HIF-1在卵巢黄体发育过程中对血管新生的调控作用

在哺乳动物中,卵巢黄体（corpus luteum,CL）是由破裂排卵后的卵泡所形成的,也是血管增生比较激烈的地方。尤其是在卵巢黄体早期发育阶段,这种快速形成的致密毛细血管网可以确保产生激素的细胞获得氧气、营养和合成激素等所必要的前体,同时释放大量的激素用于早期妊娠的建立和维持。目前的研究已经表明,血管内皮生长因子（vascular endothel ial growth factor,VEGF）作为重要的促血管生成因子,在卵巢黄体发育过程中对血管增生具有至关重要的调节作用,而VEGF作为转录因子HIF－1的下游靶基因,受缺氧诱导因子HIF－1信号通路的调控。该文一方面对卵巢黄体发育过程中VEGF依赖性血管增生的调控机制进行概述,另一方面就转录因子H1F－1对VEGF的转录激活调控机制进行系统阐述,从而揭示HIF－1对卵巢黄体发育过程dgVEGF依赖性血管新生的调控作用,为进一步研究哺乳动物卵巢黄体发育过程中血管增生的分子调控机制提供坚实的理论基础。     

血管内皮生长因子受体信号转导通路与肿瘤血管生成

血管内皮生长因子是促进血管生成的重要调节因子.它能促进内皮细胞增殖、迁移,阻止内皮细胞凋亡、管腔网状结构退化,增加血管渗透性.所有这些作用都是通过血管内皮生长因子受体信号转导通路实现的.它们在肿瘤血管生成、肿瘤生长中起着重要的作用.以血管内皮生长因子受体信号转导通路为靶点是开发肿瘤血管生成抑制剂的理想策略.     

阻断VEGF旁分泌通路抑制乳腺癌血管生成与肿瘤生长

以人乳腺癌细胞株MCF 7为研究对象 ,通过构建有义与反义血管内皮生长因子 (VEGF)基因表达质粒 ,并转染MCF 7细胞 ,建立了高与低水平表达VEGF的细胞克隆。稳定转染反义VEGF表达质粒的细胞产生和分泌VEGF的能力明显下降 ,尽管在体外培养条件下细胞的增殖速度与未经转染的对照相比不是减慢而是略有增快 ,但在体内的成瘤能力、生长速度和转移能力等却明显低于未经转染的对照细胞或稳定转染有义VEGF表达质粒高水平表达VEGF的细胞克隆。通过体内电穿孔技术介导反义VEGF12 1及可溶性VEGF受体sFlk 1表达质粒转移至荷瘤鼠肿瘤组织内 ,反义VEGF12 1及sFlk 1的表达能显著抑制肿瘤的生长。研究结果证实了VEGF旁分泌通路在诱导乳腺癌肿瘤血管生成、促进肿瘤生长和转移方面起重要作用 ,阻断VEGF旁分泌通路能有效抑制乳腺癌的生长     

Apatinib inhibits the growth of small cell lung cancer via a mechanism mediated by VEGF,PI3K/Akt and Ki-67/CD31

This study aimed to investigate the anti-tumour effect of apatinib on extensive-stage small cell lung cancer (SCLC) and elucidate the associated mechanisms. NCI-H345 cells were selected as model cells because of high expression of vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2) and phosphorylated-VEGFR2 (pVEGFR2). Cells were exposed to recombinant human VEGF (rhVEGF) and apatinib. Cells were then divided into eight groups, namely, control, rhVEGF, apatinib, rhVEGF+apatinib, serum-free medium (SM), SM+rhVEGF, SM+apatinib and SM+rhVEGF+apatinib. In comparison with the control group, cell proliferation in vitro in apatinib, SM, SM+apatinib and SM+rhVEGF+apatinib groups was inhibited, particularly in SM+apatinib group. The effect of apatinib on tumour growth in vivo was investigated using a mouse xenograft tumour model. In comparison with the control group, tumour sizes were reduced in apatinib-treated group on days 34 and 37. Immunohistochemical and immunofluorescence staining revealed that VEGF, pVEGFR2, PI3K, AKT, p-ERK1/2, Ki-67 and CD31 in the tumour cells of apatinib-treated group were downregulated compared with control group. Haematoxylin and eosin staining revealed that apatinib promoted the necrosis of SCLC cells in vivo. In conclusion, apatinib inhibited the growth of SCLC cells by downregulating the expression of VEGF, pVEGFR2, p-PI3K, p-AKT, p-ERK1/2, Ki-67 and CD31.     

