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.     

Inhibition of vascular endothelial growth factor-induced angiogenesis by resveratrol through interruption of Src-dependent vascular endothelial cadherin tyrosine phosphorylation

Resveratrol, a polyphenolic compound found in grapes and other fruits, has been reported to inhibit angiogenesis with an as yet elusive mechanism. Here, we investigate the detailed mechanism by which resveratrol inhibits vascular endothelial growth factor (VEGF)-induced angiogenic effects in human umbilical endothelial cells (HUVECs). Exposure of HUVECs to 1 to 2.5 muM resveratrol significantly blocked VEGF-mediated migration and tube formation but not cell proliferation. Under the same concentrations, resveratrol failed to affect VEGF-stimulated activation of VEGF receptor, extracellular signal-regulated protein kinase 1/2, p38 mitogen-activated protein kinase, and Akt. Of interest, resveratrol, at the dose of 1 or 2.5 muM, effectively abrogated VEGF-mediated tyrosine phosphorylation of vascular endothelial (VE)-cadherin and its complex partner, beta-catenin. This inhibitory effect of resveratrol reflected on the retention of VE-cadherin at cell-cell contacts as demonstrated by immunofluorescence. Src kinase assay showed that VEGF-induced endogenous Src kinase activation was strongly inhibited by 1 and 2.5 muM resveratrol. Supportively, inhibition of Src activity by overexpression of Csk resulted in attenuation of the tyrosine phosphorylation of VE-cadherin and endothelial cell (EC) tube formation. Again, transfection with v-Src, an active form of Src, could reverse resveratrol inhibition of VE-cadherin tyrosine phosphorylation and EC tube formation. Reactive oxygen species (ROS) has been shown to be involved in VE-cadherin phosphorylation and its related functions. Flow cytometric analysis showed that VEGF stimulated an evident increase of peroxide, which was strongly attenuated by resveratrol. In addition, antioxidant N-acetyl-cysteine was demonstrated to strongly inhibit VEGF-mediated Src activation, VE-cadherin tyrosine phosphorylation, and HUVEC tube formation. Together, our data suggest that resveratrol inhibition of VEGF-induced angiogenesis was mediated by disruption of ROS-dependent Src kinase activation and the subsequent VE-cadherin tyrosine phosphorylation.     

Inhibition of vascular endothelial growth factor activity by transfection with the soluble FLT-1 gene

Vascular endothelial growth factor (VEGF)-induced angiogenesis is involved in the etiology of some cardiovascular diseases. The soluble form of VEGF receptor, FLT-1 (sFLT-1), is a potent antagonist of VEGF. Therefore, we investigated whether transfection with the sFLT-1 gene could inhibit VEGF-induced angiogenesis. Human embryonic kidney (HEK)-293 cells were transfected with plasmids containing VEGF and sFLT-1 (pCMV-VEGF and pCMV-sFLT-1) by the calcium-phosphate co-precipitation method. VEGF- and/or sFLT-1-transfected HEK-293 cells were incubated for 24 h, and then conditioned medium was collected. The effects of conditioned medium on angiogenesis were tested by incorporation of [3H]thymidine into human umbilical vein endothelial cells (HUVECs). Expression of VEGF protein was determined by Western blotting. The conditioned medium from sFLT-1 gene-transfected HEK-293 cells significantly inhibited recombinant VEGF-induced increase in [3H]thymidine incorporation by HUVECs. VEGF gene-transfected HEK-293 cells secreted VEGF protein into conditioned medium. This conditioned medium increased [3H]thymidine incorporation by HUVECs, which was significantly inhibited by co-transfection of sFLT-1 gene with VEGF gene. These observations suggested that sFLT-1 gene transfer could inhibit VEGF-induced DNA synthesis of vascular endothelial cells.     

