Biomedical subjects

Shigeru Kanda

Publications and source records attributed to Shigeru Kanda.

At least 19 recordsLinked to original sources

PubMed2003

Deficiency of gelatinase a suppresses smooth muscle cell invasion and development of experimental intimal hyperplasia.

BACKGROUND: Although it has been demonstrated that matrix metalloproteinases (MMPs) play an important role in the arterial remodeling in atherosclerosis and restenosis, it is not clear which MMP is involved in which process. To define the role of MMP-2 in arterial remodeling, we evaluated the influence of the targeted deletion of the MMP-2 gene on vascular remodeling after flow cessation in the murine carotid arteries. METHODS AND RESULTS: The left common carotid arteries of wild-type and MMP-2-deficient mice were ligated just proximal to their bifurcations, and the animals were then processed for morphological and biochemical studies at specific time points. MMP-2 activity and mRNA levels increased in ligated carotid arteries of wild-type mice on the basis of observation by gelatin zymography and quantitative real-time RT-PCR. There was significantly less intimal hyperplasia in MMP-2-deficient mice at 2 and 4 weeks after ligation than there in wild-type mice. Arterial explants from the aorta of MMP-2-deficient mice showed that smooth muscle cell (SMC) migration was inhibited in comparison with wild-type mice. The chemoattractant-directed invasion through a reconstituted basement membrane barrier was significantly reduced in cultured SMCs derived from MMP-2-deficient mice, although no difference was observed in SMC migration across the filter or in proliferative response between the control and MMP-2-deficient mice. CONCLUSIONS: In a mouse carotid artery blood flow cessation model, MMP-2 contributes to intimal hyperplasia mainly through the SMC migration from the media into the intima by degrading and breaching the extracellular matrix proteins surrounding each cell and the internal elastic lamina.

Animals↗

PubMed2003

The role of c-Fes in vascular endothelial growth factor-A-mediated signaling by endothelial cells.

c-Fes plays pivotal roles in angiogenic cellular responses of endothelial cells. Here we examined the role of c-Fes in vascular endothelial growth factor-A (VEGF-A)-mediated signaling pathways in endothelial cells. We introduced either wild-type or kinase-inactive c-Fes in porcine aortic endothelial (PAE) cell lines, which endogenously express VEGF receptor (VEGFR)-1, and PAE cells ectopically expressing VEGFR-2 (denoted KDR/PAE cells) and generated stable cell lines. VEGF-A induced autophosphorylation of c-Fes only in KDR/PAE cells, suggesting that VEGFR-2 was required for its activation. Expression of kinase-inactive c-Fes failed to demonstrate dominant negative effect on VEGF-A-induced chemotaxis and capillary morphogenesis. Phosphoinositide 3-kinase (PI3-kinase) was activated in KDR/PAE cells and c-Fes contributed to this process in a kinase activity-dependent manner. However, VEGFR-2, insulin receptor substrate-1, and c-Src were also involved in VEGF-A-induced activation of PI3-kinase, resulting in the compensation in cells expressing kinase-inactive c-Fes. Interestingly, overexpression of wild-type c-Fes in PAE cells induced VEGF-A-independent capillary morphogenesis. Considered collectively, VEGF-A activated PI3-kinase partly through c-Fes and increase in c-Fes kinase activity enhanced capillary morphogenesis by yet unknown signaling pathways.

Animals↗

PubMed2003

Epigallocatechin-3-gallate binding to MMP-2 inhibits gelatinolytic activity without influencing the attachment to extracellular matrix proteins but enhances MMP-2 binding to TIMP-2.

Although epigallocatechin-3-gallate (EGCg), a dominant component of green tea catechins, has been demonstrated to have anti-gelatinase properties, the molecular mechanisms by which EGCg blocks gelatinolytic activities remain unknown. We investigated whether EGCg may affect matrix metalloproteinase-2 (MMP-2) binding to native and denatured-type I collagen, and binding to the tissue inhibitor of metalloproteinase-2 (TIMP-2). Here, we report that EGCg forms a reversible complex with MMP-2, resulting in the inhibition of gelatinolytic activity of MMP-2. EGCg had no effect on the MMP-2 binding to immobilized native and denatured-type I collagen, but significantly enhanced pro- and activated MMP-2 binding to TIMP-2, as assessed by immunoprecipitation. These findings provide a new understanding of the molecular mechanisms underlying the inhibitory effect of EGCg on the gelatinolytic activity of MMP-2.

