
Keyword(s):  
Protein C ◽  
Mononuclear Cells ◽  
Activated Protein C ◽  
Endothelial Protein C Receptor ◽  
Coagulation Activation ◽  
Limited Role ◽  
Important Regulator ◽  
Local Inflammatory Reaction ◽  
Pulmonary Granulomas

SummaryThe protein C (PC) system is an important regulator of both coagulation and inflammation. Activated PC (APC), together with its receptor the endothelial protein C receptor (EPCR), has anticoagulant and anti-inflammatory properties. During tuberculosis (TB), a devastating chronic pulmonary disease caused by Mycobacterium (M.) tuberculosis, both a local inflammatory reaction characterised by the recruitment of mainly mononuclear cells and the formation of pulmonary granulomas as well as activation of coagulation occurs as part of the host immune response. We investigated the role of EPCR and APC in a mouse model of TB using mice overexpressing EPCR (Tie2-EPCR), mice deficient for EPCR (EPCR−/−), mice treated with APC-inhibiting antibodies and mice overexpressing APC (APChigh) and compared them with wild-type (WT) mice. Blood and organs were harvested to quantify bacterial loads, cellular influxes, cytokines, histopathology and coagulation parameters. Additionally observation studies were performed. Lung EPCR expression was upregulated during experimental TB. No significant differences in bacterial growth were seen between WT and Tie2-EPCR mice. However, Tie2-EPCR mice had decreased pulmonary coagulation activation, displayed an increased influx of macro-phages 2 and 6 weeks after infection, but no increase in other proin-flammatory markers. On the other hand, in EPCR−/−-mice coagulation activation was decreased 6 weeks post-infection, with little impact on other inflammation markers. APC-overexpression or treatment with anti-(A)PC antibodies displayed minimal effects during experimental TB. In conclusion, EPCR and APC play a limited role in the host response during experimental pulmonary TB.

Regulation of inflammatory responses by activated protein C: the molecular mechanism(s) and therapeutic implications

2004 ◽  
Vol 42 (2) ◽  
Author(s):  
Kenji Okajima
Keyword(s):  
Severe Sepsis ◽  
Protein C ◽  
Inflammatory Responses ◽  
Activated Protein C ◽  
Therapeutic Effects ◽  
Endothelial Protein C Receptor ◽  
Therapeutic Implications ◽  
Coagulation Abnormalities ◽  
Tnf Α

AbstractActivated protein C (APC), a natural anticoagulant, is formed from protein C by the action of the thrombinthrombomodulin (TM) complex on the endothelial cell surface. Endothelial protein C receptor augments the activation of protein C by the thrombin/TM system. APC inactivates the activated form of coagulation factors V and VIII in the presence of protein S. Administration of APC reduced the pulmonary vascular injury and hypotension as well as the coagulation abnormalities by inhibiting production of the tumor necrosis factor-α (TNF-α) in rats given endotoxin (ET). These therapeutic effects of APC could not be attributed to its anticoagulant effects. APC inhibited ET-induced TNF-α production in human monocytes by inhibiting activation of nuclear factor k-B and activator protein-1 in vitro. Administration of the human plasma-derived APC ameliorated coagulation abnormalities without any adverse effects in patients with disseminated intravascular coagulation (DIC). Recombinant APC was reported to reduce the mortality of patients with severe sepsis, and the therapeutic effect was more marked in such patients with overt DIC than those without it.These observations strongly suggest that APC plays important roles in the regulation of inflammation as well as coagulation. Both anti-inflammatory and anticoagulant properties of APC might contribute to the therapeutic usefulness in patients with severe sepsis.

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