Inhibitors targeting hepatocyte growth factor receptor and vascular endothelial growth factor receptor tyrosine kinases

Amgen disclosed a series of 4-heteroaryloxy quinoline/quinazoline compounds as multiple kinase inhibitors, including hepatocyte growth factor (HGF) receptor tyrosine kinase c-Met and vascular endothelial growth factor (VEGF) receptor tyrosine kinase. These compounds are stated to have wide therapeutic applications for the treatment of a variety of cancers, hypertension, arteriosclerosis, myocardial infarction and rheumatoid arthritis.     

Phosphatidylinositol inhibits vascular endothelial growth factor-A--induced migration of human umbilical vein endothelial cells

Phosphatidylinositol (PI), a phospholipid in component of cell membranes, is widely distributed in animals, plants, and microorganisms. Here, we examined in vitro whether PI inhibits the angiogenesis induced by vascular endothelial growth factor-A (VEGF-A). PI concentration-relatedly and significantly (at 10 and 30 microg/ml) inhibited VEGF-A-induced tube formation in a co-culture of human umbilical vein endothelial cells (HUVECs) and fibroblasts. PI also inhibited the migration, but not proliferation, induced in HUVECs by VEGF-A. Furthermore, PI at 30 microg/ml inhibited the VEGF-A-induced phosphorylation of serine/threonine protein kinase family protein kinase B (Akt) and p38 mitogen activate kinase (p38MAPK), key molecules in cell migration, but not phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), a key molecule in cell proliferation. These findings indicate that PI inhibits VEGF-induced angiogenesis by inhibiting HUVECs migration and that inhibition of phosphorylated-Akt and -p38MAPK may be involved in the mechanism. Therefore, PI may be expected to prevent some diseases caused by angiogenesis.     

欧芹素乙对人脐静脉内皮细胞的保护作用及对血管内皮生长因子表达的影响

目的:研究欧芹素乙对内皮细胞的保护作用;溶血磷脂酰胆碱(LPC)对人脐静脉内皮细胞株HUVEC细胞中血管内皮生长因子(VEGF)表达的影响以及欧芹素乙的影响.方法:应用四唑盐(MTT)法检测溶血磷脂酰胆碱对HUVEC细胞的毒性作用及欧芹素乙的保护作用;应用基础酶联免疫吸附试验(ELISA)检测各组条件培养基中VEGF蛋白含量;采用RT-PCR法及Reahime PCR方法检测溶血磷脂酰胆碱对VEGF mRNA的表达及欧芹素乙的影响.结果:MTT检测结果显示,溶血磷脂酰胆碱对HUVEC细胞具有较强的生长抑制作用,而欧芹素乙对溶血磷脂酰胆碱所致的细胞增殖抑制具有较好的保护作用.ELISA结果显示,HUVEC细胞暴露于溶血磷脂酰胆碱后,VEGF蛋白含量明显升高;加入欧芹素乙后剂量依赖性地降低VEGF蛋白的表达.RT-PCR结果显示,溶血磷脂酰胆碱可以增加3种VEGF异构体的转录水平,其中VEGF165的表达显著增加,欧芹素乙可剂量依赖性地抑制溶血磷脂酰胆碱引起的VEGF mRNA的高表达.结论:欧芹素乙对溶血磷脂酰胆碱引起的细胞损伤有明显的保护作用;欧芹素乙可抑制溶血磷脂酰胆碱所诱导的HUVEC细胞中VEGF蛋白及VEGF mRNA的高表达,对内皮细胞起到保护作用.     

