bFGF-induced Angiogenesis Research Articles

Analysis of anti-angiogenic mechanism of HangAmDan-B (HAD-B), a Korean traditional medicine, using antibody microarray chip

The inhibitory effects of the water extract of HangAmDan-B(WEHAD-B), which is a crude extract of eight Korean medicinal animals and plants on bFGF-induced neovascularization were investigated. WEHAD-B significantly prevented bFGF-induced HUVE cell proliferation, adhesion, migration, and capillary-like tubular network formation. Half-maximal inhibition of proliferation on the endothelial cells by WEHAD-B was observed at a concentration of approximately 250 μg/mL. Our antibody microarray-based ProteoChip data showed that WEHAD-B increased the expression of STAT1 and Rb2, which are involved in cell growth, apoptosis, and controlling the cell cycle in bFGF-induced HUVECs. These results indicate that the inhibition of bFGF-induced angiogenesis by WEHAD-B may be due to upregulation of cell signaling proteins, STAT1 and Rb2. The blood vessel formation in a chick chorioallantoic membrane (CAM) treated with WEHAD-B was markedly reduced in length compared with a PBS-treated control group. Taken together, these data suggest that antibody-arrayed ProteoChip technology may be an useful tool for determining molecular mechanism of natural products in biological samples.

Paeonol Oxime Inhibits bFGF-Induced Angiogenesis and Reduces VEGF Levels in Fibrosarcoma Cells

BackgroundWe previously reported the anti-angiogenic activity of paeonol isolated from Moutan Cortex. In the present study, we investigated the negative effect of paeonol oxime (PO, a paeonol derivative) on basic fibroblast growth factor (bFGF)-mediated angiogenesis in human umbilical vein endothelial cells (HUVECs) (including tumor angiogenesis) and pro-survival activity in HT-1080 fibrosarcoma cell line.Methodology/Principal FindingsWe showed that PO (IC50 = 17.3 µg/ml) significantly inhibited bFGF-induced cell proliferation, which was achieved with higher concentrations of paeonol (IC50 over 200 µg). The treatment with PO blocked bFGF-stimulated migration and in vitro capillary differentiation (tube formation) in a dose-dependent manner. Furthermore, PO was able to disrupt neovascularization in vivo. Interestingly, PO (25 µg/ml) decreased the cell viability of HT-1080 fibrosarcoma cells but not that of HUVECs. The treatment with PO at 12.5 µg/ml reduced the levels of phosphorylated AKT and VEGF expression (intracellular and extracelluar) in HT-1080 cells. Consistently, immunefluorescence imaging analysis revealed that PO treatment attenuated AKT phosphorylation in HT-1080 cells.Conclusions/SignificanceTaken together, these results suggest that PO inhibits bFGF-induced angiogenesis in HUVECs and decreased the levels of PI3K, phospho-AKT and VEGF in HT-1080 cells.

A novel RGD-toxin protein, Lj-RGD3, from the buccal gland secretion of Lampetra japonica impacts diverse biological activities

RGD (Arg-Gly-Asp) motif toxin proteins from snake venoms, saliva glands secretion of leech or tick have typical characteristics of inhibiting platelet aggregation, angiogenesis, and tumor growth. Here we report cloning and characterization of a novel RGD-toxin protein from the buccal gland of Lampetra japonica. In an attempt to study the activities of anticoagulant in the buccal gland secretion of L. japonica, we established buccal gland cDNA library and identified a gene encoding a predicted protein of 118 amino acids with 3 RGD motifs. The predicted protein was named Lj-RGD3. We generated the cDNA of Lj-RGD3 and obtained the recombinant protein rLj-RGD3. The polyclonal antibodies against rLj-RGD3 recognized the native Lj-RGD3 protein in buccal gland secretion in Western blot analyses. The biological function studies reveal that rLj-RGD3 inhibited human platelet aggregation in a dose-dependent manner with IC 50 value at 5.277 μM. In addition, rLj-RGD3 repressed bFGF-induced angiogenesis in the chick chorioallantoic membrane model. rLj-RGD3 also inhibited the adhesion of ECV304 cells to vitronectin. Furthermore, rLj-RGD3 induced apoptosis and significantly inhibited proliferation, migration, and invasion evoked by bFGF in ECV304 cells. Taken together, these results suggested that rLj-RGD3 is a novel RGD-toxin protein possessing typical functions of the RGD-toxin protein.

