HEPARIN AND NON-ANTICOAGULANT HEPARINS INHIBIT HEPARANASE ACTIVITY IN NORMAL AND MALIGNANT CELLS:POSSIBLE THERAPEUTIC USE IN PREVENTION OF EXTRAVASATION AND DISSEMINATION OF BLOOD BORNE CELLS

1987 ◽  
Author(s):  
A Eldor ◽  
M Bar-Ner ◽  
L Wasserman ◽  
Y matzner ◽  
Z Fuks ◽  
...  
Keyword(s):  
Heparan Sulfate ◽  
Inhibitory Activity ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Therapeutic Use ◽  
Lymphoma Cells ◽  
In Vivo Experiments ◽  
Acetyl Group ◽  
Mouse Lymphoma

Degradation of vascular subendothelium occurs in_vivo during the process of inflammation and tumor invasion. Various observations suggest that the capacity of some blood-borne cells to extravasate may depend in part on their ability to express hepara-nase activity. Incubation of human platelets, human nc-utrophils, or highly metastatic mouse lymphoma cells with sulfate-labeled extracellular matrix (ECM) results in heparanase mediated release of labeled heparan sulfate cleavage fragments (0.5<Kav<0.85 on Sepharose 5B) (J. Clin.Invest. 74: 1842 and 76: 1306; Cancer Res. 43: 2704). The present study was undertaken to test the heparanase inhibitory effect of heparin and non-anticoagulant species of heparin that might havea potential therapeutic use in preventing heparanase mediated extravasation ofblood-borne cells. We prepared totallyor N-desulfated heparins which were either left with their N-position exposed or were subsequently N-acetylated or N-resulfated. These heparins exhibited less than 5% of the anticoagulant activityof native heparin. It was found that total desulfation of heparin abolished its heparanase inhibitory activity whether desulfation was followed by N-acetylation or not. Inhibitory effect was restored by resulfation of the N-position. When only the N-sulfate group was desulfated, inhibitory activity was lost but could be restored by acetylation of the N-position. These results indicate that N-sulfate groups of heparin are necessary for its heparanase inhibitory activity but can be substituted by an acetyl group provided that the 0-sulfate groups are retained. Low Mr heparins (main Mr species of 2500 and 4500 daltons) and heparin fragments as small as the tetrasaccharide inhibited degradation of heparan sulfate in the ECM, albeit to a lower extent than native heparin. Similar effects of the different heparins were observed with heparanase activities from platelets, neutrophils and lymphoma cells. Preliminary in vivo experiments suggest that non-anticoagulant heparins interfere with tumor metastasis and experimental autoimmune diseases (some heparins were kindly provided by Inst. Choay, Paris and Kabi Vitrum, Stockholm).

scholarly journals Inhibition of heparanase-mediated degradation of extracellular matrix heparan sulfate by non-anticoagulant heparin species

Blood ◽  
1987 ◽  
Vol 70 (2) ◽  
pp. 551-557 ◽  
Author(s):  
M Bar-Ner ◽  
A Eldor ◽  
L Wasserman ◽  
Y Matzner ◽  
IR Cohen ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Heparan Sulfate ◽  
Inhibitory Activity ◽  
Anticoagulant Activity ◽  
Molecular Size ◽  
Inhibitory Effect ◽  
Basement Membranes ◽  
Human Neutrophils ◽  
Lymphoma Cells ◽  
Intact Cells

Abstract Incubation of human platelets, human neutrophils, or highly metastatic mouse lymphoma cells with sulfate-labeled extracellular matrix (ECM) results in heparanase-mediated release of labeled heparan sulfate cleavage fragments (0.5 less than Kav less than 0.85 on Sepharose 6B). This degradation was inhibited by native heparin both when brought about by intact cells or their released heparanase activity. Degradation of heparan sulfate in ECM may facilitate invasion of normal and malignant cells through basement membranes. The present study tested the heparanase inhibitory effect of nonanticoagulant species of heparin that might be of potential use in preventing heparanase mediated extravasation of bloodborne cells. For this purpose, we prepared various species of low-sulfated or low-mol-wt heparins, all of which exhibited less than 7% of the anticoagulant activity of native heparin. N-sulfate groups of heparin are necessary for its heparanase inhibitory activity but can be substituted by an acetyl group provided that the O-sulfate groups are retained. O-sulfate groups could be removed provided that the N positions were resulfated. Total desulfation of heparin abolished its heparanase inhibitory activity. Heparan sulfate was a 25-fold less potent heparanase inhibitor than native heparin. Efficiency of low-mol-wt heparins to inhibit degradation of heparan sulfate in ECM decreased with their main molecular size, and a synthetic pentasaccharide, representing the binding site to antithrombin III, was devoid of inhibitory activity. Similar results were obtained with heparanase activities released from platelets, neutrophils, and lymphoma cells. We propose that heparanase inhibiting nonanticoagulant heparins may interfere with dissemination of bloodborne tumor cells and development of experimental autoimmune diseases.

