Search

Endostatin (ES) has attracted considerable attention for the treatment of anti-angiogenesis-related disorders. An 11-amino-acid peptide (ES2, IVRRADRAAVP) from the amino terminal of ES is of interest because it is the main active fragment of ES. However, both ES and ES2 have a poor stability and a short half-life, and other disadvantages need to be further resolved. Thus, we conjugated ES2 to glycol-split heparin derivatives (GSHPs) to yield the polymer-peptide conjugate, GSHP-ES2. This study showed that GSHP-ES2 exhibited increased stability, a wider pH activity range, better inhibition of endothelial cell proliferation, migration and tube formation in vitro, better anti-angiogenic activity and a longer half-life in vivo compared with ES2. These results also indicate that GSHP-ES2 has good potential for the treatment of angiogenesis-related diseases, either alone or in combination with other chemicals., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Anti-flt1 peptide (GNQWFI, AF) specifically binds to Vascular Endothelial Growth Factor Receptor 1 (VEGFR1), thereby inhibiting the interaction of VEGFR1 with a series of ligands. ES2 (IVRRADRAAVP) can effectively inhibit the proliferation and invasion of endothelial cells and play a key role in anti-angiogenesis. AF and ES2 peptides differ in their activity. To better exploit the advantages of both, we designed a new peptide called ES2-AF (IVRRADRAAVPGGGGGGNQWFI). Hyaluronic acid (HA) is widely used in the pharmaceutical industry because of its biodegradable and high load performance. The HA-specific cell surface receptor CD44 was highly expressed in the tumour site during the anti-tumour study. Therefore, we used HA as a modifier to chemically modify ES2-AF; it was expected that the modified compound would have preferable solubility, stronger targeting, longer half-life, and better anti-angiogenesis effects in vivo. In this study, the anti-proliferative, anti-migration and targeting activities of HA-ES2-AF in vitro were studied by MTT, ELISA, transwell and SPR assays. Meanwhile, the anti-neovascularization activity of HA-ES2-AF in vivo was studied by CAM assay, and the targeting of HA-ES2-AF to tumour tissue was studied by bioimaging techniques. Finally, we also studied the half-life of HA-ES2-AF in vivo. In short, the bioactivity of the new peptide ES2-AF was enhanced to a certain extent, and ES2-AF modified by HA had higher anti-neovascularization activity in vitro and in vivo, had stronger targeting to tumour tissue, and had a significantly prolonged half-life in vivo. These results laid the foundation for its further development into targeting anti-tumour drugs., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Endostatin (ES) is a promising anti-angiogenesis protein and has been approved for the treatment of non-small cell lung cancer, but short half-life, poor stability and nonspecific delivery caused great pain to patients and produced unsatisfactory treatment effectiveness., Objective: In this work, in order to overcome these disadvantages, ES was covalently modified by polysulfated heparin (PSH) with the expectancy of longer half-life, higher anti-angiogenesis activity and better cellular uptake., Methods: To characterize the cellular uptake, flow cytometry and confocal laser scanning microscopy were used to study the intracellular localization of fluorescein isothiocyanate-labeled ES and PSH-ES in EAhy926 endothelial cells. Zebrafish model was used to study the anti-angiogenesis activities of ES and its derivatives in vivo. The 125I-radiolabeled ES and PSH-ES were administered to healthy BALC/c mice for the pharmacokinetics study., Results: Compared with ES, better cellular uptake effects were detected in PSH-ES group. Both ES and PSH-ES showed inhibition on the intersegmental vessels formation, while PSH-ES displayed a higher one. The half-life of PSH-ES was lengthened and area under the curve (AUC) was increased. At the same time, ES and PSH-ES were both widely and rapidly distributed in the lungs, livers, kidneys and hearts with little difference., Conclusion: The results indicated that PSH displayed good properties as a novel glyco-modifier for protein and peptide. The results also showed that PSH-ES displayed better cellular uptake, higher antiangiogenesis activity and prolonged half-life, which would lead to better anti-tumour effects., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Soluble O-(2-hydroxyl)propyl-3-trimethyl ammonium chitooligosaccharide chloride (HTCOSC) was covalently conjugated to the 11-amino-acid peptide derived from amino terminus of endostatin (endostatin2, ES2, IVRRADRAAVP) to overcome its poor stability, low cell affinity and instable activity. Nuclear magnetic resonance spectroscopy and mass spectrometry was used to study the structure and molecular weight information. The anti-angiogenic activities were evaluated using cell counting Kit-8 assay, flow cytometry assay, wounding migration assay, transwell migration assay, chicken chorioallantoic membrane (CAM) assay and zebra fish angiogenesis assay. In contrast with ES2, the novel carbohydrate-polymer HTCOSC-ES2 displayed improved heat stability, higher cell affinity, better inhibition on endothelial cell proliferation, tube formation, 2-dimensional and 3-dimensional migration in vitro. According to the evaluation in CAM and zebra fish, HTCOSC-ES2 also displayed better anti-angiogenic activity than ES2 in vivo. These results indicate that HTCOSC has good properties as potential candidate for protein/peptide modifier and HTCOSC-ES2 has good potential in angiogenesis related diseases treatment., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Endostatin, a specific inhibitor of endothelial cell proliferation and angiogenesis, has been proved to have effects on ocular neovascular diseases by intraocular injection. In order to increase its permeability to ocular barriers and make it effective on fundus oculi angiogenesis diseases via non-invasive administration (eye drops), endostatin was fused to Tat PTD via a genetic engineering method., Methods: Most of the Tat PTD- endostatin was expressed as inclusion bodies in Escherichia coli, so pure and active Tat PTD-endostatin was prepared by a series of operations, including inclusion body denaturation, refolding and chromatography. The anti-angiogenesis activity of Tat PTD-endostatin was investigated by cell proliferation experiments and chick embryo chorioallantoic membrane assay. In addition, its translocating ability and concrete entry mechanism into cells were also investigated by fluorescence microscope and flow cytometry. The penetrating ability to ocular barriers was also studied by immunohistochemistry. A mouse choroidal neovascularization model was established to investigate the pharmacodynamics of Tat PTD-endostatin., Results: The obtained Tat PTD-endostatin had excellent anti-angiogenesis activity and was superior to Es in cellular translocating. Macropinocytosis may be the dominant route of entry of Tat PTD-endostatin into cells. Tat PTD-endostatin could cross ocular barriers and arrive at the retina after eye-drop administration. In addition, it displayed inhibitory effects on choroidal neovascularization via eye drops., Conclusions: Tat PTD-endostatin possessed excellent ocular penetrating ability and anti-angiogenesis effects., General Significance: Tat PTD is a promising ocular delivery tool, and Tat PTD-endostatin is a potential drug for curing fundus oculi angiogenesis diseases., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Endostatin (ES), a potent endogenous angiogenesis inhibitor found in 1997 by O'Reilly, can effectively inhibit angiogenesis, inhibit the growth and metastasis of tumors. ES can also decrease drug resistance in long term and repeated treatment when it is used in combination with other chemotherapeutic agents. But there are still lots of obstacles on its clinical application, such as the need of a high dose to maintain its efficacy short half-life, poor stability, expensive, and some other shortcomings just like other protein drugs. Chemical modification on ES by polyethylene glycol (PEG) and low molecular weight heparin (LMWH) were successfully carried out in order to obtain a better ES derivative. Several classic experimental models were employed to study the bioactivity of ES and modified ES, including chicken chorioallantoic membrane (CAM) assay, corneal neovascularization (CNV) assay and Sarcoma 180 tumor bearing mice assay. The results showed that PEG-ES and LMWH-ES had better anti-angiogenesis and anti-tumor activity than ES, which indicates that LMWH was also a good protein modifier., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