Pigpen, a nuclear coiled body component protein, is involved in angiogenesis

We previously reported that puromycin-insensitive leucyl-specific aminopeptidase (PILSAP) is required for vascular endothelial growth factor (VEGF)- and basic fibroblast growth factor (bFGF)-induced angiogenesis and for endothelial differentiation from embryonic stem (ES) cells via the aminopeptidase activity of PILSAP. In this study, we searched for molecules that function during angiogenesis with PILSAP. We performed proteome analysis of nuclear extracts from embryoid bodies (EBs) made from ES cells transfected with mutant PILSAP lacking aminopeptidase activity and mock EBs. We identified pigpen, a 67-kDa nuclear coiled body component protein. Immunoprecipitation and western blotting demonstrated the binding of PILSAP and pigpen in endothelial cells (ECs), and this interaction was enhanced by VEGF and bFGF. Pigpen was reported to be expressed in actively growing ECs such as those in embryos and tumors. However, whether Pigpen is involved in angiogenesis is not known. Therefore, we examined the effect of pigpen on angiogenesis by silencing pigpen with siRNA (siPigpen). Compared with scrambled RNA (scrPigpen), transfection of siPigpen into mouse ECs inhibited proliferation, migration, and network formation. These results were confirmed with other two siRNAs. Moreover, siPigpen suppressed bFGF-induced angiogenesis in a Matrigel plug assay, and injection of siPigpen into Lewis lung carcinoma cell tumors implanted subcutaneously into 5-week-old C57/BL male mice prevented tumor growth and tumor angiogenesis. These data indicate that Pigpen is involved in angiogenesis and that pigpen may be a target for blocking tumor angiogenesis.

Resveratrol Inhibits Angiogenic Response of Cultured Endothelial F-2 Cells to Vascular Endothelial Growth Factor, but Not to Basic Fibroblast Growth Factor

Resveratrol, a natural polyphenol in grapes, is known to prevent the cardiovascular diseases and to exert the antiangiogenic effect in in vivo models with vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF). We examined the effect of resveratrol on tubule formation of cultured endothelial F-2 cells. In collagen gel matrix, F-2 cells formed an extended network of tubular structures in response to VEGF or bFGF. Resveratrol dose-dependently prevented the VEGF-induced tubule formation, but failed to inhibit the angiogenic response to bFGF. We next examined whether the inhibition of nitric oxide (NO) production is linked to the antiangiogenic effect of resveratrol on VEGF-stimulated F-2 cells, because NO plays a crucial role in VEGF-induced tubular network formation. NO production was increased by VEGF, but not by bFGF, and resveratrol inhibited VEGF-stimulated NO production. N(G)-nitro-L-arginine methyl ester (L-NAME) potently inhibited NO production under all conditions, including VEGF stimulation, and abrogated VEGF-induced tubule formation. However, L-NAME did not inhibit bFGF-induced tubule formation. To investigate the bFGF-induced in vivo antiangiogenic effect of resveratrol, we examined the effect of resveratrol on prostaglandin E(2) (PGE(2)) production and cyclooxygenase (COX) expression in NRK-F fibroblasts. COX-2 and its derived PGE(2) are important factors for bFGF-induced in vivo angiogenesis. Resveratrol dose-dependently prevented both COX-2 induction and PGE(2) production in bFGF-stimulated fibroblasts. These results suggest that resveratrol exerts the inhibitory effects on VEGF- and bFGF-induced angiogenesis through different mechanisms including inhibition of NO production in VEGF-stimulated endothelial cells and inhibition of COX-2 induction in bFGF-stimulated fibroblasts.

