Insulin-like growth factor binding protein-7 (IGFBP7) blocks vascular endothelial cell growth factor (VEGF)-induced angiogenesis in human vascular endothelial cells

Insulin-like growth factor binding protein-7 (IGFBP7) and vascular endothelial growth factor (VEGF) are expressed in vascular endothelial cells in several tumor types. In this study, we examined the effect of IGFBP7 on VEGF-induced tube formation in cultured human umbilical vein endothelial cells (HUVECs) and its potential action in the modulation of VEGF signaling in vascular cells. IGFBP7 treatment suppressed VEGF-induced tube formation, proliferation, and the phosphorylation of mitogen-activated protein kinase kinase (MEK) and extracellular signal-regulated kinase (ERK) 1/2 in HUVECs. IGFBP7 attenuated VEGF-enhanced cyclooxygenase (COX)-2 and VEGF mRNA expression, and prostaglandin E₂ secretion. Knocking down endogenous IGFBP7 enhanced COX-2 and VEGF mRNA expression. A significant increase in IGFBP7-induced caspases was not observed in the presence of VEGF. These findings indicate that IGFBP7 can modulate the stimulatory effect of VEGF on angiogenesis by interfering with VEGF expression as well as VEGF signaling and not by inducing apoptosis.     

Relationship between prostaglandin E2 and vascular endothelial growth factor (VEGF) in angiogenesis in human vascular endothelial cells

To address the role of prostaglandin E2 (PGE2) in tube formation of endothelial cells and the relationships between the action of PGE2 and vascular endothelial growth factor (VEGF), cultured human umbilical vein endothelial cells (HUVECs) were used to evaluate tube formation on Matrigel and the expression of angiogenesis-related genes. PGE2 treatment stimulated the tube-like formation of HUVECs. Whereas VEGF-induced tube formation was significantly suppressed by ETYA, an inhibitor of arachidonic acid metabolism, or SU5614, an inhibitor of VEGF-receptor tyrosine kinase, the stimulatory effect of PGE2 was observed in the presence of ETYA or SU5614. Thus, PGE2 counteracted both ETYA- and SU5614-induced blockage of angiogenesis in the presence of VEGF. VEGF induced cyclooxygenase (COX) -2 mRNA expression in HUVECs and increased the PGE2 concentration in the medium. PGE2 treatment enhanced the expression of VEGF mRNA. These findings suggest that PGE2 directly stimulates angiogenesis, apart from VEGF signaling, and further induces VEGF expression in HUVECs. In addition, the effect of VEGF on angiogenesis may be mediated, in part, by PGE2 secretion.     

雷公藤内酯抑制内皮细胞血管内皮生长因子表达与合成

目的:研究雷公藤内酯对血管内皮细胞生长因子(VEGF)mRNA表达及VEGF合成与分泌的影响,进一步探讨雷公藤内酯降低肾小球肾炎患者尿蛋白的作用机制。方法:以人内皮细胞系ECV-304为研究对象,利用半定量逆转录聚合酶链反应(RT-PCR),流式细胞仪,酶联免疫吸附法(ELISA)检测不同剂量雷公藤内酯对佛波脂(TPA)诱导的内皮细胞VEGFmRNA表达及VEGF合成与分泌的影响,用RT-PCR检测雷公藤内酯对内皮细胞c-fos/c-jun mRNA表达的影响。结果:TPA能够明显上调VEGF mRNA表达,蛋白合成与分泌。而雷公藤内酯可以抑制TPA诱导的内皮细胞VEGF mRNA表达及VEGF蛋白合成与分泌,该作用在10μg·L~(-1)时更为明显。同样,雷公藤内酯剂量依赖性地抑制TPA诱导的内皮细胞c-fos/c-jun mRNA的表达。结论:雷公藤内酯通过影响c-fos/c-jun基因转录而抑制内皮细胞VEGFmRNA表达及VEGF合成与分泌是雷公藤内酯降低肾小球肾炎患者尿蛋白的作用机制之一。     

