沙蟾毒精抑制血管生成的作用

探讨沙蟾毒精(arenobufagin)对体内外血管生成的抑制作用。采用MTT法检测沙蟾毒精对人鼻咽癌细胞(CNE-2)、人喉癌细胞(Hep2)、人神经母细胞瘤(SH-SY5Y)、人结肠癌细胞(LOVO)、人前列腺癌细胞(PC-3及DU145)和人脐静脉内皮细胞(HUVECs)的细胞毒性及运用光学显微镜观察细胞形态的变化,发现沙蟾毒精剂量依赖性抑制CNE-2、Hep2、SH-SY5Y、LOVO、PC-3、DU145和HUVECs增殖,且在对人癌细胞亚细胞毒浓度下能够有效抑制HUVECs的增殖。采用鸡胚尿囊膜(chick embryo chorioallantoic membrane,CAM)模型观察新生血管的生成,结果发现沙蟾毒精作用24 h后,尿囊膜新生血管生成明显减少。采用细胞周期分析法观察到沙蟾毒精阻滞HUVECs于G2/M期,且随着浓度增加,细胞出现sub-G1凋亡峰。运用流式细胞术检测沙蟾毒精作用HUVECs后的凋亡现象以及线粒体膜电位的变化,确证沙蟾毒精呈时间和剂量依赖性诱导HUVECs凋亡,同时检测到线粒体膜电位下降。Western blotting检测发现,沙蟾毒精作用HUVECs后,凋亡标志...     

cis-hinokiresinol, a norlignan from Anemarrhena asphodeloides, inhibits angiogenic response in vitro and in vivo

cis-Hinokiresinol (CHR) is a norlignan constituent from Anemarrhena asphodeloides BUNGE (Liliaceae), which shows hyaluronidase inhibitory activity. In the present studies, we have demonstrated that CHR selectively inhibited endothelial cell proliferation compared with cancer cells, and especially basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF)-induced endothelial cell proliferation. Furthermore, endothelial cell migration and tube formation, two important steps in the angiogenic process, were also inhibited by CHR. Moreover, CHR reduced the vessel growth induced by VEGF in the mouse corneal neovascularization model. These results suggest that CHR may prove useful for the development of a novel angiogenesis inhibitor.     

Protective role of wogonin against lipopolysaccharide-induced angiogenesis via VEGFR-2, not VEGFR-1

Wogonin, one of flavonoid derived from particular plants, enriches the property of anti-inflammation. Inflammation-stimulated angiogenesis plays an important role in many pathological diseases, such as rheumatoid arthritis, atherosclerosis, and cancer. The aim of this study was to investigate the suppressive effect of wogonin on lipopolysaccharide (LPS)-induced angiogenesis in human umbilical endothelial cell (HUVEC) cultures. By cell differentiation assays, migration and tube formation activity under LPS treatment were evaluated. Besides, IL-6 neutralizing antibody was added to test the inhibitory effect in the phenotypic alteration. Western blot analysis, ELISA cytokine assay, and quantitative real time-PCR were performed for VEGF, IL-6, VEGF receptors, and IL-6 receptor gene expressions on HUVEC with wogonin treatment. Furthermore, in vivo chorioallantoic membrane (CAM) assay was applied to evaluate the percentage of new vessels formation. The results revealed that wogonin (10(-8)-10(-5) M) inhibited LPS-induced angiogenesis in a concentration-dependent manner. The mRNA and protein expressions of VEGF, VEGFR-2, IL-6, and sIL-6Ralpha were attenuated (P<0.05), but not VEGFR-1. In the LPS-induced CAM model, our data suggested that wogonin (10(-8)-10(-5) M) significantly decreased new vessel formation and vascular network (P<0.05). We conclude that wogonin suppresses both in vitro and in vivo LPS-induced angiogenesis, through VEGFR-2, but not VEGFR-1.     

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.     

Anti-angiogenic activity of resveratrol, a natural compound from medicinal plants

Resveratrol (3,4',5-trihydroxy-trans-stilbene), a naturally occurring phytoalexin found in grapes and wine, possesses cancer-preventive activity. Angiogenesis is a crucial step in the growth and metastasis of cancers. We have investigated the effect of resveratrol on angiogenesis in vitro and ex vivo, and found that resveratrol directly inhibited human umbilical vein endothelial cell growth and decreased the gelatinolytic activities of matrix metalloproteinase-2. Tube formation was inhibited by treatment with resveratrol after plating endothelial cells on Matrigel. Resveratrol treatment also inhibited endothelial cell attachment to basement membrane components fibronectin and laminin, and displays similar behavior on cell chemotaxis. In addition, resveratrol has been found to be an angiogenesis inhibitor in the rat aorta matrix culture model. Therefore, inhibition of angiogenesis associated with cancer may be a novel mechanism for the anticancer activity of resveratrol.     