Moscatilin, a bibenzyl derivative from the India orchid Dendrobrium loddigesii, suppresses tumor angiogenesis and growth in vitro and in vivo

Attacking angiogenesis is considered an effective strategy for controls the expansion and metastasis of tumors and other related-diseases. The aim of this study was to assess the effects of moscatilin, a bibenzyl derivative, on VEGF and bFGF-induced angiogenesis in cultured human umbilical vein endothelial cells (HUVECs) in vitro and in vivo. Moscatilin significantly inhibited growth of lung cancer cell line A549 (NSCLC) and suppressed growth factor-induced neovascularization. In addition, VEGF- and bFGF-induced cell proliferation, migration, and tube formation of HUVECs was markedly inhibited by moscatilin. Western blotting analysis of cell signaling molecules indicated that moscatilin inhibited ERK1/2, Akt, and eNOS signaling pathways in HUVECs. These results suggest that inhibition of angiogenesis by moscatilin may be a major mechanism in cancer therapy.

The Calcineurin Inhibitor Tacrolimus Inhibits Breast Tumor Growth In Vivo.

Abstract Background: We recently reported a novel angiogenesis factor, secreted frizzle-related protein 2 (SFRP2), that stimulates angiogenesis via a calcineurin/ NFAT pathway and is highly expressed in human breast tumor endothelium (Courtwight et. al., Cancer Research 2009). NFAT is a transcription factor that mediates vascular development and VEGF and bFGF-induced angiogenesis. Tacrolimus (FK506) is a calcineurin inhibitor that inhibits NFAT activation and is FDA approved to prevent organ transplant rejection. Based on its mechanism of action, we hypothesized that tacrolimus would inhibit angiogenesis and breast tumor growth.Materials and Methods: Tumor growth in vivo: MMTV-neu transgenic mice were treated with tacrolimus 3 mg/kg/day i.p. for 21 days or control when tumors became palpable. Tumor volumes were measured with 3D ultrasound. Endothelial tube formation in vitro: ECMatrix was solidified into wells of a 96 well plate and endothelial cells were seeded onto the matrix at a concentration of 1x104 cells/well with SFRP2 7nM or VEGFA 60ng/ml. Tacrolimus 1µM or 1.5% DMSO control was added to the wells. The number of branch points were counted after 8 hours. MMTV-neu migration in vitro: Breast tumor cells were plated at 10,000 cells/well into a 96 well plate and allowed to become confluent. The cells were quiesced for 18 hours and tacrolimus (1µM) or 0.5% DMSO control was added to the wells and the wound was formed using a 1 ml pipette tip. Migration distance was measured with an ocular micrometer after 16 hours. Western blot analyses: Endothelial cells were treated for 1 hour with negative control, SFRP2 7nM, or SFRP2 7nM plus tacrolimus 10 µM. Nuclear protein was extracted and Western blot for NFATc3 was performed. Statistics: Means were compared with a two-tailed t-test.Results: Tumor growth in vivo: Tacrolimus inhibited the growth rate of MMTV-neu tumors by 49% (n=12 treated, n=9 controls, p=0.04), without signs of toxicity. Endothelial tube formation: Tacrolimus (1µM) inhibited SFRP2 induced endothelial tube formation by 64% (0.002, n=4), and VEGF induced tube formation by 69% (p=0.004, n=4). MMTV-neu tumor cell migration: Tacrolimus (1µM) inhibited MMTV-neu cell migration by 36% (p<0.05, n=4). Western blot for NFATc3: Treatment of endothelial cells with SFRP2 induced nuclear NFATc3 at 1 hour compared to control, and this increase was abolished by treatment with tacrolimus.Conclusion: The calcineurin inhibitor tacrolimus inhibits the growth rate of MMTV-neu transgenic tumors in vivo. The in vitro cellular effects of tacrolimus include inhibiting SFRP2 and VEGF-induced endothelial tube formation, abolishing SFRP2 activation of NFATc3 in endothelial cells, and inhibiting MMTV-neu cell migration, demonstrating a direct effect of tacrolimus on both the endothelial and tumor cell compartments. This establishes that NFAT may be a favorable therapeutic target to inhibit angiogenesis and breast cancer growth. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3170.