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。     

Pseudolarix acid B inhibits angiogenesis by antagonizing the vascular endothelial growth factor-mediated anti-apoptotic effect

Angiogenesis is controlled by a number of growth factors, including vascular endothelial growth factor (VEGF). In this study, pseudolarix acid B, isolated from the traditional Chinese medicinal plant Pseudolarix kaempferi and originally identified as an early pregnancy-terminating agent, was evaluated for its potential as an angiogenesis inhibitor, using in vitro and in vivo models. After exposure to pseudolarix acid B 0.625-5 microM for 72 h, the proliferation of human umbilical vein endothelial cells was significantly inhibited. Pseudolarix acid B 0.313-2.5 microM for 24 h potently blocked the VEGF-induced tube formation of human umbilical vein endothelial cells in a dose-dependent manner. Matrigel plug assays disclosed that pseudolarix acid B reduced angiogenesis induced by VEGF in vivo. In addition, pseudolarix acid B antagonized VEGF-mediated anti-apoptotic effects on serum-deprived human umbilical vein endothelial cells and increased apoptosis of endothelial cells induced by VEGF in Matrigel plug assays. Moreover, pseudolarix acid B significantly inhibited VEGF-induced tyrosine phosphorylation of kinase insert domain-containing receptor/fetal liver kinase-1 (KDR/flk-1), in correlation with a marked decrease in the phosphorylation of Akt and extracellular signal-regulated kinases (ERK). These findings collectively suggest that pseudolarix acid B possesses anti-angiogenic activity. One of the main anti-angiogenesis mechanisms of pseudolarix acid B may involve antagonism of the VEGF-mediated anti-apoptosis effect via inhibition of KDR/flk-1, ERK1/2, and Akt phosphorylation in endothelial cells.     

Inhibition of vascular endothelial growth factor (VEGF)-induced endothelial proliferation, arterial relaxation, vascular permeability and angiogenesis by dobesilate

Vascular endothelial growth factor (VEGF) is a key factor in angiogenesis and vascular permeability which is associated with many pathological processes. 2,5-hydroxybenzene sulfonate (DHBS; dobesilate) is a small molecule with anti-angiogenic activity that has been described as an inhibitor of fibroblast growth factors (FGF). The aim of the present study was to evaluate the effects of DHBS on VEGF-induced actions. The effects of DHBS were evaluated on VEGF-induced proliferation in human umbilical vein endothelial cells (HUVEC) and rat aorta relaxation, as well as on in vivo VEGF-induced skin vascular permeability and neovascularization in rats. DHBS at 50 and 100 μM concentration significantly inhibited the proliferation of HUVEC induced by VEGF (10 ng/ml), without significantly affecting HUVEC proliferation in the absence of VEGF. Rapid VEGF-induced activation of Akt in HUVEC was also prevented by DHBS (100 μM). Additionally, DHBS (2 μM) specifically inhibited the relaxation of rat aorta induced by VEGF (0.1 to 30 ng/ml), but not endothelium-dependent relaxation to acetylcholine (1 nM to 10 μM). The in vivo enhancement of vascular permeability caused by VEGF injection (50 μl at 10 ng/ml) in rat skin was also inhibited by DHBS co-administration (200 μM) (74.8±3.8% inhibition of dye extravasation). Administration of DHBS (200 mg/kg/day; i.p.) also reduced VEGF-induced angiogenesis in vivo. DHBS inhibits main responses elicited in vitro and in vivo by VEGF. As a dual antagonist of VEGF and FGF activities, DHBS could be of therapeutic interest in the treatment of diseases related to VEGF/FGF overproduction and excessive angiogenesis.     

Prostaglandin E2 regulates cellular migration via induction of vascular endothelial growth factor receptor-1 in HCA-7 human colon cancer cells

An important event in the development of tumors is angiogenesis, or the formation of new blood vessels. Angiogenesis is also known to be involved in tumor cell metastasis and is dependent upon the activity of the vascular endothelial growth factor (VEGF) signaling pathway. Studies of mice in which the EP3 prostanoid receptors have been genetically deleted have shown a role for these receptors in cancer growth and angiogenesis. In the present study, human colon cancer HCA-7 cells were used as a model system to understand the potential role of EP3 receptors in tumor cell migration. We now show that stimulation of HCA-7 cells with PGE₂ enhanced the up-regulation of VEGF receptor-1 (VEGFR-1) expression by a mechanism involving EP3 receptor-mediated activation of phosphatidylinositol 3-kinase and the extracellular signal-regulated kinases. Moreover, the PGE₂ stimulated increase in VEGFR-1 expression was accompanied by an increase in the cellular migration of HCA-7 cells. Given the known involvement of VEGFR-1 in cellular migration, our results suggest that EP3 receptors may contribute to tumor cell metastasis by increasing cellular migration through the up-regulation of VEGFR-1 signaling.     