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 PGE? 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 PGE? 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.     

LYG-202, a Newly Synthesized Flavonoid,Exhibits Potent Anti-angiogenic Activity In Vitro and In Vivo

LYG-202 (C₂₅H₃₀N₂O₅) is a newly synthesized flavonoid that has been confirmed to possess an antitumor effect, but the mechanism is unclear. Our present study was performed to identify the anti-angiogenic activity of this novel compound in vitro and in vivo. LYG-202 inhibited vascular endothelial growth factor (VEGF) stimulated migration and tube formation of human umbilical vein endothelial cells and arrested microvessel outgrowth from rat aortic rings in vitro. Meanwhile, LYG-202 suppressed the neovascularization of Chicken Chorioallantoic Membrane in vivo. Mechanistic studies revealed that LYG-202 suppressed the VEGF-induced tyrosine phosphorylation of KDR/Flk-1 (VEGFR-2) as well as its downstream protein kinases activation, by decreasing phosphorylated forms of serine/threonine kinase Akt, extracellular signal-regulated kinase, and p38 mitogen-activated protein kinase. LYG-202 exerts anti-angiogenic activity both in vitro and in vivo, and these results suggest that it deserves further investigation as a promising anti–tumor angiogenesis compound.     

Flexible heteroarotinoid (Flex-Het) SHetA2 inhibits angiogenesis in vitro and in vivo

Summary  Flexible heteroarotinoids (Flex-Hets) compounds regulate growth, differentiation and apoptosis in cancer cells. The hypothesis of this study was that the lead Flex-Het, SHetA2, inhibits angiogenesis by blocking cytokine release from cancer cells. SHetA2 altered secretion of thrombospondin-4 (TSP-4), vascular endothelial growth factor A (VEGF) and fibroblast growth factor (bFGF) proteins from normal and cancerous ovarian and renal cultures. Thymidine phosphorylase (TP) expression was inhibited in cancer, but not normal cultures. Endothelial tube formation was stimulated by conditioned media from cancer but not normal cultures, and SHetA2 reduced secretion of this angiogenic activity. SHetA2 directly inhibited endothelial cell tube formation and proliferation through G1 cell cycle arrest, but not apoptosis. Recombinant TP reversed SHetA2 anti-angiogenic activity. SHetA2 inhibition of in vivo angiogenesis was observed in Caki-1 renal cancer xenografts. In conclusion, SHetA2 inhibits angiogenesis through alteration of angiogenic factor secretion by cancer cells and through direct effects on endothelial cells. Tashanna Myers, Shylet Chengedza, Stan Lightfoot, and Yanfang Pan contributed equally to this research.     

Novel Anti-Angiogenic and Anti-Tumour Activities of the N-Terminal Domain of NOEY2 via Binding to VEGFR-2 in Ovarian Cancer

The imprinted tumour suppressor NOEY2 is downregulated in various cancer types, including ovarian cancers. Recent data suggest that NOEY2 plays an essential role in regulating the cell cycle, angiogenesis and autophagy in tumorigenesis. However, its detailed molecular function and mechanisms in ovarian tumours remain unclear. In this report, we initially demonstrated the inhibitory effect of NOEY2 on tumour growth by utilising a xenograft tumour model. NOEY2 attenuated the cell growth approximately fourfold and significantly reduced tumour vascularity. NOEY2 inhibited the phosphorylation of the signalling components downstream of phosphatidylinositol-3’-kinase (PI3K), including phosphoinositide-dependent protein kinase 1 (PDK-1), tuberous sclerosis complex 2 (TSC-2) and p70 ribosomal protein S6 kinase (p70S6K), during ovarian tumour progression via direct binding to vascular endothelial growth factor receptor-2 (VEGFR-2). Particularly, the N-terminal domain of NOEY2 (NOEY2-N) had a potent anti-angiogenic activity and dramatically downregulated VEGF and hypoxia-inducible factor-1α (HIF-1α), key regulators of angiogenesis. Since no X-ray or nuclear magnetic resonance structures is available for NOEY2, we constructed the three-dimensional structure of this protein via molecular modelling methods, such as homology modelling and molecular dynamic simulations. Thereby, Lys15 and Arg16 appeared as key residues in the N-terminal domain. We also found that NOEY2-N acts as a potent inhibitor of tumorigenesis and angiogenesis. These findings provide convincing evidence that NOEY2-N regulates endothelial cell function and angiogenesis by interrupting the VEGFR-2/PDK-1/GSK-3β signal transduction and thus strongly suggest that NOEY2-N might serve as a novel anti-tumour and anti-angiogenic agent against many diseases, including ovarian cancer.     

