A new family of angiogenic factors

Clinical Potential of Adrenomedullin Signaling in the Cardiovascular System

Numerous clinical studies have revealed the utility of circulating AM (adrenomedullin) or MR-proAM (mid-regional proAM 45-92) as an effective prognostic and diagnostic biomarker for a variety of cardiovascular-related pathophysiologies. Thus, there is strong supporting evidence encouraging the exploration of the AM-CLR (calcitonin receptor-like receptor) signaling pathway as a therapeutic target. This is further bolstered because several drugs targeting the shared CGRP (calcitonin gene-related peptide)-CLR pathway are already Food and Drug Administration-approved and on the market for the treatment of migraine. In this review, we summarize the AM-CLR signaling pathway and its modulatory mechanisms and provide an overview of the current understanding of the physiological and pathological roles of AM-CLR signaling and the yet untapped potentials of AM as a biomarker or therapeutic target in cardiac and vascular diseases and provide an outlook on the recently emerged strategies that may provide further boost to the possible clinical applications of AM signaling.

SDF‑1α/CXCR4 signaling promotes capillary tube formation of human retinal vascular endothelial cells by activating ERK1/2 and PI3K pathways in vitro

The purpose of this study is to address the effect and mechanism of stromal cell‑derived factor‑1 (SDF‑1)α/chemokine (C‑X‑C motif) receptor 4 (CXCR4) signaling on capillary tube formation of human retinal vascular endothelial cells (HRECs). The expression of CXCR4 in HRECs was quantified by reverse transcription (RT‑PCR) and western blotting. The effects of SDF‑1α/CXCR4 signaling in capillary tube formation and migration of HRECs was examined using three‑dimensional Matrigel assay and wound scratching assay respectively in vitro. Cell proliferation of HRECs was examined using cell counting kit (CCK)‑8 assay in the presence of different concentrations of SDF‑1α protein. The effect of SDF‑1α/CXCR4 signaling in HREC expression of VEGF, basic fibroblast growth factor (bFGF), IL‑8 and intercellular cell adhesion molecule (ICAM)‑1 was examined using RT‑PCR and western blotting. RT‑PCR and western blot analysis revealed CXCR4 was expressed in HRECs. The number of intact capillary tubes formed by HRECs in the presence of SDF‑1α was markedly more compared with a PBS treated control group. However, it was reduced with treatment with an CXCR4 antagonist. Wound scratching assay showed a significant increase in the number of migrated HRECs under SDF‑1α stimulation and the number was reduced with treatment with an CXCR4 antagonist. RT‑PCR and western blotting showed that SDF‑1α significantly promoted VEGF, bFGF, IL‑8 and ICAM‑1 expression in HRECs. The proliferation of HRECs in the presence of SDF‑1α was promoted in a dosage‑dependent manner. SDF‑1α/CXCR4 signaling can increase HREC capillary tube formation through promoting HREC migration, proliferation and expression of VEGF, bFGF, IL‑8 and ICAM‑1.

Biological aspects in controlling angiogenesis: current progress

All living beings continue their life by receiving energy and by excreting waste products. In animals, the arteries are the pathways of these transfers to the cells. Angiogenesis, the formation of the arteries by the development of pre-existed parental blood vessels, is a phenomenon that occurs naturally during puberty due to certain physiological processes such as menstruation, wound healing, or the adaptation of athletes' bodies during exercise. Nonetheless, the same life-giving process also occurs frequently in some patients and, conversely, occurs slowly in some physiological problems, such as cancer and diabetes, so inhibiting angiogenesis has been considered to be one of the important strategies to fight these diseases. Accordingly, in tissue engineering and regenerative medicine, the highly controlled process of angiogenesis is very important in tissue repairing. Excessive angiogenesis can promote tumor progression and lack of enough angiogensis can hinder tissue repair. Thereby, both excessive and deficient angiogenesis can be problematic, this review article introduces and describes the types of factors involved in controlling angiogenesis. Considering all of the existing strategies, we will try to lay out the latest knowledge that deals with stimulating/inhibiting the angiogenesis. At the end of the article, owing to the early-reviewed mechanical aspects that overshadow angiogenesis, the strategies of angiogenesis in tissue engineering will be discussed.

