VEGF与肿瘤血管生成及其在抗肿瘤药物开发中的应用

肿瘤血管生成在肿瘤的形成和转移过程中起到很重要的作用,众多的血管生成因子和抑制因子在肿瘤血管生成中起到调控作用,而血管生成因子（VEGF）是其中很重要的一类,通过研究其在肿瘤血管形成过程的调节机制,找到了一条有效的预防和治疗肿瘤的新途径。本文就肿瘤血管生成、VEGF家族的特性、VEGF在抗肿瘤药物开发中的应用做一综述。     

抗VEGF/VEGFR靶向肿瘤血管药物的研究进展

研究表明,肿瘤的生长转移和新血管的生成有密切关系,其中血管内皮细胞生长因子(vascular endothelial growth factor,VEGF)及其信号途径在肿瘤血管生成中起关键作用。阻断该途径的任何环节均可有效抑制肿瘤血管的生成,进而抑制肿瘤的生长和转移。近年来,已有多种以VEGF/VEGFR为靶点的抗肿瘤血管生成药物投入临床应用,其中bevacizumab为第一个获批上市的抗肿瘤血管生成药物。继bevacizumab后,一种以基因工程手段获得的人Fc融合蛋白Zaltrap也成功在美国上市,这种杂交分子的药代动力学明显优于单克隆抗体,能更好的遏制肿瘤血管的发生并消退已形成的肿瘤血管。在肿瘤的临床治疗中,Zaltrap比bevacizumab显示出更大的优势。此外,VEGFC/D Trap及小分子酪氨酸激酶抑制剂也能有效抑制肿瘤血管的生成。在此对以VEGF/VEGFR为靶点的抗肿瘤血管生成药物进行综述。     

胃癌组织中PTEN、VEGF表达与肿瘤新生血管形成

目的探讨胃癌组织中PTEN、vascular endothelial growthfactor（VEGF）基因表达及其与肿瘤侵袭转移的关系。方法用RT-PCR和免疫组化方法检测胃癌、淋巴结转移组织中PTEN、VEGF mRNA和蛋白表达;用CD34检测肿瘤细胞微血管数。结果PTEN和VEGF mRNA表达阳性率在正常胃黏膜为76.5%与0.0%、胃癌组织为30.9%与69.1%、淋巴结转移组织23.6%与74.5%;PTEN和VEGF蛋白阳性率在正常胃黏膜为76.5%与0.0%、胃癌组织27.9%与82.4%、淋巴结转移组织16.3%与91.0%;胃癌组织中新生血管呈浸润生长,以淋巴结转移组织中明显。胃癌组织PTEN mRNA和蛋白低于正常胃黏膜（P〈0.01）,VEGF高于正常胃黏膜（P〈0.01）,PTEN与VEGF表达负相关（P〈0.05）,VEGF表达与新生血管形成正相关（P〈0.05）。结论PTEN基因失活和VEGF的过表达与新生血管形成相关,可能是通过调节包括VEGF在内的血管生成因子而在血管形成中起作用。     

血管内皮生长因子家族及其受体与肿瘤血管生成研究进展

血管内皮生长因子(vascular endothelial growth factor,VEGF),又名血管通透性因子(vascular permeability factor,VPF)是重要的血管生成正性调节因子,是目前抗癌治疗的研究靶点之一。现已发现的VEGF家族成员包括VEGF—A、VEGF—B、VEGF—C、VEGF—D、VEGF—E和胎盘生长因子(placenta growth factor,PLGF)。VEGF的受体有VEGFR—1(fit—1)、VEGFR-2(flk-1／KDR)、VEGFR-3(fit-4)、neuropilin(NPR1／NPR2)。该家族的成员可以选择性地增强血管和／或淋巴管内皮细胞的有丝分裂,刺激内皮细胞增殖并促进血管生成,提高血管特别是微小血管的通透性,使血浆大分子外渗沉积在血管外的基质中,促进新生毛细血管网的建立,为肿瘤细胞的生长提供营养等。作者对VEGF家族成员及其受体的理化特征、VEGF与肿瘤的关系、VEGF抑制剂的研制作一综述。     

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     

逆转录病毒介导人VEGF在兔皮肤成纤维细胞中的表达

A replication-deficient recombinant retrovirus containing the cDNA coding for human vascular endothelial growth factor (VEGF) was generated, and then infected rabbit primary skin fibroblasts. After selection with G418, the transduced colonies have the ability of producing VEGF. The integration and expression of VEGF in transduced cells were confirmed by Southern blot, PCR, Northern blot and RT-PCR assay. The VEGF secreted by transduced cells has strong bioactivity when assayed by endothelial proliferation and Miles vascular permeability assay. Thus, this study pave the way for future study of biological and physiological effect of VEGF in vivo.     

