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M Ziche

Publications and source records attributed to M Ziche.

At least 37 records · Page 2Linked to original sources
PubMed1999

Induction of inflammatory angiogenesis by monocyte chemoattractant protein-1.

Almost any growth of tumors is to some extent associated with an inflammatory reaction which may be anti-tumorigenic by acting directly on tumor cells or protumorigenic cells presumably by inducing tumor-associated angiogenesis. In this study, we have analyzed the angiogenesis-inducing capacity of monocyte chemoattractant protein-1 (MCP-1), a key regulatory molecule of monocyte trafficking to sites of inflammation. MCP-1 was found to be potently angiogenic when implanted into rabbit cornea, exerting potency similar to the specific angiogenic vascular endothelial growth factor (VEGF)-A(121). MCP-1-induced angiogenesis in the cornea is associated with prominent recruitment of macrophages, whereas VEGF-A(121)-induced corneal angiogenesis is devoid of inflammatory cell recruitment. Based on these findings, we studied MCP-1 expression and macrophage recruitment in human invasive ductal mammary carcinomas in comparison with the physiological angiogenic processes in bovine ovarian corpus luteum. Macrophage recruitment was always associated with MCP-1 expression. High macrophage counts in mammary tumors corresponded with poor prognosis. In contrast, physiological ovarian angiogenesis was associated with only minimal inflammatory recruitment of macrophages. Our data show that MCP-1 is an indirect inflammation-associated inducer of angiogenesis and demonstrate distinct qualitative differences between tumor angiogenesis in human mammary tumors and physiological angiogenesis in the ovary.

Animals↗
PubMed1999

c-fos-induced growth factor/vascular endothelial growth factor D induces angiogenesis in vivo and in vitro.

c-fos-induced growth factor/vascular endothelial growth factor D (Figf/Vegf-D) is a secreted factor of the VEGF family that binds to the vessel and lymphatic receptors VEGFR-2 and VEGFR-3. Here we report that Figf/Vegf-D is a potent angiogenic factor in rabbit cornea in vivo in a dose-dependent manner. In vitro Figf/Vegf-D induces tyrosine phosphorylation of VEGFR-2 and VEGFR-3 in primary human umbilical cord vein endothelial cells (HUVECs) and in an immortal cell line derived from Kaposi's sarcoma lesion (KS-IMM). The treatment of HUVECs with Figf/Vegf-D induces dose-dependent cell growth. Figf/VEGF-D also induces HUVEC elongation and branching to form an extensive network of capillary-like cords in three-dimensional matrix. In KS-IMM cells Figf/Vegf-D treatment results in dose-dependent mitogenic and motogenic activities. Taken together with the previous observations that Figf/Vegf-D expression is under the control of the nuclear oncogene c-fos, our data uncover a link between a nuclear oncogene and angiogenesis, suggesting that Figf/Vegf-D may play a critical role in tumor cell growth and invasion.

Animals↗
PubMed1999

Purine analogue 6-methylmercaptopurine riboside inhibits early and late phases of the angiogenesis process.

Angiogenesis has been identified as an important target for antineoplastic therapy. The use of purine analogue antimetabolites in combination chemotherapy of solid tumors has been proposed. To assess the possibility that selected purine analogues may affect tumor neovascularization, 6-methylmercaptopurine riboside (6-MMPR), 6-methylmercaptopurine, 2-aminopurine, and adenosine were evaluated for the capacity to inhibit angiogenesis in vitro and in vivo. 6-MMPR inhibited fibroblast growth factor-2 (FGF2)-induced proliferation and delayed the repair of mechanically wounded monolayer in endothelial GM 7373 cell cultures. 6-MMPR also inhibited the formation of solid sprouts within fibrin gel by FGF2-treated murine brain microvascular endothelial cells and the formation of capillary-like structures on Matrigel by murine aortic endothelial cells transfected with FGF2 cDNA. 6-MMPR affected FGF2-induced intracellular signaling in murine aortic endothelial cells by inhibiting the phosphorylation of extracellular signal-regulated kinase-2. The other molecules were ineffective in all of the assays. In vivo, 6-MMPR inhibited vascularization in the chick embryo chorioallantoic membrane and prevented blood vessel formation induced by human endometrial adenocarcinoma specimens grafted onto the chorioallantoic membrane. Also, topical administration of 6-MMPR caused the regression of newly formed blood vessels in the rabbit cornea. Thus, 6-MMPR specifically inhibits both the early and the late phases of the angiogenesis process in vitro and exerts a potent anti-angiogenic activity in vivo. These results provide a new rationale for the use of selected purine analogues in combination therapy of solid cancer.