Adrenomedullin: Not Just Another Gastrointestinal Peptide

Adrenomedullin (AM) and proadrenomedullin N-terminal 20 peptide (PAMP) are two bioactive peptides derived from the same precursor with several biological functions including vasodilation, angiogenesis, or anti-inflammation, among others. AM and PAMP are widely expressed throughout the gastrointestinal (GI) tract where they behave as GI hormones, regulating numerous physiological processes such as gastric emptying, gastric acid release, insulin secretion, bowel movements, or intestinal barrier function. Furthermore, it has been recently demonstrated that AM/PAMP have an impact on gut microbiome composition, inhibiting the growth of bacteria related with disease and increasing the number of beneficial bacteria such as Lactobacillus or Bifidobacterium. Due to their wide functions in the GI tract, AM and PAMP are involved in several digestive pathologies such as peptic ulcer, diabetes, colon cancer, or inflammatory bowel disease (IBD). AM is a key protective factor in IBD onset and development, as it regulates cytokine production in the intestinal mucosa, improves vascular and lymphatic regeneration and function and mucosal epithelial repair, and promotes a beneficial gut microbiome composition. AM and PAMP are relevant GI hormones that can be targeted to develop novel therapeutic agents for IBD, other GI disorders, or microbiome-related pathologies.

Helicobacter pylori-induced adrenomedullin modulates IFN-γ-producing T-cell responses and contributes to gastritis

Adrenomedullin (ADM) is a multifunctional peptide that is expressed by many surface epithelial cells, but its relevance to Helicobacter pylori (H. pylori)-induced gastritis is unknown. Here, we found that gastric ADM expression was elevated in gastric mucosa of H. pylori-infected patients and mice. In H. pylori-infected human gastric mucosa, ADM expression was positively correlated with the degree of gastritis; accordingly, blockade of ADM resulted in decreased inflammation within the gastric mucosa of H. pylori-infected mice. During H. pylori infection, ADM production was promoted via PI3K–AKT signaling pathway activation by gastric epithelial cells in a cagA-dependent manner, and resulted in increased inflammation within the gastric mucosa. This inflammation was characterized by the increased IFN-γ-producing T cells, whose differentiation was induced via the phosphorylation of AKT and STAT3 by ADM derived from gastric epithelial cells. ADM also induced macrophages to produce IL-12, which promoted the IFN-γ-producing T-cell responses, thereby contributing to the development of H. pylori-associated gastritis. Accordingly, blockade of IFN-γ or knockout of IFN-γ decreased inflammation within the gastric mucosa of H. pylori-infected mice. This study identifies a novel regulatory network involving H. pylori, gastric epithelial cells, ADM, macrophages, T cells, and IFN-γ, which collectively exert a pro-inflammatory effect within the gastric microenvironment.

B-cell leukemia/lymphoma 10 promotes angiogenesis in an experimental corneal neovascularization model

PURPOSE

Corneal neovascularization (CrNV) arises from many causes including corneal inflammatory, infectious, or traumatic insult, and frequently leads to impaired vision. This study seeks to determine the role of B-cell leukemia/lymphoma 10 (BCL-10) in the development of experimental CrNV.

METHODS

Corneas from BCL-10 knockout (KO) mice and wild-type (WT) mice were burned by sodium hydroxide (NaOH) to create the CrNV model and neovascular formation in the corneas was assessed 2 weeks later. Intracorneal macrophage accumulation and the expression of angiogenic factors were quantified by flow cytometric analysis (FCM) and real-time PCR, respectively.

RESULTS

The amount of CrNV was determined 2 weeks after alkali burn. Compared to WT mice, the amount of CrNV in BCL-10 KO mice was significantly decreased. FCM revealed that F4/80-positive macrophages were markedly decreased in BCL-10 KO mice compared with WT mice. Reverse transcription PCR showed that the mRNA expression levels of intracorneal vascular endothelial growth factor-A (VEGF-A), basic fibroblast growth factor (bFGF) and monocyte chemotactic protein 1 were reduced in BCL-10 KO mice compared with WT mice.

CONCLUSION

BCL-10 KO mice exhibited reduced alkali-induced CrNV by suppressing intracorneal macrophage infiltration, which subsequently led to decreased VEGF-A and bFGF expression, suggesting that BCL-10 may become a potential clinical intervening target of CrNV.