VEGFⅡ/GRP融合蛋白的构建、表达、纯化及其抗小鼠RM-1前列腺癌的作用研究

设计并构建一种含VEGF和GRP抗原表位的表达载体pET28a-VEGFI-M2-GRP质粒,将其转化至大肠杆菌中,并对重组菌进行乳糖诱导表达,超声破碎,包涵体经洗涤、溶解、透析复性、离子交换层析等方法进行分离纯化后得到目的蛋白VEGFⅡ/GRP,Western blot 鉴定。建立前列腺癌RM-1细胞的C57BL/6J小鼠皮下移植瘤模型,以VEGFⅡ/GRP作为疫苗进行免疫。观察荷瘤小鼠的肿瘤生长情况计算抑瘤率,比较各组血管生成数以及ELISA检测抗VEGF抗体浓度,并研究该蛋白疫苗的抗肿瘤生长作用和抗血管生成作用。结果显示：ELISA结果表明小鼠血清中抗VEGF抗体比NS组高（P<0.05）,重组蛋白VG组与NS组相比抗血管作用显著（P<0.05）。初步显示构建的重组蛋白有抑制肿瘤血管生长的作用。     

VEGF受体Flt—1在大肠杆菌中的高效融合表达

鉴于Ｆｌｔ－１有肿瘤及其他由于病理血管生成而导致的多种疾病中的核心作用,本文通过ＰＣＲ扩增出的ＶＥＧＦ受体Ｆｌｔ－１Ｎ端１－３个ＩｇＧ样ｌｏｏｐ基因,经过基因重组实现了Ｆｌｔ－１在原核表达体系５Ｘ－１的融合表达。     

非小细胞肺癌中DPC4、VEGF基因的表达及相关性研究

目的:研究DPC4和VEGF基因在非小细胞肺癌中的表达及相关性.方法:利用免疫组织化学SP法检测60例NSCLC组织、10例相应的癌旁正常肺组织中DPC4、VEGF的表达.结果:DPC4在60例NSCLC标本中的阳性表达率为63.3%(38/60),癌旁正常肺组织中的阳性表达率90.0%(9/10),差别有显著性意义(P＜0.05);DPCA与患者的年龄、性别、组织学类型、TNM分期、肿瘤细胞分化程度无关(P＞0.05),而与淋巴结转移显著相关(P＜0.05).肺癌组织中VEGF阳性率(81.7%,49/60)明显高于正常肺组织(20.0%,2/10),有显著性差别(P＜0.05);VEGF的阳性表达与患者的年龄、性别、组织学类型无关(P＞0.05),而与TNM分期、肿瘤细胞分化程度、淋巴结转移明显相关.60例NSCLC中,DPCA的表达与VEGF呈明显的负相关(r=0.303,P＜0.05).结论:DPC4在肺癌组织中低表达,可促进肺癌的淋巴结转移.VEGF在肺癌组织中高表达,可促进肺癌的发生、发展、转移.DPC4、VEGF在肺癌中的表达呈负相关,提示DPC4可能通过下调VEGF的表达而抑制血管的生成.     

肿瘤血管生成抑制剂的作用机制研究进展

肿瘤血管生成抑制剂批能破坏或抑制血管生成,有效地阻止肿瘤生长和转移的药物,可分为特异性和非特异性两大类。其作用机制主要有：（１）调控血管形成生长因子;（２）抑制基底膜降解;（３）影响信号转导通路;（４）调控细胞生长周期;（５）调控肿瘤机关基因。本文对其作用机制的进展作一综述。     

肿瘤组织缺氧诱导VEGF表达的分子机制

血管新生是恶性肿瘤生长、浸润和转移的前提条件,血管内皮生长因子是体内最重要的血管生长因子之一,而缺氧又是诱导肿瘤血管内皮生长因子表达的主要因素,本文对肿瘤组织缺氧诱导血管内皮生长因子表达的分子机制进行综述。     

肿瘤组织缺氧诱导VEGF表达的分子机制

血管新生是恶性肿瘤生长、浸润和转移的前提条件,血管内皮生长因子是体内最重要的血管生长因子之一,而缺氧又是诱导肿瘤血管内皮生长因子表达的主要因素,本文对肿瘤组织缺氧诱导血管内皮生长因子表达的分子机制进行综述。     