The effects of cadmium on VEGF-mediated angiogenesis in HUVECs

Cadmium (Cd) is a highly toxic element that causes morphologic alterations and dysfunction in blood vessels. The altered vascular function caused by cadmium has been implicated in a range of chronic diseases, including hypertension. The effects of cadmium are a multisystem phenomenon involving inflammation, hypertrophy, apoptosis, angiogenesis and important processes involved in vascular remodeling systems. Vascular endothelial growth factor (VEGF) plays a major role in cell growth and angiogenesis under pathologic conditions. VEGF secretion is related to anti-apoptosis protein expression and attenuates apoptosis in endothelial cells. This study examined the VEGF-dependent mechanisms of angiogenesis and apoptosis in cadmium-treated endothelial cells (HUVECs). The effects and mechanisms of cadmium in endothelial cells (HUVECs) were examined by exposing the cells to different doses of cadmium chloride (2.5-40 μ m). After the cadmium treatment, the angiogenesis and apoptosis mechanisms related to VEGF in cadmium-treated HUVECs were examined. As a result, the low concentration of cadmium increased the tube formation in HUVECs. In addition, cadmium at concentrations of 5 and 10 μ m increased VEGF secretion and VEGFR2 activity, which suggest that cadmium affects the growth of blood vessels. All three MAPK pathways, namely ERK, JNK and p38, were activated by cadmium in HUVECs. However, high concentrations of cadmium caused cell damage, disrupted tube formation and inhibited VEGF expression and the activities of VEGFR2 and MAPK in HUVECs. Cadmium has dual functions through VEGF-dependent mechanisms in a dose-dependent manner. In this study, the dual effects of cadmium might alter angiogenesis and induce apoptosis through VEGF pathways in HUVECs.     

卡立泊来德对K562细胞诱导的血管生成的影响

目的研究卡立泊来德(cariporide)处理对K562细胞诱导的血管生成能力的影响。方法应用MTT检测K562细胞上清液对脐静脉内皮细胞增殖能力的影响;transwell检测K562细胞上清液对脐静脉内皮细胞迁移能力的影响;基质胶血管形成法检测K562细胞上清液对脐静脉内皮细胞体外血管形成能力的影响;激光扫描共聚焦显微镜测定K562细胞的细胞内的pH;酶联免疫吸附实验(ELISA)检测K562细胞上清中血管内皮生长因子的表达水平。结果cariporide处理可以明显降低K562细胞上清液对脐静脉内皮细胞增殖,迁移和体外成管能力的诱导;cariporide处理后K562细胞的细胞内pH明显下降,分泌VEGF能力也受到抑制。结论 cariporide能抑制K562细胞的血管生成诱导能力,这种抑制是通过细胞内pH下降以及VEGF分泌减少引起的。     

Daphnetin inhibits TNF‐α and VEGF‐induced angiogenesis through inhibition of the IKKs/IκBα/NF‐κB,Src/FAK/ERK1/2 and Akt signalling pathways

Coumarins, identified as plant secondary metabolites possess diverse biological activities including anti‐angiogenic properties. Daphnetin (DAP), a plant derived dihydroxylated derivative of coumarin has shown significant pharmacological properties such as anticancer, anti‐arthritic and anti‐inflammatory. The present study was performed to investigate the anti‐angiogenic potential of DAP, focusing on the mechanism of action. The in vivo anti‐angiogenic potential of DAP was evaluated by vascular endothelial growth factor (VEGF)‐induced rat aortic ring (RAR) assay and chick chorioallantoic membrane (CAM) assay. For in vitro evaluation, wounding migration, transwell invasion, tube formation and apoptosis assays were performed on VEGF (8 ng/mL)‐induced human umbilical vein endothelial cells (HUVECs). The cellular mechanism of DAP was examined on TNFα (10 ng/mL) and VEGF‐induced HUVECs by extracting the mRNA and protein levels using RT‐qPCR and western blotting. Our data demonstrated that DAP inhibited the in vivo angiogenesis in the RAR and CAM assay. DAP also inhibited the different steps of angiogenesis, such as migration, invasion, and tube formation in HUVECs. DAP inhibited nuclear factor‐κB signalling together including TNF‐α induced IκBα degradation; phosphorylation of IκB kinase (IKKα/β) and translocation of the NF‐κB‐p65 protein. Furthermore, western blotting revealed that DAP significantly down‐regulated the VEGF‐induced signalling such as c‐Src, FAK, ERK1/2 and the related phosphorylation of protein kinase B (Akt) and VEGFR2 expressions. DAP reduced the elevated mRNA expression of iNOS, MMP2 and also, induced apoptosis in VEGF‐stimulated HUVECs by the caspase‐3 dependent pathway. Taken together, this study reveals that DAP may have novel prospective as a new multi‐targeted medication for the anti‐angiogenesis and cancer therapy.     