scholarly journals Inhibition of heparanase-mediated degradation of extracellular matrix heparan sulfate by non-anticoagulant heparin species

Blood ◽  
1987 ◽  
Vol 70 (2) ◽  
pp. 551-557 ◽  
Author(s):  
M Bar-Ner ◽  
A Eldor ◽  
L Wasserman ◽  
Y Matzner ◽  
IR Cohen ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Heparan Sulfate ◽  
Inhibitory Activity ◽  
Anticoagulant Activity ◽  
Molecular Size ◽  
Inhibitory Effect ◽  
Basement Membranes ◽  
Human Neutrophils ◽  
Lymphoma Cells ◽  
Intact Cells

Incubation of human platelets, human neutrophils, or highly metastatic mouse lymphoma cells with sulfate-labeled extracellular matrix (ECM) results in heparanase-mediated release of labeled heparan sulfate cleavage fragments (0.5 less than Kav less than 0.85 on Sepharose 6B). This degradation was inhibited by native heparin both when brought about by intact cells or their released heparanase activity. Degradation of heparan sulfate in ECM may facilitate invasion of normal and malignant cells through basement membranes. The present study tested the heparanase inhibitory effect of nonanticoagulant species of heparin that might be of potential use in preventing heparanase mediated extravasation of bloodborne cells. For this purpose, we prepared various species of low-sulfated or low-mol-wt heparins, all of which exhibited less than 7% of the anticoagulant activity of native heparin. N-sulfate groups of heparin are necessary for its heparanase inhibitory activity but can be substituted by an acetyl group provided that the O-sulfate groups are retained. O-sulfate groups could be removed provided that the N positions were resulfated. Total desulfation of heparin abolished its heparanase inhibitory activity. Heparan sulfate was a 25-fold less potent heparanase inhibitor than native heparin. Efficiency of low-mol-wt heparins to inhibit degradation of heparan sulfate in ECM decreased with their main molecular size, and a synthetic pentasaccharide, representing the binding site to antithrombin III, was devoid of inhibitory activity. Similar results were obtained with heparanase activities released from platelets, neutrophils, and lymphoma cells. We propose that heparanase inhibiting nonanticoagulant heparins may interfere with dissemination of bloodborne tumor cells and development of experimental autoimmune diseases.

scholarly journals Synthesis and Characterization of Polyvinylpyrrolidone-Modified ZnO Quantum Dots and Their In Vitro Photodynamic Tumor Suppressive Action

2021 ◽  
Vol 22 (15) ◽  
pp. 8106
Author(s):  
Tianming Song ◽  
Yawei Qu ◽  
Zhe Ren ◽  
Shuang Yu ◽  
Mingjian Sun ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Photodynamic Therapy ◽  
Inhibitory Effect ◽  
Therapeutic Effects ◽  
In Vivo Experiments ◽  
Potential Applications ◽  
Zno Quantum Dots ◽  
Zno Qds

Despite the numerous available treatments for cancer, many patients succumb to side effects and reoccurrence. Zinc oxide (ZnO) quantum dots (QDs) are inexpensive inorganic nanomaterials with potential applications in photodynamic therapy. To verify the photoluminescence of ZnO QDs and determine their inhibitory effect on tumors, we synthesized and characterized ZnO QDs modified with polyvinylpyrrolidone. The photoluminescent properties and reactive oxygen species levels of these ZnO/PVP QDs were also measured. Finally, in vitro and in vivo experiments were performed to test their photodynamic therapeutic effects in SW480 cancer cells and female nude mice. Our results indicate that the ZnO QDs had good photoluminescence and exerted an obvious inhibitory effect on SW480 tumor cells. These findings illustrate the potential applications of ZnO QDs in the fields of photoluminescence and photodynamic therapy.