Catechin↗

PubMed2003

Overexpression of hepatocyte growth factor receptor in renal carcinoma cells indirectly stimulates tumor growth in vivo.

We examined the role of increased expression of HGFR kinase in in vivo growth of renal carcinoma. Human renal carcinoma cell line, ACHN cells, was transfected with plasmid encoding wild-type HGFR gene to generate cell lines with increased HGFR protein. ACHN cells with elevated HGFR expression, denoted clones 8 and 10, respectively, showed higher basal kinase activities of HGFR and PI3-kinase than those of empty-vector (mock)-transfected cells. Clone 8 and 10 cells grew similar to mock cells in culture. In mice, tumors of these clones grew more rapidly than those of mock cells. Microvessel density of clone 8 or 10 tumors was higher than that of mock tumors. Clone 8 and 10 cells secreted vascular endothelial growth factor-A (VEGF-A) more than mock cells and the secretion was PI3-kinase inhibitor, LY294002-sensitive. Anti-VEGF-A neutralizing antibody significantly inhibited tumor growth of clones 8 and 10 in mice. These results indicate for the first time that overexpression of HGFR tyrosine kinase in renal carcinoma cells participates in rapid tumor growth in vivo.

Animals↗

PubMed2003

Sonic hedgehog induces capillary morphogenesis by endothelial cells through phosphoinositide 3-kinase.

Sonic hedgehog (Shh) acts as a morphogen in many cell types. Recent studies have shown that hedgehog signaling is involved in vascular development as well as postnatal angiogenesis. However, the direct action of Shh on cultured endothelial cells has not been clearly shown. To address this issue, we examined the effect of Shh on morphological changes by murine brain capillary endothelial cells (IBE cells) and human umbilical endothelial cells (HUVECs). Shh induced capillary morphogenesis by these cells. The effect was inhibited by cyclopamine or pertussis toxin. Shh-induced capillary morphogenesis was also blocked by LY294002, a phosphoinositide 3-kinase (PI3-kinase) inhibitor. Shh rapidly increased PI3-kinase activity in IBE cells and HUVECs; this activity was inhibited by cyclopamine. Nuclear localization of Gli1 was increased in Shh-treated IBE cells, which was not affected by LY294002. Actinomycin D and cycloheximide inhibited Shh-induced capillary morphogenesis. In IBE cells expressing kinase-inactive c-Fes, Shh failed to stimulate PI3-kinase activity and capillary morphogenesis. Considered collectively, Shh induced capillary morphogenesis of endothelial cells through both rapid activation of c-Fes/PI3-kinase pathways and transcriptionally regulated pathways.

Animals↗

PubMed2003

Visual field defects after uneventful vitrectomy for epiretinal membrane with indocyanine green-assisted internal limiting membrane peeling.

PURPOSE: To report visual field defects after vitrectomy for epiretinal membrane with indocyanine green (ICG)-assisted internal limiting membrane (ILM) peeling. DESIGN: Interventional consecutive case series. METHODS: A retrospective review of 16 eyes of 16 patients who underwent vitrectomy for idiopathic epiretinal membrane. Indocyanine green-assisted ILM peeling was performed in 7 of 16 eyes. The main outcome measure was postoperative visual field. RESULTS: Four of seven eyes (57%) with ICG-assisted ILM peeling had visual field defects postoperatively. The field defects identified were nasal in three eyes; in the fourth eye, the visual field was constricted to approximately 30 degrees. None of the nine eyes without ICG-assisted ILM peeling had a visual field defect. CONCLUSIONS: Peripheral visual field defects may occur after vitrectomy with ICG-assisted ILM peeling. Although the cause of the defects is unclear, the potential role of ICG toxicity requires further investigation.

Aged↗

PubMed2003

Vitrectomy with internal limiting membrane peeling for macular retinoschisis and retinal detachment without macular hole in highly myopic eyes.

PURPOSE: To report anatomic and visual improvement following vitrectomy with internal limiting membrane (ILM) peeling for two highly myopic patients with retinoschisis and/or retinal detachment without a macular hole. DESIGN: Two interventional case reports. METHODS: Two highly myopic patients who had retinoschisis and/or retinal detachment without a full-thickness macular hole underwent vitrectomy, internal limiting membrane peeling, and long-acting gas injection. Main outcome measures included best-corrected visual acuity, biomicroscopic appearance, and optical coherent tomography finding. RESULTS: Vitrectomy with ILM peeling results in biomicroscopic, functional, and tomographic improvement in both patients, for follow-up periods of 12 months and 8 months, respectively. CONCLUSIONS: Vitrectomy with ILM peeling and gas tamponade is an effective method for retinoschisis and/or retinal detachment without a macular hole in highly myopic patients.