Nanoparticles designed to regulate tumor microenvironment for cancer therapy

Increasing understanding in tumor pathology reveals that tumor microenvironment (TME), which supports tumor progression and poses barriers for available therapies, takes a great responsibility in inefficient treatment and poor prognosis. In recent years, the versatile nanotechnology employed in TME regulation has made great progress. The nanoparticles (NPs) can be tailored as needed to accurately target TME components by distinguishing healthy tissues from malignancy, and to regulate TME to promote tumor regression. Meanwhile, the emerging microRNAs (miRNAs) demonstrate great potentials for TME regulation, but are regrettably restricted by quick degradation. NPs systems enable the successful delivery of miRNA to TME without the limitation, expanding the application of nucleic acid drug. In this review, we summarized recent NPs-based strategies aiming at regulating TME in different ways, including anti-angiogenesis, extracellular matrix (ECM) remodeling, tumor-associated fibroblasts (TAFs) treatment and tumor-associated macrophages (TAMs) treatment, along with the miRNAs-loaded NPs for TME regulation. Catching and utilizing the features of TME for NPs design can contribute to reversing drug-resistance, optimized drug distribution, and eventually more efficient cancer therapy.

Discovery of novel anti-angiogenesis agents. Part 8: Diaryl thiourea bearing 1H-indazole-3-amine as multi-target RTKs inhibitors

VEGFR-2, TIE-2, and EphB4 are essential for both angiogenesis and tumorigenesis. Herein, we designed and prepared three classes of multi-target inhibitors based on the extensive sequence homology along the kinase domain of angiogenic RTKs. Biological evaluation indicated that these multi-target inhibitors exhibited considerable potential as novel anti-angiogeneic and anticancer agents. Among them, a diaryl thiourea bearing 1H-indazole-3-amine (16a) displayed the most potent RTK inhibition and excellent selectivity. It also showed inhibition on viability of human umbilical vein endothelial cells and anti-proliferation against a broad spectrum of cancer cells. Therefore, 1H-indazole-3-amine could serve as a promising hinge binding group for multi-target inhibitors of VEGFR-2, Tie-2, and EphB4.

Effects of interleukin-17 on human retinal vascular endothelial cell capillary tube formation in vitro

The present study aimed to investigate the effect of and mechanism underlying interleukin (IL)‑17 on human retinal vascular endothelial cell (HREC) capillary tube formation in vitro. The expression of IL‑17 receptor (IL‑17R) in human HRECs was quantified using reverse transcriptase‑polymerase chain reaction (RT‑PCR) and western blot analyses. The roles of IL‑17 in HREC migration and capillary tube formation were detected using a wound scratching assay and three‑dimensional Matrigel assay, respectively, in vitro. HREC proliferation was examined using a cell counting kit‑8 assay with administration of serial doses of IL‑17. The effects of IL‑17 on the expression of vascular endothelial growth factor (VEGF), intercellular cell adhesion molecule (ICAM)‑1, IL‑6 and IL‑8 in HRECs were evaluated using RT‑PCR and western blot analyses. The results revealed that the HRECs expressed IL‑17R, and the number of intact capillary tubes formed by HRECs in the presence of IL‑17 was markedly higher, compared with that in the blank control group. The wound scratching assay showed that the numbers of migrated HRECs stimulated with IL‑17 at concentrations of 100 or 500 ng/ml were significantly higher, compared with the number in the control group. The RT‑PCR and western blot analyses showed that IL‑17 significantly promoted the expression of VEGF, ICAM‑1, IL‑6 and IL‑8 by the HRECs. The proliferation of HRECs in the presence of IL‑17 was also significantly increased. Therefore, IL‑17 increased HREC capillary tube formation through promoting HREC migration, proliferation, and expression levels of VEGF, ICAM‑1, IL‑6 and IL-8.

Inhibitory effect of dexamethasone on residual Lewis lung cancer cells in mice following palliative surgery

Previous studies found that glucocorticoids were closely associated with the oncogenesis and development of numerous types of tumors. The aim of the present study was to investigate the effect of dexamethasone on the growth and angiogenesis of Lewis lung cancer cells in mice who received palliative surgery. Lewis lung carcinoma cells were inoculated subcutaneously into the right axilla of C57BL/6 mice. When tumor diameter reached 0.5 cm, 2 weeks later, palliative surgery was performed, and the mice were randomly divided into 3 groups with 6 animals in each group (control group, cisplatin group and dexamethasone group). From the first postoperative day, all the mice were administered with saline, cisplatin or dexamethasone for 10 days, and changes in xenograft tumor volumes were monitored. Cisplatin and dexamethasone were dissolved in normal saline (0.9%). All mice were sacrificed on postoperative day 11, and the whole body and the local tumors were weighed immediately. The expression levels of hypoxia inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF), proliferating cell nuclear antigen and the microvessel density (MVD) in the tumor mass, were measured by immunohistochemistry, western blotting and quantitative polymerase chain reaction. In the present study, tumor growth was inhibited in the cisplatin group and dexamethasone group, and the weights of tumors were significantly decreased in the cisplatin group and dexamethasone group compared with the control group (P<0.001). The expression levels of HIF-1α and VEGF and the MVD were significantly lower in the cisplatin group and dexamethasone group than in the control group (P<0.01). In conclusion, dexamethasone can inhibit the growth and angiogenesis of residual Lewis lung carcinoma subsequent to palliative surgery partially through downregulation of HIF-1α and VEGF signaling pathways.