In Vitro and in Vivo Anti-angiogenic Activities and Inhibition of Hormone-Dependent and -Independent Breast Cancer Cells by Ceramide Methylaminoethylphosphonate

Ceramide methylaminoethylphosphonate (CMAEPn) was isolated from eastern oyster ( Crassostrea virginica ) and screened against in vitro and in vivo angiogenesis and against MCF-7 and MDA-MB-435s breast cancer cell lines. In vitro angiogenesis was evaluated by the vascular endothelial growth factor (VEGF)-induced human umbilical vein endothelial cell (HUVEC) tube formation assay. MCF-7 and MDA-MB-435s cell viability was evaluated by the CellTiter 96 AQ(ueous) One Solution Cell Proliferation assay. Apoptosis was evaluated by the caspase-9 assay, autophagy by acridine orange staining and beclin-1 level. Our study indicates that CMAEPn at 50 microM inhibited VEGF-induced tube formation by HUVEC. The viability of MCF-7 and MDA-MB-435s breast cancer cells exposed to 125 microM CMAEPn for 48 h was reduced to 76 and 85%, respectively. The viability of MCF-7 and MDA-MB-435s cells exposed to 250 microM CMAEPn for 48 h under the same conditions was reduced to 38 and 45%, respectively. CMAEPn at 125 microM inhibited VEGF-induced MDA-MB-435s cell migration and invasion. CMAEPn at 125 microM also decreased VEGF, EGF levels in the conditioned media, PI3K, IkappaB phosphorylation and degradation in the cytoplasmic extracts, and NFkappaB nuclear translocation. Both acridine orange staining and beclin-1 indicated autophagic cell death in MCF-7 and MDA-MB-435s cells, respectively. In vivo, CMAEPn at 30 mg/kg body weight inhibited bFGF-induced angiogenesis and caused a 57% reduction in hemoglobin levels in the matrigel plug assay within 7 days. This is the first report on CMAEPn-inhibited angiogenesis both in vitro and in vivo.

449 POSTER In vivo evaluation of ALB 109564, a novel tubulin inhibitor with improved efficacy over existing members of the Vinca alkaloid class

The aim of this study was to investigate the anti-angiogenic, vascular-disrupting and anti-metastatic properties of vinflunine, the latest vinca alkaloid in phase III clinical development. The effects of vinflunine on in vitro endothelial cell functions relevant to the performance of an already formed vasculature and to the angiogenic process were evaluated. The in vivo anti-angiogenic properties of vinflunine were also investigated, as were its activity against a model of experimental metastasis. In vitro vinflunine induced a rapid change in the morphology of endothelial cells and disrupted the network of capillary-like structures, indicating potential vascular-disrupting activity. Furthermore, vinflunine showed anti-angiogenic properties, since it inhibited endothelial cell migration and the capacity of these cells to organise into a network of capillary-like structures. All these effects were observed under conditions that only marginally affect endothelial cell proliferation. In vivo, vinflunine inhibited bFGF-induced angiogenesis in Matrigel implants at doses 40–20-fold lower than its maximal therapeutic dose (MTD). Treatment of mice with vinflunine reduced the number of liver metastases induced by intrasplenic injection of LS174T cells, with significant effects also observed at low doses; i.e. 16-fold lower than the MTD. This study demonstrates that vinflunine expresses both vascular-disrupting and anti-angiogenic activities and induced marked effects against experimental metastases, all properties that support its ongoing clinical development.

