内源性肿瘤血管形成抑制剂研究进展

肿瘤血管生成(angiogenesis)是指血管内皮细胞从现存的血管系统中分化、迁移而形成新的微血管的复杂生物学过程.成人的血管内皮细胞基本处于静止状态,在伤口愈合、组织修复、妇女生育和月经期、胎儿发育等生理刺激下出现新生血管生成,属于生理性血管生成.此时在血管生成刺激因子和抑制因子的严格控制和协调下,血管生成成为一个发生在有限时间内的有序生理过程,增生的内皮细胞很快恢复到正常的静止状态.只有当血管生成调节机制失控和血管生成过度时,血管生成才成为致病因素,导致风湿性关节炎、糖尿病性或黄斑变性视网膜病变、婴儿血管瘤和恶性肿瘤等血管生成依赖性疾病的发生和发展.内源性肿瘤血管形成抑制剂的研究将为这类疾病的治疗提供理论基础和临床治疗新药.     

内皮细胞与血管形成

最近的研究表明 ,虽然病原性血管因子很多 ,但在释放或受体水平 ,抑制专一性血管形成因子这一策略 ,可能成为安全、有效地治疗由血管形成介导的疾病的方法基础。生理性血管形成对血管的再生、成长和修复是至关重要的 ;而病理性血管形成则维系着血管疾病、肿瘤和致炎性疾病的发展进程。血管形成因子的种类有多种 ,都间接或直接作用于内皮细胞 ,这就说明内皮细胞对血管形成的影响尤为重要 ,这一作用靶点为一些与病理性血管形成有关的人类疾病提供了新的治疗策略。目前 ,大量的临床实验已证明了这一靶标在诊断与治疗中的重要作用     

靶向血管内皮生长因子/血管内皮生长因子受体-2的血管生成抑制剂

血管内皮生长因子(VEGF)及血管内皮生长因子受体-2(VEGFR-2)是调节血管生成、内皮细胞增殖和迁移等的关键调控因子。通过阻断VEGF与VEGFR-2的结合可抑制新生血管形成,而新生血管的形成是肿瘤生长和转移的基础。介绍VEGF/VEGFR-2在血管形成中的作用,以及具有抗肿瘤作用的靶向VEGF/VEGFR-2的血管生成抑制剂的研究近况。     

血管新生在心肌梗死中作用机制的研究进展

血管新生是指从已有的毛细血管或毛细血管后静脉发展而形成新的血管,是一个涉及多种细胞的多种分子的复杂过程。血管新生除对于恶性实体肿瘤外,在心血管疾病特别是缺血性心脏病中具有极其重要的意义。本文对血管新生机制进行了简单介绍,尤其是对与血管新生密切相关的多种调节因子、炎症因子以及凋亡相关因子等进行了初步探讨。     

VEGF及其促肿瘤血管形成作用的研究进展

肿瘤新血管的形成，对于直径大于2mm的实体肿瘤的生长及转移是必不可少的条件。恶性肿瘤组织可分泌多种促血管形因子，其中血管内生长因子(VEGF)是最重要的因子，在生理及病理条件下，具有很强的促血管形成作用，能调节血管内皮细胞的多种生物学功能。     

早期动脉粥样硬化血管内皮细胞损伤机制研究进展

自Ross提出动脉粥样硬化（AS）发病机制的＂损伤反应假说＂以来,血管内皮细胞损伤在AS的形成与发展中的地位日趋受到关注。糖尿病、高血脂和高血压等多种疾病,氧化应激以及炎症反应等各种相关因子作用于内皮细胞后,致其内皮细胞的调节血管张力、抗凝与促凝等功能障碍,血管活性物质、细胞因子、     

肿瘤血管生成抑制剂

恶性肿瘤的发展与侵袭均依赖于新生血管生成。肿瘤新生血管的生成受多种调节因子作用,这些调控因子主要有：血管内皮生长因子、血管生成素,成纤维细胞生长因子,血管抑素,内皮抑素,thrombospondin(TSP-1)等。通过抑制肿瘤新生血管的生成可以阻止肿瘤的发展和转移,甚至使肿瘤消退。抗血管生成药物为肿瘤的治疗提供了一个全新的思路,本文简单讨论了肿瘤血管生成与调节机制并着重介绍肿瘤血管生成抑制剂的研究进展。     