Antiangiogenic effect of licochalcone A

To date, no antiangiogenic activity has been demonstrated for licochalcone A (LicA), a major phenolic constituent of Glycyrrhiza inflata, although it shows significant antitumor activity in human malignant cell lines. Our previous work demonstrated that LicA down-regulates inflammatory responses to lipopolysaccharide in murine macrophages. The purpose of the present study was to evaluate whether LicA inhibits angiogenesis, which is crucial for cancer development and progression. LicA significantly inhibited proliferation (20 μM), migration (5-20 μM), and tube formation (10-20 μM) of human umbilical vascular endothelial cells (HUVECs) as well as microvessel growth from rat aortic rings (10-20 μM). Furthermore, LicA significantly inhibited the growth of CT-26 colon cancer implants in BALB/c mice, with fewer CD31- and Ki-67-positive cells but more apoptotic cells. The underlying antiangiogenic mechanism of LicA correlated with down-regulation of vascular endothelial growth factor receptor (VEGFR)-2 activation. Our findings provide the first evidence that LicA inhibits angiogenesis in vitro and in vivo, perhaps by blocking VEGF/VEGFR-2 signaling. Inhibition of tumor growth may be attributed, at least in part, to decreased angiogenesis in LicA-treated mice. These findings emphasize the potential use of LicA against tumor development and progression in which angiogenesis is stimulated.     

Inhibition of human cancer cell line growth and human umbilical vein endothelial cell angiogenesis by artemisinin derivatives in vitro.

Artemisinin derivatives artesunate (ART) and dihydroartemisinin are remarkable anti-malarial drugs with low toxicity to humans. In the present investigation, we find they also inhibited tumor cell growth and suppressed angiogenesis in vitro. The anti-cancer activity was demonstrated by inhibition (IC(50)) of four human cancer cell lines: cervical cancer Hela, uterus chorion cancer JAR, embryo transversal cancer RD and ovarian cancer HO-8910 cell lines growth by the MTT assay. IC(50) values ranged from 15.4 to 49.7 microM or from 8.5 to 32.9 microM after treatment with ART or dihydroartemisinin for 48 h, indicating that dihydroartemisinin was more effective than ART in inhibiting cancer cell lines. The anti-angiogenic activities were tested on in vitro models of angiogenesis, namely, proliferation, migration and tube formation of human umbilical vein endothelial (HUVE) cells. We investigated the inhibitory effects of ART and dihydroartemisinin on HUVE cells proliferation by cell counting, migration into the scratch wounded area in HUVE cell monolayers and microvessel tube-like formation on collagen gel. The results showed ART and dihydroartemisinin significantly inhibited angiogenisis in a dose-dependent form in range of 12.5-50 microM and 2.5-50 microM, respectively. They indicated that dihydroartemisinin was more effective than ART in inhibiting angiogenesis either. These results and the known low toxicity are clues that ART and dihydroartemisinin may be promising novel candidates for cancer chemotherapy.     

Novel VEGFR-2 inhibitors with an N-acylhydrazone scaffold

Vascular endothelial growth factor receptor 2 (VEGFR-2) is a tyrosine kinase that mediates a large number of cell responses associated with angiogenesis. The control of the angiogenic pathway in tumorigenesis by the inhibition of VEGFR-2 is considered a promising therapeutic strategy for the prevention and control of solid tumor growth. In this study, the design, synthesis, and biological evaluation of a novel series of VEGFR-2 inhibitors with an N-acylhydrazone (NAH) scaffold ( 9a – h ) are reported. The molecular design is validated by docking studies and by in vitro inhibitory activity assays. Compounds 9b , 9c , 9d , and 9f effectively inhibited neovascularization induced by VEGF in the chorioallantoic membrane assay. Thus, these NAH derivatives are promising antiangiogenic prototypes.     

