Heparin Octasaccharides Inhibit Angiogenesis In vivo

Abstract

Background: In previous experiments, we showed that heparin oligosaccharides inhibit the angiogenic cytokine fibroblast growth factor-2. Here, we present the first in vivo study of sizefractionated heparin oligosaccharides in four models of angiogenesis that are progressively less dependent on fibroblast growth factor-2. Experimental Design: Heparin oligosaccharides were prepared using size-exclusion gel filtration chromatography and characterized through depolymerization and strong anion exchange high-performance liquid chromatography. Size-defined oligosaccharides (20 mg/kg/d) were given to mice bearing s.c. sponges that were injected with fibroblast growth factor-2 (100 ng/d). After 14 days, octasaccharides and decasaccharides reduced the microvessel density to levels below control. In a second experiment, HEC-FGF2 human endometrial cancer cells that overexpress fibroblast growth factor-2 were implanted in a hollow fiber placed s.c. in vivo. Oligosaccharides were given at 20 mg/kg/d for 2 weeks and the data again showed that octasaccharides significantly reduced microvessel density around the fiber (P = 0.03). In a more complex model, where angiogenesis was induced by a broad spectrum of growth factors, including vascular endothelial growth factor, we implanted H460 lung carcinoma cells in hollow fibers and treated the animals with oligosaccharides at 20 mg/kg/d over 3 weeks. Octasaccharides reduced the microvessel density to that of control. Preliminary investigation of 6-O-desulfated heparins showed that these also had antiangiogenic activity. Results: Finally, we examined the inhibitory potential of hexasaccharides and octasaccharides given at 20 mg/kg/d and these inhibited the growth of H460 lung carcinoma in vivo. At clinically attainable concentrations, significant anticoagulation (activated partial thromboplastin time, anti^factor Xa, and anti^factor IIa) was not observed in vitro unless species containing z16 saccharide residues were investigated. Conclusions: Thus, our preclinical data show that heparin octasaccharides represent novel antiangiogenic compounds that can be given without the anticoagulant effects of low molecular weight heparin.

Heparin Impairs Angiogenesis through Inhibition of MicroRNA-10b

“…5B). These results confirm previous reports that heparin can inhibit angiogenesis in vivo (36,37). Quantitative real-time PCR analysis of tumor tissues revealed that heparin treatment significantly reduced levels of miR-10b expression when compared with tumors from control animals (Fig.…”

Modulatory effects of heparin and short-length oligosaccharides of heparin on the metastasis and growth of LMD MDA-MB 231 breast cancer cells in vivo

“…It is therefore most probable that dp12 is affecting factors other than CXCL12 in mediating its effects on tumour growth. For example, heparin derivatives as short as eight monosaccharide units can bind both FGF-2 and VEGF in vivo Tyrrell et al, 1993;Hurwitz et al, 2004); this prevents these growth factors from binding to heparan sulphate leading to inhibition of angiogenesis (Hasan et al, 2005). As these oligosaccharides prevent FGF-2 and VEGF from binding to heparan sulphate, they function as antagonists of angiogenesis and have been shown in vivo to inhibit the development of new vasculature (Hasan et al, 2005).…”

Therapeutic value of glycosaminoglycans in cancer

“…Among the glycosaminoglycan-based pharmaceutics already in clinical use, modulation of angiogenesis by different heparins has been shown. For example, the low molecular weight heparin tinzaparin was found to be a potent angiogenesis inhibitor in vitro (106) and heparin octasaccharides inhibited tumor angiogenesis in animal models (107). Mechanistically, this antiangiogenic effect is due to heparin-induced cellular release of tissue factor pathway inhibitor.…”