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.     

Celecoxib,a selective cyclooxygenase-2 inhibitor,inhibits retinal vascular endothelial growth factor expression and vascular leakage in a streptozotocin-induced diabetic rat model

Overexpression of vascular endothelial growth factor (VEGF) is implicated in the development of vascular leakage and retinal neovascularization in diabetic subjects. The objective of this study was to determine whether celecoxib, a selective cyclooxygenase-2 enzyme inhibitor, reaches ocular tissues following oral administration and inhibits the retinal VEGF expression and vascular leakage in a streptozotocin-induced diabetic rat model. After administering a single intraperitoneal injection of streptozotocin (60 mg/kg) to Sprague-Dawley rats and ensuring the induction of diabetes at the end of 24 h, celecoxib was administered b.i.d. by oral gavage (50 mg/kg). On day 8, the animals were sacrificed and the retinal VEGF and cyclooxygenase-2 mRNA levels, ocular tissue celecoxib concentrations, and the vitreous/plasma protein ratio were determined. In diabetic rats, the retinal VEGF mRNA expression was 2.3-fold compared to controls, with a corresponding increase in cyclooxygenase-2 mRNA expression. Celecoxib treatment inhibited VEGF mRNA expression without any significant reduction in cyclooxygenase-2 mRNA. Furthermore, the retinal vascular leakage estimated as vitreous to plasma protein ratio increased in diabetic animals from 0.35+/-0.1 to 1.1+/-0.1 and celecoxib treatment significantly decreased this ratio to 0.4+/-0.1. Celecoxib levels were 24.8+/-6.6, 1.9+/-1, 1.7+/-0.8, and 6.9+/-0.9 ng/mg in the retina, vitreous, lens, and cornea, respectively. The plasma celecoxib levels were 85+/-24 ng/ml. Thus, celecoxib reaches the retina after oral administration and reduces diabetes-induced retinal VEGF mRNA expression and vascular leakage by inhibiting the activity of cyclooxygenase-2 enzyme.     

Vascular endothelial growth factor and vascular endothelial growth factor receptor inhibitors as anti-angiogenic agents in cancer therapy

New blood vessel formation (angiogenesis) is fundamental to the process of tumor growth, invasion, and metastatic dissemination. The vascular endothelial growth factor (VEGF) family of ligands and receptors are well established as key regulators of these processes. VEGF is a glycoprotein with mitogenic activity on vascular endothelial cells. Specifically, VEGF-receptor pathway activation results in signaling cascades that promote endothelial cell growth, migration, differentiation, and survival from pre-existing vasculature. Thus, the role of VEGF has been extensively studied in the pathogenesis and angiogenesis of human cancers. Recent identification of seven VEGF ligand variants (VEGF [A-F], PIGF) and three VEGF tyrosine kinase receptors (VEGFR- [1-3]) has led to the development of several novel inhibitory compounds. Clinical trials have shown inhibitors to this pathway (anti-VEGF therapies) are effective in reducing tumor size, metastasis and blood vessel formation. Clinically, this may result in increased progression free survival, overall patient survival rate and will expand the potential for combinatorial therapies. Having been first described in the 1980s, VEGF patenting activity since then has focused on anti-cancer therapeutics designed to inhibit tumoral vascular formation. This review will focus on patents which target VEGF-[A-F] and/or VEGFR-[1-3] for use in anti-cancer treatment.     