血管内皮生长因子受体-2所介导信号通路的研究进展

血管新生是许多生理和病理进程发生的重要机理．在生物体内,血管新生需经过多步精细调控历程,现有研究表明,血管内皮生长因子(VEGF)及其受体蛋白酪氨酸激酶,尤其是血管内皮生长因子受体-2(VEGFR-2)所介导的信号级联通路是其中关键性的调节途径．VEGF/VEGFR-2所介导的信号级联通路可以调控血管内皮细胞的增殖、迁移、存活和通透性的改变,促进血管的新生．VEGF与VEGFR-2的胞外区特异性结合后,引起受体的二聚化和自身的交互磷酸化,使胞内特定的酪氨酸残基磷酸化．下游信号蛋白可以通过其Src同源结构域-2(SH2)与VEGFR-2结合,随后激活下游的效应蛋白,调控内皮细胞的生物学活性．此外,VEGF/VEGFR-2信号通路还可以下调树突细胞(DC)的活性．对VEGF/VEGFR-2信号通路作用的深入了解,将有助于新药的研发．     

Mammalian sprouty-1 and -2 are membrane-anchored phosphoprotein inhibitors of growth factor signaling in endothelial cells

Growth factor-induced signaling by receptor tyrosine kinases (RTKs) plays a central role in embryonic development and in pathogenesis and, hence, is tightly controlled by several regulatory proteins. Recently, Sprouty, an inhibitor of Drosophila development-associated RTK signaling, has been discovered. Subsequently, four mammalian Sprouty homologues (Spry-1-4) have been identified. Here, we report the functional characterization of two of them, Spry-1 and -2, in endothelial cells. Overexpressed Spry-1 and -2 inhibit fibroblast growth factor- and vascular endothelial growth factor-induced proliferation and differentiation by repressing pathways leading to p42/44 mitogen-activating protein (MAP) kinase activation. In contrast, although epidermal growth factor-induced proliferation of endothelial cells was also inhibited by Spry-1 and -2, activation of p42/44 MAP kinase was not affected. Biochemical and immunofluorescence analysis of endogenous and overexpressed Spry-1 and -2 reveal that both Spry-1 and -2 are anchored to membranes by palmitoylation and associate with caveolin-1 in perinuclear and vesicular structures. They are phosphorylated on serine residues and, upon growth factor stimulation, a subset is recruited to the leading edge of the plasma membrane. The data indicate that mammalian Spry-1 and -2 are membrane-anchored proteins that negatively regulate angiogenesis-associated RTK signaling, possibly in a RTK-specific fashion.     

Reversible acetylation regulates vascular endothelial growth factor receptor-2 activity

The tyrosine kinase receptor vascular endothelial growth factor receptor 2 （VEG FR2） is a key regulator of angiogenesis. Here we show that VEGFR2 is acetylated in endothelial cells both at four lysine residues forming a dense cluster in the kinase insert domain and at a single lysine located in the receptor activation loop. These modifications are under dynamic control of the acetyltransferase p300 and two deacetyiases HDAC5 and HDAC6. We demonstrate that VEGFR2 acetylation essentially regulates receptor phosphorylation. In par- ticular, VEGFR2 acetylation significantly alters the kinetics of receptor phosphorylation after ligand binding, allowing receptor phos- phoryiation and intraceUular signaling upon proLonged stimulation with VEGF. Molecular dynamics simulations indicate that acetylation of the lysine in the activation loop contributes to the transition to an open active state, in which tyrosine phosphorylation is favored by better exposure of the kinase target residues. These findings indicate that post-translational modification by acetyiation is a critical mechanism that directLy affects VEGFR2 function.     

血管内皮生长因子和抗肿瘤血管新生药物研究进展

肿瘤的生长与迁移离不开新血管的形成,这使得抗血管新生成为肿瘤治疗的重要途径之一。血管内皮生长因子（VEGF）是针对内皮细胞作用最强、特异性最高的血管新生促进因子,因而VEGF是抗肿瘤治疗的重要靶点。我们简要介绍了VEGF的一些生物学特点及肿瘤血管新生,着重介绍了一些抗血管新生药物的最新研究成果及其临床应用。     

Vascular permeability factor: a unique regulator of blood vessel function.

