Androgens Stimulate EPC-Mediated Neovascularization and Are Associated with Increased Coronary Collateralization

Endocrinology ◽  
2020 ◽  
Vol 161 (5) ◽  
Author(s):  
Yuen Ting Lam ◽  
Chi-Jen Hsu ◽  
Philippa J L Simpson ◽  
Louise L Dunn ◽  
Renee W Chow ◽  
...  
Keyword(s):  
Blood Flow ◽  
Serum Testosterone ◽  
Receptor Expression ◽  
Flow Index ◽  
Vegf Receptor ◽  
Collateral Flow ◽  
Dependent Manner ◽  
Artery Disease

Abstract Endothelial progenitor cells (EPCs) play a key role in neovascularization and have been linked to improved cardiovascular outcomes. Although there is a well-established inverse relationship between androgen levels and cardiovascular mortality in men, the role of androgens in EPC function is not fully understood. In this study, we investigated the effects of androgens on 2 subpopulations of EPCs, early EPCs (EEPCs) and late outgrowth EPCs (OECs), and their relationships with coronary collateralization. Early EPCs and OECs were isolated from the peripheral blood of young healthy men and treated with dihydrotestosterone (DHT) with or without androgen receptor (AR) antagonist, hydroxyflutamide, in vitro. Dihydrotestosterone treatment enhanced AR-mediated proliferation, migration, and tubulogenesis of EEPCs and OECs in a dose-dependent manner. Furthermore, DHT augmented EPC sensitivity to extracellular stimulation by vascular endothelial growth factor (VEGF) via increased surface VEGF receptor expression and AKT activation. In vivo, xenotransplantation of DHT pretreated human EPCs augmented blood flow recovery and angiogenesis in BALB/c nude male mice, compared to mice receiving untreated EPCs, following hindlimb ischemia. In particular, DHT pretreated human OECs exhibited higher reparative potential than EEPCs in augmenting postischemic blood flow recovery in mice. Furthermore, whole blood was collected from the coronary sinus of men with single vessel coronary artery disease (CAD) who underwent elective percutaneous intervention (n = 23). Coronary collateralization was assessed using the collateral flow index. Serum testosterone and EPC levels were measured. In men with CAD, circulating testosterone was positively associated with the extent of coronary collateralization and the levels of OECs. In conclusion, androgens enhance EPC function and promote neovascularization after ischemia in mice and are associated with coronary collateralization in men.

Chemoprotection by VEGF: Rationale for combination nab-paclitaxel and bevacizumab

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 1064-1064 ◽  
Author(s):  
V. Trieu ◽  
S. Ran ◽  
C. Bivens ◽  
N. Desai
Keyword(s):  
Protective Effect ◽  
Tumor Cells ◽  
Breast Tumor ◽  
T Test ◽  
Receptor Expression ◽  
Vegf Receptor ◽  
Vegf Expression ◽  
Clonogenic Assays

1064 Background: Nanoparticle albumin-bound (nab-) paclitaxel (ABX) has shown greater efficacy and less toxicity than solvent-based paclitaxel (TAX) in xenograft models and clinical trials. The goal of this study was to determine the effects of VEGF modulation in human MDA-MB-231 breast tumor cell line and the effects of ABX and VEGF-neutralizing antibody bevacizumab (AVA) combination on the growth and metastasis of orthotopically implanted MDA-MB-231 tumors. Methods: VEGF expression was evaluated by ELISA in MDA-MB-231 tumor extract one week after treatment (qdx5) with saline, doxorubicin (10 mg/kg), TAX (10 mg/kg), or ABX (15 mg/kg). VEGF-receptor expression in MDA-MB-231 was quantitated by RT-PCR. MDA-MB-231 cytotoxicity with ABX, VEGF, AVA alone or in combination was measured by cytotoxicity and clonogenic assays. Implanted MDA-MB-231 tumors expressing luciferase were treated with saline, 2 cycles of ABX (10 mg/kg, two qdx5 cycles separated by 1 week, N=5) alone or in combination with AVA (2, 4 and 8 mg/kg, 2/wkx6). Tumor lymph node and pulmonary metastasis was determined by measuring luciferase activity. Results: Compared with saline, MDA-MB-231 tumors following chemotherapies exhibited significant tumor shrinkage (p≤0.006, t-test) and VEGF induction (p<0.0001, t-test). MDA-MB-231 was shown to express VEGFR2. Exogenous VEGF had a protective effect on MDA-MB-231 tumor cells by reducing cytotoxicity of ABX in both cytotoxicity and clonogenic assays. Sequestration of VEGF with AVA increased cytotoxicity of ABX in vitro. Treatment of MDA-MB-231 breast tumors with ABX and AVA combination resulted in greater than additive antitumor response and significantly reduced metastasis to the lungs (p=0.025 vs control) and LN (p=0.022) at the highest AVA dose. Conclusions: Chemotherapies induced VEGF expression in MDA-MD-231 breast tumor in vivo. In vitro, VEGF exerted a protective effect against ABX chemotherapy in VEGFR2-expressing MDA-MD-231 cells, which was abrogated by addition of AVA. In vivo, ABX and AVA combination significantly inhibited the metastatic potential of MDA-MB-231 tumor cells. These data provide a rational basis for the combination of nab- paclitaxel and bevacizumab in VEGF-receptor expressing tumors. [Table: see text]