2-Aminopurine↗
PubMed1999

A novel vascular endothelial growth factor encoded by Orf virus, VEGF-E, mediates angiogenesis via signalling through VEGFR-2 (KDR) but not VEGFR-1 (Flt-1) receptor tyrosine kinases.

The different members of the vascular endothelial growth factor (VEGF) family act as key regulators of endothelial cell function controlling vasculogenesis, angiogenesis, vascular permeability and endothelial cell survival. In this study, we have functionally characterized a novel member of the VEGF family, designated VEGF-E. VEGF-E sequences are encoded by the parapoxvirus Orf virus (OV). They carry the characteristic cysteine knot motif present in all mammalian VEGFs, while forming a microheterogenic group distinct from previously described members of this family. VEGF-E was expressed as the native protein in mammalian cells or as a recombinant protein in Escherichia coli and was shown to act as a heat-stable, secreted dimer. VEGF-E and VEGF-A were found to possess similar bioactivities, i.e. both factors stimulate the release of tissue factor (TF), the proliferation, chemotaxis and sprouting of cultured vascular endothelial cells in vitro and angiogenesis in vivo. Like VEGF-A, VEGF-E was found to bind with high affinity to VEGF receptor-2 (KDR) resulting in receptor autophosphorylation and a biphasic rise in free intracellular Ca2+ concentration, whilst in contrast to VEGF-A, VEGF-E did not bind to VEGF receptor-1 (Flt-1). VEGF-E is thus a potent angiogenic factor selectively binding to VEGF receptor-2. These data strongly indicate that activation of VEGF receptor-2 alone can efficiently stimulate angiogenesis.

Amino Acid Sequence↗
PubMed1999

Role of nitric oxide in the angiogenesis of avascular tissue.

A number of independent lines of evidence converge indicating a role for nitric oxide (NO) in angiogenesis. Our data support the existence of an autocrine loop exerted by microvascular endothelium in angiogenesis which involves NO production, cyclic GMP elevation and fibroblast growth factor-2 (FGF-2) expression. Our results indicate that NO production significantly contributes to the growth-promoting effect of vasodilating peptides and vascular endothelial growth factor (VEGF), but not for that of FGF-2. On these basis, the nitric oxide pathway appears to be a promising target to be considered in pro- and anti-angiogenic therapeutic strategies.

Animals↗
PubMed1999

Interaction of fibroblast growth factor-2 (FGF-2) with free gangliosides: biochemical characterization and biological consequences in endothelial cell cultures.