Aged↗

PubMed2003

Green tea catechins inhibit the cultured smooth muscle cell invasion through the basement barrier.

Epidemiological studies suggest that green tea consumption is associated with a reduced risk of cardiovascular disease. Antioxidative properties of green tea flavonoids, catechins, have been believed to be involved in the antiatherogenic effect of green tea, since catechins inhibit low density lipoprotein oxidation. The migration of vascular smooth muscle cells (SMCs) from the tunica media to the subendothelial region is a key event in the development and progression of atherosclerosis and post-angioplasty vascular remodeling. Matrix metalloproteinases (MMPs) play a key role in these processes of SMC migration. In the present study, we investigated the effect of catechins on the gelatinolytic activity of MMP-2 that was derived from cultured bovine aortic SMCs. We also investigated the effect of catechins on the SMC invasion through the reconstituted basement membrane barrier. A major constituent of green tea catechins, (-)-epigallocatechin gallate (EGCG), inhibited the gelatinolytic activity of MMP-2 and concanavalin A (ConA)-induced pro-MMP-2 activation without the influence of membrane-type MMP expression in SMCs. EGCG also inhibited the SMC invasion through the basement membrane barrier in a concentration-dependent manner without any influence of SMC migration across the basement membrane protein thin-coated filter. The antagonistic effects of other catechins, namely (-)-epigallocatechin (EGC) and (-)-epicatechin gallate (ECG), on gelatinolytic activity of MMP-2, ConA-induced pro-MMP-2 activation, or PDGF-BB-directed SMC invasion were much less pronounced than those of EGCG. Also, (+)-catechin and (-)-epicatechin failed to show any effect. These findings may suggest that the anti-invasive and anti-metalloproteinase activities involve at least part of the anti-atherogenic action of catechin in accordance with the antioxidant properties of catechin.

Basement Membrane↗

PubMed2003

The selective tyrosine kinase inhibitor, STI571, inhibits growth of anaplastic thyroid cancer cells.

To establish a molecular targeting therapy for anaplastic thyroid carcinomas, we studied the effect of the specific tyrosine kinase inhibitor, STI571, on anaplastic thyroid cancer cell lines highly expressing c-ABL ARO (mutated p53) and FRO (undetectable p53). These lines showed marked inhibition of cell growth after treatment with STI571. In contrast, the growth of papillary thyroid cancer cell lines that harbor wild-type p53 and have low levels of c-ABL was not affected by STI571. Fluorescent-activated cell sorting analysis revealed that STI571 treatment increased the fraction of FRO and ARO cells in S and G(2)/M phases, respectively, indicating induction of S and G(2)/M transition arrest. These changes were accompanied by inhibition of c-ABL phosphorylation/activation and increased expression of p21(cip1) in FRO and p27(kip1) in both FRO and ARO cells. Treatment with STI571 also led to reduction of cyclin A, B1, and CDC2 levels. The growth of FRO cells implanted into immunocompromised mice was significantly inhibited by STI571. Taken together, these results suggest that selective suppression of c-ABL activity by STI571 may represent a potential anticancer strategy for p53-mutated undifferentiated thyroid carcinomas.

Animals↗

PubMed2003

Expression of the c-Met proto-oncogene and its possible involvement in liver invasion in adult T-cell leukemia.

c-Met is a tyrosine kinase receptor for hepatocyte growth factor and suggested to be involved in oncogenesis ormetastatic phenotypes in many malignancies. Adult T-cell leukemia (ATL) is a neoplasia characterized by massive invasion of the leukemic cells into various organs. Recently, we have reported frequent hepatic involvement and the relationship between liver invasion and the poor prognosis in ATL. In the present study, we investigated the expression of c-Met in ATL cells and its relation to liver dysfunction. In three of four human T-cell lymphotrophic virus-I-positive T-cell lines, c-Met was expressed both at mRNA and protein levels, whereas it was not expressed in human T-cell lymphoma virus-I-negative T-cell lines. The expressed c-Met should be functional, because hepatocyte growth factor could induce the autophosphorylation of c-Met. Although the viral-transactivating protein Tax has been shown to be involved in the deregulated expression of cellular genes, Tax mRNA was not detected in c-Met mRNA-expressed cell lines. From freshly isolated peripheral blood mononuclear cells, the expression of c-Met mRNA was detected in 10 of 16 ATL patients but not from healthy individuals. Finally, serum transaminase levels were significantly increased in c-Met-positive ATL cases, and all of the infiltrated c-Met-positive cells into liver were shown to be multilobularly nucleated phenotype. Taken together, these data suggest for the first time that c-Met is involved in the liver invasive phenotype of ATL.

