P-selectin- and heparanase-dependent antimetastatic activity of non-anticoagulant heparins

Oligosaccharide-assisted resolution of holothurian fucosylated chondroitin sulfate for fine structure and P-selectin inhibition

Fucosylated chondroitin sulfate (FCS) from Holothuria mexicana (FCSHm) was selected for investigation because of its intriguing branch features. Selective β-eliminative depolymerization and the bottom-up assembly were performed to unravel that FCSHm consisted of a {D-GlcA-β1,3-D-GalNAc4S6S} backbone and branches of alternating FucS (55 %) and D-GalNAcS-α1,2-L-FucS (45 %), the highest proportion of disaccharide branch reported to date. In branches, sulfation could occur at every free -OH site except O-3 of GalNAc, being the most complex and various structure features of natural FCS. Detailed structure-activity relationship analyses showed that FCSHm and its depolymerized products (>8 kDa) effectively competed with SLeX and PSGL-1 to bind with P-sel at nano-molar level and the inhibition potency increased with Mw increasing. For the structural trisaccharide unit, di-O-sulfation of the FucS (Fuc2S4S and Fuc3S4S) was almost 10-fold more potent than mono-O-sulfation (Fuc4S). Unexpectedly, higher sulfation of the disaccharide-branched tetrasaccharide unit reduced inhibition. The reversal may attribute to fewer interactions with P-sel by molecular docking study. These results suggested that the specific configuration underpinned the potent inhibition, whereas the size and sulfate number of branches were not the key factors for the specific binding. dHmF4 (8.0 kDa) potently blocked the platelet-leukocyte aggregates formation, further verifying the potential value in use.

Towards an emerging role for anticoagulants in cancer therapy: a systematic review and meta-analysis

Background

Anticoagulants, renowned for their role in preventing blood clot formation, have captivated researchers' attention for the exploitation of their potential to inhibit cancer in pre-clinical models.

Objectives

To undertake a systematic review and meta-analysis of the effects of anticoagulants in murine cancer research models. Further, to present a reference tool for anticoagulant therapeutic modalities relating to future animal pre-clinical models of cancer and their translation into the clinic.

Methods

Four databases were utilized including Medline (Ovid), Embase (Ovid), Web of science, and Scopus databases. We included studies relating to any cancer conducted in murine models that assessed the effect of traditional anticoagulants (heparin and its derivatives and warfarin) and newer oral anticoagulants on cancer.

Results

A total of 6,158 articles were identified in an initial multi-database search. A total of 157 records were finally included for data extraction. Studies on heparin species and warfarin demonstrated statistically significant results in favour of tumour growth and metastasis inhibition.

Conclusion

Our findings constitute a valuable reference guide for the application of anticoagulants in cancer research and explore the promising utilization of non-anticoagulants heparin in preclinical cancer research.

Systematic Review Registration

PROSPERO [CRD42024555603].

Propylene glycol alginate sodium sulfate suppressed lung metastasis by blocking P-selectin to recruit CD4 regulatory T cells

P-selectin has been shown to enhance growth and metastasis of mouse tumors by promoting regulatory T cell (Treg) infiltration into the tumors. Theoretically, a P-selectin antagonist could suppress the process. Popylene glycol alginate sodium sulfate (PSS) is a heparin-like marine drug, which was originally approved to treat cardiovascular disease in China. Previously, we reported that PSS was an effective P-selectin antagonist in vitro. However, it is unknown whether PSS can regulate Treg infiltration and its effect on lung metastasis in vivo. Our results showed that PSS at 30 mg/kg significantly suppressed lung metastasis and improved overall survival, with potency comparable to the positive control LMWH. Mechanistic study indicated that PSS blocked tumor cells adhesion and activated platelets by directly binding with activated platelet's P-selectin. Compared to the model group, PSS decreased the percent of Tregs by 63 % in lungs after treating for 21 days while increasing CD8+ T cells (1.59-fold) and Granzyme B+ CD8 T cells (2.08-fold)' percentage for generating an adaptive response for systemic tumor suppression. The study indicated that the P-selectin antagonist, PSS, suppressed lung metastasis by inhibiting the infiltration of regulatory T cells (Treg) into the tumors.

A low-anticoagulant heparin suppresses metastatic dissemination through the inhibition of tumor cell-platelets association

Metastasis is the leading cause of cancer-related deaths. Despite this relevance, there is no specific therapy targeting metastasis. The interaction of the tumor cell with platelets, forming microemboli is crucial for successful hematogenous dissemination. Heparin disrupts it by a P-selectin-mediated event. However, its clinical use for this purpose is hindered by the requirement of high doses, leading to anticoagulant-related side effects. In this study, we obtained a low-anticoagulant heparin through the fractionation of a pharmaceutical bovine heparin. This derivative was referred to as LA-hep and we investigated its efficacy in inhibiting metastases and explored its capacity of suppressing the interaction between tumor cells and platelets. Our data revealed that LA-hep is as efficient as porcine unfractionated heparin in attenuating lung metastases from melanoma and colon adenocarcinoma cells in an assay with a single intravenous administration. It also prevents platelet arrest shortly after cell injection in wild-type mice and suppresses melanoma-platelets interaction in vitro. Moreover, LA-hep blocks P-selectin's direct binding to tumor cells and platelet aggregation, providing further evidence for the role of P-selectin as a molecular target. Even in P-selectin-depleted mice which developed a reduced number of metastatic foci, both porcine heparin and LA-hep further inhibited metastasis burden. This suggests evidence of an additional mechanism of antimetastatic action. Therefore, our results indicate a dissociation between the heparin anticoagulant and antimetastatic effects. Considering the simple and highly reproducible methodology used to purify LA-hep along with the data presented here, LA-hep emerges as a promising drug for future use in preventing metastasis in cancer patients.