Porphyromonas gingivalis, Periodontal pathogen, lipopolysaccharide induces angiogenesisvia extracellular signal-regulated kinase 1/2 activation in human vascular endothelial cells

Porphyromonas gingivalis is a major periodontal pathogen. The lipopolysaccharide (LPS) secreted from P. gingivalis is implicated in the initiation and progression of periodontitis. Aberrant angiogenesis is often associated with lesion formation in chronic periodontitis. In this study, we report that P. gingivalis LPS activates angiogenic cascade, migration, invasion and tube formation in human umbilical vein endothelial cells (HUVECs). Furthermore, P. gingivalis LPS potently stimulated in vivo neovascularization in chick chorioallantoic membrane (CAM) and the mouse Matrigel plug assay. P. gingivalis LPS had no effect on the expression of vascular endothelial growth factor (VEGF) or its receptor, Flk-1, implying that P. gingivalis LPS-induced angiogenesis may result from its direct action on endothelial cells. P. gingivalis LPS evoked activation of the mitogen-activated protein kinase ERK1/2 in HUVECs, which is closely linked to angiogenesis. Taken together, these results strongly suggest P. gingivalis LPS plays an important role in the pathological angiogenesis for periodontal diseases, such as periodontitis.     

Proteomic characterization of angiogenic endothelial cells stimulated with cancer cell-conditioned medium

To characterize the protein expression profiles and identify the molecules associated with tumor angiogenesis, the cellular proteins of human umbilical vein endothelial cells (HUVECs) in response to cancer cell-conditioned medium (CM) prepared from HT1080 human fibrosarcoma cells were analyzed using fluorescence-labeled 2D gel-based proteomics. Most differentially expressed proteins in HT1080-CM-stimulated cells were found to be downregulated (88%) rather than upregulated (12%) based on statistical analysis of protein spot signals. Additionally, we examined the effects of vascular endothelial cell growth factor (VEGF), a proangiogenic factor, on cellular protein expression. In contrast, most differentially expressed proteins were found to be upregulated (59%) rather than downregulated (41%) in VEGF-stimulated HUVECs. Comparative analyses of 29 and 35 protein species identified in CM-stimulated and VEGF-stimulated HUVECs, respectively, revealed the remarkable differences between these two stimulations. Only four proteins were differentially expressed by both treatments: annexin A2, enolase 1, and T-plastin (downregulated by CM but upregulated by VEGF), and RAN (downregulated by both CM and VEGF). These findings provide new information regarding the regulation of protein expression associated with tumor angiogenesis.     

VEGF与卵巢癌的研究进展

血管内皮生长因子（VEGF）及其受体在卵巢癌高表达,与卵巢癌的发生、发展、转移和预后等密切相关。VEGF受体不仅有酪氨酸激酶活性,而且可刺激血管内皮的分裂、增殖,促进肿瘤血管的生成,提高微血管的通透性,加快肿瘤细胞与血管内营养物质的交换,促进肿瘤的发生、发展。     

Prevention of FGF-2-induced angiogenesis by scopoletin, a coumarin compound isolated from Erycibe obtusifolia Benth, and its mechanism of action

Previous work in our laboratory has shown that scopoletin, one of the main bioactive constituents of Erycibe obtusifolia Benth stems, exerts anti-arthritic activity in vivo partly by preventing synovial angiogenesis. The present study was performed to further investigate the anti-angiogenic potential of scopoletin, focusing on the mechanisms of action in vitro. In the aortic ring sprouting assay, scopoletin (10, 30 and 100 μM) significantly inhibited the growth of endothelial sprouts in a concentration-dependent manner. As to human umbilical vein endothelial cells (HUVECs), scopoletin could inhibit their proliferation, migration and tubule formation induced by FGF-2, especially the proliferation. It also remarkably decreased the expression of VEGF at mRNA and protein levels, and the phosphorylations of IKKα and IκB but not Akt, as well as the degradation of IκB caused by FGF-2 in HUVECs. These findings suggest that scopoletin is substantially able to attenuate FGF-2-induced angiogenesis, and it might act by directly preventing the stimulation action of FGF-2 and by indirectly decreasing the production of VEGF. Scopoletin down-regulated the VEGF expression through NF-κB rather than PI-3K/Akt signaling pathway.     