Blotting, Western↗

PubMed2003

[Clinical study of sarcomatoid renal cell carcinoma].

Patients with sarcomatoid renal cell carcinoma are rare and have poor survival. We evaluated 14 patients who had renal cell carcinoma with a sarcomatoid component between 1982 and 2000. There were 9 men and 5 women with a median age of 59.5 years (range 32 to 77). Seven patients had a tumor on the right side and 7 on the left side. Thirteen patients had some symptoms and 11 had metastases at the initial visit. Most of them were stage T4 and high nuclear grade cancer and showed elevated acute phase reactants. There were 7 patients followed by interferon therapy, and the cause-specific 5-year survival rate was less than 10%. We confirmed that renal cell carcinoma with a sarcomatoid component often showed local invasion, distant metastasis and poor prognosis.

Adult↗

PubMed2003

Expression of thrombospondin-derived 4N1K peptide-containing proteins in renal cell carcinoma tissues is associated with a decrease in tumor growth and angiogenesis.

PURPOSE: We have reported that the 4N1K peptide (KRFYVVMWKK) from thrombospondin (TSP) 1 has antiangiogenic activities. The goal of this study was to examine whether the expression of 4N1K-containing proteins correlates with reduced growth of human renal cell carcinoma (RCC). EXPERIMENTAL DESIGN: We examined the expression of 4N1K-containing proteins and TSP1, microvessel density, proliferation index, and apoptotic index in 119 surgically excised RCC tissues by immunohistochemical techniques. The correlation between the above variables and clinicopathological features was analyzed statistically. RESULTS: The antibody raised against the 4N1K peptide recognized protein fragments of matrix metalloproteinase 3-digested TSP1 and positively stained the sections of renal cancer tissues. These reactions disappeared when the antibody was preincubated with immobilized 4N1K peptide, suggesting that the reactions were 4N1K peptide specific. Although TSP1 expression did not correlate with various clinicopathological features and tumor size, all 4N1K-positive tumors were locally confined and of significantly smaller size (median, 3.3 cm; range, 2.0-4.4 cm) than 4N1K-negative tumors (median, 5.2 cm; range, 2.8-8.8 cm; P < 0.001). 4N1K-positive tumors exhibited significantly lower microvessel density and higher apoptotic index of tumor cells than 4N1K-negative tumors (P < 0.001 and P = 0.042, respectively). CONCLUSIONS: Our data suggest that expression of 4N1K-containing proteins in tumor tissues is associated with reduced angiogenesis and tumor growth; thus, it would be a potentially predictive marker for progression of RCC.

Adult↗

PubMed2003

Expression of cyclooxygenase-2 in renal cell carcinoma: correlation with tumor cell proliferation, apoptosis, angiogenesis, expression of matrix metalloproteinase-2, and survival.

PURPOSE: Cyclooxygenase (COX)-2 plays an important role in tumor cell proliferation, resistance to apoptosis, angiogenesis, and invasion in various malignant tumors. However, the relationships between COX-2 expression and these biological processes, clinicopathological features, and survival rate in patients with renal cell carcinoma are not clear. EXPERIMENTAL DESIGN: Tumor sections surgically removed from 131 patients were examined for COX-2 expression by immunohistochemistry. We also examined Ki-67 labeling index, apoptotic index, microvessel density, and matrix metalloproteinase (MMP)-2 expression, and correlated COX-2 expression with various clinicopathological features and survival. RESULTS: Of 131 sections, 70 (53.4%) were positive for COX-2 expression. COX-2 expression was associated significantly with various clinicopathological features, and correlated with the Ki-67 labeling index, microvessel density, and MMP-2 expression (P < 0.01), but not with the apoptotic index (P = 0.054). COX-2 expression was also identified as an independent risk factor for large tumor size (>7 cm) in multivariate logistic regression model. COX proportional hazards analysis showed that distant metastasis and high T stage were independent prognostic factors [odds ratio (OR), 9.41; 95% confidence interval (CI), 2.16-41.11; P < 0.01 and OR, 5.19; 95% CI, 1.02-26.54; P = 0.048, respectively), whereas COX-2 expression was not (OR, 1.46; 95% CI, 0.24-9.00; P = 0.68). CONCLUSION: COX-2 expression in patients with renal cell carcinoma is associated with several clinicopathological factors, and appeared to play an important role in tumor cell proliferation and MMP-2 expression, but is not a significant prognostic factor.