Effect of an oversulfated exopolysaccharide on angiogenesis induced by fibroblast growth factor-2 or vascular endothelial growth factor in vitro

The aim of this study was to determine the angiogenic properties of an oversulfated exopolysaccharide (OS-EPS) derived from a polysaccharide secreted by the mesophilic bacterium Alteromonas infernus. We compared the effect of this OS-EPS with that of a non-oversulfated exopolysaccharide (EPS) on human umbilical vein endothelial cell (HUVEC) proliferation, migration and differentiation induced by basic fibroblast growth factor (FGF-2) or vascular endothelial growth factor (VEGF). OS-EPS enhanced HUVEC proliferation by 58% when used alone, and by respectively 30% and 70% in the presence of FGF-2 and VEGF. OS-EPS also increased the density of tubular structures on Matrigel in the presence of FGF-2 or VEGF. Vascular tube formation was related to alpha(6) integrin subunit expression, which was enhanced by 50% in the presence of the growth factors. Indeed, a monoclonal anti-alpha(6) blocking antibody abolished this vascular tube formation. EPS had no effect in any of the experimental conditions, underlying the importance of sulfation in the angiogenic effects of exopolysaccharide. By potentiating the angiogenic activity of FGF-2 and/or VEGF, OS-EPS, which possesses low anticoagulant activity and thus a low hemorrhagic risk, could potentially be used to accelerate vascular wound healing or to promote the growth of collateral blood vessels in ischemic tissues.     

碱性成纤维细胞生长因子上调原代培养鼠星形胶质细胞中血管内皮生长因子的表达(英文)

目的:观察碱性成纤维细胞生长因子(bFGF)对鼠星形胶质细胞中血管内皮生长因子(VEGF)表达的影响。方法:用半定量聚合酶链反应(PCR)法和免疫组织化学法分别考察bFGF对VEGF信使RNA(mRNA)水平和蛋白质水平的影响。对不同剂量bFGF(1,10,100 ug·L~(-1))和不同孵育时间(3,6,12,24 h)的作用均进行了分析。 结果:bFGF可以剂量依赖性升高VEGF的mRNA水平。bFGF 10ug·L~(-1)在孵育3 h后即可上调VEGF mRNA水平,孵育24 h后细胞内VEGF mRNA水平显著高于对照组。免疫细胞化学分析结果表明bFGF也能升高细胞的VEGF蛋白质水平。结论:碱性成纤维细胞生长因子可以上调鼠星形胶质细胞中血管内皮生长因子的表达。     

脉络宁注射液对人血管内皮细胞缺氧损伤的保护作用

目的:研究脉络宁注射液对人脐静脉血管内皮细胞缺氧损伤的保护作用及其机制。方法:常规进行人血管内皮细胞(HUVECs)培养,将细胞随机分为正常对照组、缺氧组和脉络宁20 mg.L-1组。采用CCK-8法检测细胞存活率;Hochest33258荧光染料检测细胞凋亡率;RT-PCR法检测各组细胞中血管内皮生长因子(VEGF),血管生成素-2(Ang-2)mRNA表达水平。结果:脉络宁注射液可显著提高缺氧损伤细胞的存活率(P<0.05);与正常对照组比较,缺氧组细胞内VEGF和Ang-2 mRNA表达水平明显增高。与缺氧组比较,脉络宁组VEGF和Ang-2的表达进一步增强,各组间比较均有差异(P<0.05)。结论:脉络宁注射液可减轻血管内皮细胞缺氧损伤,上调缺氧血管内皮细胞中VEGF和Ang-2的表达,对血管内皮细胞缺氧损伤有一定的保护作用。     

Enhancement of glucose transporter expression of brain endothelial cells by vascular endothelial growth factor derived from glioma exposed to hypoxia

