scholarly journals Inhibitory Effects of a Reengineered Anthrax Toxin on Canine Oral Mucosal Melanomas

Toxins ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 157 ◽  
Author(s):  
Adriana Tomoko Nishiya ◽  
Marcia Kazumi Nagamine ◽  
Ivone Izabel Mackowiak da Fonseca ◽  
Andrea Caringi Miraldo ◽  
Nayra Villar Scattone ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Evaluation Criteria ◽  
Anthrax Toxin ◽  
Treatment Modalities ◽  
Inhibitory Effects ◽  
Upa Receptor ◽  
New Treatment ◽  
Oral Malignancy

Canine oral mucosal melanomas (OMM) are the most common oral malignancy in dogs and few treatments are available. Thus, new treatment modalities are needed for this disease. Bacillus anthracis (anthrax) toxin has been reengineered to target tumor cells that express urokinase plasminogen activator (uPA) and metalloproteinases (MMP-2), and has shown antineoplastic effects both, in vitro and in vivo. This study aimed to evaluate the effects of a reengineered anthrax toxin on canine OMM. Five dogs bearing OMM without lung metastasis were included in the clinical study. Tumor tissue was analyzed by immunohistochemistry for expression of uPA, uPA receptor, MMP-2, MT1-MMP and TIMP-2. Animals received either three or six intratumoral injections of the reengineered anthrax toxin prior to surgical tumor excision. OMM samples from the five dogs were positive for all antibodies. After intratumoral treatment, all dogs showed stable disease according to the canine Response Evaluation Criteria in Solid Tumors (cRECIST), and tumors had decreased bleeding. Histopathology has shown necrosis of tumor cells and blood vessel walls after treatment. No significant systemic side effects were noted. In conclusion, the reengineered anthrax toxin exerted inhibitory effects when administered intratumorally, and systemic administration of this toxin is a promising therapy for canine OMM.

scholarly journals Modulation of Cellular Migration and Survival by c-Myc through the Downregulation of Urokinase (uPA) and uPA Receptor

2010 ◽  
Vol 30 (7) ◽  
pp. 1838-1851 ◽  
Author(s):  
Daniela Alfano ◽  
Giuseppina Votta ◽  
Almut Schulze ◽  
Julian Downward ◽  
Mario Caputi ◽  
...  
Keyword(s):  
Cell Motility ◽  
Cellular Transformation ◽  
Tumor Formation ◽  
Cellular Migration ◽  
Epithelial Cell Line ◽  
Cellular Motility ◽  
Upa Receptor ◽  
Upar Expression ◽  
Repressive Effect ◽  
Cell Invasiveness

ABSTRACT It has been proposed that c-Myc proapoptotic activity accounts for most of its restraint of tumor formation. We established a telomerase-immortalized human epithelial cell line expressing an activatable c-Myc protein. We found that c-Myc activation induces, in addition to increased sensitivity to apoptosis, reductions in cell motility and invasiveness. Transcriptome analysis revealed that urokinase (uPA) and uPA receptor (uPAR) were strongly downregulated by c-Myc. Evidence is provided that the repression of uPA and uPAR may account for most of the antimigratory and proapoptotic activities of c-Myc. c-Myc is known to cooperate with Ras in cellular transformation. We therefore investigated if this cooperation could converge in the control of uPA/uPAR expression. We found that Ras is able to block the effects of c-Myc activation on apoptosis and cellular motility but not on cell invasiveness. Accordingly, the activation of c-Myc in the context of Ras expression had only minor influence on uPAR expression but still had a profound repressive effect on uPA expression. Thus, the differential regulation of uPA and uPAR by c-Myc and Ras correlates with the effects of these two oncoproteins on cell motility, invasiveness, and survival. In conclusion, we have discovered a novel link between c-Myc and uPA/uPAR. We propose that reductions of cell motility and invasiveness could contribute to the inhibition of tumorigenesis by c-Myc and that the regulation of uPA and uPAR expression may be a component of the ability of c-Myc to reduce motility and invasiveness.

uPA Receptor

2012 ◽  
pp. 1945-1945
Author(s):  
Mitsi A. Blount ◽  
Janet D. Klein ◽  
Jeff M. Sands
Keyword(s):  
Upa Receptor

scholarly journals Regulation of urokinase receptors in monocytelike U937 cells by phorbol ester phorbol myristate acetate.