Adult↗

PubMed2002

Stromal cell-derived factor-1alpha induces tube-like structure formation of endothelial cells through phosphoinositide 3-kinase.

Stromal cell-derived factor-1alpha (SDF-1alpha) is a CXC chemokine, which induces tube formation of endothelial cells. Although SDF-1alpha transduces signals via CXC receptor 4 (CXCR4), resulting in activating a panel of downstream signaling molecules, such as phosphoinositide 3-kinase (PI3-kinase), little is known about the SDF-1alpha-mediated signaling pathways leading to tube formation. Here we examined the signal transduction pathway involved in SDF-1alpha-mediated tube formation by primary human umbilical endothelial cells and murine brain capillary endothelial cell line (IBE (immortalized murine brain capillary endothelial) cells). SDF-1alpha stimulated tube formation by IBE cells, which was blocked by LY294002 and pertussis toxin, suggesting that PI3-kinase and G(i) protein were involved in this process. SDF-1 also stimulated tube formation of human umbilical endothelial cells, and the response was LY294002-sensitive. SDF-1alpha activated PI3-kinase in IBE cells. In stable IBE cell lines expressing either the mutant p85 subunit of PI3-kinase (denoted Deltap85-8 cells), which lacks association with the p110 subunit, or kinase-inactive c-Fes (denoted KEFes 5-15 cells), SDF-1alpha failed to activate PI3-kinase and to stimulate tube formation. SDF-1alpha-induced tube formation was inhibited by an antibody against murine vascular endothelial cadherin. The antibody as well as LY294002 attenuated SDF-1alpha-mediated compact cell-cell contact, which proceeded to tube formation. Taken together, SDF-1alpha induces compact cell-cell contact through PI3-kinase, resulting in tube formation of endothelial cells.

Animals↗

PubMed2002

Negative regulation of urokinase-type plasminogen activator production through FGF-2-mediated activation of phosphoinositide 3-kinase.

Activation of phosphoinositide 3-kinase (PI3-kinase) is involved in many cellular responses. FGF-2 is one of the potent inducers of urokinase-type plasminogen activator (uPA) production in endothelial cells. However, little is known about the molecular mechanisms underlying FGF-2-mediated uPA production. Here we examined the signal transduction pathways involved in the regulation of uPA production by FGF-2-treatment. FGF-2 potently upregulated uPA production in murine brain capillary endothelial cells (IBE cells), as well as porcine aortic endothelial (PAE) cells and L6 myoblasts ectopically expressing FGFR1. PI3-kinase inhibitors, wortmannin and LY294002, both enhanced FGF-2-dependent uPA production by these cells. Stable expression of activated mutant p110alpha catalytic subunit of PI3-kinase into IBE cells decreased FGF-2-mediated uPA production, suggesting that PI3-kinase exhibited the negative regulatory effect on uPA production. No increase in FGF-2-induced PI3-kinase activity was observed in proteins immunoprecipitated by anti-phosphotyrosine antibody. Although stable expression of deleted mutant p85alpha regulatory subunit, which lacks association with p110 catalytic subunit, in IBE cells showed no dominant negative effect, transient expression of dominant negative Ras inhibited FGF-2-mediated PI3-kinase activation. These results suggest that only activated Ras contributed the FGF-2-mediated PI3-kinase activation. In cells stably expressing mutant p85alpha subunit, FGF-2 efficiently induced uPA production. Taken together, activation of PI3-kinase by FGF-2 is Ras-dependent and results in down-regulation of uPA production.

Animals↗

PubMed2002

Effects of vitamin D(3)-binding protein-derived macrophage activating factor (GcMAF) on angiogenesis.

