Heparin has been used clinically as an anticoagulant for over 60 years. Typically isolated from porcine intestine, heparin is a mixture of dimeric glycosidic sequences generating complex polysaccharide glycosaminoglycan chains. Recently, certain lots of heparin have been associated with an acute, rapid onset of significant side effects indicative of an allergic-type reaction. To identify potential causes for this serious rise in side effects, we examined lots of heparin that correlated with adverse events using orthogonal high resolution analytical techniques. Through comparison of these results with those obtained on reference lots, suspect lots were found to contain a highly sulfated chondroitin sulfate contaminant. Through detailed structural analysis, the contaminant was found to contain a disaccharide repeat unit of glucuronic acid linked β1→3 to a β-galactosamine. Surprisingly, the disaccharide unit contains an unusual sulfation pattern and is sulfated at the 2-O and 3-O positions of the glucuronic acid as well as at the 4-O and 6-O positions of the galactosamine. The presence of such a contaminant could elicit a biological response as highly sulfated polysaccharides, such as dextran sulfate, are known to be potent mediators of the immune system. Given the nature of the contaminant, traditional screening tests -such as those present as part of the current United States Pharmacopeia heparin monograph -cannot differentiate between affected and unaffected lots. Our analysis suggests effective screening methods that can be employed to determine whether or not heparin lots contain the contaminants reported here.

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Purpose: Heparanase promotes myeloma growth, dissemination, and angiogenesis through modulation of the tumor microenvironment, thus highlighting the potential of therapeutically targeting this enzyme. SST0001, a nonanticoagulant heparin with antiheparanase activity, was examined for its inhibition of myeloma tumor growth in vivo and for its mechanism of action.Experimental Design: The ability of SST0001 to inhibit growth of myeloma tumors was assessed using multiple animal models and a diverse panel of human and murine myeloma cell lines. To investigate the mechanism of action of SST0001, pharmacodynamic markers of angiogenesis, heparanase activity, and pathways downstream of heparanase were monitored. The potential use of SST0001 as part of a combination therapy was also evaluated in vivo.Results: SST0001 effectively inhibited myeloma growth in vivo, even when confronted with an aggressively growing tumor within human bone. In addition, SST0001 treatment causes changes within tumors consistent with the compound's ability to inhibit heparanase, including downregulation of HGF, VEGF, and MMP-9 expression and suppressed angiogenesis. SST0001 also diminishes heparanase-induced shedding of syndecan-1, a heparan sulfate proteoglycan known to be a potent promoter of myeloma growth. SST0001 inhibited the heparanase-mediated degradation of syndecan-1 heparan sulfate chains, thus confirming the antiheparanase activity of this compound. In combination with dexamethasone, SST0001 blocked tumor growth in vivo presumably through dual targeting of the tumor and its microenvironment.Conclusions: These results provide mechanistic insight into the antitumor action of SST0001 and validate its use as a novel therapeutic tool for treating multiple myeloma.

Chitosan is a biopolymer obtained from chitin, one of the most abundant and renewable materials on Earth. Chitin is a primary component of cell walls in fungi, the exoskeletons of arthropods such as crustaceans, e.g., crabs, lobsters and shrimps, and insects, the radulae of molluscs, cephalopod beaks, and the scales of fish and lissamphibians. The discovery of chitin in 1811 is attributed to Henri Braconnot while the history of chitosan dates back to 1859 with the work of Charles Rouget. The name of chitosan was, however, introduced in 1894 by Felix Hoppe-Seyler. Chitosan has attracted major scientific and industrial interests from the late 1970s due to its particular macromolecular structure, biocompatibility, biodegradability and other intrinsic functional properties. Chitosan and derivatives have practical applications in the food industry, agriculture, pharmacy, medicine, cosmetology, textile and paper industries, and in chemistry. In recent years, chitosan has also received much attention in dentistry, ophthalmology, biomedicine and bioimaging, hygiene and personal care, veterinary medicine, packaging industry, agrochemistry, aquaculture, functional textiles and cosmetotextiles, catalysis, chromatography, beverage industry, photography, wastewater treatment and sludge dewatering, and biotechnology. Nutraceuticals and cosmeceuticals are actually growing markets, and therapeutic and biomedical products should be the next markets in the development of chitosan. Chitosan is also the object of numerous fundamental studies. In this review, we highlight a selection of works on chitosan applications published over the past two decades.