Zerumbone,Sesquiterpene Photochemical from Ginger,Inhibits Angiogenesis

Here, we investigated the role of zerumbone, a natural cyclic sesquiterpene of Zingiber zerumbet Smith, on angiogenesis using human umbilical vein endothelial cells (HUVECs). Zerumbone inhibited HUVECs proliferation, migration and tubule formation, as well as angiogenic activity by rat aorta explants. In particular, zerumbone inhibited phosphorylation of vascular endothelial growth factor receptor-2 and fibroblast growth factor receptor-1, which are key regulators of endothelial cell function and angiogenesis. In vivo matrigel plug assay in mice demonstrated significant decrease in vascularization and hemoglobin content in the plugs from zerumbone-treated mice, compared with control mice. Overall, these results suggest that zerumbone inhibits various attributes of angiogenesis, which might contribute to its reported antitumor effects.     

The mechanisms that regulate the localization and overexpression of VEGF receptor-2 are promising therapeutic targets in cancer biology

The vascular endothelial growth factor (VEGF) family has been proposed to be the most important signaling protein family in vessel formation and maturation. VEGF receptor-2 (VEGFR-2) plays an abundant role in the most common forms of cancer. The localization of VEGFR-2 expression is important in cancer pathogenesis; however, so far, little attention has been paid to this phenomenon. Induced cytoplasmic VEGFR-2 transition from the nucleus is associated with poor prognostic cancer stages. Current VEGFR-2-targeted therapy approaches are effective in inhibiting or arresting tumor growth. Moreover, VEGFR-2-targeted therapy was demonstrated to restore the abnormal vasculature in tumors, enhancing their susceptibility toward conventional therapy. Most effects can be found when VEGFR-2-targeted therapy inhibits not only the induced angiogenesis but also the cancer cells that sometimes overexpress VEGFR-2. Nevertheless, we still have little knowledge about the mechanisms that regulate VEGFR-2 expression and how its localization is exactly involved in cancer prognosis. Further research and evaluation of VEGFR-2 regulation and its nuclear transition is necessary to develop more accurate therapeutic strategies to improve the patients' quality of life and their survival.     

国产创新药安罗替尼抗肿瘤治疗的研究进展

血管新生是恶性肿瘤细胞增殖、生长、转移过程中的重要环节,抗肿瘤血管新生药物在肿瘤治疗中起重要作用。安罗替尼是我国自主研发的多靶点小分子酪氨酸激酶抑制剂,其主要作用于血管内皮生长因子受体(VEGFR)-1、VEGFR-2、VEGFR-3、血小板衍生生长因子受体、成纤维细胞生长因子受体、c-Kit、Ret等多个靶点,可以阻断肿瘤血管生成并抑制肿瘤生长。多项临床试验证实安罗替尼在非小细胞肺癌、软组织肉瘤、小细胞肺癌、甲状腺髓样癌、肾癌和结直肠癌中均具有良好的疗效和安全性。     

Synthesis and structure-activity relationships of pyrazine-pyridine biheteroaryls as novel, potent, and selective vascular endothelial growth factor receptor-2 inhibitors

There is much evidence that direct inhibition of the kinase activity of vascular endothelial growth factor receptor-2 (VEGFR-2) will result in the reduction of angiogenesis and the suppression of tumor growth. Palladium-catalyzed C-C bond, C-N bond formation reactions were used to assemble various pyrazine-pyridine biheteroaryls as potent VEGFR-2 inhibitors. Among them, 4-{5-[6-(3-chloro-phenylamino)-pyrazin-2-yl]-pyridin-3-ylamino}-butan-1-ol (39) and N-{5-[6-(3-chloro-phenylamino)-pyrazin-2-yl]-pyridin-3-yl}-N',N'-dimethyl-ethane-1,2-diamine (41) exhibited the highest kinase selectivity against fibroblast growth factor receptor kinase, platelet-derived growth factor receptor kinase, and glycogen synthase kinase-3. All of these compounds showed good cellular potency to inhibit VEGF-stimulated proliferation of human umbilical vein endothelial cells (HUVEC) but with modest effects on the unstimulated growth of HUVEC. The low inhibition of these compounds to the growth of tumor cell lines, such as HeLa, HCT-116, and A375 further confirms that these VEGFR-2 inhibitors are not cytotoxic agents. The in vivo antitumor activity of 39 and 41 were demonstrated in the A375 human melanoma xenograft nude mice model. Molecular modeling (QSAR analysis) was conducted in an attempt to rationalize the observed structure-activity relationship.     

