Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:4.2.2.7 (heparinase)
1,270 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of crude and purified glycosaminoglycan (GAG) lyases on cell adhesion to plastic substrates were studied in three established cell lines. In the presence of crude heparinase, BALB/c 3T3 and B16.F10 melanoma cells and a fibrosarcoma line were markedly inhibited in their ability to attach and spread on two types of tissue culture-grade plastic. The crude enzyme effect was dose dependent, reversible, and co-eluted with heparinase activity by Sepharose Cl-6B chromatography. Boiling of the preparation, however, did not eliminate its effect. Furthermore, none of the purified GAG lyases which were tested reproduced the effect of the crude preparation. Therefore, our results indicate that although GAG lyases are effective in digesting the GAGs of cell surfaces, the removal of these substances has no perceptible effect on the substrate adhesion of the three cell types evaluated.
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PMID:The digestion of cell surface-associated glycosaminoglycans by crude and purified flavobacter heparinum enzymes: disparate effects on cell adhesion. 357 52

The glycosaminoglycans produced by human fetal uveal melanocytes and by human melanoma cells were examined. The cells were grown in the presence of [3H]glucosamine and [35S]sulfate, and the labeled glycosaminoglycans were isolated from the cells, spend medium, and intracellular material. The distribution of the glycosaminoglycans was similar in both cells and spent media, which together accounted for 95% of the total. Of the total 3H]labeled glycosaminoglycans produced by the melanocyte culture, 42% was in chondroitin 4-sulfate, 25% in heparan sulfate, 16% in chondroitin 6-sulfate, and 17% in hyaluronic acid. In contrast, HM7 human melanoma cultures produced no chondroitin 6-sulfate, increased quantities of heparan sulfate, and less hyaluronic acid. A heparan sulfate fraction obtained from melanocytes required both heparitinase and heparinase for complete degradation, indicating the presence of heparin-like molecules in this fraction. The corresponding fraction from melanoma cells was totally degraded by heparitinase alone.
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PMID:Glycosaminoglycans of cultured human fetal uveal melanocytes and comparison with those produced by cultured human melanoma cells. 729 96

Four vascular endothelial growth factor (VEGF) splice variants containing 121, 165, 189, and 206 amino acids are produced from a single human gene as a result of alternative splicing. VEGF121 is not a heparin-binding protein, while the other VEGF species possess heparin binding ability. YU-ZAZ6 human melanoma cells expressed the mRNA encoding the VEGF receptor flt-1, but not the mRNA encoding the VEGF receptor KDR/flk-1. Both VEGF121 and VEGF165 bound to the VEGF receptors of these cells. Unexpectedly, heparin inhibited the binding of VEGF121 as well as the binding of VEGF165 to the VEGF receptors of the melanoma cells. Digestion of the cells with heparinase also inhibited the binding of both VEGF variants. The VEGF165 binding ability of heparinase-digested cells could be partially restored by the addition of exogenous heparin to the binding reaction. In contrast, the addition of heparin to heparinase-digested cells did not restore VEGF121 binding. These results suggest that cell-surface heparan sulfates may regulate the binding ability of the VEGF receptors of the melanoma cells. They also indicate that heparin is not able to fully substitute for cell surface-associated heparan sulfates since VEGF121 binding to the VEGF receptors of heparinase-treated cells is not restored by heparin. These data suggest that changes in the composition of cell-surface heparin-like molecules may differentially affect the interaction of various VEGF isoforms with VEGF receptors.
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PMID:VEGF121, a vascular endothelial growth factor (VEGF) isoform lacking heparin binding ability, requires cell-surface heparan sulfates for efficient binding to the VEGF receptors of human melanoma cells. 774 69

Vascular endothelial growth factor (VEGF) is a specific mitogen for endothelial cells in vitro and an angiogenic factor in vivo. Its role in other cell types is not yet clear. To explore its possible involvement in malignant transformation, we studied the expression of its receptors in normal and malignant melanocytes. Binding and cross-linking experiments showed that human melanoma cells but not normal melanocytes express VEGF receptors. Separation of reaction products by SDS-PAGE demonstrated the presence of 125I-VEGF/receptor complexes of 180 and 165 kDa in the melanoma cells. A diffuse complex with a mass of approximately 235 kDa was also detected in some experiments. Heparin enhanced the binding of the radioactive ligand to the receptors of the WW94 and SW1614 melanoma cell lines. This binding was completely abolished by heparinase digestion and was restored by the addition of exogenous heparin, indicating that heparin-like molecules are necessary for ligand/receptor interaction. This study suggests that the aberrant expression of VEGF receptors is one of the phenotypic changes occurring in melanoma cells during malignant transformation.
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PMID:Human melanoma cells but not normal melanocytes express vascular endothelial growth factor receptors. 843 21