VEGF inhibition: insights from preclinical and clinical studies

Angiogenesis, the growth of new blood vessels, is required for a variety of normal proliferative processes. Furthermore, angiogenesis is well established as also playing an important role in neoplastic growth and metastasis. Numerous regulators of angiogenesis have been identified and characterized over the last few decades. Among these, vascular endothelial growth factor (VEGF)-A appears especially important in several pathophysiological processes. Several VEGF inhibitors have been approved, by the US Food and Drug Administration, for the treatment of tumors or age-releted macular degeneration. This review examines the various mouse tumor models in which VEGF inhibitors have been tested and the lessons learned from these studies.     

CD147与MMPs、VEGF在肿瘤发生发展中相互作用的研究进展

细胞外基质金属蛋白酶诱导因子（CD147）是一种高度糖基化的跨膜蛋白,属于免疫蛋白超家族成员。CD147为多功能型蛋白,可以参与人体的多种病理生理机制,其通过调节血管内皮生长因子（VEGF）和基质金属蛋白酶（MMPs）的表达参与恶性肿瘤的新生血管的生成及多重耐药性的产生。近年来随着对CD147在肿瘤发生发展中的研究不断深入,越来越多的发现使得CD147在肿瘤进展中的作用日益凸显。已经明确了其对肿瘤的进展及治疗的作用,在多种肿瘤中高表达,并随着肿瘤的恶性程度增高而增加,可以作为某些恶性肿瘤治疗的靶点。然而,CD147其他的功能包括充当T细胞的活化剂、神经识别分子和受体伴侣亲环素A的生理和病理机制还未明确。因此,有必要探索CD147在肿瘤中的特定功能,并阐明其产生机制是至关重要的。在此研究的基础上,现就CD147与MMPs、VEGF之间相互作用对肿瘤的转移和浸润的影响作一综述。     

Essential Role for Endocytosis in the Growth Factor-stimulated Activation of ERK1/2 in Endothelial Cells

Vascular endothelial growth factor (VEGF) stimulates angiogenesis by binding to VEGF receptor 2 (VEGFR2) on endothelial cells (ECs). Downstream activation of the extracellular related kinases 1/2 (ERK1/2) is important for angiogenesis to proceed. Receptor internalization has been implicated in VEGFR2 signaling, but its role in the activation of ERK1/2 is unclear. To explore this question we utilized pitstop and dynasore, two small molecule inhibitors of endocytosis. First, we confirmed that both inhibitors block the internalization of VEGFR2 in ECs. We then stimulated ECs with VEGF in the presence and absence of the inhibitors and examined VEGFR2 signaling to ERK1/2. Activation of VEGFR2 and C-Raf still occurred in the presence of the inhibitors, whereas the activation of MEK1/2 and ERK1/2 was abrogated. Therefore, although internalization is not required for activation of either VEGFR2 or C-Raf in ECs stimulated with VEGF, internalization is necessary to activate the more distal kinases in the cascade. Importantly, inhibition of internalization also prevented activation of ERK1/2 when ECs were stimulated with other pro-angiogenic growth factors, namely fibroblast growth factor 2 and hepatocyte growth factor. In contrast, the same inhibitors did not block ERK1/2 activation in fibroblasts or cancer cells stimulated with growth factors. Finally, we show that these small molecule inhibitors of endocytosis block angiogenesis in vitro and in vivo. Therefore, receptor internalization may be a generic requirement for pro-angiogenic growth factors to activate ERK1/2 signaling in human ECs, and targeting receptor trafficking may present a therapeutic opportunity to block tumor angiogenesis.     

Ligustrazine inhibits B16F10 melanoma metastasis and suppresses angiogenesis induced by Vascular Endothelial Growth Factor

Angiogenesis is crucial for tumor metastasis, with many compounds that inhibit tumor metastasis acting through suppression of angiogenesis. We investigated anti-angiogenic properties of Ligustrazine in a series of in vitro and in vivo models. Ligustrazine inhibited VEGF-induced HUVECs migration and tube formation in a dose-dependent manner in vitro, and had limited cytotoxicity to HUVECs and normal fibroblasts even at a dose up to 100 μg/ml. Ligustrazine also suppressed VEGF-induced rat aortic ring sprouting dose-dependently. Invivo, Ligustrazine reduced the Hb content in a Matrigel plug implanted in mice and inhibited new vessel formation in CAM. In addition, in a B16F10 spontaneous metastasis model, Ligustrazine decreased the expression of CD34 and VEGF in primary tumor tissue and reduced the number of metastasis nodi on the lung surface. Our data suggests that Ligustrazine may inhibit tumor metastasis, at least in part, through its anti-angiogenic activity.     