Exogenous gangliosides affect the angiogenic activity of fibroblast growth factor-2 (FGF-2), but their mechanism of action has not been elucidated. Here, a possible direct interaction of sialo-glycolipids with FGF-2 has been investigated. Size exclusion chromatography demonstrates that native, but not heat-denatured, 125I-FGF-2 binds to micelles formed by gangliosides GT1b, GD1b, or GM1. Also, gangliosides protect native FGF-2 from trypsin digestion at micromolar concentrations, the order of relative potency being GT1b > GD1b > GM1 = GM2 = sulfatide > GM3 = galactosyl-ceramide, whereas asialo-GM1, neuraminic acid, and N-acetylneuramin-lactose were ineffective. Scatchard plot analysis of the binding data of fluorochrome-labeled GM1 to immobilized FGF-2 indicates that FGF-2/GM1 interaction occurs with a Kd equal to 6 microM. This interaction is inhibited by the sialic acid-binding peptide mastoparan and by the synthetic fragments FGF-2(112-129) and, to a lesser extent, FGF-2(130-155), whereas peptides FGF-2(10-33), FGF-2(39-59), FGF-2(86-96), and the basic peptide HIV-1 Tat(41-60) were ineffective. These data identify the COOH terminus of FGF-2 as a putative ganglioside-binding region. Exogenous gangliosides inhibit the binding of 125I-FGF-2 to high-affinity tyrosine-kinase FGF-receptors (FGFRs) of endothelial GM 7373 cells at micromolar concentrations. The order of relative potency was GT1b > GD1b > GM1 > sulfatide a = sialo-GM1. Accordingly, GT1b,GD1b, GM1, and GM2, but not GM3 and asialo-GM1, prevent the binding of 125I-FGF-2 to a soluble, recombinant form of extracellular FGFR-1. Conversely, the soluble receptor and free heparin inhibit the interaction of fluorochrome-labeled GM1 to immobilized FGF-2. In agreement with their FGFR antagonist activity, free gangliosides inhibit the mitogenic activity exerted by FGF-2 on endothelial cells in the same range of concentrations. Also in this case, GT1b was the most effective among the gangliosides tested while asialo-GM1, neuraminic acid, N-acetylneuramin-lactose, galactosyl-ceramide, and sulfatide were ineffective. In conclusion, the data demonstrate the capacity of exogenous gangliosides to interact with FGF-2. This interaction involves the COOH terminus of the FGF-2 molecule and depends on the structure of the oligosaccharide chain and on the presence of sialic acid residue(s) in the ganglioside molecule. Exogenous gangliosides act as FGF-2 antagonists when added to endothelial cell cultures. Since gangliosides are extensively shed by tumor cells and reach elevated levels in the serum of tumor-bearing patients, our data suggest that exogenous gangliosides may affect endothelial cell function by a direct interaction with FGF-2, thus modulating tumor neovascularization.

Animals↗
PubMed1998

Role of nitric oxide in angiogenesis and tumor progression in head and neck cancer.

BACKGROUND: Angiogenesis (formation of new blood vessels) is associated with tumor growth and metastasis in patients with solid tumors, including those of the head and neck. Nitric oxide (NO) production may contribute to these processes. We assessed the role of the NO pathway in angiogenesis and tumor progression in patients with head and neck cancer. METHODS: Biochemical assays were used to measure NO synthase (NOS) activity and cyclic guanosine monophosphate (cGMP) levels in specimens of tumor and normal mucosa obtained from 27 patients. Microvessels in tumor specimens were identified by CD-31-specific immunohistochemical staining. Associations between microvessel densities, levels of NOS, and cGMP were examined by use of two-sided statistical tests. Tumor specimens and human squamous carcinoma A-431 cells were grown as explants on the corneas of rabbits, and the effect of the NOS inhibitor N(omega)-nitro-L-arginine-methyl ester (L-NAME) was tested. RESULTS: Levels of total NOS, inducible NOS, and cGMP were higher in tumor specimens than in specimens of normal mucosa (all P<.0001). Tumor specimens from patients with lymph node metastases presented a higher total NOS activity (P = .005) and were markedly more vascularized than tumor specimens from patients with no lymph node involvement (P = .0002). Microvessel density at the tumor edge was an independent predictor of metastasis for this series of patients (odds ratio = 1.19; 95% confidence interval = 1.07-2.89; P = .04). A-431 cells and tumor specimens exhibiting high levels of NOS activity induced angiogenesis in the rabbit cornea assay; when NO production was blocked, tumor angiogenesis and growth were repressed. CONCLUSIONS: The NO pathway appears to play a key role in tumor angiogenesis and spread in patients with head and neck cancer.

Adult↗
PubMed1998

Nitric oxide is an upstream signal of vascular endothelial growth factor-induced extracellular signal-regulated kinase1/2 activation in postcapillary endothelium.