PPARγ ligands, rosiglitazone and pioglitazone, inhibit bFGF- and VEGF-mediated angiogenesis

To study the effect of peroxisome proliferator-activated receptor-gamma (PPAR gamma) agonists, pioglitazone and rosiglitazone, on vascular endothelial growth factor (VEGF)- and basic fibroblast growth factor (bFGF)-induced angiogenesis and on endothelial cell migration. Chick chorioallantoic membrane (CAM) model was used to evaluate the efficacy of pioglitazone and rosiglitazone on VEGF- and bFGF-induced angiogenesis. In addition, the effect of pioglitazone and rosiglitazone on endothelial cell migration was evaluated using 8 mm pore filter to a feeder layer containing vitronectin as chemoattractant. Pioglitazone and rosiglitazone inhibited the pro-angiogenic effects of bFGF and VEGF in the CAM model significantly (P < 0.001) to the same extent. Endothelial cell migration was also inhibited by both pioglitazone and rosiglitazone (P < 0.001). These results suggest that PPAR gamma ligands, pioglitazone and rosiglitazone, in addition to their important regulatory role in adipogenesis and inflammation, possess anti-angiogenic properties. Thus, PPAR gamma ligands may be useful in the treatment of diabetic retinopathy, macular degeneration, and other ocular disorders and may lower the risk to develop cancer in diabetic patients.

Differential Suppression of Vascular Permeability and Corneal Angiogenesis by Nonsteroidal Anti-inflammatory Drugs

Angiogenesis, the formation of new capillary blood vessels, is an essential biological process under physiological conditions, including embryonic development, reproduction, and wound repair. Under pathologic conditions, this process plays a critical role in a variety of diseases such as cancer, rheumatoid arthritis, atherosclerosis, endometriosis, diabetic retinopathy, and age-related macular degeneration. The purpose of this study was to examine the effects of cyclooxygenase inhibitors on basic fibroblast growth factor (bFGF)- and vascular endothelial growth factor (VEGF)-mediated ocular neovascularization and permeability. A modified Miles vascular permeability assay was used to examine VEGF-induced vascular hyperpermeability, and the mouse corneal model of angiogenesis was used to compare the efficacy of systemic treatment with different nonsteroidal anti-inflammatory drugs (NSAIDs) on bFGF- and VEGF-induced angiogenesis. The authors demonstrated that systemic application of most NSAIDs, but not acetaminophen, blocked VEGF-induced permeability in mice. However, systemic treatment of mice with NSAIDs resulted in the differential inhibition of bFGF-induced (5%-57%) and VEGF-induced (3%-66%) corneal angiogenesis. The selective COX-2 inhibitors were more effective at suppressing bFGF-induced angiogenesis than VEGF-induced angiogenesis. Though most NSAIDS are effective at suppressing vascular leak, there exists a differential efficacy at suppressing the angiogenic response of specific cytokines such as bFGF and VEGF.

Self-assembled glycol chitosan nanoparticles for the sustained and prolonged delivery of antiangiogenic small peptide drugs in cancer therapy