肿瘤血管内皮细胞和成纤维细胞表达血管形成因子

目的 :探讨肿瘤血管内皮细胞和成纤维细胞在肿瘤血管形成中的作用。方法 :对肿瘤血管内皮细胞和成纤维细胞模型ECV304 -SKOV3和L929-H22 细胞 ,用免疫细胞化学测定促进血管形成因子的表达、RT -PCR测定其端粒酶活性 ,并与亲代细胞比较。结果 :ECV304 -SKOV3细胞和L929-H22 细胞的端粒酶活性明显强于亲代细胞ECV304、L929,分别为0.778±0.011、0.875±0.026、0.692±0.014、0.684±0.012(P<0.001)。ECV304 -SKOV3细胞表达血管形成因子MMP -9、bcl -2增强 (P<0.05) ,TN减弱(P<0.05) ;L929-H22 细胞表达MMP -9、TGF -β1、TN、bcl-2增强 (P<0.01) ;二者表达PCNA增强 (P<0.01)。结论 :肿瘤血管内皮细胞和成纤维细胞存活能力、血管形成因子表达增强 ,可能参与肿瘤血管生成。     

子宫内膜异位症与新血管生成

子宫内膜异位症(endometriosis,Ems)是一种具有“恶性行为”的良性疾病,它的发病机制至今尚未完全明确,最被公认的Sampson经血逆流种植学说指出新血管生成是Ems发生的必要条件,大量的基础实验和临床研究也证实了该观点。本文仅就血管促进因子在新血管生成中的作用以及血管生成抑制剂对Ems的治疗作用两方面做一综述。     

肿瘤血管生成的靶向调控及其药物研究进展

肿瘤血管生成(Tumor Angiogenesis)对大多数实体瘤的生长和转移具有重要意义,是多步骤多因素参与复杂的病理过程.选择肿瘤血管生成中的一些关键环节或参与的重要因子作为靶点,研制应用特异性肿瘤血管生成抑制剂或抗体,以靶向调控肿瘤血管生成,控制肿瘤的生长和转移,达到治疗肿瘤的目的.本文对近年来肿瘤血管生成机制和肿瘤血管生成抑制剂的研究进展进行综述.     

Inhibition of angiogenesis by staurosporine, a potent protein kinase inhibitor.

The effect of staurosporine, a potent inhibitor of protein kinases, on embryonic angiogenesis was studied in an in vivo assay system involving chorioallantoic membranes of growing chick embryo. Staurosporine inhibited embryonic angiogenesis in a dose-related manner, the ID50 value being 71 pmol/egg. Staurosporine dose-dependently suppressed the proliferation of vascular endothelial cells, an important event involved in the angiogenesis process. The IC50 value was 0.88 nM. In contrast, staurosporine did not affect the migration of vascular endothelial cells. These results suggest that staurosporine affected embryonic angiogenesis probably by inhibiting endothelial cell proliferation. In addition, these results might support the notion that certain protein kinase(s) could be implicated in induction of angiogenesis and also that staurosporine would be a useful compound for studying a mode of action of angiogenesis occurring in various diseases, including tumor development.     

Antiangiogenic properties of an unusual benzo[k,l]xanthene lignan derived from CAPE (Caffeic Acid Phenethyl Ester)

Angiogenesis is normally a highly regulated process that occurs during development, reproduction, and wound repair. However, angiogenesis can also become a fundamental pathogenic process in cancer and several other diseases. To date, the synthesis of angiogenesis inhibitors has been researched in several ways also starting from bioactive plant compounds. In the present study, we tested both in an angiogenesis bioassay and in ovarian cell culture, the potential antiangiogenic effect of a natural-derived benzo[k,l]xanthene lignan (5). This unusual compound was synthesized through the biomimetic dimerization of CAPE (Caffeic Acid Phenetyl Ester), a bioactive component of honeybee propolis. The lignan showed a significant, dose-related inhibitory effect on new vessel growth in the angiogenesis bioassay and it inhibited Vascular Endothelial Growth Factor secretion in ovarian cell culture. Therefore, we indicate the natural-derived benzo[k,l]xanthene lignan 5 as a potential new angiogenesis inhibitor.     

Angiogenesis and its inhibition: potential new therapies in oncology and non-neoplastic diseases.