Adrenomedullin regulates intestinal physiology and pathophysiology

Adrenomedullin (AM) and proadrenomedullin N-terminal 20 peptide (PAMP) are 2 biologically active peptides produced by the same gene, ADM, with ubiquitous distribution and many physiological functions. Adrenomedullin is composed of 52 amino acids, has an internal molecular ring composed by 6 amino acids and a disulfide bond, and shares structural similarities with calcitonin gene-related peptide, amylin, and intermedin. The AM receptor consists of a 7-transmembrane domain protein called calcitonin receptor-like receptor in combination with a single transmembrane domain protein known as receptor activity-modifying protein. Using morphologic techniques, it has been shown that AM and PAMP are expressed throughout the gastrointestinal tract, being specially abundant in the neuroendocrine cells of the gastrointestinal mucosa; in the enterochromaffin-like and chief cells of the gastric fundus; and in the submucosa of the duodenum, ileum, and colon. This wide distribution in the gastrointestinal tract suggests that AM and PAMP may act as gut hormones regulating many physiological and pathologic conditions. To date, it has been proven that AM and PAMP act as autocrine/paracrine growth factors in the gastrointestinal epithelium, play key roles in the protection of gastric mucosa from various kinds of injury, and accelerate healing in diseases such as gastric ulcer and inflammatory bowel diseases. In addition, both peptides are potent inhibitors of gastric acid secretion and gastric emptying; they regulate the active transport of sugars in the intestine, regulate water and ion transport in the colon, modulate colonic bowel movements and small-intestine motility, improve endothelial barrier function, and stabilize circulatory function during gastrointestinal inflammation. Furthermore, AM and PAMP are antimicrobial peptides, and they contribute to the mucosal host defense system by regulating gut microbiota. To get a formal demonstration of the effects that endogenous AM and PAMP may have in gut microbiota, we developed an inducible knockout of the ADM gene. Using this model, we have shown, for the first time, that lack of AM/PAMP leads to changes in gut microbiota composition in mice. Further studies are needed to investigate whether this lack of AM/PAMP may have an impact in the development and/or progression of intestinal diseases through their effect on microbiota composition.

Bench-to-bedside pharmacology of adrenomedullin

The bioactive peptide adrenomedullin (AM) exerts pleiotropic actions in various organs and tissues. In the heart, AM has an inhibitory effect on ventricular remodeling, suppressing cardiomyocyte hypertrophy and the proliferation of cardiac fibroblasts. This pharmacological property was shown not only in rat models of acute myocardial infarction, but also clinically in patients with this cardiac disease. An originally characterized feature of AM was a potent vasodilatory effect, but this peptide was found to be important for vascular integrity and angiogenesis. AM-induced angiogenesis is involved in tumor growth, while AM inhibits apoptosis of some types of tumor cell. A unique pharmacological property is anti-inflammatory activity, which has been characterized in sepsis and inflammatory bowel diseases; thus, there is an ongoing clinical trial to test the efficacy of AM for patients with intractable ulcerative colitis. These activities are assumed to be mediated via the specific receptor formed by calcitonin receptor-like receptor and receptor activity-modifying protein 2 or 3, while some questions remain to be answered about the molecular mechanisms of this signal transduction system. Taking these findings together, AM is a bioactive peptide with pleiotropic effects, with potential as a therapeutic tool for a wide range of human diseases from myocardial infarction to malignant tumors or inflammatory bowel diseases.