Vascular permeability factor (VPF), also known as vascular endothelial growth factor (VEGF), is a potent polypeptide regulator of blood vessel function. VPF promotes an array of responses in endothelium, including hyperpermeability, endothelial cell growth, angiogenesis, and enhanced glucose transport. VPF regulates the expression of tissue factor and the glucose transporter. All of the endothelial cell responses to VPF are evidently mediated by high affinity cell surface receptors. Thus, endothelial cells have a unique and specific spectrum of responses to VPF. Since each of the responses of endothelial cells to VPF are also elicited by agonists, such as bFGF, TNF, histamine and others, it remains a major challenge to determine how post-receptor signalling pathways maintain both specificity and redundancy in cellular responses to various agonists.     

VEGF signalling enhances lesion burden in KRIT1 deficient mice

The exact molecular mechanisms underlying CCM pathogenesis remain a complicated and controversial topic. Our previous work illustrated an important VEGF signalling loop in KRIT1 depleted endothelial cells. As VEGF is a major mediator of many vascular pathologies, we asked whether the increased VEGF signalling downstream of KRIT1 depletion was involved in CCM formation. Using an inducible KRIT1 endothelial‐specific knockout mouse that models CCM, we show that VEGFR2 activation plays a role in CCM pathogenesis in mice. Inhibition of VEGFR2 using a specific inhibitor, SU5416, significantly decreased the number of lesions formed and slightly lowered the average lesion size. Notably, VEGFR2 inhibition also decreased the appearance of lesion haemorrhage as denoted by the presence of free iron in adjacent tissues. The presence of free iron correlated with increased microvessel permeability in both skeletal muscle and brain, which was completely reversed by SU5416 treatment. Finally, we show that VEGFR2 activation is a common downstream consequence of KRIT1, CCM2 and CCM3 loss of function, though the mechanism by which VEGFR2 activation occurs likely varies. Thus, our study clearly shows that VEGFR2 activation downstream of KRIT1 depletion enhances the severity of CCM formation in mice, and suggests that targeting VEGF signalling may be a potential future therapy for CCM.     

匹伐他汀对Klotho基因敲除杂合子小鼠血管新生的促进作用

目的：探讨匹伐他汀对Klotho基因敲除杂合子小鼠血管新生的促进作用及其作用机制。方法：建立Klotho基因敲除杂合子小鼠（hetero kl＋／-）和同窝出生野生型小鼠（wild kl＋／＋）下肢缺血模型并分为4组：①hetero正常组;②hetero匹伐他汀组;③wild正常组;④wild匹伐他汀组。使用激光多普勒血流测定仪测定klotho（kl＋／-,kl＋／＋）小鼠投药前、下肢缺血手术后双下肢血流。免疫荧光组化SP法计数Klotho（kl＋／-,kl＋／＋）小鼠缺血肢毛细血管数。免疫酶组化直接法计数Klotho（kl＋／-,kl＋／＋）小鼠缺血肢磷酸化Akt阳性细胞数。蛋白印迹杂交方法检测Klotho（kl＋／-）小鼠缺血肢VEGF蛋白表达。结果：匹伐他汀使Klotho（kl＋／-,kl＋／＋）小鼠术后缺血肢血流恢复明显,缺血肢与非缺血肢血流面积比明显增加;匹伐他汀使Klotho（kl＋／-、kl＋／＋）小鼠缺血肢毛细血管密度增加、p-Akt阳性细胞数明显增加;匹伐他汀使Klotho（kl＋／-）缺血肢VEGF蛋白表达增强。结论：匹伐他汀有促进Klotho基因敲除杂合子小鼠血管新生的作用。其作用机制可能是通过VEGF—p—Akt—NO径路实现的。     