To summarise the key points: The ability to mount an angiogenic response is probably present in all tissues, and stimulation of endothelial cells by any one of a wide variety of factors initiates a cascade of events leading to angiogenesis. In most tissues the overall lack of angiogenesis in normal situations probably results from the interaction of a complex series of multifactorial systems, each of which maintained in a state of balance between stimulation and inhibition. An imbalance in any one of these systems, for example by an increase in the concentration of a growth factor, may lead to angiogenesis. Inhibition of angiogenic stimuli is unlikely to be effective as an approach to new angiostatic drugs, given the multiple stimulatory pathways available. Tumour cells for example may induce angiogenesis via release of numerous growth factors, prostaglandins etc, and by their attraction of inflammatory cells which in turn release multiple angiogenic stimuli. Inhibitory modulation of many of the individual steps of capillary growth which occur following an angiogenic stimulus can block the angiogenic response. This leads to the expectation that an effective inhibitor of a single key step in this cascade would be able to completely suppress angiogenesis. Inappropriate angiogenesis is an important factor in many diseases including cancer and arthritis. In particular angiogenesis is an absolute requirement for neoplastic growth of solid tumours, and the establishment of secondary growths. There is also a strong link between induction of angiogenesis by a tumour and its ability to metastasise. Several drugs with proven clinical effects in diseases involving angiogenesis have recently been found to be angiogenesis inhibitors, and this may be their primary mechanism of action. In particular the activities of methotrexate and gold compounds in arthritis, and alpha-interferon and medroxyprogesterone in cancer therapy may be due to inhibition of angiogenesis. In animal models, treatment with angiogenesis inhibitors has proven anti-tumour effects in vivo, and can both reduce metastases and lead to regression of the primary growth by necrosis following capillary retraction. In man the success of alpha-interferon and TNF alpha in AIDS related Kaposi's sarcoma may be due to inhibition of angiogenesis. Interferon has also been successfully used to treat pulmonary hemangiomatosis, in which angiogenesis in the lung may be the pathogenic basis of the disease.     

Characterization of rat aortic fragment within collagen gel as an angiogenesis model; capillary morphology may reflect the action mechanisms of angiogenesis inhibitors

A fragment of rat thoracic aorta within type I collagen gel was employed as a model of angiogenesis, including the processes of cell migration, proliferation and capillary tube formation. Endogenous angiogenic factors in this model were studied. Expressions of vascular endothelial growth factor (VEGF) and its receptor, and proteolytic enzyme activities (matrix metalloprotease-2; MMP-2 and plasminogen activator; PA) increased during angiogenesis. The angiogenesis was inhibited by VEGF receptor kinase inhibitor and MMP inhibitor, confirming that these endogenous factors played an important role in angiogenesis. Interestingly, these inhibitors induced different capillary morphologies, including differences of cell migration and sprouting. Furthermore, dexamethasone (a down-regulator of MMP and PA) and TNP-470 (an endothelial cell growth inhibitor) induced another capillary morphology. The results suggest that the capillary structure in this model is dramatically influenced by the inhibition of angiogenic signalling and extracellular matrix (ECM) degradation. We also found that a novel angiogenesis inhibitor, the microbial metabolite luminacin, which was recently identified by us (Wakabayashi et al., J. Antiobiot., 53, 591-596 (2000)), induced a different morphology compared with other inhibitors examined, suggesting that it has a unique mechanism of action. Our results indicate that this rat aorta model should be useful for screening novel angiogenesis inhibitors.     

Angiogenesis: Future of pharmacological modulation

Angiogenesis is a fundamental biological process that is regulated by a fine balance between pro- and antiangiogenic molecules, and is deranged in various diseases. Historically, angiogenesis was only implicated in few diseases, such as, cancer, arthritis, and psoriasis. However, in recent years, it has been increasingly evident that excessive, insufficient or abnormal angiogenesis contributes to the pathogenesis of many more disorders. Research in angiogenesis offers a potential to cure a variety of diseases such as Alzheimer''s and AIDS. Modulation of angiogenesis may have an impact on diseases in the twenty-first century similar to that which the discovery of antibiotics had in the twentieth century.     