A polysaccharide from mushroom Huaier retards human hepatocellular carcinoma growth, angiogenesis, and metastasis in nude mice

Mushroom Huaier has become a focus of interest in the treatment of hepatocellular carcinoma (HCC). Presently, we isolated and purified one polysaccharide from this mushroom. This study aimed to investigate the effects of SP1 on tumor growth and metastasis in a HCC xenograft model and explore its possible mechanism of action. Our results showed that SP1 not only significantly inhibited the proliferation of SMMC-7721 cells in vitro at the concentration ranging from 0 to 800 μg/ml but also suppressed the HCC tumor growth and metastatic nodules to the lung in SMMC-7721-bearing mice by oral administration at three doses of 30, 60, and 120 mg/kg. Concomitantly, immunohistochemistry analysis of tumor tissues identified that SP1 administration at three doses significantly inhibited the in vivo cancer cell proliferation and microvessel density (MVD) formation, evidenced by a low proliferating cell nuclear antigen (PCNA) and CD34 expression, but increased the percentage of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells. Keeping in line with this observation, SP1 treatment decreased serum matrix metalloproteinase (MMP) 2 and vascular endothelial growth factor (VEGF) levels, downregulated the protein expression of hypoxia-inducible factor (HIF)-1alpha, VEGF, MMP2, bcl-2, N-cadherin, signal transducer and activator of transcription 3 (STAT3), and metadherin (MTDH), and upregulated bax and NE-cadherin protein expression in tumor tissues. Taken together, our data suggest that SP1 appears to be a promising chemopreventive agent for the tumorigenesis and metastasis in patients with HCC, especially at advanced stages.

Adrenomedullin and tumour microenvironment

Adrenomedullin (AM) is a regulatory peptide whose involvement in tumour progression is becoming more relevant with recent studies. AM is produced and secreted by the tumour cells but also by numerous stromal cells including macrophages, mast cells, endothelial cells, and vascular smooth muscle cells. Most cancer patients present high levels of circulating AM and in some cases these higher levels correlate with a worst prognosis. In some cases it has been shown that the high AM levels return to normal following surgical removal of the tumour, thus indicating the tumour as the source of this excessive production of AM. Expression of this peptide is a good investment for the tumour cell since AM acts as an autocrine/paracrine growth factor, prevents apoptosis-mediated cell death, increases tumour cell motility and metastasis, induces angiogenesis, and blocks immunosurveillance by inhibiting the immune system. In addition, AM expression gets rapidly activated by hypoxia through a HIF-1α mediated mechanism, thus characterizing AM as a major survival factor for tumour cells. Accordingly, a number of studies have shown that inhibition of this peptide or its receptors results in a significant reduction in tumour progression. In conclusion, AM is a great target for drug development and new drugs interfering with this system are being developed.

Autophagy mediates paracrine regulation of vascular endothelial cells

Gastrin-releasing peptide (GRP) is a proangiogenic ligand secreted by tumors and acts directly upon binding to GRP receptor in endothelial cells. Angiogenesis plays a critical role in the pathology of various diseases, including cancer, as the formation of new blood vessels potentiates the rate of tumor growth and dissemination. GRP increases the migration of endothelial cells, but much is unknown about its role on endothelial cell proliferation and survival, as well as the signaling pathways involved. In the present study, we showed that GRP increases endothelial cell proliferation and tubule formation. There was a time-dependent increase in the levels of phosphorylated AKT, mammalian target of rapamycin (mTOR), and S6R in human umbilical vein endothelial cells treated with GRP. Interestingly, GRP treatment decreased the expression of proautophagic factors, ATG5, BECN1, and LC3 proteins. GRP also attenuated rapamycin-induced formation of autophagosomes. Moreover, overexpression of ATG5 or BECN1 significantly decreased tubule formation induced by exogenous GRP, whereas siRNA against ATG5 or BECN1 resulted in increased tubule formation with GRP treatment. Our results show that GRP inhibits the process of autophagy in vascular endothelial cells, thereby increasing endothelial cell proliferation and tubule formation. Here, we describe a novel role of GRP in the regulation of autophagy of endothelial cells, thereby providing a potential new therapeutic strategy in targeting angiogenesis during cancer progression.