Fibrinogen binding to the integrin αIIbβ3 modulates store-mediated calcium entry in human platelets

Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2648-2656 ◽  
Author(s):  
Juan A. Rosado ◽  
Else M. Y. Meijer ◽  
Karly Hamulyak ◽  
Irena Novakova ◽  
Johan W. M. Heemskerk ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Polymerization ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Integrin Αiibβ3 ◽  
Fibrinogen Binding

Abstract Effects of the occupation of integrin αIIbβ3 by fibrinogen on Ca++signaling in fura-2–loaded human platelets were investigated. Adding fibrinogen to washed platelet suspensions inhibited increases in cytosolic [Ca++] concentrations ([Ca++]i) evoked by adenosine diphosphate (ADP) and thrombin in a concentration-dependent manner in the presence of external Ca++ but not in the absence of external Ca++ or in the presence of the nonselective cation channel blocker SKF96365, indicating selective inhibition of Ca++entry. Fibrinogen also inhibited store-mediated Ca++ entry (SMCE) activated after Ca++ store depletion using thapsigargin. The inhibitory effect of fibrinogen was reversed if fibrinogen binding to αIIbβ3 was blocked using RDGS or abciximab and was absent in platelets from patients homozygous for Glanzmann thrombasthenia. Fibrinogen was without effect on SMCE once activated. Activation of SMCE in platelets occurs through conformational coupling between the intracellular stores and the plasma membrane and requires remodeling of the actin cytoskeleton. Fibrinogen inhibited actin polymerization evoked by ADP or thapsigargin in control cells and in cells loaded with the Ca++ chelator dimethyl BAPTA. It also inhibited the translocation of the tyrosine kinase p60src to the cytoskeleton. These results indicate that the binding of fibrinogen to integrin αIIbβ3 inhibits the activation of SMCE in platelets by a mechanism that may involve modulation of the reorganization of the actin cytoskeleton and the cytoskeletal association of p60src. This action may be important in intrinsic negative feedback to prevent the further activation of platelets subjected to low-level stimuli in vivo.

scholarly journals In vivo hypotensive effect and in vitro inhibitory activity of some Cyperaceae species

2013 ◽  
Vol 49 (4) ◽  
pp. 803-809
Author(s):  
Monica Lacerda Lopes Martins ◽  
Henrique Poltronieri Pacheco ◽  
Iara Giuberti Perini ◽  
Dominik Lenz ◽  
Tadeu Uggere de Andrade ◽  
...  
Keyword(s):  
Inhibitory Activity ◽  
Colorimetric Assay ◽  
Hypotensive Effect ◽  
Ace Inhibition ◽  
Inhibitory Effect ◽  
Positive Control ◽  
Total Phenolic ◽  
Before And After

In 1820, French naturalist August Saint Hillaire, during a visit in Espírito Santo (ES), a state in southeastern Brazil, reported a popular use of Cyperaceae species as antidote to snake bites. The plant may even have a hypotensive effect, though it was never properly researched. The in vitro inhibitory of the angiotensin converting enzyme (ACE) activity of eigth ethanolic extracts of Cyperaceae was evaluated by colorimetric assay. Total phenolic and flavonoids were determined using colorimetric assay. The hypotensive effect of the active specie (Rhychonospora exaltata, ERE) and the in vivo ACE assay was measured in vivo using male Wistar Kyoto (ERE, 0.01-100mg/kg), with acetylcholine (ACh) as positive control (5 µg/kg, i.v.). The evaluation of ACE in vivo inhibitory effect was performed comparing the mean arterial pressure before and after ERE (10 mg/kg) in animals which received injection of angiotensin I (ANG I; 0,03, 03 and 300 µg/kg, i.v.). Captopril (30 mg/kg) was used as positive control. Bulbostylis capillaris (86.89 ± 15.20%) and ERE (74.89 ± 11.95%, ERE) were considered active in the in vitro ACE inhibition assay, at 100 µg/mL concentration. ACh lead to a hypotensive effect before and after ERE's curve (-40±5% and -41±3%). ERE showed a dose-dependent hypotensive effect and a in vivo ACE inhibitory effect. Cyperaceae species showed an inhibitory activity of ACE, in vitro, as well as high content of total phenolic and flavonoids. ERE exhibited an inhibitory effect on both in vitro and in vivo ACE. The selection of species used in popular medicine as antidotes, along with the in vitro assay of ACE inhibition, might be a biomonitoring method for the screening of new medicinal plants with hypotensive properties.