Antiangiogenic peptide drugs have received much attention in the fields of tumor therapy and tumor imaging because they show promise in the targeting of integrins such as α vβ 3 on angiogenic endothelial cells. However, systemic antiangiogenic peptide drugs have short half-lives in vivo, resulting in fast serum clearance via the kidney, and thus the therapeutic effects of such drugs remain modest. In this study, we prepared self-assembled glycol chitosan nanoparticles and explored whether this construct might function as a prolonged and sustained drug delivery system for RGD peptide, used as an antiangiogenic model drug in cancer therapy. Glycol chitosan hydrophobically modified with 5β-cholanic acid (HGC) formed nanoparticles with a diameter of 230 nm, and RGD peptide was easily encapsulated into HGC nanoparticles (yielding RGD-HGC nanoparticles) with a high loading efficiency (>85%). In vitro work demonstrated that RGD-HGC showed prolonged and sustained release of RGD, lasting for 1 week. RGD-HGC also inhibited HUVEC adhesion to a βig-h3 protein-coated surface, indicating an antiangiogenic effect of the RGD peptide in the HGC nanoparticles. In an in vivo study, the antiangiogenic peptide drug formulation of RGD-HGC markedly inhibited bFGF-induced angiogenesis and decreased hemoglobin content in Matrigel plugs. Intratumoral administration of RGD-HGC significantly decreased tumor growth and microvessel density compared to native RGD peptide injected either intravenously or intratumorally, because the RGD-HGC formulation strongly enhanced the antiangiogenic and antitumoral efficacy of RGD peptide by affording prolonged and sustained RGD peptide delivery locally and regionally in solid tumors.

Molecular mechanism of the inhibitory effect of KS-5 on bFGF-induced angiogenesis in vitro and in vivo

Inhibition of angiogenesis controls the expansion and metastasis of many solid tumors and other related-diseases. KS-5 (1,7-dihydroxy-3-methoxyacridone), is an inactive analogue of the substituted 1-hydroxy acridone antiviral class. This study aimed at studying the effects of KS-5 on bFGF-induced angiogenesis in cultured human umbilical vein endothelial cells (HUVECs) in vitro and in vivo. KS-5 inhibited bFGF (10 ng/ml)-induced cell proliferation in a concentration-dependent manner, but did not exhibit significant cytotoxic effect examined by LDH release assay. KS-5 inhibited bFGF-induced angiogenesis was associated with decreasing DNA synthesis as evaluated by BrdU incorporation assay, and abrogating endothelial cell ERK1/2 and Akt protein phosphorylation, the major signaling pathways involved in cellular processes of angiogenesis. In addition, KS-5 also inhibited bFGF-induced phosphorylation of mTOR and the major downstream effectors, eIF4E and p70 S6K. Moreover, bFGF-induced protein synthesis was also inhibited by KS-5. Most importantly, KS-5 treatment in nude mice inhibited in vivo angiogenesis as revealed by Matrigel implant assay. In conclusion, the present study suggests that KS-5 has potential anti-angiogenetic effect for cancer therapy and other angiogenesis-dependent diseases.

Semaphorin 3A suppresses VEGF-mediated angiogenesis yet acts as a vascular permeability factor

Semaphorin 3A (Sema3A), a known inhibitor of axonal sprouting, also alters vascular patterning. Here we show that Sema3A selectively interferes with VEGF- but not bFGF-induced angiogenesis in vivo. Consistent with this, Sema3A disrupted VEGF- but not bFGF-mediated endothelial cell signaling to FAK and Src, key mediators of integrin and growth factor signaling; however, signaling to ERK by either growth factor was unperturbed. Since VEGF is also a vascular permeability (VP) factor, we examined the role of Sema3A on VEGF-mediated VP in mice. Surprisingly, Sema3A not only stimulated VEGF-mediated VP but also potently induced VP in the absence of VEGF. Sema3A-mediated VP was inhibited either in adult mice expressing a conditional deletion of endothelial neuropilin-1 (Nrp-1) or in wild-type mice systemically treated with a function-blocking Nrp-1 antibody. While both Sema3A- and VEGF-induced VP was Nrp-1 dependent, they use distinct downstream effectors since VEGF- but not Sema3A-induced VP required Src kinase signaling. These findings define a novel role for Sema3A both as a selective inhibitor of VEGF-mediated angiogenesis and a potent inducer of VP.