Common polymorphisms in angiogenesis

A wide variety of diseases have a significant genetic component, including major causes of morbidity and mortality in the western world. Many of these diseases are also angiogenesis dependent. In humans, common polymorphisms, although more subtle in effect than rare mutations that cause Mendelian disease, are expected to have greater overall effects on human disease. Thus, common polymorphisms in angiogenesis-regulating genes may affect the response to an angiogenic stimulus and thereby affect susceptibility to or progression of such diseases. Candidate gene studies have identified several associations between angiogenesis gene polymorphisms and disease. Similarly, emerging pharmacogenomic evidence indicates that several angiogenesis-regulating polymorphisms may predict response to therapy. In contrast, genome-wide association studies have identified only a few risk alleles in obvious angiogenesis genes. As in other traits, regulatory polymorphisms appear to dominate the landscape of angiogenic responsiveness. Rodent assays, including the mouse corneal micropocket assay, tumor models, and a macular degeneration model have allowed the identification and comparison of loci that directly affect the trait. Complementarity between human and animal approaches will allow increased understanding of the genetic basis for angiogenesis-dependent disease.

Total Saponin from Root of Actinidia valvata Dunn Inhibits Hepatoma 22 Growth and Metastasis In Vivo by Suppression Angiogenesis

The root of Actinidia valvata dunn has been widely used in the treatment of hepatocellular carcinoma (HCC), proved to be beneficial for a longer and better life in China. In present work, total saponin from root of Actinidia valvata Dunn (TSAVD) was extracted, and its effects on hepatoma H22-based mouse in vivo were observed. Primarily transplanted hypodermal hepatoma H22-based mice were used to observe TSAVD effect on tumor growth. The microvessel density (MVD), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) are characterized factors of angiogenesis, which were compared between TSAVD-treated and control groups. Antimetastasis effect on experimental pulmonary metastasis hepatoma mice was also observed in the study. The results demonstrated that TSAVD can effectively inhibit HCC growth and metastasis in vivo, inhibit the formation of microvessel, downregulate expressions of VEGF and bFGF, and retrain angiogenesis of hepatoma 22 which could be one of the reasons.

Inhibition of tumor-induced angiogenesis and its mechanism by ardipusilloside I purified from Ardisia pusilla

The aim of this study was to evaluate the effects of ardipusilloside I isolated from Ardisia pusilla on tumor angiogenesis and its mechanism of action. The anti-angiogenic effect in vivo was evaluated on xenograft in the athymic mice model and the chicken chorioallantoic membrane (CAM) neovascularization model, the inhibition of growth in vitro was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and the mechanism was demonstrated through detecting microvessel density (MVD), vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2) and P-VEGFR2 protein expressions, as well as mRNA expressions of VEGF and VEGFR2. The results showed that ardipusilloside I had a good inhibitory effect on A549 xenografted tumor growth, angiogenesis of CAM, and A549 cell growth. Compared to the negative control, MVD protein and mRNA expressions of VEGF and VEGFR were significantly inhibited by ardipusilloside I in a dose-dependent manner. These findings suggested that ardipusilloside I might be a promising candidate as angiogenesis inhibitors.

Dynamic changes of vascular endothelial growth factor and angiopoietin-1 in association with circulating endothelial progenitor cells after severe traumatic brain injury

BACKGROUND

Vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1) can promote angiogenesis and vascular stability after brain injury. Circulating endothelial progenitor cells (EPCs) also play a crucial role in neovascularization and tissue repair after traumatic brain injury (TBI). We sought to compare the expression of VEGF and Ang-1 in serum and the circulating EPCs in patients after severe TBI with that of healthy control subjects.

METHODS

We obtained peripheral blood and serum samples from 21 patients with severe TBI and 11 healthy control subjects. EPCs in blood samples from severe TBI patients and healthy controls were quantified by flow cytometry 1 day, 4 days, 7 days, 14 days, and 21 days after severe TBI. VEGF and Ang-1 were measured by enzyme linked immunosorbent assay at the same time points.

RESULTS

Compared with control subjects, circulating EPCs in patients with severe TBI decreased 4 days (p < 0.05), but increased 7 days and 14 days (p < 0.05) after TBI. VEGF increased significantly during the follow-up period (p < 0.05). Ang-1 increased gradually and reached peak at 7 days and 14 days after TBI. The circulating EPCs were significantly correlated with VEGF and Ang-1 at 7 days and 14 days after severe TBI.

CONCLUSIONS

Our results suggest that the increased VEGF and Ang-1 are closely related to increase in circulating EPCs in response to severe TBI, which may be needed for vascular repairs after severe TBI.