缺氧条件下血管活性因子对血管内皮细胞中VEGF表达的影响

 探讨在缺氧条件下人脐静脉血管内皮细胞对血管内皮生长因子 (vascular endothelialgrowth factor,VEGF)表达及缩血管活性物质内皮素 (ET)、舒血管活性物质一氧化氮 (NO)和 NO抑制剂 LNNA对 VEGF基因表达的影响 .体外培养人脐静脉血管内皮细胞 ,经缺氧及血管活性物质处理 .Northern杂交、酶联免疫检测和计算机图象分析等观察 VEGF m RNA和蛋白表达水平 .发现缺氧 6h内皮细胞可见 VEGF表达 .ET可促进 VEGF m RNA的表达 ,NO可明显抑制 VEGFm RNA的表达 ,NO抑制剂 LNNA也影响 VEGF m RNA的表达 .ELISA检测 VEGF蛋白水平分别为 6h组 8.2± 1 .1 ng/ L,ET+6h组 9.37± 1 .0 2 ng/ L,NO+6h组 2 .86± 0 .91 ng/ L,L - NNA+6h组 1 4.75± 1 .87ng/ L.缺氧可诱导人脐静脉血管内皮细胞分泌 VEGF并受血管活性物质ET和 NO的调控 ,ET促进其表达 ,NO抑制其表达 .     

血小板活化因子对大鼠黄体细胞孕酮分泌及血管内皮生长因子表达的作用

本文旨在研究血小板活化因子(platelet-activating factor,PAF)对大鼠黄体细胞孕酮分泌及血管内皮生长因子(vascularendothelial growth factor,VEGF)mRNA表达的作用.将未成年(25～28 d)Sprague-Dawley雌性大鼠颈部皮下注射50 IU孕马血清促性腺激素(pregnant mare serum gonadotrophin,PMSG),48 h后注射25 IU人绒毛膜促性腺激素(human chorionicgonadotrophin.hCG)诱导卵泡发育和黄体生成,第6天(hCG注射日为第1天)收集卵巢黄体细胞,体外培养24 h后,不加或加入不同剂量(0.1 μg/mL、1 μg/mL、10 μg/mL)PAF,37℃、5%CO2培养箱内培养24 h.用放射免疫方法测定培养液中孕酮的含量,流式细胞仪和RT-PCR方法检测黄体细胞凋亡以及VEGF mRNA的表达.结果显示,PAF促进黄体细胞孕酮分泌,1 μg/mL PAF作用最强(P<0.05);PAF促进黄体细胞凋亡无明显剂量依赖性,但10 μg/mL PAF显著促进大鼠黄体细胞凋亡(P<0.05):PAF刺激黄体细胞VEGF mRNA表达,1 μg/mL PAF效果最显著(P<0.01).结果提示,PAF可通过调节黄体细胞孕酮的分泌和VEGF mRNA的表达来促进黄体形成.     

Jumping the barrier: VE-cadherin, VEGF and other angiogenic modifiers in cancer

The endothelial barrier controls the passage of fluids, nutrients and cells through the vascular wall. This physiological function is closely related to developmental and adult angiogenesis, blood pressure control, as well as immune responses. Moreover, cancer progression is frequently characterized by disorganized and leaky blood vessels. In this context, vascular permeability drives tumour-induced angiogenesis, blood flow disturbances, inflammatory cell infiltration and tumour cell extravasation. Although various molecules have been implicated, the vascular endothelial adhesion molecule, VE-cadherin (vascular endothelial cadherin), has emerged as a critical player involved in maintaining endothelial barrier integrity and homoeostasis. Indeed, VE-cadherin coordinates the endothelial cell-cell junctions through its adhesive and signalling properties. Of note, many angiogenic and inflammatory mediators released into the tumour microenvironment influence VE-cadherin behaviour. Therefore restoring VE-cadherin function could be one very promising target for vascular normalization in cancer therapies. In this review, we will mainly focus on recent discoveries concerning the molecular mechanisms involved in modulating VE-cadherin plasticity in cancer.     

肿瘤饥饿疗法的新靶标——内分泌腺衍生血管内皮生长因子

“肿瘤饥饿疗法”是通过抑制促肿瘤血管新生细胞因子的作用,阻断肿瘤血管形成,最终实现“饿死”肿瘤细胞的一种治疗方法．内分泌腺衍生血管内皮生长因子(EG-VEGF)是在2001年被发现的一个组织选择性促血管新生因子．近年来的研究表明,EG-VEGF还兼有促进造血干细胞分化、刺激胃肠道收缩及影响肠神经系统发育等多种生理功能．EG-VEGF的异常表达与多种肿瘤及血管新生依赖性疾病的发生发展密切相关,有望作为相应的治疗靶点开发诊断及治疗试剂．本文对有关研究进展及应用前景作一简要综述．