Lymphocytic microparticles inhibit angiogenesis by stimulating oxidative stress and negatively regulating VEGF-induced pathways

2008 ◽  
Vol 294 (2) ◽  
pp. R467-R476 ◽  
Author(s):  
Chun Yang ◽  
Bupe R. Mwaikambo ◽  
Tang Zhu ◽  
Carmen Gagnon ◽  
Josiane Lafleur ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Cell Function ◽  
Umbilical Vein ◽  
Ros Generation ◽  
Vegf Receptor ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Endothelial Cell Function

Recent studies have demonstrated that lymphocyte-derived microparticles (LMPs) impair endothelial cell function. However, no data currently exist regarding the contribution of LMPs in the regulation of angiogenesis. In the present study, we investigated the effects of LMPs on angiogenesis in vivo and in vitro and demonstrated that LMPs strongly suppressed aortic ring microvessel sprouting and in vivo corneal neovascularization. In vitro, LMPs considerably diminished human umbilical vein endothelial cell survival and proliferation in a concentration-dependent manner. Mechanistically, the antioxidants U-74389G and U-83836E were partially protective against the antiproliferative effects of LMPs, whereas the NADPH oxidase (NOX) inhibitors apocynin and diphenyleneiodonium significantly abrogated these effects. Moreover, LMPs increased not only the expression of the NOX subunits gp91phox, p22phox, and p47phox, but also the production of ROS and NOX-derived superoxide (O2−). Importantly, LMPs caused a pronounced augmentation in the protein expression of the CD36 antiangiogenic receptor while significantly downregulating the protein levels of VEGF receptor type 2 and its downstream signaling mediator, phosphorylated ERK1/2. In summary, LMPs potently suppress neovascularization in vivo and in vitro by augmenting ROS generation via NOX and interfering with the VEGF signaling pathway.

Extracellular RNA promotes leukocyte recruitment in the vascular system by mobilising proinflammatory cytokines

2012 ◽  
Vol 108 (10) ◽  
pp. 730-741 ◽  
Author(s):  
Judith I. Pagel ◽  
Marlene Tschernatsch ◽  
Markus Sperandio ◽  
Klaus T. Preissner ◽  
Silvia Fischer ◽  
...  
Keyword(s):  
Proinflammatory Cytokines ◽  
Leukocyte Adhesion ◽  
Leukocyte Recruitment ◽  
Vegf Receptor ◽  
Dependent Manner ◽  
Monocytic Cells ◽  
Extracellular Rna ◽  
Tnf Α