Anti-angiogenic genistein inhibits VEGF-induced endothelial cell activation by decreasing PTK activity and MAPK activation

Genistein (Gen), a soy isoflavone, is considered to exert potent antitumor effect partially through its anti-angiogenesis property. However, the precise molecular mechanism is still unknown. Our previous investigations have demonstrated that genistein down-regulates expression of pro-angiogenic factors via inhibiting protein tyrosine kinase (PTK) activity both in breast cancer cells and in xenograft tumors. In the present experiment, we chose cultured human umbilical vein endothelial cells (HUVECs), which have a considerable role in tumor angiogenesis formation, to explore the influence of genistein on VEGF-stimulated endothelial cell activation and the underlying mechanism. Stimulation of human primary HUVECs by VEGF not only increased endothelial cell protein tyrosine kinase (PTK) activity but also augmented matrix metalloproteinase-2 (MMP-2), -9 secretions and increased MMP-2, -9 activities. Treatment of ECs with genistein induced VEGF-loaded endothelial apoptosis by inhibiting production and activity of matrix metalloproteinases (MMPs). In addition, exposure to genistein decreased activation of JNK and p38, not ERK-1/2, induced by VEGF. Collectively, our findings suggested that the inhibition of PTK activity and MAPK activation and the decrease in MMPs production and activity by genistein interrupt VEGF-stimulated endothelial cell activation, which thereby may represent a mechanism that would explain the anti-angiogenesis effect of genistein and its cancer-protective function.

Suppression of tumor growth by palm tocotrienols via the attenuation of angiogenesis

Previous studies have revealed that tocotrienol-rich fractions (TRF) from palm oil inhibit the proliferation and the growth of solid tumors. The anticancer activity of TRF is said to be caused by several mechanisms, one of which is antiangiogenesis. In this study, we looked at the antiangiogenic effects of TRF. In vitro investigations of the antiangiogenic activities of TRF, delta-tocotrienol (deltaT3), and alpha-tocopherol (alphaToc) were carried out in human umbilical vein endothelial cells (HUVEC). TRF and deltaT3 significantly inhibited cell proliferation from 4 microg/ml onward (P < 0.05). Cell migration was inhibited the most by deltaT3 at 12 microg/ml. Anti-angiogenic properties of TRF were carried out further in vivo using the chick embryo chorioallantoic membrane (CAM) assay and BALB/c mice model. TRF at 200 microg/ml reduced the vascular network on CAM. TRF treatment of 1 mg/mouse significantly reduced 4T1 tumor volume in BALB/c mice. TRF significantly reduced serum vascular endothelial growth factor (VEGF) level in BALB/c mice. In conclusion, this study showed that palm tocotrienols exhibit anti-angiogenic properties that may assist in tumor regression.

Polymorphisms and clinical outcome in recurrent ovarian cancer treated with cyclophosphamide and bevacizumab

PURPOSE

This study was designed to evaluate the associations between angiogenesis gene polymorphisms and clinical outcome in ovarian cancer patients treated with low-dose cyclophosphamide and bevacizumab.

EXPERIMENTAL DESIGN

Seventy recurrent/metastatic epithelial ovarian cancer patients were enrolled in a phase II clinical trial. Genomic DNA was available from 53 blood samples. Polymorphisms were analyzed using the PCR-RFLP protocol. A 5' end 33P gammaATP-labeled PCR protocol was used to analyze dinucleotide repeats.

RESULTS

Patients genotyped A/A or A/T for the IL-8 T-251A gene polymorphism had a statistically significant lower response rate (19%; 0%) than those homozygous T/T (50%; P = 0.006, Fisher's exact test). Patients carrying a minimum one C allele (C/C; C/T) of the CXCR2 C+785T polymorphism showed a median progression-free survival (PFS) of 7.4 months compared with the PFS of 3.7 months for those homozygous T/T (P = 0.026, log-rank test). Patients with the VEGF C+936T polymorphism C/T genotype had a longer median PFS of 11.8 months, compared with those with the C/C and T/T genotype, which had median PFS of 5.5 months and 3.2 months, respectively (P = 0.061, log-rank test). Patients carrying both AM 3'end alleles < 14 CA repeats had the shortest median PFS of 3.4 months; patients with at least one allele > 14 repeats or both alleles > 14 repeats showed a median PFS of 6.4 months and 7.2 months, respectively (P = 0.008, log-rank test).

CONCLUSION

Our data suggest that the IL-8 A-251T polymorphism may be a molecular predictor of response to bevacizumab-based chemotherapy. The CXCR2 C+785T, VEGF C+936T single nucleotide polymorphisms and the AM 3' dinucleotide repeat polymorphisms may be molecular markers for PFS in ovarian cancer patients.

