Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P39060 (endostatin)
 2,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endostatin, a collagen XVIII fragment, is a potent anti-angiogenic protein. We sought to identify its endothelial cell surface receptor(s). Alkaline phosphatase- tagged endostatin bound endothelial cells revealing two binding affinities. Expression cloning identified glypican, a cell surface proteoglycan as the lower-affinity receptor. Biochemical and genetic studies indicated that glypicans' heparan sulfate glycosaminoglycans were critical for endostatin binding. Furthermore, endostatin selected a specific octasulfated hexasaccharide from a sequence in heparin. We have also demonstrated a role for endostatin in renal tubular cell branching morphogenesis and show that glypicans serve as low-affinity receptors for endostatin in these cells, as in endothelial cells. Finally, antisense experiments suggest the critical importance of glypicans in mediating endostatin activities.
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PMID:Cell surface glypicans are low-affinity endostatin receptors. 1133 4

Patients with metastatic neuroblastoma are rarely curable with currently available therapy, and the search for new treatment options, which include the use of inhibitors of tumor angiogenesis, is warranted. Here, we have evaluated the efficacy of one of the most promising natural inhibitors of angiogenesis described to date, endostatin, in a human neuroblastoma xenograft model in nude mice. Murine endostatin cDNA was cloned in a bacterial expression vector, expressed as a polyHis-Endostatin fusion protein and purified on Ni2+-NTA beads. The in vitro activity of soluble endostatin was confirmed on bovine capillary endothelial cells and human umbilical vein endothelial cells. The human neuroblastoma cell line SKNAS was injected subcutaneously in the flank of nude mice and administration of the recombinant angiogenesis inhibitor started when tumors reached the size of 100 microm3. Twenty mg/kg of recombinant precipitated endostatin or PBS was subcutaneously injected daily for 12 days. Serum endostatin levels were measured using a competitive enzyme immunoassay. Tumor growth was only slowed down in endostatin-treated mice when compared to control mice, and no statistically significant difference in serum levels of endostatin was observed between endostatin-treated and control groups. The lack of correlation between serum concentration and tumor response raises concern regarding the mechanism of action of endostatin.
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PMID:Lack of antitumor activity of recombinant endostatin in a human neuroblastoma xenograft model. 1134 75

Endostatin is a cleavage product of collagen XVIII that inhibits tumor angiogenesis and growth. Interferon alpha2a blocks tumor angiogenesis and causes regression of hemangiomas, but has no effect on choroidal neovascularization (CNV). Therefore, inhibitors of tumor angiogenesis do not necessarily inhibit ocular neovascularization. In this study, we used an intravenous injection of adenoviral vectors containing a sig-mEndo transgene consisting of murine immunoglobulin kappa-chain leader sequence coupled to sequence coding for murine endostatin to investigate the effect of high serum levels of endostatin on CNV in mice. Mice injected with a construct in which sig-mEndo expression was driven by the Rous sarcoma virus promoter had moderately high serum levels of endostatin and significantly smaller CNV lesions at sites of laser-induced rupture of Bruch's membrane than mice injected with null vector. Mice injected with a construct in which sig-mEndo was driven by the simian cytomegalovirus promoter had approximately 10-fold higher endostatin serum levels and had nearly complete prevention of CNV. There was a strong inverse correlation between endostatin serum level and area of CNV. This study provides proof of principle that gene therapy to increase levels of endostatin can prevent the development of CNV and may provide a new treatment for the leading cause of severe loss of vision in patients with age-related macular degeneration.
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PMID:Inhibition of choroidal neovascularization by intravenous injection of adenoviral vectors expressing secretable endostatin. 1143 78

Endostatin, a C-terminal fragment of collagen XVIII, is a promising protein drug which is in development for cancer therapy due to its anti-angiogenic activity. Although several endogenous molecular forms of human endostatin differing in their N-terminal length and their post-translational modifications (18.5-22 kDa) have been discovered, only one recombinant form of 20 kDa is used in clinical trials. This protein, recombinantly expressed in Pichia pastoris, contains four cysteines forming two disulfide bonds (Cys1-Cys4 and Cys2-Cys3). In contrast, there are conflicting data about the disulfide pattern of endogenous material. This report presents the disulfide analyses of both the endogenous circulating endostatins isolated from human hemofiltrate and the recombinant protein. The determination of the disulfide pattern was performed by Edman degradation, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) and electrospray ionization ion trap mass spectrometry (ESI-ITMS) performed in the off-line nanospray mode. All native and recombinant endostatins exhibited a Cys1-Cys4 (Cys(162)-Cys(302)) and Cys2-Cys3 (Cys(264)-Cys(294)) linkage. For a clear discussion of fragmented disulfide-bridged peptide chains obtained from MS(n) experiments, a modified general nomenclature is proposed.
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PMID:Determination of the disulfide bond pattern of the endogenous and recombinant angiogenesis inhibitor endostatin by mass spectrometry. 1144 6