We recently demonstrated that nitric oxide (NO) significantly contributes to the mitogenic effect of vascular endothelial growth factor (VEGF), suggesting a role for the NO pathway in the signaling cascade following kinase-derivative receptor activation in vascular endothelium. The aim of this study was to investigate the intracellular pathways linked to VEGF/NO-induced endothelial cell proliferation. We assessed the activity of the mitogen-activated protein kinase (MAPK) that is specifically activated by growth factors, extracellular-regulated kinase (ERK1/2), on cultured microvascular endothelium isolated from coronary postcapillary venules. ERK1/2 was immunoprecipitated, and its activity was assessed with an immunocomplex kinase assay. In endothelial cells exposed for 5 min to the NO donor drug sodium nitroprusside at a concentration of 100 microM, ERK1/2 activity significantly increased. VEGF produced a time- and concentration-dependent activation of ERK1/2. Maximal activity was obtained after 5 min of stimulation at a concentration of 10 ng/ml. The specific MAPK kinase inhibitor PD 98059 abolished ERK1/2 activation and endothelial cell proliferation in a concentration-dependent manner in response to VEGF and sodium nitroprusside. The NO synthase inhibitor Nomega-monomethyl-L-arginine, as well as the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, blocked the activation of ERK1/2 induced by VEGF, suggesting that NO and cGMP contributed to the VEGF-dependent ERK1/2 activation. These results demonstrate for the first time that kinase-derivative receptor activation triggers the NO synthase/guanylate cyclase pathway to activate the MAPK cascade and substantiates the hypothesis that the activation of ERK1/2 is necessary for VEGF-induced endothelial cell proliferation.

Calcium↗
PubMed1998

Endothelial cell migration is induced by soluble P-selectin.

We have assessed the role of soluble P-selectin in promoting endothelial cell migration. Human endothelial cells (HUVEC) and bovine microvascular endothelial cells (CVEC) were assessed for migration in the Neuroprobe 48-well microchemotaxis chamber. Soluble P-selectin promoted a dose-dependent (0.1-10 nM) migration of both cell types, with maximal response at 10 nM, producing approximately 60% increment over basal migration. Anti-P-selectin monoclonal antibody (5 microg/ml) selectively blocked P-selectin induced migration. Fibronectin and collagen were essential to disclose the migration induced by P-selectin. It is suggested that at vascular level in the presence of modifications of the extracellular matrix milieu, the production of soluble P-selectin could contribute to angiogenesis by promoting endothelial cell migration.

Animals↗
PubMed1998

Linomide blocks angiogenesis by breast carcinoma vascular endothelial growth factor transfectants.

The blocking of angiogenesis provides a novel therapeutic target to inhibit tumour spreading. In this study, we investigated the effect of linomide on angiogenesis induced in vivo by highly angiogenic breast carcinoma cells. The rabbit cornea was used to assess neovascular growth in the absence of a tumour mass. MCF-7 cells stably transfected with the cDNA encoding for vascular endothelial growth factor 121 (VEGF121) (V12 clone) were used to elicit a potent VEGF-dependent corneal angiogenesis. After tumour cell implant, albino rabbits received 100 mg kg(-1) day(-1) linomide for 5 consecutive days. Daily observation of neovascular progression indicated that linomide blocked angiogenesis. The antiangiogenic effect of linomide was apparent within 48 h from the beginning of the treatment and was both angiosuppressive and angiostatic. The block of neovascular growth lasted over 10 days from treatment suspension, and preformed vessels, which had regressed, remained dormant, suggesting the persistence of unfavourable conditions for capillary progression. Linomide (50-200 microg ml[-1]) was not cytotoxic in vitro on resting capillary endothelial cells but blocked endothelial cell replication induced by VEGF. Our data indicate that linomide can efficiently and persistently block VEGF-dependent angiogenesis in vivo in the absence of a growing tumour mass. These data suggest that linomide could be a chemopreventive drug in breast cancer patients and a valuable tool in clinical settings in which metastatic spreading occurs in the absence of a detectable tumour mass.

Animals↗
PubMed1998

B1 receptor involvement in the effect of bradykinin on venular endothelial cell proliferation and potentiation of FGF-2 effects.