TGF-β1 enhances tumor-induced angiogenesis via JNK pathway and macrophage infiltration in an improved zebrafish embryo/xenograft glioma model

Angiogenesis plays a crucial role at the early stage of tumorigenesis and tumor progression. A suitable model will be useful not only for the clarification of the underlying molecular mechanisms, but also for high-throughput identification of novel anti-angiogenesis compounds. Here, we established a zebrafish model for the purpose to investigate angiogenesis and screen anti-angiogenic compounds. Glioma U87 cells expressing red fluorescent protein (RFP) were transplanted in fli:GFP transgenic zebrafish embryos where significant angiogenesis was observed. TGF-β1 enhanced glioma-induced angiogenesis, which was inhibited by JNK inhibitor SP600125 but not p38 MAPK inhibitor SB202190, ERK inhibitor PD98059, or PI3K inhibitor LY294002, indicating the important role of TGF-β1 and JNK pathways in this process. Moreover, the glioma-induced angiogenesis was associated with macrophage infiltration that was further enhanced by TGF-β1. Therefore, our zebrafish model provides a powerful in vivo tool for the investigation of tumor-induced angiogenesis, and a cost-effective system for high-throughput screening of anti-angiogenic compounds.     

血管生成抑制剂的研究进展

目的探讨血管生成抑制剂的作用靶点及其分类,对临床研究进展进行综述,尤其在肿瘤方面,为新药合成和发现提供参考。方法综述了近年来国内外相关报道,根据血管生成抑制剂的作用靶点进行分类,并对临床研究和作用机制进行讨论,重点强调了小分子酪氨酸激酶(protein-tyrosine kinases,PTK)抑制剂的分类和作用机制。结果血管生成抑制剂分为八大类,分别进行抗肿瘤治疗的讨论,并就其代表药物及开发上市状况进行概述,同时阐明血管生成抑制剂的其他应用。结论血管生成抑制剂与传统的化疗药物抑制肿瘤细胞相比,能够直接抑制血管生成,这将在抗肿瘤转移方面有广阔的前景。     

Vascular endothelial growth factor increases heme oxygenase-1 protein expression in the chick embryo chorioallantoic membrane

(1) Vascular endothelial growth factor (VEGF) is a potent angiogenic factor. It has been recently suggested that the inducible heme oxygenase (HO-1) isoform may play a role in angiogenesis. (2) The aims of this study were to determine, in chicken embryo chorioallantoic membranes (CAM), whether VEGF increases HO-1 protein expression, and, if so, by which molecular mechanism, and whether HO-1 activity is required for VEGF-induced angiogenesis. (3) Treatment of CAMs with VEGF for 48 h caused a significant increase in HO-1 protein expression, simultaneously with angiogenesis. (4) VEGF-stimulated angiogenesis in CAMs was markedly attenuated by the HO inhibitor zinc mesoporphyrin (ZnMP). This inhibitory effect of ZnMP was not observed with copper mesoporphyrin (CuMP), a metalloporphyrin that has a similar structure to ZnMP but does not inhibit HO enzymatic activity. (5) Overexpression of HO-1 protein elicited by VEGF in CAMs was significantly attenuated by the intracellular calcium chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA-AM). The effects of BAPTA-AM were, in turn, compensated by the calcium ionophore A-23187. (6) In addition, the protein kinase C inhibitor staurosporine significantly attenuated, in a dose-dependent manner, the VEGF-stimulated HO-1 induction observed in CAMs. (7) These results demonstrate, for the first time, that VEGF upregulates HO-1 protein expression in vivo in CAMs by a mechanism dependent on an increase in cytosolic calcium levels and activation of protein kinase C. Our findings also suggest that HO-1 activity is necessary for VEGF-induced angiogenesis in CAMs.     

Role of angiopoietin-2 in inflammatory autoimmune diseases: A comprehensive review

Angiogenesis is defined as the growth of new capillaries sprouting from pre-existing vasculature. Pathological angiogenesis signals can lead to dysregulated development of new vessels. Inflammation is accompanied by pathological angiogenesis. During an inflammatory process, newly formed blood vessels provide oxygen and nutrients to the inflamed tissue, facilitating the transport of inflammatory cells. Therefore, angiogenesis is closely related to pathogenesis of inflammatory autoimmune diseases. As a member of the angiopoietin family, Angiopoietin-2 (Ang-2) plays an irreplaceable role in angiogenesis. This review will narrate the expression of Ang-2 and its role in inflammatory autoimmune diseases. Collecting this information may improve the acquaintance of Ang-2 and provide a theoretical foundation for clinical trials and drug development in the future.