Endostatin, a M(r) 20,000 COOH-terminal fragment of collagen XVIII, is currently in preclinical development as a novel antiangiogenic agent. The gene expression of this molecule in 23 normal ovaries with follicle or corpus luteum and in 64 cases of epithelial ovarian cancer (27 serous, 18 mucinous, 13 endometrioid, 4 clear cell, and 2 undifferentiated carcinomas) was analyzed by PCR of RNA after reverse transcription. Seven of the cases were of low malignant potential. With regard to staging, 23 cases had stage I disease, 5 had stage II disease, 29 had stage III disease, and 7 had stage IV disease. The level of endostatin gene expression was described in terms of the ratio of the relative yield of the endostatin gene to that of the beta2-microglobulin gene. Endostatin gene expression in ovarian cancers (median, 0.14; range, 0.02-1.11) was significantly higher than that in normal ovaries with follicle or corpus luteum (median, 0.08; range, 0.03-0.26; P = 0.009). International Federation of Gynecology and Obstetrics stage (P = 0.009) and residual tumor (P = 0.005) were significantly associated with endostatin gene expression; however, other clinicopathological features (e.g., patient age at diagnosis, histological subtype, and histological grade) were not significantly associated with endostatin gene expression. Survival data were available for all patients. Univariate Cox regression analysis showed the prognosis of the patients with high endostatin gene expression [equal to or greater than the median (> or =0.14)] to be significantly worse than that of patients with low endostatin gene expression [less than the median (<0.14); P = 0.044]. Our results with regard to the gene expression of this endogenous inhibitor of angiogenesis present a new insight to understand the biology of epithelial ovarian cancer and may lead to the development of a new therapeutic strategy for epithelial ovarian cancer.
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PMID:Expression of the Endostatin gene in epithelial ovarian cancer. 1148 19

Endostatin is a newly found inhibitor of angiogenesis, which is identified as c-terminal 184 amino acid fragment of collagen XVIII NC1-domain. A 570 bp cDNA fragment of endostatin has been amplified by PCR from a commercial human fetal liver cDNA library. After subcloned into the yeast vector pPIC9 and subsequence to prove its correctness, Pichia pastoris was transformed with the recombinant pPIC9-endostatin. The expressed endostatin in P. pastoris was purified by heparin-sapherose affinity chromatography. It's purity identified by SDS-PAGE thin layer scanning analysis was up to 98.7% and its Mol. Weight measured by MS was 20.34 kD. The expression level was up to 40 mg/L. The first fifteen amino acid sequence of the N-terminal was completely identical with the inner sequence C-terminal fragment of collagen XVIII NC1 domain as has been designed. Bioassay indicated that the recombinant endostatin can inhibit angiogenesis stimulated by bFGF in CAM test and also the proliferation of both HUVEC and ECV304 in an in vitro test.
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PMID:[Inhibition effect in vitro of purified endostatin expressed in Pichia pastoris]. 1151

Endostatin, a M(r) 20,000 fragment of collagen XVIII, is able to inhibit angiogenesis and induce apoptosis in endothelial cells in vivo. We analyzed the effectsof recombinant endostatin on human microvascular endothelial cells, focusing on pericellular plasminogen activation and its targeting by the focal adhesion-associated cytoskeletal structures. Analysis of the proteolytic plasminogen activator system revealed that endostatin modulates the distribution of soluble and cell surface-associated urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor, type 1 (PAI-1). Casein zymographic and immunoprecipitation analyses indicated that endostatin exerts its effects by decreasing the levels of soluble uPA and PAI-1 and their complexes in a dose-dependent manner. Immunofluorescence analysis of cell surface-associated uPA indicated that endostatin treatment caused the redistribution of receptor-bound uPA from focal contacts, resulting in diffuse cell surface staining. In accordance with this observation, immunofluorescence staining of the urokinase receptor revealed that endostatin treatment removed uPAR from focal adhesions. Accordingly, endostatin caused a rapid disassembly of focal adhesions as observed by immunofluorescence analysis of the focal adhesion proteins vinculin and paxillin. A prominent change in the cytoskeletal architecture was observed as the actin stress fiber network was dissociated in response to endostatin treatment. The effect of focal adhesion disassembly was reversible, persisting from 1 h up to 6 h. Our results suggest that the antiangiogenic activity of endostatin involves the modulation of focal adhesions and actin stress fibers and the down-regulation of the urokinase plasminogen activator system.
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PMID:Endostatin-induced modulation of plasminogen activation with concomitant loss of focal adhesions and actin stress fibers in cultured human endothelial cells. 1152 48