SummaryExtracellular RNA (eRNA), released from cells under conditions of injury or vascular disease, acts as potent prothrombotic factor and promotes vascular hyperpermeability related to oedema formation in vivo. In this study, we aimed to investigate the mechanism by which eRNA triggers inflammatory processes, particularly associated with different steps of leukocyte recruitment. Using intravital microscopy of murine cremaster muscle venules, eRNA (but not DNA) significantly induced leukocyte adhesion and transmigration in vivo, which was comparable in its effects to the function of tumour-necrosis-factor-α (TNF-α). In vitro, eRNA promoted adhesion and transmigration of monocytic cells on and across endothelial cell monolayers. eRNA-induced monocyte adhesion in vitro was mediated by activation of the vascular endothelial growth factor (VEGF)/VEGF-receptor-2 system and was abolished by neutralising antibodies against intercellular adhesion molecule-1 or the p2-inte-grin Mac-1. Additionally, eRNA induced the release of TNF-α from monocytic cells in a time- and concentration-dependent manner, which involved activation of TNF- α -converting enzyme (TACE) as well as the nuclear factor kB signalling machinery. In vivo, inhibiton of TACE significantly reduced eRNA-induced leukocyte adhesion. Our findings present evidence that eRNA in connection with tissue/vascular damage provokes a potent inflammatory response by inducing leukocyte recruitment and by mobilising proinflammatory cytokines from monocytes.

scholarly journals VEGFR2 induces c-Src signaling and vascular permeability in vivo via the adaptor protein TSAd

2012 ◽  
Vol 209 (7) ◽  
pp. 1363-1377 ◽  
Author(s):  
Zuyue Sun ◽  
Xiujuan Li ◽  
Sara Massena ◽  
Simone Kutschera ◽  
Narendra Padhan ◽  
...  
Keyword(s):  
Vascular Permeability ◽  
Adaptor Protein ◽  
Cell Junctions ◽  
Vegf Receptor ◽  
Dependent Manner ◽  
Src Tyrosine Kinase ◽  
Rous Sarcoma ◽  
Src Homology 2 Domain

Regulation of vascular endothelial (VE) growth factor (VEGF)–induced permeability is critical in physiological and pathological processes. We show that tyrosine phosphorylation of VEGF receptor 2 (VEGFR2) at Y951 facilitates binding of VEGFR2 to the Rous sarcoma (Src) homology 2-domain of T cell–specific adaptor (TSAd), which in turn regulates VEGF-induced activation of the c-Src tyrosine kinase and vascular permeability. c-Src was activated in vivo and in vitro in a VEGF/TSAd-dependent manner, and was regulated via increased phosphorylation at pY418 and reduced phosphorylation at pY527. Tsad silencing blocked VEGF-induced c-Src activation, but did not affect pathways involving phospholipase Cγ, extracellular regulated kinase, and endothelial nitric oxide. VEGF-induced rearrangement of VE–cadherin–positive junctions in endothelial cells isolated from mouse lungs, or in mouse cremaster vessels, was dependent on TSAd expression, and TSAd formed a complex with VE-cadherin, VEGFR2, and c-Src at endothelial junctions. Vessels in tsad−/− mice showed undisturbed flow and pressure, but impaired VEGF-induced permeability, as measured by extravasation of Evans blue, dextran, and microspheres in the skin and the trachea. Histamine-induced extravasation was not affected by TSAd deficiency. We conclude that TSAd is required for VEGF-induced, c-Src-mediated regulation of endothelial cell junctions and for vascular permeability.

VASODILATOR PEPTIDES - CGRP AND VIP

1987 ◽  
Author(s):  
S Thom ◽  
A Hughes ◽  
G Martin ◽  
P Goldberg ◽  
P Server
Keyword(s):  
Blood Flow ◽  
Nervous System ◽  
Cerebral Arteries ◽  
Venous Occlusion ◽  
Dependent Manner ◽  
Pial Arteries ◽  
Parasympathetic System ◽  
Perivascular Nerves