Bradykinin promotes vascular endothelial growth factor expression and increases angiogenesis in human prostate cancer cells

Prostate cancer is the most commonly diagnosed malignancy in men and shows a tendency for metastasis to distant organs. Angiogenesis is required for metastasis. Bradykinin (BK) is an inflammatory mediator involved in tumor growth and metastasis, but its role in vascular endothelial growth factor (VEGF) expression and angiogenesis in human prostate cancer remains unknown. The aim of this study was to examine whether BK promotes prostate cancer angiogenesis via VEGF expression. We found that exogenous BK increased VEGF expression in prostate cancer cells and further promoted tube formation in endothelial progenitor cells and human umbilical vein endothelial cells. Pretreatment of prostate cancer with B2 receptor antagonist or small interfering RNA (siRNA) reduced BK-mediated VEGF production. The Akt and mammalian target of rapamycin (mTOR) pathways were activated after BK treatment, and BK-induced VEGF expression was abolished by the specific inhibitor and siRNA of the Akt and mTOR cascades. BK also promoted nuclear factor-κB (NF-κB) and activator protein 1 (AP-1) activity. Importantly, BK knockdown reduced VEGF expression and abolished prostate cancer cell conditional medium-mediated angiogenesis. Taken together, these results indicate that BK operates through the B2 receptor, Akt, and mTOR, which in turn activate NF-κB and AP-1, activating VEGF expression and contributing to angiogenesis in human prostate cancer cells.     

Prevention of FGF-2-induced angiogenesis by scopoletin,a coumarin compound isolated from Erycibe obtusifolia Benth,and its mechanism of action

Previous work in our laboratory has shown that scopoletin, one of the main bioactive constituents of Erycibe obtusifolia Benth stems, exerts anti-arthritic activity in vivo partly by preventing synovial angiogenesis. The present study was performed to further investigate the anti-angiogenic potential of scopoletin, focusing on the mechanisms of action in vitro. In the aortic ring sprouting assay, scopoletin (10, 30 and 100 μM) significantly inhibited the growth of endothelial sprouts in a concentration-dependent manner. As to human umbilical vein endothelial cells (HUVECs), scopoletin could inhibit their proliferation, migration and tubule formation induced by FGF-2, especially the proliferation. It also remarkably decreased the expression of VEGF at mRNA and protein levels, and the phosphorylations of IKKα and IκB but not Akt, as well as the degradation of IκB caused by FGF-2 in HUVECs. These findings suggest that scopoletin is substantially able to attenuate FGF-2-induced angiogenesis, and it might act by directly preventing the stimulation action of FGF-2 and by indirectly decreasing the production of VEGF. Scopoletin down-regulated the VEGF expression through NF-κB rather than PI-3K/Akt signaling pathway.     

芸香宁碱抑制血管生成作用的研究

目的：研究芸香宁碱对血管生成的抑制作用,并研究其初步的作用机制。方法用人脐静脉内皮细胞（HUVEC）的生长、迁移实验及体内动物模型－鸡胚绒毛尿囊膜法（CAM 法）研究化合物的体内外抗血管生成作用;用酶联免疫吸附法检测芸香宁碱在非凋亡剂量时对肿瘤细胞培养上清液中 VEGF 蛋白分泌量的影响。结果芸香宁碱对血管内皮细胞具有优先抑制作用,对 HUVEC 的半数抑制剂量为（33．2±0．4）μmol·L －1,而对其他肿瘤细胞的 IC50值均大于这一数值;芸香宁碱在体外能够明显抑制内皮细胞的迁移和对细胞外基质黏附作用,并呈剂量依赖性,体内实验显示30μmol·L －1剂量浓度时显著抑制 CAM新生血管形成;芸香宁碱在15μmol·L －1和30μmol·L －1的浓度剂量时显著抑制人肝癌 HepG2细胞培养上清液中VEGF 蛋白的分泌,具有显著性差异。结论芸香宁碱在非凋亡浓度剂量具有抑制新生血管形成作用,其机制与抑制血管内皮细胞增殖以及抑制肿瘤细胞表达 VEGF 有关。     

OSU-A9 inhibits angiogenesis in human umbilical vein endothelial cells via disrupting Akt–NF-κB and MAPK signaling pathways