1. Bradykinin (BK) contributes to the inflammatory response inducing vasodilation of postcapillary venules and has been demonstrated to induce neovascular growth in subcutaneous rat sponges. 2. In this study the ability of BK to stimulate cell growth and migration in cultured endothelium from coronary postcapillary venules (CVEC) has been investigated. 3. [3H]-thymidine incorporation in subconfluent and synchronised CVEC was used to monitor DNA synthesis over 24 h. BK promoted a concentration-dependent increase of DNA synthesis with maximal activity at 100 nM. At this concentration BK also induced 18 fold accumulation of c-Fos protein immunoreactivity in the nucleus within 1 h from peptide exposure. 4. The total number of cells recovered after 48 h exposure to BK was increased in a concentration-dependent manner. Maximal effect was produced by 100 nM concentration of the peptide which produced 50% increase in cell number. The selective B1 receptor agonist Des-Arg9-BK mimicked the proliferative effect of BK, while the B2 receptor agonist kallidin was devoid of any activity. The proliferation induced by BK was abolished in a concentration-dependent manner by the addition of the B1 selective antagonist Des-Arg9-Leu8-BK, while the selective B2 receptor antagonist HOE140 did not modify BK-induced growth. 5. DNA synthesis and growth promoted by a threshold concentration of fibroblast growth factor-2 (FGF-2) (0.25 nM) were potentiated by increasing concentrations of BK and Des-Arg9-BK. 6. Endothelial cell migration assessed by the Boyden Chamber procedure was not promoted by BK or the selective B1 and B2 receptor agonists. 7. These data are the first demonstration that BK promotes growth of endothelial cells from postcapillary venules. The mitogenic activity of BK involves c-Fos expression and potentiates the growth promoting effect of FGF-2. Only the B1 receptor appears to be responsible for the proliferation induced by BK and suggests that this type of receptor might be implicated in favouring angiogenesis of coronary venules.

Animals↗
PubMed1998

VEGF upregulates ecNOS message, protein, and NO production in human endothelial cells.

Vascular endothelial growth factor (VEGF) is an endothelium-specific secreted protein that potently stimulates vasodilation, microvascular hyperpermeability, and angiogenesis. Nitric oxide (NO) is also reported to modulate vascular tone, permeability, and capillary growth. Therefore, we hypothesized that VEGF might regulate endothelial production of NO. The production of nitrogen oxides by human umbilical vein endothelial cells (HUVECs) was measured after 1, 12, 24, and 48 h of incubation with VEGF. VEGF treatment resulted in both an acute (1 h) and chronic (> 24 h) stimulation of NO production. Furthermore, Western and Northern blotting revealed a VEGF-elicited, dose-dependent increase in the cellular content of endothelial cell nitric oxide synthase (ecNOS) message and protein that may account for the chronic upregulation of NO production elicited by VEGF. Finally, endothelial cells pretreated with VEGF for 24 h and subsequently exposed to A-23187 for 1 h produced NO at approximately twice the rate of cells that were not pretreated with VEGF. We conclude that VEGF upregulates ecNOS enzyme and elicits a biphasic stimulation of endothelial NO production.

Calcium↗
PubMed1998

Urokinase-dependent angiogenesis in vitro and diacylglycerol production are blocked by antisense oligonucleotides against the urokinase receptor.

The plasminogen activator system is known to play a crucial role in the angiogenesis process by modulating the adhesive properties of endothelial cells to the extracellular matrix and cell-cell interaction. In the present study, we demonstrated that the urokinase-type plasminogen activator (u-PA) induced neovascular growth in the avascular rabbit cornea and dose-dependently promoted growth, chemotaxis, and matrix invasion of cultured endothelial cells. Interaction between u-PA and its receptor appears to be mandatory for the angiogenic effect of u-PA because monoclonal antibodies anti-u-PA and anti-u-PA receptor (u-PAR) blocked the proangiogenic effects of u-PA at the endothelial cell level. We then assessed the signaling pathway activated in endothelial cells by u-PA. u-PAR activation by u-PA produced de novo synthesis of diacylglycerol (DAG) from glucose by a cytochalasin B-inhibitable mechanism, indicating the involvement of a specific glucose transporter (GLUT). Endothelial cells expressed GLUT2, whose activation was tyrosine kinase-dependent and protein kinase C (PKC)-independent. The increase of glucose uptake led to DAG production, which resulted in PKC activation/translocation. Impairment of u-PAR availability by monoclonal antibodies and by antisense oligonucleotides (aODN) against u-PAR mRNA inhibited glucose uptake, DAG neosynthesis, and PKC activation, resulting in the blockade of endothelial cell proliferation, chemotaxis, and chemoinvasion. These data suggest that u-PAR activation consequent to the binding of u-PA can be regarded as an "angiogenic switch" and disclose the possibility that an anti-u-PAR aODN strategy may efficiently target endothelial cell function to control angiogenesis in vivo.