An unexplained paradox of malignant melanoma is the apparent failure of the blood within the tumor to clot despite the presence of multiple factors that should promote blood clotting. Here we present histochemical evidence that human and murine melanomas are extensively infiltrated by abundant mast cells. Because mast cells contain the natural anticoagulant heparin, the present studies were aimed at defining the role of mast cell heparin in preventing the blood from clotting within B16 melanoma grafts in C57BL/6 J mice. Mice bearing B16 melanoma grafts were treated with non-specific or specific inhibitors of mast cell heparin (protamine or heparinase, respectively). After the drug treatment there was histologic and functional evidence of selective thrombosis of the blood vessels within the protamine and heparinase treated melanoma grafts. A similar, high degree of thrombosis was also observed in B16 tumors grown in transgenic NDST-2 knockout mice bearing a targeted disruption in the gene coding for mast cell heparin synthesis. The tumors grown in the protamine-treated animals were significantly smaller than the tumors from control (untreated mice). By contrast, the tumors treated with heparinase or grown in the NDST-2 knockout mice were significantly larger than the tumors from control (untreated) mice. We conclude that the intrinsic procoagulant properties of malignant melanoma are neutralized in vivo by the anticoagulant properties of endogenous heparin produced by mast cells that naturally infiltrate the tumor. Our results also suggest that thrombosis and hemostasis within melanoma may play a complex role in modulating the growth of the tumor.
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PMID:Inhibition of thrombosis in melanoma allografts in mice by endogenous mast cell heparin. 1288 84

Heparanase has been previously associated with the metastatic potential, inflammation, and angiogenesis of tumor cells. Heparanase activity has been detected by means of UV absorption, radiolabeled substrates, electrophoretic migration, and heparan sulfate affinity assays. However, those methods have proven to be somewhat problematic with regards to application to actual biological samples, the accessibility of the immobilized substrates, experimental sensitivity, and the separation of degraded products. Rather than focusing on heparanase activity, then, we have developed a rapid, alternative colorimetric heparinase assay, on the basis of the recent finding that sulfated disaccharides generated from heparin by bacterial heparinase exhibit biological properties comparable to those from heparan sulfate by mammalian heparanase. In this study, the concentrations of porcine heparin and bacterial heparinase I were determined using a Sigma Diagnostics Kit. Morus alba was selected as a candidate through this assay system, and an inhibitor, resveratrol, was purified from its methanol extract. Its anti-metastatic effects on the pulmonary metastasis of murine B16 melanoma cells were also evaluated. Our findings suggest that this assay may prove useful as a diagnostic tool for heparinase inhibition, as an alternative anti-metastatic target.
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PMID:Colorimetric heparinase assay for alternative anti-metastatic activity. 1680 78

The peptide pVEC is a recently described cell-penetrating peptide, derived from the murine vascular endothelial-cadherin protein. In order to define which part of this 18-amino acid long peptide is important for the cellular translocation, we performed a structure-activity relationship study of pVEC. Together with the l-alanine substituted peptides, the retro-pVEC, D-pVEC and the scramble pVEC are studied for comparison. The peptide analogues are labeled with carboxyfluorescein at the N-terminus for monitoring the cellular uptake into human Bowes melanoma cells with different efficacy. We show that all the Fl-pVEC analogues internalize in live Bowes melanoma cells. l-Alanine substitution of the five respective N-terminal hydrophobic amino acids significantly decreases the translocation property, while replacing of Arg(6), Arg(8) or Ser(17) by alanine enhances the uptake. The uptake of pVEC is significantly reduced by treatment with an endocytosis inhibitor wortmannin. Treatment with heparinase III, nystatin and EIPA had no effect on the peptide uptake. The data presented here show that the N-terminal hydrophobic part of pVEC is crucial for efficient cellular translocation.
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PMID:Structure-activity relationship study of the cell-penetrating peptide pVEC. 1680 94

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