The two peptides calcitonin gene related peptide (C6RP) and vasoactive intestinalpeptide (VIP) are widely distributed in animal species including man and a number ofdiverse actions of the peptides have been described [1,2]. They share vasoactive properties [3,4] and may have important functions as neurotransmitters in a non-adrenergic, non-cholinergic nervous system [5]. VIP has been located in perivascular nerves supplying several tissues and is co-stored with acetylcholine in the parasympathetic system [6]. CGRP has also been widely identified in the nervous system, the cardiovascular system and perivascular nerves, where it is located with substance P[7]. Our studies have assessed the activity of these peptides in a human vascular resistance bed -the forearm, and on isolated human blood vessels.Forearm studies were performed by infusingCGRP (10,30,100 ng/min) or ViP (10,30,100 ng/min) via the brachial artery for 5 min at each dose level and measuring blood flow by venous occlusion plethysmography. In vitro studies were performed using ringsegments of pulmonary, gastric, coronary, radial, and transverse cervical arteries freshly obtained from surgical resection specimens and cerebral arteries obtained from autogsy tissue within 4 hours of death. Vessels were mounted in organ baths containing Krebs buffer aerated with 95% 02, 5% C02 at 37C, and preconstricted using a submaximal concentration of noradrenaline (1-3 μM) or prostaglandin F2a (I-IO11μ7.CGRP or VIP was added to the tissue bath in a cumulative fashion. All arterial segments used for these studies relaxed in response to acetylcholine (0.1-3μM)or A23187 (0.1-3μM) and this was regarded as indicative of functional endothelial integrity. Studies were performed in the presence of indomethacin (lOμM). The endothelium was deliberately removed from some rings and in others haemoglobin (5μM) ormethylene blue (lOμM) were added to the tissue bath after the arterialrings were effectively relaxed by CGRP orVIP. Both peptides produced marked dose dependent increases in forearm blood flow; at 100 ng/min the mean net increase was 174 ± 24% (mean ±s.e.m.) with CGRP, and 223 + 34% (mean +s.e.m.) with VIP. In vitro CGRP (InM-lμM) relaxed preconstricted segments ofradial Tn=2), coronary (n=4), gastric (n=5) and cerebral (n=3) arteries in an endothelium dependent manner. VIP (1 nM - 1pm) also relaxed human gastric (n=2), splenic (n=2), cervical (n=3) and pulmonary (n=5) arteries VIP relaxation of the gastric and cervical arteries was dependent on the presence of endothelium; however, VIP inducedrelaxation of pulmonary artery was not dependent on functional endothelium. The endothelium dependent relaxations could be abolished either by luminal rubbing, additionor haemoglobin or methylene blue. Together these results might be taken to imply that the forearm vasodilatation response is mediated by EDRF. However, caution is necessary in extrapolating from in vitro observations of large vessels to the in vivo response of a resistance vascular bed.Others have demonstrated that the CGRPand VIP relaxatory responses of smaller human pial arteries (ID 250-600 pm) are endothelium independent [8] and preliminary work in our department supports this. The EDRF mechanism is cyclic GMP linked, but most of the studied functions of VIP and CGRP seem to be linked to a rise in cyclic AMP-. A further paradox is that the blood flow response to infused acetylcholine, the archetypal releaser of EDRF, is evanescent, and yet the vasodilator response to CGRP is persistent.

Immunization of male rabbits with sheep luteal receptor to LH results in production of antibodies exhibiting hormone-agonistic and -antagonistic activities

1996 ◽  
Vol 150 (3) ◽  
pp. 431-443 ◽  
Author(s):  
M Jeyakumar ◽  
N R Moudgal
Keyword(s):  
Leydig Cells ◽  
Serum Testosterone ◽  
Fold Increase ◽  
Dependent Manner ◽  
Primary Immunization ◽  
Testosterone Production ◽  
Dose Dependent ◽  
Receptor Antibodies