Synthesis and discovery of pyrazine-pyridine biheteroaryl as a novel series of potent vascular endothelial growth factor receptor-2 inhibitors

Pathological angiogenesis is associated with disease states such as cancer, diabetic retinopathy, rheumatoid arthritis, endometriosis, and psoriasis. There is much evidence that direct inhibition of the kinase activity of vascular endothelial growth factor receptor-2 (VEGFR-2) will result in the reduction of angiogenesis and the suppression of tumor growth. Attempts to optimize a cyclin-dependent kinase-1 (CDK1) inhibitor by using palladium-catalyzed C-C bond, C-N bond formation reactions to assemble diverse biheteroaryl molecules led to the unexpected discovery of a pyrazine-pyridine biheteroaryl as a novel series of potent VEGFR-2 inhibitors. Compound 15, which had IC(50) = 0.084 microM at VEGFR-2, showed very modest selectivity against fibroblast growth factor receptor-2 (IC(50) = 0.21 microM), platelet-derived growth factor receptor (IC(50) = 0.36 microM), and glycogen synthase kinase-3 (IC(50) = 0.478 microM), while it exhibited more than 10-fold selectivity against epidermal growth factor receptor (IC(50) = 1.36 microM) and insulin-R kinase (IC(50) = 1.69 microM). On the other hand, compound 15 exhibited more than 100-fold selectivity against calmodulin kinase 2; casein kinase-1 and -2; CDK1 and -4; mitogen-activated protein kinase; and protein kinase A, Cbeta2, and Cgamma (IC(50) >10 microM). Compound 15 also displayed high inhibitory potency on VEGF-stimulated human umbilical vein endothelial cell (HUVEC) proliferation (IC(50) = 0.005 microM) and good selectivity against cell lines such as HUVEC, human aortic smooth muscle cells, and MRC5 lung fibroblasts. Molecular docking studies were conducted in an attempt to rationalize the unexpected high VEGFR-2 selectivity of 15.     

Modulation of human NK cell lines by vascular endothelial growth factor and receptor VEGFR-1 (FLT-1)

Our laboratory has previously reported that natural killer (NK) cells bind to angiogenic microvessels in established cancer metastases. Vascular endothelial growth factor (VEGF) plays an important role in solid tumor angiogenesis by enhancing new blood vessel formation to transport nutrients and oxygen into tumors. Here we report that the human natural killer cell lines, NK-92 and YT, express the mRNA message and protein product for VEGF-B and its receptor, VEGFR-1/Flt-1. While stimulation of these cells by the potent angiogenic factor VEGF-A165, which also binds to VEGFR-1, does not alter the proliferation of the cells, it does increase adhesion to a model basement membrane-like extracellular matrix, Matrigel. VEGF-A165 also induces NK cell binding to human microvascular endothelial cells in newly forming but not established microvessels in vitro. These results suggest that human NK cells produce an angiogenic factor which may be involved in autocrine and paracrine regulations of angiogenesis. VEGF-A165 appears to stimulate NK cell adhesion to the microvasculature within established cancer metastases.     

Vandetanib, a novel multitargeted kinase inhibitor, in cancer therapy

In clinical trials thus far, single-targeted kinase inhibitors have shown only limited success in demonstrating survival benefits in cancer. This has led to the development of multitargeted kinase inhibitors capable of disrupting various mitogenic pathways in both cancer cells and associated vasculature. Vandetanib is a novel multitargeted kinase inhibitor exhibiting potent activity against vascular endothelial growth factor receptor-2 (VEGFR-2; kinase insert domain-containing receptor [KDR]) and, to a lesser extent, epidermal growth factor receptor (EGFR) and RET kinase. Vascular endothelial growth factor (VEGF) and VEGFR-2 play a pivotal role in regulating angiogenesis and vascular permeability in cancers. In addition to its antiangiogenic effects, vandetanib acts against EGFR, which is overexpressed or mutated in several solid tumors. Furthermore, vandetanib exerts activity against oncogenic RET kinase, the overexpression of which is common in medullary and papillary thyroid carcinomas. Therefore, the multitargeted kinase inhibitor vandetanib represents a new approach, targeting both tumor cells and tumor-associated endothelial cells. Preclinical studies of vandetanib have demonstrated antitumor efficacy against multiple human cancer xenografts in subcutaneous, orthotopic and metastatic models. Phase I clinical trials have demonstrated that vandetanib is well tolerated. Common adverse events included rash, diarrhea and asymptomatic QTc prolongation. Phase II clinical studies in patients with non-small-cell lung cancer have shown promising results, employing vandetanib as both monotherapy and in combination with docetaxel. Phase II studies in other cancers have likewise been initiated. This review summarizes preclinical and clinical studies of vandetanib for the treatment of cancers.