International Union of Pharmacology. LXVIII. Mammalian bombesin receptors: nomenclature, distribution, pharmacology, signaling, and functions in normal and disease states

The mammalian bombesin receptor family comprises three G protein-coupled heptahelical receptors: the neuromedin B (NMB) receptor (BB(1)), the gastrin-releasing peptide (GRP) receptor (BB(2)), and the orphan receptor bombesin receptor subtype 3 (BRS-3) (BB(3)). Each receptor is widely distributed, especially in the gastrointestinal (GI) tract and central nervous system (CNS), and the receptors have a large range of effects in both normal physiology and pathophysiological conditions. The mammalian bombesin peptides, GRP and NMB, demonstrate a broad spectrum of pharmacological/biological responses. GRP stimulates smooth muscle contraction and GI motility, release of numerous GI hormones/neurotransmitters, and secretion and/or hormone release from the pancreas, stomach, colon, and numerous endocrine organs and has potent effects on immune cells, potent growth effects on both normal tissues and tumors, potent CNS effects, including regulation of circadian rhythm, thermoregulation; anxiety/fear responses, food intake, and numerous CNS effects on the GI tract as well as the spinal transmission of chronic pruritus. NMB causes contraction of smooth muscle, has growth effects in various tissues, has CNS effects, including effects on feeding and thermoregulation, regulates thyroid-stimulating hormone release, stimulates various CNS neurons, has behavioral effects, and has effects on spinal sensory transmission. GRP, and to a lesser extent NMB, affects growth and/or differentiation of various human tumors, including colon, prostate, lung, and some gynecologic cancers. Knockout studies show that BB(3) has important effects in energy balance, glucose homeostasis, control of body weight, lung development and response to injury, tumor growth, and perhaps GI motility. This review summarizes advances in our understanding of the biology/pharmacology of these receptors, including their classification, structure, pharmacology, physiology, and role in pathophysiological conditions.

Adrenomedullin is increased by pulsatile shear stress on the vascular endothelium via periodic acceleration (pGz)

Periodic acceleration (pGz) is produced by a platform which moves the supine body repetitively in a headward to footward direction. The imparted motion produces pulsatile shear stress on the vascular endothelium. Pulsatile shear stress on the vascular endothelium has been shown to elicit production of a host of cardioprotective, cytoprotective mediators. The purpose of this study was to ascertain if pGz also enhances production of adrenomedullin (AM) in normal healthy swine. Twelve pigs (weight range 20-30 kg) were anesthetized, intubated and placed on conventional mechanical ventilation. All animals were secured to the motion platform. In one group (pGz) (n=7) was activated for 1h, and monitored for an additional 3h. A control group (CONT) (n=5) served as time control. Arterial blood gases, hemodynamic measurements, and serum for AM, interleukin 4, 6 and thromboxane B(2) (TBXB2) were measured at baseline, immediately after pGz, and 3h after pGz had been discontinued. There was no significant change from baseline value in IL-4, IL-6 or TBXB2. Mean arterial blood pressure decreased in pGz-treated animals from 115+/-10 at baseline to 90+/-8 after 60 min of pGz (p<0.01). AM levels increase from 776+/-176 pg/ml baseline to 1160+/-68 pg/ml immediately after pGz, and remained elevated to 1584+/-160 pg/ml, 3h after pGz (p<0.01 vs. BL). This is the first report of AM-enhanced production using a non-invasive method of increasing pulsatile shear stress on the vascular endothelium. pGz increases production of AM in normal healthy swine. These changes are independent of IL-4, IL-6 or TBXB2 production.

Neovascularization following traumatic brain injury: possible evidence for both angiogenesis and vasculogenesis

OBJECTIVE

Our goal was to characterize the angiogenic response following traumatic brain injury (TBI).

METHODS

Western analysis for vascular endothelial growth factor (VEGF) expression, double immunofluorescence labeling of endothelium and vascular endothelial growth factor receptor 2 (VEGFR2), bromodioxyuridine (BrdU) incorporation and measurement of capillary density, were all used to determine the temporal angiogenic response following TBI.

RESULTS

The angiogenic factors, VEGF and VEGFR2, increase following trauma. Capillary density increases and BrdU incorporation confirm the presence of newly formed vessels up to 48 hours post-injury.

DISCUSSION

Our results indicated that following TBI, there is a substantial increase in angiogenesis and based on morphologic characterization of BrdU-positive nuclei within the endothelium, we provide evidence for vasculogenesis following injury.