Angiogenesis Inhibition and Choroidal Neovascularization Suppression by Sustained Delivery of an Integrin Antagonist, EMD478761

To evaluate the angiogenic inhibitory effects of an alpha(v)beta(3)/alpha(v)beta(5) integrin antagonist, EMD478761, released from a polymeric implant in a chick chorioallantoic membrane (CAM) assay and laser-induced experimental choroidal neovascularization (CNV) in rats. Polyvinyl alcohol-based reservoir implants releasing EMD478761 were designed for placement onto a CAM or intravitreally in rats. In vitro release rates of the implants were measured using HPLC. Angiogenesis was induced on 10-day-old chick embryos by basic fibroblast growth factor (bFGF), and areas of neovascularization were measured. Experimental CNV was induced in the Brown-Norway rat with a diode laser. EMD478761 or sham microimplants were placed within the vitreous chamber of Brown-Norway rats. Two weeks later, areas of CNV were determined by FITC-dextran staining of choroidal flatmounts. Sustained delivery of EMD478761 significantly inhibited bFGF-induced angiogenesis in CAM, as determined by a reduction in angiogenesis areas, without drug toxicity to the normal CAM vasculature. In an experimental rat model, intravitreal EMD478761 implants significantly suppressed laser-induced CNV compared with intravitreal sham implants, with the mean area reduced by 63% (P < 0.05). Sustained delivery of EMD478761demonstrates potent antiangiogenic properties in vivo. These results suggest that an EMD478761 implant may be beneficial in the treatment of neovascular ocular diseases.

A novel αvβ3-blocking disintegrin containing the RGD motive, DisBa-01, inhibits bFGF-induced angiogenesis and melanoma metastasis

The integrin alpha(v)beta(3) is involved in multiple aspects of malignant cancer, including tumor angiogenesis and metastasis, which makes the receptor a key target for the development of anti-cancer therapies. We report here on the production, the characterization and the in vivo anti-angiogenic and anti-metastatic properties of a novel alpha(v)beta(3)-binding disintegrin, DisBa-01, isolated from a cDNA library made with RNAs from the venom gland of Bothrops alternatus. The 11,637 Da-recombinant monomeric form of DisBa-01 displayed an RGD motif and interacted with purified alpha(v)beta(3) integrin in surface plasmon resonance studies, in a dose-dependent and cation sensitive manner. A three-dimensional molecular model of DisBa-01 in complex with alpha(v)beta(3) predicted a large surface of contacts with the beta(3) subunit. DisBa-01 inhibited the adhesion of alpha(v)beta(3)-expressing human microvascular endothelial cell line-1 (HMEC-1) and murine melanoma cell line B16F10 to vitronectin (IC(50) = 555 nM and 225 nM, respectively), and transiently inhibited their proliferation without direct cell toxicity, but did not affect the binding nor the proliferation of a human breast cancer-derived cell line (MDA-MB-231) not expressing alpha(v)beta(3). In vivo, DisBa-01 dose-dependently decreased bFGF-induced angiogenesis in a matrigel plug assay in athymic nude mice (IC(50) = 83 nM). When injected intravenously to C57BL/6 mice together with B16F10 melanoma cells, DisBa-01 time- and dose-dependently inhibited lung metastasis monitored by bioluminescent imaging. We conclude that DisBa-01 is a potent new inhibitor of alpha(v)beta(3)-dependent adherence mechanisms involved in neo-vascularization and tumor metastasis processes.

BFGF-induced angiogenesis in ischemic myocardium is associated with calreticulin downregulation

Basic fibroblast growth factor (bFGF) plays an integral role in therapeutic angiogenesis associated with myocardial infarct healing. Calreticulin, a 46-kDa Ca2+-binding chaperone mainly in the endoplasmic reticulum, plays an important role in regulating calcium homeostasis and anti-angiogenesis. To investigate the role of CRT in bFGF-induced angiogenesis and its signaling pathways in ischemic myocardium, two dimensional gel electrophoresis and MALDI-MS were employed to analyze CRT's differential expression in myocardial microvascular endothelial cells (MECs) treated with or without bFGF.