Mobilization of Fibrinogen Receptor Sites on Human Platelets Stimulated with ADP is Prevented by Prostacyclin

1979 ◽  
Author(s):  
J. Hawiger ◽  
S. Parkinson ◽  
S. Timmons
Keyword(s):  
Inhibitory Effect ◽  
Human Platelets ◽  
Affinity Constant ◽  
Human Fibrinogen ◽  
Fibrinogen Receptor ◽  
Receptor Sites ◽  
Plasma Factor ◽  
Potent Inhibitory Effect

Fibrinogen is a plasma factor required for aggregation of human platelets by ADP. The mechanism of platelet-ADP-fibrinogen interaction was studied by measuring the equilibrium binding of 125I-fibrinogen to human platelets separated from plasma proteins. Binding of 125I-fibrinogen to platelets not stimulated with ADP was low and unaffected by an excess of unlabel led fibrinogen. However, when platelets were stimulated with 4μM of ADP, there was an eightfold increase In the number of available binding sites for human fibrinogen, with affinity constant of 1.9 x 109M-1. This striking increase in fibrinogen receptor sites on human platelets was specific for ADP as contrasted to ATP, AMP, and adenosine. Prostacyclin (Prostaglandin I2, PGI2), a novel prostaglandin produced by the blood vessel wall, completely blocked this ADP-induced increase in fibrinogen receptor sites on human platelets. The effect of PGI2 was prompt and concentration dependent, reaching maximum at 10-9M. 6-keto PGF2 a stable derivative ot PGI2, did not have such an effect. Thus movement of fibrinogen receptor sites on human platelet membrane stimulated with ADP is prevented by PGI2. This represents a new biologic property of this vascular hormone and contributes to better understanding of its potent inhibitory effect in vitro and in vivo on ADP-induced platelet aggregation requiring mobilization of fibrinogen receptor.

scholarly journals LOWERING URIC ACID EFFICACY TEST OF THE COMBINED EXTRACT OF UNCARIA GAMBIR (HUNTER) ROXB. AND CAESALPINIA SAPPAN L. IN VIVO AND IN VITRO

2018 ◽  
Vol 11 (8) ◽  
pp. 166
Author(s):  
Sri Ningsih ◽  
Fahri Fahrudin
Keyword(s):  
Antioxidant Activity ◽  
Uric Acid ◽  
Inhibitory Activity ◽  
Positive Control ◽  
Polyphenol Content ◽  
Caesalpinia Sappan ◽  
In Vivo Experiments ◽  
A Value

 Objective: Hyperuricemia (high uric acid levels) prevalence increased year by year. This study was aimed to elaborate the in vitro xanthine oxidase (XO) inhibitory activity and in vivo lowering hyperuricemic effect of Uncaria gambir (Hunter) Roxb) (gambir), Caesalpinia sappan L. (secang) and the combined extract of secang and gambir (formulae extract [FE]).Methods: Gambir and secang extracts were prepared by maceration with ethanol and FE was the proportioned combination of these two extracts. XO inhibitory activity was determined by measuring the formation of uric acid in the xanthine/XO system in vitro using allopurinol as a positive control at 100 ug/mL. Antioxidant activity was by 1,1-diphenyl-2-picrylhydrazyl radical reducing methods. The in vivo experiments were conducted in the oxonate-induced hyperuricemia rat model, in which FE was gavaged p.o. at the arrange dose of 75, 150, and 300 mg/kg bw for 2 weeks. Polyphenol content was measured using Folin–Ciocalteu reagent spectrophotometrically.Results: The XO inhibitory activity of FE was 80% of allopurinol, while secang and gambir were 98% and 50%, respectively. The strength was appropriate to the total polyphenol content, in which it decreased in the order of secang (99%) > FE (86%) > gambir (46%). Furthermore, FE at all tested doses was able to decrease uric acid levels. FE also demonstrated antioxidant activity with a value of 74% relative to Vitamin C at 4 ug/mL.Conclusion: These studies could be concluded that FE exhibited the ability to decrease uric acid level so that it was potential to be developed further as a uric acid-lowering agent.

scholarly journals Regulatory Functions of Serine-46-Phosphorylated HPr in Lactococcus lactis