Basement membrane molecules and fragments derived from them are regulators of biological activities such as cell growth, differentiation and migration. This review describes proteolytically derived fragments from the non-collagenous (NC1) domain at the C-terminus of the basement membrane collagens type IV, XV and XVIII, which have been implicated as regulators of angiogenesis. Endostatin is an endogenous collagen XVIII/NC1 derivative, inhibiting endothelial cell proliferation and migration in vitro and tumor-growth in vivo. A homologous NC1 domain fragment of type XV collagen has anti-angiogenic activity as well. Furthermore, NC1 domain fragments of the most abundant basement membrane collagen, type IV collagen, have been shown to inhibit induced vessel growth.
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PMID:The role of collagen-derived proteolytic fragments in angiogenesis. 1156 68

Endostatin is a potent endogenous inhibitor of angiogenesis that was recently shown to be stored in platelets and released in response to thrombin, but not ADP. In the present study, we have tested the hypothesis that thrombin-induced endostatin release from rat platelets is mediated via proteinase-activated receptor-4 (PAR4). Immunoprecipitation and Western blotting confirmed that endostatin is contained within rat platelets. Aggregation and release of endostatin could be elicited by thrombin (0.5 - 1.0 U ml(-1)) or by specific PAR4 agonist (AYPGKF-NH(2); AY-NH(2); 15 - 50 microM). Significant release of endostatin could be induced by a dose of thrombin below that necessary for induction of aggregation. An adenosine diphosphate (ADP) scavenger, apyrase, inhibited the platelet aggregation induced by thrombin, but not the release of endostatin. In contrast, a selective PAR4 antagonist (trans-cinnamoyl-YPGKF-NH(2); tcY-NH(2)) prevented endostatin release and aggregation induced by thrombin or by AY-NH(2). We conclude that thrombin-induced endostatin release from rat platelets is PAR4-mediated via an ADP-independent mechanism that can occur independently of platelet aggregation.
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PMID:Thrombin-induced platelet endostatin release is blocked by a proteinase activated receptor-4 (PAR4) antagonist. 1160 9

In the first Phase I clinical trials of endostatin as an antiangiogenic therapy for cancer, the protein was administered as an i.v. bolus for approximately 20-30 min each day. This protocol was based on experimental studies in which animals were treated by s.c. bolus once a day. However, it was not clear in the previous studies whether this schedule could be maximized further. Therefore, we developed experimental models involving continuous administration of endostatin to determine the potency and efficacy of this approach. Endostatin was administered to tumor-bearing mice either s.c. or i.p. in single bolus doses. The efficacy of these regimens was compared with endostatin administered continuously via an i.p. implanted mini-osmotic pump. Our results show that endostatin remains stable and active in mini-osmotic pumps for at least 7 days. We show that endostatin injected i.p. is rapidly cleared within 2 h, whereas endostatin administered continuously via mini-osmotic pump maintains systemic concentrations of 200-300 ng/ml for the duration of administration. Furthermore, continuous i.p. administration of endostatin results in more effective tumor suppression at significantly reduced doses (5-fold), compared with bolus administration. Additional experiments using a human pancreatic cancer model in severe combined immunodeficient mice showed that there was a significant decrease in the microvessel density between the treatment groups and the control group. These data show that continuous administration of human endostatin results in sustained systemic concentrations of the protein leading to: (a) increased efficacy manifested as increased tumor regression; and (b) an 8-10-fold decrease in the dose required to achieve the same antitumor effect as the single daily bolus administration of endostatin. On the basis of this approach, an additional clinical trial has been designed and initiated and is under way in two countries.
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PMID:Continuous administration of endostatin by intraperitoneally implanted osmotic pump improves the efficacy and potency of therapy in a mouse xenograft tumor model. 1160 10


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