Proangiogenic Role of ephrinB1/EphB1 in Basic Fibroblast Growth Factor-Induced Corneal Angiogenesis

Corneal neovascularization is a vision-threatening condition caused by various ocular pathological conditions. The aim of this study was to evaluate the function of the ephrin ligands and Eph receptors in vitro and in vivo in corneal angiogenesis in a mouse model. The Eph tyrosine kinase receptors and their ligands, ephrins, are expressed on the cell surface. The functions of Eph and ephrins have been shown to regulate axonal guidance, segmentation, cell migration, and angiogenesis. Understanding the roles of Eph and ephrin in corneal angiogenesis may provide a therapeutic intervention for the treatment of angiogenesis-related disorders. Immunohistochemical studies demonstrated that ephrinB1 and EphB1 were expressed in basic fibroblast growth factor (bFGF)-induced vascularized corneas. EphB1 was specifically colocalized with vascular endothelial marker CD31 surrounded by type IV collagen. EphrinB1 was expressed in corneal-resident keratocytes and neutrophils. Recombinant ephrinB1-Fc, which induces EphB receptor activation, enhanced bFGF-induced tube formation in an in vitro aortic ring assay and promoted bFGF-induced corneal angiogenesis in vivo in a corneal pocket assay. Synergistically enhanced and sustained activation of extracellular signal-regulated kinase was noted in vascular endothelial cell lines after stimulation with ephrin B1 and bFGF combinations. These results suggest that ephrinB1 plays a synergistic role in corneal neovascularization.

Effect of acetyl 11-keto β-boswellic acid on metastatic growth factor responsible for angiogenesis

Basic fibroblast growth factor (bFGF), a metastatic growth factor is known to be one of the promoting factors in the tumor induced angiogenesis. The antiangiogenic activity of acetyl 11-keto β-boswellic acid was screened against bFGF-induced angiogenesis using in-vivo Matrigel Plug Assay. Histological & colorimetric examination confirmed that numerous blood vessels were present in Matrigel + bFGF group in comparison to Matrigel alone treated mice. Acetyl 11-keto β-boswellic acids (10 mg/kg/d) inhibited the Matrigel + bFGF-induced angiogenesis significantly ( P < 0.01) in contrast to anti-inflammatory agent indomethacin (10 mg/kg/d) and alkylating agent cyclophosphamide (10 mg/kg/d).

Inhibition of Tumor Endothelial ERK Activation, Angiogenesis, and Tumor Growth by Sorafenib (BAY43-9006)

Activation of the Raf-MEK-ERK signal transduction pathway in endothelial cells is required for angiogenesis. Raf is the kinase most efficiently inhibited by the multikinase inhibitor sorafenib, which has shown activity against certain human cancers in clinical trials. To understand the mechanisms underlying this activity, we studied how it controlled growth of K1735 murine melanomas. Therapy caused massive regional tumor cell death accompanied by severe tumor hypoxia, decreased microvessel density, increased percentage of pericyte-covered vessels, and increased caliber and decreased arborization of vessels. These signs of K1735 angiogenesis inhibition, along with its ability to inhibit Matrigel neovascularization, showed that sorafenib is an effective anti-angiogenic agent. Extracellular signal-regulated kinase (ERK) activation in tumor endothelial cells, revealed by immunostaining for phospho-ERK and CD34, was inhibited, whereas AKT activation, revealed by phospho-AKT immunostaining, was not inhibited in K1735 and two other tumor types treated with sorafenib. Treatment decreased endothelial but not tumor cell proliferation and increased both endothelial cell and tumor cell apoptosis. These data indicate that sorafenib's anti-tumor efficacy may be primarily attributable to angiogenesis inhibition resulting from its inhibition of Raf-MEK-ERK signaling in endothelial cells. Assessing endothelial cell ERK activation in tumor bio-psies may provide mechanistic insights into and allow monitoring of sorafenib's activity in patients in clinical trials.