2001 ◽  
Vol 183 (11) ◽  
pp. 3391-3398 ◽  
Author(s):  
Vicente Monedero ◽  
Oscar P. Kuipers ◽  
Emmanuel Jamet ◽  
Josef Deutscher
Keyword(s):  
Lactococcus Lactis ◽  
Inhibitory Effect ◽  
Wild Type ◽  
Phosphotransferase System ◽  
Inducer Exclusion ◽  
Gram Positive Bacteria ◽  
In Vivo Experiments ◽  
Regulatory Functions

ABSTRACT In most low-G+C gram-positive bacteria, the phosphoryl carrier protein HPr of the phosphoenolpyruvate:sugar phosphotransferase system (PTS) becomes phosphorylated at Ser-46. This ATP-dependent reaction is catalyzed by the bifunctional HPr kinase/P-Ser-HPr phosphatase. We found that serine-phosphorylated HPr (P-Ser-HPr) of Lactococcus lactis participates not only in carbon catabolite repression of an operon encoding a β-glucoside-specific EII and a 6-P-β-glucosidase but also in inducer exclusion of the non-PTS carbohydrates maltose and ribose. In a wild-type strain, transport of these non-PTS carbohydrates is strongly inhibited by the presence of glucose, whereas in a ptsH1 mutant, in which Ser-46 of HPr is replaced with an alanine, glucose had lost its inhibitory effect. In vitro experiments carried out with L. lactis vesicles had suggested that P-Ser-HPr is also implicated in inducer expulsion of nonmetabolizable homologues of PTS sugars, such as methylβ-d-thiogalactoside (TMG) and 2-deoxy-d-glucose (2-DG). In vivo experiments with theptsH1 mutant established that P-Ser-HPr is not necessary for inducer expulsion. Glucose-activated 2-DG expulsion occurred at similar rates in wild-type and ptsH1 mutant strains, whereas TMG expulsion was slowed in the ptsH1 mutant. It therefore seems that P-Ser-HPr is not essential for inducer expulsion but that in certain cases it can play an indirect role in this regulatory process.

Role of Activated Platelets in the Homing, Maturation, and Differentiation of Endotheleal Progenitor Cells (EPCs) to Vascular Subendotheleal Matrix.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3938-3938
Author(s):  
Eli I. Lev ◽  
Jing-fei Dong ◽  
Marcin Bujak ◽  
Khatira Aboulfatova ◽  
Neal S. Kleiman ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Vascular Injury ◽  
Human Platelets ◽  
In Vitro Experiments ◽  
Cell Markers ◽  
Femoral Arteries ◽  
In Vivo Experiments

Abstract We and others have found that platelets play an important role in the recruitment of endothelial progenitor cells to sights of vascular injury. However, it is not clear whether the EPCs mature and differentiate to endothelial cells following recruitment to the vascular injury sites. In addition, there is limited in vivo data to support the role of EPCs in re-endothlialization following vascular injury. We conducted in vitro experiments to investigate the maturation of EPCs on platelet based-media and in vivo experiments to evaluate the recruitment of EPCs following vascular injury. In in vitro experiments human EPCs were isolated from donated buffy coats by magnetic microbeads and flow cytometry cell sorting using CD133 and VEGFR-2, respectively, as cell markers. Isolated viable EPCs (CD133+, VEGFR-2+ cells) were plated on human fibronectin or a monolayer of washed human platelets. Cell colonies were counted 7 days after plating and stained for the endothelial cell markers CD31 (PECAM-1) and CD144 (VE-cadherin). The mean number of colony-forming cells was 35±2.6 colonies/106 cells on platelets, which was significantly higher than 18±4.2 colonies/106 cells on fibronectin (n = 4, P&lt;0.01). Apart from the difference in colony numbers, the EPC colonies grew faster on the platelet substrate, were larger, and had more spindle-shaped cells (Figure 1 - staining of EPC colonies for CD31 and CD144). In the in vivo experiments a model of transluminal injury to mouse femoral arteries was used. Femoral artery denudation was performed by 0.25-mm-diameter angioplasty guidewire. Injured femoral arteries were compared to the contra-lateral controls (uninjured), and were harvested 1.5 hours following the injury and immunostaining performed with an anti-VEGFR-2 antibody. Four experiments showed a markedly higher number of VEGFR-2+ cells in the artery that has undergone denudation. These experiments indicate that a media composed of platelets promotes the maturation and differentiation of EPCs. Furthermore, in vivo, EPCs are recruited early following vascular injury. Thus, homing, maturation, and differentiation of EPCs are mediated by platelets.

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