1989 ◽  
Vol 108 (2) ◽  
pp. 693-702 ◽  
Author(s):  
R Picone ◽  
E L Kajtaniak ◽  
L S Nielsen ◽  
N Behrendt ◽  
M R Mastronicola ◽  
...  
Keyword(s):  
Phorbol Myristate Acetate ◽  
Gel Electrophoresis ◽  
U937 Cell ◽  
Tissue Destruction ◽  
Myristate Acetate ◽  
Amino Terminal ◽  
Upa Receptor ◽  
Surface Receptor ◽  
Dependent Processes ◽  
Extracellular Proteolysis

A specific surface receptor for urokinase plasminogen activator (uPA) recognizes the amino-terminal growth factor-like sequence of uPA, a region independent from and not required for the catalytic activity of this enzyme. The properties of the uPA receptor (uPAR) and the localization and distribution of uPA in tumor cells and tissues suggest that the uPA/uPAR interaction may be important in regulating extracellular proteolysis-dependent processes (e.g., invasion, tissue destruction). Phorbol myristate acetate (PMA), an inducer of U937 cell differentiation to macrophage-like cells, elicits a time- and concentration-dependent increase in the number of uPAR molecules as shown by binding, cross-linking, and immunoprecipitation studies. The effect of PMA is blocked by cycloheximide. Overall, the data indicate that PMA increases the synthesis of uPA. PMA treatment also causes a decrease in the affinity of the uPAR for uPA, thus uncovering another way of regulating the interaction between uPA and uPAR. In addition, the PMA treatment causes a modification of migration of the cross-linked receptor in mono- and bidimensional gel electrophoresis.

Antimetastatic Potential of Quercetin Analogues with Improved Pharmacokinetic Profile: Pharmacoinformatic Preliminary Study

2021 ◽  
Vol 21 ◽  
Author(s):  
Nebojša Pavlović ◽  
Nastasija Milošević ◽  
Maja Đjanić ◽  
Svetlana Goločorbin-Kon ◽  
Bojan Stanimirov ◽  
...  
Keyword(s):  
Membrane Permeability ◽  
Anticancer Agents ◽  
Inhibitory Activity ◽  
Computational Models ◽  
Aqueous Solubility ◽  
Pharmacokinetic Profile ◽  
Limiting Factor ◽  
Hydroxyl Groups ◽  
Molegro Virtual Docker ◽  
Upa Receptor

Background: Urokinase-type plasminogen activator (uPA) system is a crucial pathway for tumor invasion and metastasis. Recently, multiple anticancer effects of quercetin have been described, including inhibitory activity against uPA. However, the clinical use of this flavonoid has been limited due to its low oral bioavailability. Objective: The objectives of the study were to assess the antimetastatic potential of quercetin analogues by analyzing their binding affinity for uPA and to select the compounds with improved pharmacological profiles. Methods: Binding affinities of structural analogues of quercetin to uPA receptor were determined by molecular docking analysis using Molegro Virtual Docker software, and molecular descriptors relevant for estimating pharmacological profile were calculated from ligand structures using computational models. Results: Among 44 quercetin analogues, only one quercetin analogue (3,6,2’,4’,5’-pentahydroxyflavone) was found to possess both higher aqueous solubility and membrane permeability, and a stronger affinity for uPA than quercetin, which makes it the potential lead compound for anticancer drug development. Like quercetin, this compound has five hydroxyl groups but is arranged differently, which contributes to the higher aqueous solubility and higher amphiphilic moment compared to quercetin. Since membrane permeability is not recognized as the limiting factor for quercetin absorption, analogues with higher aqueous solubility and retained or stronger uPA inhibitory activity should also be further experimentally validated for potential therapeutic use. Conclusion: Identified quercetin analogues with better physicochemical and pharmacological properties have a high potential to succeed in later stages of research in biological systems as potential anticancer agents with antimetastatic activity.

Urokinase receptor expression on human microvascular endothelial cells is increased by hypoxia: implications for capillary-like tube formation in a fibrin matrix

Blood ◽  
2000 ◽  
Vol 96 (8) ◽  
pp. 2775-2783 ◽  
Author(s):  
Marielle E. Kroon ◽  
Pieter Koolwijk ◽  
Bea van der Vecht ◽  
Victor W. M. van Hinsbergh
Keyword(s):  
Endothelial Cells ◽  
Tube Formation ◽  
Microvascular Endothelial Cells ◽  
Tubular Structures ◽  
Angiogenic Response ◽  
Fibrin Matrix ◽  
Hypoxic Conditions ◽  
Upa Receptor ◽  
Tnf Α ◽  
Blocking Antibodies