富亮氨酸alpha2 糖蛋白1（LRG1）在肿瘤中的研究进展

富亮氨酸琢2 糖蛋白1(Leucine-rich-alpha-2-glycoprotein1,LRG1）是富亮氨酸重复序列(leucine-rich repeat, LRR)家族蛋白成 员之一。LRG1 在人类多种肿瘤中表达异常,可以作为部分肿瘤早期诊断的潜在生物标记,而且这种异常表达可能提示患者预后 不良。LRG1 在肿瘤的发生、侵袭转移、上皮间质转化和血管生成中发挥重要作用。这些环节中,协同参与调控的辅助因子众多且 有差异,因而经历的信号途径有所不同。本文综合目前的研究进展,旨在阐述LRG1 与肿瘤的关系以及其调控肿瘤发生发展的分 子机制。LRG1 有望成为一种新的肿瘤分子标志物,将为恶性肿瘤的分子诊断及靶向治疗提供新的方向和手段。     

R-Ras Protein Inhibits Autophosphorylation of Vascular Endothelial Growth Factor Receptor 2 in Endothelial Cells and Suppresses Receptor Activation in Tumor Vasculature

Abnormal angiogenesis is associated with a broad range of medical conditions, including cancer. The formation of neovasculature with functionally defective blood vessels significantly impacts tumor progression, metastasis, and the efficacy of anticancer therapies. Vascular endothelial growth factor (VEGF) potently induces vascular permeability and vessel growth in the tumor microenvironment, and its inhibition normalizes tumor vasculature. In contrast, the signaling of the small GTPase R-Ras inhibits excessive angiogenic growth and promotes the maturation of regenerating blood vessels. R-Ras signaling counteracts VEGF-induced vessel sprouting, permeability, and invasive activities of endothelial cells. In this study, we investigated the effect of R-Ras on VEGF receptor 2 (VEGFR2) activation by VEGF, the key mechanism for angiogenic stimulation. We show that tyrosine phosphorylation of VEGFR2 is significantly elevated in the tumor vasculature and dermal microvessels of VEGF-injected skin in R-Ras knockout mice. In cultured endothelial cells, R-Ras suppressed the internalization of VEGFR2, which is required for full activation of the receptor by VEGF. Consequently, R-Ras strongly suppressed autophosphorylation of the receptor at all five major tyrosine phosphorylation sites. Conversely, silencing of R-Ras resulted in increased VEGFR2 phosphorylation. This effect of R-Ras on VEGFR2 was, at least in part, dependent on vascular endothelial cadherin. These findings identify a novel function of R-Ras to control the response of endothelial cells to VEGF and suggest an underlying mechanism by which R-Ras regulates angiogenesis.     

谷氨酰胺对胃癌患者血清VEGF，IL-8 及肿瘤标志物水平的影响

目的:探讨谷氨酰胺对胃癌术后血清VEGF、IL-8及肿瘤标志物水平影响。方法:收集我院胃癌需进行胃癌根治术患者92例,随机分为实验组和对照组。两组患者均根据自身病情进行胃癌根治术。术后第1天予250 mL生理盐水+2 mL亚甲蓝确认无反流后,对照组予以5%葡萄糖溶液500 mL泵入,第2天予能全力500 mL,第3天开始予以能全力1500 mL泵入;实验组在对照组基础上加用谷氨酰胺。两组均术前及术后第10天进行血清VEGF、IL-8及肿瘤标志物CEA、CA72-4、CA19-9水平检测。并于术前及术后1个月进行疼痛评估和生存质量评分。结果:1术后第10天两组患者血清VEGF、IL-8及肿瘤标志物CEA、CA72-4、CA19-9水平均下降,与对照组比较,实验组下降均更明显,差异有统计学意义(P0.05);2术后1个月两组患者VRS疼痛等级均下降,生存质量WHOQOL评分均上升,与对照组比较,实验组无疼痛人数明显增多、生存质量评分更高,差异有统计学意义(P0.05)。结论:谷氨酰胺可更显著改善胃癌术后患者血清VEGF、IL-8及肿瘤标志物水平,对提高患者机体免疫力、改善营养状态、提高患者生活质量有重要意义。