Abstract Antibodies to LH/chorionic gonadotrophin receptor (LH/CG-R; molecular weight 67 000), isolated in a homogenous state (established by SDS-PAGE and ligand blotting) from sheep luteal membrane using human CG (hCG)–Sepharose affinity chromatography, were raised in three adult male rabbits (R-I, R-II and R-III). Each of the rabbits received 20–30 μg of the purified receptor in Freund's complete adjuvant at a time. Primary immunization was followed by booster injection at intervals. Production of receptor antibodies was monitored by (1) determining the dilution of the serum (IgG fraction) that could specifically bind 50% of 125I-LH/CG-R added and (2) analysing sera for any change in testosterone levels. Following primary immunization and the first booster, all three rabbits exhibited a 2·5- to 6·0-fold increase in serum testosterone over basal levels and this effect was spread over a period of time (∼40 days) coinciding with the rise and fall of receptor antibodies. The maximal antibody titre (ED50) produced at this time ranged from 1:350 to 1:100 to below detectable limits for R-I, R-II and R-III respectively. Subsequent immunizations followed by the second booster resulted in a substantial increase in anti-body titre (ED50 of 1:5000) in R-I, but this was not accompanied by any change in serum testosterone over preimmune levels, suggesting that with the progress of immunization the character of the antibody produced had also changed. Two pools of antisera from R-I collected 10 days following the booster (at day 70 (bleed I) and day 290 (bleed II)) were used in further experiments. IgG isolated from bleed I but not from bleed II antiserum showed a dose-dependent stimulation of testosterone production by mouse Leydig cells in vitro, thus confirming the in vivo hormone-mimicking activity of antibodies generated during the early immunization phase. The IgG fractions from both bleeds were, however, capable of inhibiting (1) 125I-hCG binding to crude sheep luteal membrane (EC50 of 1:70 and 1:350 for bleed I and II antisera respectively) and (2) ovine LH-stimulated testosterone production by mouse Leydig cells in vitro, indicating the presence of antagonistic antibodies irrespective of the period of time during which the rabbits were immunized. The fact that bleed I-stimulated testosterone production could be inhibited in a dose-dependent manner by the addition of IgG from bleed II to the mouse Leydig cell in vitro assay system showed that the agonistic activity is intrinsic to the bleed I antibody. The receptor antibody (bleed II) was also capable of blocking LH action in vivo, as rabbits passively (for 24 h with LH/CG-R antiserum) as well as actively (for 430 days) immunized against LH/CG-R failed to respond to a bolus injection of LH (50 μg). At no time, however, was the serum testosterone reduced below the basal level. This study clearly shows that, unlike with LH antibody, attempts to achieve an LH deficiency effect in vivo by resorting to immunization with holo LH receptor is difficult, as receptor antibodies exhibit both hormone-mimicking (agonistic) as well as hormone-blocking (antagonistic) activities. Journal of Endocrinology (1996) 150, 431–443

scholarly journals Apigenin Inhibits Histamine-Induced Cervical Cancer Tumor Growth by Regulating Estrogen Receptor Expression

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1960 ◽  
Author(s):  
Erkang Zhang ◽  
Yani Zhang ◽  
Zhuoyan Fan ◽  
Lei Cheng ◽  
Shiwen Han ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Cell Proliferation ◽  
Tumor Growth ◽  
Antioxidant Properties ◽  
Xenograft Model ◽  
Receptor Expression ◽  
Dependent Manner ◽  
Antitumor Effects

Apigenin is a natural flavone with anti-inflammatory and antioxidant properties and antitumor abilities against several types of cancers. Previous studies have found that the antitumor effects of apigenin may be due to its similar chemical structure to 17β-estradiol (E2), a main kind of estrogen in women. However, the precise mechanism underlying the antitumor effects of apigenin in cervical cancer remains unknown. On the other hand, there is increasing evidence that describes a histamine role in cancer cell proliferation. In this study, we examined whether apigenin can attenuate the effects of histamine on tumors by regulating the expression level of estrogen receptors (ERs) to inhibit cervical cancer growth. Our in vitro data indicates that apigenin inhibited cell proliferation in a dose-dependent manner in human cervical cancer cells (HeLa), while histamine shows the opposite effects. After that, the xenograft model was established to explore the antitumor effects of apigenin in vivo, the results show that apigenin inhibited cervical tumor growth by reversing the abnormal ER signal in tumor tissue which was caused by histamine. We also demonstrate that apigenin inhibited cell proliferation via suppressing the PI3K/Akt/mTOR signaling pathway. Collectively, our results suggest that apigenin may inhibit tumor growth through the ER-mediated PI3K/Akt/mTOR pathway and that it can also attenuate the effects of histamine on tumors.

scholarly journals The vitamin K–dependent anticoagulant factor, protein S, inhibits multiple VEGF-A–induced angiogenesis events in a Mer- and SHP2-dependent manner