Abstract Hypoxia stimulates angiogenesis, the formation of new blood vessels. This study evaluates the direct effect of hypoxia (1% oxygen) on the angiogenic response of human microvascular endothelial cells (hMVECs) seeded on top of a 3-dimensional fibrin matrix. hMVECs stimulated with fibroblast growth factor–2 (FGF-2) or vascular endothelial growth factor (VEGF) together with tumor necrosis factor–α (TNF-α) formed 2- to 3-fold more tubular structures under hypoxic conditions than in normoxic (20% oxygen) conditions. In both conditions the in-growth of capillary-like tubular structures into fibrin required cell-bound urokinase-type plasminogen activator (uPA) and plasmin activities. The hypoxia-induced increase in tube formation was accompanied by a decrease in uPA accumulation in the conditioned medium. This decrease in uPA level was completely abolished by uPA receptor-blocking antibodies. During hypoxic culturing uPA receptor activity and messenger RNA (mRNA) were indeed increased. This increase and, as a consequence, an increase in plasmin formation contribute to the hypoxia-induced stimulation of tube formation. A possible contribution of VEGF-A to the increased formation under hypoxic conditions is unlikely because there was no increased VEGF-A expression detected under hypoxic conditions, and the hypoxia-induced tube formation by FGF-2 and TNF-α was not inhibited by soluble VEGFR-1 (sVEGFR-1), or by antibodies blocking VEGFR-2. Furthermore, although the αv-integrin subunit was enhanced by hypoxia, blocking antibodies against αvβ3- and αvβ5-integrins had no effect on hypoxia-induced tube formation. Hypoxia increases uPA association and the angiogenic response of human endothelial cells in a fibrin matrix; the increase in the uPA receptor is an important determinant in this process.

Characterization of Cell-Associated Plasminogen Activation Catalyzed by Urokinase-Type Plasminogen Activator, but Independent of Urokinase Receptor (uPAR, CD87)

Blood ◽  
1999 ◽  
Vol 93 (11) ◽  
pp. 3839-3846 ◽  
Author(s):  
Colin Longstaff ◽  
R. Elizabeth Merton ◽  
Pere Fabregas ◽  
Jordi Felez
Keyword(s):  
Molecular Weight ◽  
Leukemic Cell ◽  
Plasminogen Activation ◽  
Single Chain ◽  
Amino Terminal ◽  
Leukemic Cell Lines ◽  
Upa Receptor ◽  
Type Plasminogen Activator

Abstract The 55-kD urokinase (uPA) receptor (uPAR, CD87) is capable of binding uPA and may be involved in regulating cell-associated plasminogen activation and pericellular proteolysis. While investigating the relationship between uPAR levels and plasmin generation, we found that uPA-catalyzed plasminogen activation is stimulated by cells which do not express uPAR. This uPAR-independent mechanism appears to be at least as effective in vitro as uPAR-dependent stimulation, such that stimulation on the order of 30-fold was observed, resulting from improvements in both apparent kcat and apparent Km. The mechanism depends on simultaneous binding of both uPA and plasminogen to the cell and requires the presence of the amino-terminal fragment (ATF), available in single chain and two chain high-molecular-weight uPA, but not low-molecular-weight uPA. Stimulation was observed in all leukemic cell lines investigated at similar optimum concentrations of 106to 107 cells/mL and may be more general. A mechanism is proposed whereby uPA can associate with binding sites on the cell surface of lower affinity, but higher capacity than uPAR, but these are sufficient to stimulate plasmin generation even at subphysiologic uPA concentrations. This mechanism is likely to operate under conditions commonly used for in vitro studies and may have some significance in vivo.

scholarly journals A high-affinity receptor for urokinase plasminogen activator on human keratinocytes: characterization and potential modulation during migration.

1990 ◽  
Vol 1 (11) ◽  
pp. 843-852 ◽  
Author(s):  
H McNeill ◽  
P J Jensen
Keyword(s):  
Molecular Weight ◽  
Plasma Membrane ◽  
Plasminogen Activator ◽  
Binding Sites ◽  
Human Keratinocytes ◽  
Urokinase Plasminogen Activator ◽  
Receptor Expression ◽  
Epithelial Migration ◽  
High Affinity ◽  
Upa Receptor

Low passage cultures of normal human keratinocytes produce several components of the plasminogen activator/plasmin proteolytic cascade, including urokinase plasminogen activator (uPA), tissue plasminogen activator (tPA), and two specific inhibitors. Studies here presented demonstrate that these cells also contain a high-affinity (Kd = 3 x 10(-10) M) plasma membrane-binding site for uPA. High molecular weight uPA, either as the single-chain precursor or two-chain activated form, bound to the receptor; however, low molecular weight (33 kD) uPA, tPA, or epidermal growth factor did not compete for binding, demonstrating specificity. Acid treatment, which removed endogenous uPA from the receptor, was required to detect maximal binding (45,000 sites per cell). To investigate the possibility that the uPA receptor on keratinocytes may be involved in epithelial migration during wound repair, cultures were wounded and allowed to migrate into the wounded site. Binding sites for uPA were localized by autoradiographic analysis of 125I-uPA binding as well as by immunocytochemical studies using anti-uPA IgG. With both techniques uPA binding sites were detected selectively on the plasma membrane of cells at the leading edge of the migrating epithelial sheet. This localization pattern suggests that uPA receptor expression on keratinocytes may be coupled to cell migration during cutaneous wounding.

Sign in / Sign up

Export Citation Format

Share Document