BACKGROUND: The vitamin D(3)-binding protein (Gc protein)-derived macrophage activating factor (GcMAF) activates tumoricidal macrophages against a variety of cancers indiscriminately. We investigated whether GcMAF also acts as an antiangiogenic factor on endothelial cells. METHODS: The effects of GcMAF on angiogenic growth factor-induced cell proliferation, chemotaxis, and tube formation were examined in vitro by using cultured endothelial cells (murine IBE cells, porcine PAE cells, and human umbilical vein endothelial cells [HUVECs]) and in vivo by using a mouse cornea micropocket assay. Blocking monoclonal antibodies to CD36, a receptor for the antiangiogenic factor thrombospondin-1, which is also a possible receptor for GcMAF, were used to investigate the mechanism of GcMAF action. RESULTS: GcMAF inhibited the endothelial cell proliferation, chemotaxis, and tube formation that were all stimulated by fibroblast growth factor-2 (FGF-2), vascular endothelial growth factor-A, or angiopoietin 2. FGF-2-induced neovascularization in murine cornea was also inhibited by GcMAF. Monoclonal antibodies against murine and human CD36 receptor blocked the antiangiogenic action of GcMAF on the angiogenic factor stimulation of endothelial cell chemotaxis. CONCLUSIONS: In addition to its ability to activate tumoricidal macrophages, GcMAF has direct antiangiogenic effects on endothelial cells independent of tissue origin. The antiangiogenic effects of GcMAF may be mediated through the CD36 receptor.

Angiogenesis Inhibitors↗

PubMed2002

Donor-specific blood transfusion prolongs cardiac allograft survival in rats by low nitric oxide production and elevated serum levels of prostaglandin E(2).

Donor-specific blood transfusion (DST) improves allograft survival, although the exact mechanism(s) is not completely understood. The purpose of this study was to determine the role of nitric oxide (NO) and prostaglandin E(2) (PGE(2)) in DST-protective effects, using a rat cardiac transplantation model. Lewis rats (RT-1(1)) were transfused with fully allogeneic ACI rats (RT-l(a)) blood (DST group) or Lewis syngeneic blood (ST) through the portal vein 7 days prior to allogeneic cardiac transplantation. Posttransplantation, aminoguanidine (AG)-treated rat received continuous intravenous infusion of AG, an inhibitor of inducible nitric oxide synthase (iNOS). The survival times of grafted hearts were 5.7+/-0.5, 6.8+/-0.8 and 9.2+/-1.2 days in ST, ST/AG, and DST groups (n=6 for each group), respectively. Inhibition of iNOS in ST/AG group prolonged allograft survival, but it was shorter than that in DST rats. Serum nitrite/nitrate levels on postgrafting day 5 were significantly higher in ST than in ST/AG and DST groups, but were similar in ST/AG and DST groups. These results were confirmed by immunohistochemical staining with anti-iNOS antibody. Serum PGE(2) concentrations in DST rats were significantly higher than in ST and ST/AG groups. Our results suggest that DST prolongs graft survival by enhanced production of PGE(2) with a resultant suppression of immune activation. In addition, DST-induced prolongation of graft survival may be partially mediated by NO suppression.

Animals↗

PubMed2002

Role of c-Fyn in FGF-2-mediated tube-like structure formation by murine brain capillary endothelial cells.

Tube formation of endothelial cells is an important step of angiogenesis. However, little is known about the molecular mechanisms underlying growth factor-mediated tube formation by endothelial cells. FGF-2 stimulates tube formation by a murine brain capillary endothelial cell line, IBE cells, when cultured on collagen gels (differentiation-associated culture condition), whereas cells proliferate and migrate without forming tube on fibronectin-coated surface (proliferation/migration-associated condition). To elucidate FGF-2-mediated signal transduction pathways leading to tube formation by endothelial cells, we focused on the contribution of Src family kinases. Src family kinase inhibitor PP2 attenuated FGF-2-induced tube formation. Stable expression of kinase-inactive c-Src in IBE cells demonstrated no dominant negative effect on FGF-2-induced tube formation. In vitro kinase assay revealed that c-Fyn was activated by FGF-2 only in cells cultured on collagen gels. Three independent cell lines, expressing kinase-inactive c-Fyn, all exhibited attenuation of FGF-2-mediated tube formation. However, FGF-2-mediated proliferation or migration was not clearly perturbed in these cells. These results show the first time that c-Fyn plays a pivotal role in tube formation by endothelial cells.

Animals↗