Animals↗
PubMed1997

Nitric oxide synthase lies downstream from vascular endothelial growth factor-induced but not basic fibroblast growth factor-induced angiogenesis.

Systemic administration of the nitric oxide (NO) synthase inhibitor Nomega-nitro--arginine methyl ester (L-NAME) to rabbits bearing a corneal implant blocked vascular endothelial growth factor (VEGF), but not basic fibroblast growth factor (bFGF)-induced angiogenesis. L-NAME completely blocked angiogenesis induced by VEGF-transfected MCF-7 breast carcinoma cells and the cells remained dormant in the cornea. Postcapillary endothelial cell migration and growth induced by VEGF were blocked by both the NO synthase inhibitor Nomega-mono-methyl--arginine and by the guanylate cyclase inhibitor LY 83583. We conclude that NO is a downstream imperative of VEGF-, but not bFGF-induced angiogenesis, and propose that the NO synthase/guanylate cyclase pathway is a potential target for controlling tumor angiogenesis in response to VEGF. Our studies support recent evidence that VEGF and bFGF induce angiogenesis by different mechanistic pathways using the alphavbeta5 and alphavbeta3 integrins, respectively.

Animals↗
PubMed1997

An angiogenic role for the neurokines midkine and pleiotrophin in tumorigenesis.

Recent analysis of bladder tumors has correlated expression of the neurokine midkine (MK) with poor patient survival. To examine a role for MK and the related pleiotrophin (PTN) in tumorigenesis, they were overexpressed in MCF-7 breast carcinoma cells. Expression had no effect on in vitro growth but conferred a growth advantage in vivo. Enhanced tumor growth correlated with increased vascular density and endothelial proliferation, implicating an angiogenic role for MK and PTN. Angiogenic activity of MK and PTN was confirmed in the rabbit corneal assay. Our data therefore identify two novel targets for antiangiogenic drug development.

Animals↗
PubMed1997

Chronic viral hepatitis induced by hepatitis C but not hepatitis B virus infection correlates with increased liver angiogenesis.

Chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections lead to cirrhosis and increase the risk for the development of hepatocellular carcinoma (HCC). Angiogenesis is an essential step in oncogenesis and contributes to tumor progression in adult organs; however, to what extent angiogenesis occurs in the liver during chronic viral hepatitis has not been studied. Ninety-nine matched patients affected by chronic hepatitis due to either HBV or HCV were studied together with 13 controls (5 patients were affected by familial hyperbilirubinemia with normal liver histology; 6 patients with stage II primary biliary cirrhosis; and 2 patients with pseudo inflammatory tumor). Microvessel density was assessed in liver biopsies by immunostaining using two different antibodies against endothelial cell antigens, QB-END/10 and Factor VIII. In addition, the liver homogenates and sera of HCV- or HBV-positive patients and controls were tested for their capacity to stimulate the migration and proliferation of freshly isolated human endothelial cells in vitro. Evidence of angiogenesis was significantly more frequent in HCV-positive patients compared with HBV-infected subjects or controls (74% vs. 39% vs. 8%) (chi2 = 20.78; P < .0001) (HCV+ vs. HBV+ vs. controls). The degree of microvessel density was also higher in HCV- than in HBV-positive patients or controls (chi2 = 12.28; P < .005). In addition, HCV-positive sera and liver homogenates stimulated a higher migration and proliferation of human endothelial cells in vitro compared with HBV-positive or control sera and liver homogenates. These observations indicate that angiogenesis is particularly linked to HCV infection, suggesting a possible contribution to HCV-related liver oncogenesis.

Adolescent↗