The aim was to study the effects and action mechanism of endostatin (ES), low molecular weight heparin-endostatin (LMWH-ES) and polyethylene glycol-endostatin (PEG-ES) on endothelial cell proliferation, choroidal neovascularization and zebrafish angiogenesis. Three-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide was used to study the effects of ES and its derivatives on endothelial cell proliferation in vitro. Choroidal neovascularization model was used to evaluate the effects of ES and its derivatives on choroidal neovascularization in vivo. Western blotting was employed to study the effects of ES and its derivatives on the expression of vascular endothelial growth factor (VEGF) and pigment epithelium derived factor (PEDF) in chorioid tissues. Zebrafish model was also used to study the anti-angiogenesis activities of ES and its derivatives. The results showed that ES and its derivatives could significantly inhibit endothelial cell proliferation in vitro (p<0.05), suppress choroidal neovascularization by down-regulating expression of VEGF and up-regulating expression of PEDF in chorioid tissues, and restrain angiogenesis in zebrafish. ES showed better activity in inhibiting endothelial cell proliferation in vitro (p<0.05), but LMWH-ES and PEG-ES showed higher activity in inhibiting choroidal neovascularization in vivo (p<0.05) and angiogenesis in zebrafish (p<0.05). These results indicate that LMWH-endostatin and PEG-endostatin are potential candidates for anti-angiogenesis drug.

Endostatin (ES), as an angiogenesis inhibitor, has been approved by the State Food and Drug Administration (SFDA) in China for the treatment of patients with non-small-cell lung cancer. However, as a protein drug, there are a lot of obstacles on its clinical application, such as need of high dose to maintain its efficacy, expensive and poor stability, etc and limits its clinical use. In order to overcome these shortcomings, we chemically modified ES by polyethylene glycol and low molecular weight heparin (LMWH), respectively. The changes of the secondary structure of the modified products were studied by Fourier transform infrared spectroscopy and Circular dichroism spectra to obtain better ES derivatives. Our study demonstrated that the modified products have a better heat tolerance than ES towards. The result of secondary structure analysis suggests the percentage of beta-turn in whole protein is an important factor on the activity and heat stability and ES modified by LMWH can maintain higher activity and its secondary structure.