Since the introduction of angiogenesis as a useful target for cancer therapy, few agents have been approved for clinical use due to the rapid development of resistance. This problem can be minimized by simultaneous targeting of multiple angiogenesis signaling pathways, a potential strategy in cancer management known as polypharmacology. The current study aimed at exploring the anti-angiogenic activity of OSU-A9, an indole-3-carbinol-derived pleotropic agent that targets mainly Akt–nuclear factor-kappa B (NF-κB) signaling which regulates many key players of angiogenesis such as vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs). Human umbilical vein endothelial cells (HUVECs) were used to study the in vitro anti-angiogenic effect of OSU-A9 on several key steps of angiogenesis. Results showed that OSU-A9 effectively inhibited cell proliferation and induced apoptosis and cell cycle arrest in HUVECs. Besides, OSU-A9 inhibited angiogenesis as evidenced by abrogation of migration/invasion and Matrigel tube formation in HUVECs and attenuation of the in vivo neovascularization in the chicken chorioallantoic membrane assay. Mechanistically, Western blot, RT-PCR and ELISA analyses showed the ability of OSU-A9 to inhibit MMP-2 production and VEGF expression induced by hypoxia or phorbol-12-myristyl-13-acetate. Furthermore, dual inhibition of Akt–NF-κB and mitogen-activated protein kinase (MAPK) signaling, the key regulators of angiogenesis, was observed. Together, the current study highlights evidences for the promising anti-angiogenic activity of OSU-A9, at least in part through the inhibition of Akt–NF-κB and MAPK signaling and their consequent inhibition of VEGF and MMP-2. These findings support OSU-A9's clinical promise as a component of anticancer therapy.     

Uncaria rhynchophylla induces angiogenesis in vitro and in vivo

Angiogenesis consists of the proliferation, migration, and differentiation of endothelial cells, and angiogenic factors and matrix protein interactions modulate this process. The aim of this study was to determine the angiogenic properties of Uncaria rhynchophylla. Uncaria rhynchophylla significantly enhanced human umbilical vein endothelial cells (HUVECs) proliferation in a dose-dependent manner. Neutralization of vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF) by monoclonal antibody suppressed the Uncaria rhynchophylla stimulatory effect on proliferation. In addition, Uncaria rhynchophylla significantly increased chemotactic-migration on gelatin and tubular structures on Matrigel of HUVECs in a dose-dependent manner. Interestingly, Uncaria rhynchophylla dose-dependently increased VEGF, and bFGF gene expression and protein secretion of HUVEC. The angiogenic activity of Uncaria rhynchophylla was confirmed using an in vivo Matrigel angiogenesis model, showing promotion of blood vessel formation. These results suggest that Uncaria rhynchophylla could potentially used to accelerate vascular wound healing or to promote the growth of collateral blood vessel in ischemic tissues.     

Effects of Cordyceps militaris extract on angiogenesis and tumor growth

INTRODUCTIONAngiogenesis is the process of new blood vesselformation from existing blood vessels and a natural re-sponse of tissues to ischemia[1]. The steps of angio-genesis involve proteolytic degradation of extracelluarmatrix, endothelial cell-matrix adhesion, migration,proliferation, and differentiation[2]. This biological re-action is often associated with some diseases, such assolid tumor[3], diabetic retinopathy[4], and rheumatoidarthritis[5].Tumor formation requires the developm…     

Wogonin inhibits H2O2-induced angiogenesis via suppressing PI3K/Akt/NF-κB signaling pathway

Wogonin, a natural monoflavonoid extracted from Scutellariae radix, has been reported for its ability of inhibiting tumor angiogenesis. In this study, we assessed the effect of wogonin on angiogenesis induced by low level of H₂O₂ (10 μM) in human umbilical vein endothelial cells (HUVECs). Wogonin suppressed H₂O₂-induced migration and tube formation of HUVECs as well as microvessel sprouting from rat aortic rings in vitro. Meanwhile, wogonin suppressed vessel growth in chicken chorioallantoic membrane (CAM) model in vivo. Mechanistic studies showed that wogonin suppressed H₂O₂-activated PI3K/Akt pathway and reduced the expression of vascular endothelial growth factor (VEGF) up-regulated by H₂O₂ in both protein and mRNA levels. In addition, wogonin also inhibited nuclear translocation of NF-κB, and decreased the binding ability of NF-κB with exogenous consensus DNA oligonucleotide. Then we further investigated the effect of wogonin on over-activated PI3K/Akt pathway by insulin-like growth factor-1 (IGF-1) and H₂O₂. We found that wogonin suppressed phosphorylation of Akt, up-regulation of VEGF and angiogenesis in vitro which was further induced by IGF-1 and H₂O₂. Moreover, in NF-κB overexpressed HUVECs, wogonin could also reduce the expression of VEGF and inhibited the migration and tube formation. Taken together, these results suggested that wogonin was potential in inhibiting H₂O₂-induced angiogenesis in vitro and in vivo via suppressing PI3K/Akt pathway and NF-κB signaling.