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Heparanase is an endo-␤-glucuronidase that cleaves heparan sulfate (HS) chains of heparan sulfate proteoglycans on cell surfaces and in the extracellular matrix (ECM). Heparanase, overexpressed by most cancer cells, facilitates extravasation of blood-borne tumor cells and causes release of growth factors sequestered by HS chains, thus accelerating tumor growth and metastasis. Inhibition of heparanase with HS mimics is a promising target for a novel strategy in cancer therapy. In this study, in vitro inhibition of recombinant heparanase was determined for heparin derivatives differing in degrees of 2-O-and 6-O-sulfation, N-acetylation, and glycol splitting of nonsulfated uronic acid residues. The contemporaneous presence of sulfate groups at O-2 of IdoA and at O-6 of GlcN was found to be non-essential for effective inhibition of heparanase activity provided that one of the two positions retains a high degree of sulfation. N-Desulfation/ N-acetylation involved a marked decrease in the inhibitory activity for degrees of N-acetylation higher than 50%, suggesting that at least one NSO 3 group per disaccharide unit is involved in interaction with the enzyme. On the other hand, glycol splitting of preexisting or of both preexisting and chemically generated nonsulfated uronic acids dramatically increased the heparanase-inhibiting activity irrespective of the degree of N-acetylation. Indeed N-acetylated heparins in their glycol-split forms inhibited heparanase as effectively as the corresponding N-sulfated derivatives. Whereas heparin and N-acetylheparins containing unmodified D-glucuronic acid residues inhibited heparanase by acting, at least in part, as substrates, their glycol-split derivatives were no more susceptible to cleavage by heparanase. Glycol-split N-acetylheparins did not release basic fibroblast growth factor from ECM and failed to stimulate its mitogenic activity. The combination of high inhibition of heparanase and low release/potentiation of ECM-bound growth factor indicates that N-acetylated, glycol-split heparins are potential antiangiogenic and antimetastatic agents that are more effective than their counterparts with unmodified backbones.

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The heparan sulfate proteoglycan syndecan-1 is expressed by myeloma cells and shed into the myeloma microenvironment. High levels of shed syndecan-1 in myeloma patient sera correlate with poor prognosis and studies in animal models indicate that shed syndecan-1 is a potent stimulator of myeloma tumor growth and metastasis. Overexpression of extracellular endosulfatases, enzymes which remove 6-O sulfate groups from heparan sulfate chains, diminishes myeloma tumor growth in vivo. Together, these findings identify syndecan-1 as a potential target for myeloma therapy. Here, 3 different strategies were tested in animal models of myeloma with the following results: (1) IntroductionSyndecan-1 (CD138) is a cell-surface heparan sulfate-bearing proteoglycan that was first detected by polymerase chain reaction (PCR) in mRNA from human patients with myeloma and later confirmed by monoclonal antibody staining to be present on all myeloma tumors. 1,2 Syndecan-1 is shed from the myeloma tumor cell surface and accumulates in the bone marrow and serum of patients. When present at high levels in the serum, syndecan-1 is an independent indicator of poor prognosis. [3][4][5] However, high-serum syndecan-1 is more than simply an indicator of poor prognosis. Studies in animal models have shown that high levels of soluble syndecan-1 enhance both the growth and metastasis of tumors. 6 Syndecan-1 exerts its growth-promoting effects by regulating the activity of many effector molecules important for myeloma growth and survival, including hepatocyte growth factor (HGF) and heparin-binding epidermal growth factor (HB-EGF) family members, among others. 7,8 The high levels of heparan sulfate in the tumor microenvironment resulting from syndecan-1 shedding also act as positive regulators that condition the microenvironment for robust tumor growth. For example, heparan sulfate binds to and promotes the activity of important angiogenic growth factors such as fibroblast growth factor-2 (FGF-2) and vascular endothelial growth factor (VEGF). This activity can occur in trans, indicating that shed syndecan-1 can contribute to the high level of angiogenesis seen in many patients with myeloma. 9,10 In addition, the syndecan-1 that becomes embedded within the myeloma tumor stroma can serve as reservoir for storage and concentration of heparan sulfate-binding growth factors that can later be mobilized by cleavage of the heparan sulfate by heparanase. 3,11 This mobilization of heparan sulfate-retained growth factors in the bone marrow likely contributes to the high rate of relapse among patients with myeloma.Because of its high level of expression on myeloma tumors, syndecan-1 has been explored as a candidate antigen for antibody targeting of toxins to the tumor cell surface. [12][13][14] In addition, antibodies to syndecan-1 show promise as facilitators of myeloma immunotherapeutic approaches. 15 However, specific strategies for disrupting the function of syndecan-1 or its heparan sulfate chains as a potential therapy for myeloma have not been reported...