Blood ◽  
2012 ◽  
Vol 120 (25) ◽  
pp. 5073-5083 ◽  
Author(s):  
Sylvain Fraineau ◽  
Arnaud Monvoisin ◽  
Jonathan Clarhaut ◽  
Julie Talbot ◽  
Claire Simonneau ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Vitamin K ◽  
Tyrosine Phosphatase ◽  
Angiogenesis Inhibitor ◽  
Protein S ◽  
Vegf Receptor ◽  
Dependent Manner ◽  
Anticoagulant Function

Abstract Protein S is a vitamin K–dependent glycoprotein, which, besides its anticoagulant function, acts as an agonist for the tyrosine kinase receptors Tyro3, Axl, and Mer. The endothelium expresses Tyro3, Axl, and Mer and produces protein S. The interaction of protein S with endothelial cells and particularly its effects on angiogenesis have not yet been analyzed. Here we show that human protein S, at circulating concentrations, inhibited vascular endothelial growth factor (VEGF) receptor 2–dependent vascularization of Matrigel plugs in vivo and the capacity of endothelial cells to form capillary-like networks in vitro as well as VEGF-A–induced endothelial migration and proliferation. Furthermore, protein S inhibited VEGF-A–induced endothelial VEGFR2 phosphorylation and activation of mitogen-activated kinase-Erk1/2 and Akt. Protein S activated the tyrosine phosphatase SHP2, and the SHP2 inhibitor NSC 87877 reversed the observed inhibition of VEGF-A–induced endothelial proliferation. Using siRNA directed against Tyro3, Axl, and Mer, we demonstrate that protein S-mediated SHP2 activation and inhibition of VEGF-A–stimulated proliferation were mediated by Mer. Our report provides the first evidence for the existence of a protein S/Mer/SHP2 axis, which inhibits VEGFR2 signaling, regulates endothelial function, and points to a role for protein S as an endogenous angiogenesis inhibitor.

scholarly journals SCFβ-TRCP suppresses angiogenesis and thyroid cancer cell migration by promoting ubiquitination and destruction of VEGF receptor 2

2012 ◽  
Vol 209 (7) ◽  
pp. 1289-1307 ◽  
Author(s):  
Shavali Shaik ◽  
Carmelo Nucera ◽  
Hiroyuki Inuzuka ◽  
Daming Gao ◽  
Maija Garnaas ◽  
...  
Keyword(s):  
Cell Migration ◽  
Thyroid Cancer ◽  
Molecular Mechanisms ◽  
Kinase Inhibitors ◽  
Inverse Correlation ◽  
Endothelial Cell Proliferation ◽  
Vegf Receptor ◽  
Dependent Manner

The incidence of human papillary thyroid cancer (PTC) is increasing and an aggressive subtype of this disease is resistant to treatment with vascular endothelial growth factor receptor 2 (VEGFR2) inhibitor. VEGFR2 promotes angiogenesis by triggering endothelial cell proliferation and migration. However, the molecular mechanisms governing VEGFR2 stability in vivo remain unknown. Additionally, whether VEGFR2 influences PTC cell migration is not clear. We show that the ubiquitin E3 ligase SCFβ-TRCP promotes ubiquitination and destruction of VEGFR2 in a casein kinase I (CKI)–dependent manner. β-TRCP knockdown or CKI inhibition causes accumulation of VEGFR2, resulting in increased activity of signaling pathways downstream of VEGFR2. β-TRCP–depleted endothelial cells exhibit enhanced migration and angiogenesis in vitro. Furthermore, β-TRCP knockdown increased angiogenesis and vessel branching in zebrafish. Importantly, we found an inverse correlation between β-TRCP protein levels and angiogenesis in PTC. We also show that β-TRCP inhibits cell migration and decreases sensitivity to the VEGFR2 inhibitor sorafenib in poorly differentiated PTC cells. These results provide a new biomarker that may aid a rational use of tyrosine kinase inhibitors to treat refractory PTC.

Effect of caffeine on theophyliine on cerebral blood flow response to brain activation: In vitro and in vivo studies

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S198-S198
Author(s):  
Joseph R Meno ◽  
Thien-son K Nguyen ◽  
Elise M Jensen ◽  
G Alexander West ◽  
Leonid Groysman ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Activation ◽  
In Vivo Studies ◽  
Blood Flow Response ◽  
Flow Response
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