Increased need for glycolysis and glucose uptake for ATP production is observed in tumor cells, particularly in cells lacking of oxygen supply. Because glucose is transported from blood to tumor, glucose molecules must be delivered across glucose transporters of the vascular endothelium and tumor cells. Here we found that glioma suffered from hypoxic insults can secrete factor(s) to regulate glucose transporter expression in brain endothelium. It was found that conditioned medium from rat C6 glioma cells under hypoxia up-regulated glucose transporter type 1 (GLUT1) expression in rat brain endothelial cells, whereas conditioned medium from C6 cells under normoxia caused no significant effect. We further investigated whether the observed potentiating effect was caused by vascular endothelial growth factor (VEGF) production from C6 cells, because secreted VEGF was markedly increased under hypoxic condition. By transfection of C6 cells with VEGF small interfering RNA, it was found that conditioned medium from transfected cells under hypoxia no longer up-regulated GLUT1 expression of endothelial cells. Moreover, the addition of VEGF-neutralizing antibody to the hypoxic conditioned medium could also exert similar inhibitory effects. Furthermore, it was found that the VEGF-induced increase of GLUT1 expression in endothelial cells was mediated by the phosphoinositide-3 kinase/Akt pathway. Our results indicate that hypoxic brain glioma may secrete VEGF to increase glucose transport across blood-brain barrier.     

链霉素及H7对机械牵张离体心肌HIF-1α、VEGF的影响及机制探讨

目的研究链霉素及H7对机械牵张大鼠心肌组织低氧诱导分子-1α和血管内皮细胞生长因子表达的影响,并探讨二者在其中的作用机制。方法采用大鼠离体灌流心脏模型,膨胀左心室30min,RT-PCR法检测左室心肌细胞HIF-1α、VEGF mRNA的表达,免疫组化观察二者在心肌细胞中定位,Western blot检测HIF-1α蛋白的表达,利用链霉素作为牵张敏感离子通道(SACs)阻断剂研究SACs和PKC抑制剂H7在其中的可能作用。结果与不牵张组HIF-1α和VEGF mRNA无表达的比较,牵张可以明显增加HIF-1α和VEGF mRNA的表达(P<0·05或P<0·01);而链霉素、H7可以明显减少HIF-1α和VEGF mRNA的表达(P<0·05);但是二者不能完全抑制急性牵张刺激激活的HIF-1α和VEGF mRNA水平升高(P<0·05),HIF-1α和VEGF在胞质和胞核中均有表达,并检测到HIF-1α蛋白表达。结论链霉素、H7对膨胀左室致HIF-1α、VEGF表达有明显抑制作用,提示心室膨胀经SACs-PKC-激活胞内信号诱导HIF-1α、VEGF表达。同时链霉素并不能完全抑制HIF-1α、VEGF表达,提示膨胀心室致HIF-1α、VEGF表达进而引起心室肥厚尚有其他传导途径,仍需进一步研究。     

Anti-angiogenic activity of triptolide in anaplastic thyroid carcinoma is mediated by targeting vascular endothelial and tumor cells

Triptolide is confirmed to suppress angiogenesis of anaplastic thyroid carcinoma. Here we further expound the precise mechanism involved in this activity. Triptolide downregulated nuclear factor kappa B (NF-κB) pathway and its targeting genes associated with endothelial cell mobilization in human umbilical vein endothelial cells (HUVECs) and impaired VEGF expression in thyroid carcinoma TA-K cells. Furthermore, both triptolide and the conditioned medium from triptolide-treated TA-K cells (CMT) significantly attenuated proliferation, migration and tube formation of HUVECs. In vivo, triptolide inhibited TA-K cell-induced tumor growth, vascular formation and VEGF expression. Our data establish that triptolide inhibits tumor angiogenesis by the dual action on vascular endothelial cells and tumor cells, thus providing a novel and overall explanation for the anti-angiogenesis action of triptolide. The multicellular targets emphasize triptolide as a high-performance and potential angiogenesis inhibitor.