Update on the Pharmacological Actions of Enoxaparin in Nonsurgical Patients

Low-molecular-weight heparins are a class of drugs derived from the enzymatic depolymerization of unfractionated heparin that includes enoxaparin. Several studies have been performed on enoxaparin in recent years, in particular for the prevention and treatment of venous thromboembolism and for the treatment of acute coronary syndrome. Furthermore, the use of enoxaparin has been extended to other clinical situations that require antithrombotic pharmacological prevention, such as hemodialysis and recurrent abortion. In this review, we report the main clinical experiences of using enoxaparin in the prevention of VTE in nonsurgical patients.

Mitochondrial pannexin1 controls cardiac sensitivity to ischaemia/reperfusion injury

AIMS

No effective therapy is available in clinics to protect the heart from ischaemia/reperfusion (I/R) injury. Endothelial cells are activated after I/R, which may drive the inflammatory response by releasing ATP through pannexin1 (Panx1) channels. Here, we investigated the role of Panx1 in cardiac I/R.

METHODS AND RESULTS

Panx1 was found in cardiac endothelial cells, neutrophils, and cardiomyocytes. After in vivo I/R, serum Troponin-I, and infarct size were less pronounced in Panx1-/- mice, but leukocyte infiltration in the infarct area was similar between Panx1-/- and wild-type mice. Serum Troponin-I and infarct size were not different between mice with neutrophil-specific deletion of Panx1 and Panx1fl/fl mice, suggesting that cardioprotection by Panx1 deletion rather involved cardiomyocytes than the inflammatory response. Physiological cardiac function in wild-type and Panx1-/- hearts was similar. The time to onset of contracture and time to maximal contracture were delayed in Panx1-/- hearts, suggesting reduced sensitivity of these hearts to ischaemic injury. Moreover, Panx1-/- hearts showed better recovery of left ventricle developed pressure, cardiac contractility, and relaxation after I/R. Ischaemic preconditioning failed to confer further protection in Panx1-/- hearts. Panx1 was found in subsarcolemmal mitochondria (SSM). SSM in WT or Panx1-/- hearts showed no differences in morphology. The function of the mitochondrial permeability transition pore and production of reactive oxygen species in SSM was not affected, but mitochondrial respiration was reduced in Panx1-/- SSM. Finally, Panx1-/- cardiomyocytes had a decreased mitochondrial membrane potential and an increased mitochondrial ATP content.

CONCLUSION

Panx1-/- mice display decreased sensitivity to cardiac I/R injury, resulting in smaller infarcts and improved recovery of left ventricular function. This cardioprotective effect of Panx1 deletion seems to involve cardiac mitochondria rather than a reduced inflammatory response. Thus, Panx1 may represent a new target for controlling cardiac reperfusion damage.

Structure-Based Design and Synthesis of Stapled 10Panx1 Analogues for Use in Cardiovascular Inflammatory Diseases

Following a rational design, a series of macrocyclic ("stapled") peptidomimetics of 10Panx1, the most established peptide inhibitor of Pannexin1 (Panx1) channels, were developed and synthesized. Two macrocyclic analogues SBL-PX1-42 and SBL-PX1-44 outperformed the linear native peptide. During in vitro adenosine triphosphate (ATP) release and Yo-Pro-1 uptake assays in a Panx1-expressing tumor cell line, both compounds were revealed to be promising bidirectional inhibitors of Panx1 channel function, able to induce a two-fold inhibition, as compared to the native 10Panx1 sequence. The introduction of triazole-based cross-links within the peptide backbones increased helical content and enhanced in vitro proteolytic stability in human plasma (>30-fold longer half-lives, compared to 10Panx1). In adhesion assays, a "double-stapled" peptide, SBL-PX1-206 inhibited ATP release from endothelial cells, thereby efficiently reducing THP-1 monocyte adhesion to a TNF-α-activated endothelial monolayer and making it a promising candidate for future in vivo investigations in animal models of cardiovascular inflammatory disease.

Anti-Inflammatory and Anticancer Effects of Anticoagulant Therapy in Patients with Malignancy

Optimizing the anticoagulation therapy is of pivotal importance in patients with a malignant tumor, as venous thromboembolism (VTE) has become the second-leading cause of death in this population. Cancer can highly increase the risk of thrombosis and bleeding. Consequently, the management of cancer-associated VTE is complex. In recent years, translational research has intensified, and several studies have highlighted the role of inflammatory cytokines in cancer growth and progression. Simultaneously, the pleiotropic effects of anticoagulants currently recommended for VTE have emerged. In this review, we describe the anti-inflammatory and anticancer effects of both direct oral anticoagulants (DOACs) and low-molecular-weight heparins (LWMHs).

Non-Anticoagulant Activities of Low Molecular Weight Heparins-A Review

Low molecular weight heparins (LMWHs) are derived from heparin through chemical or enzymatic cleavage with an average molecular weight (Mw) of 2000-8000 Da. They exhibit more selective activities and advantages over heparin, causing fewer side effects, such as bleeding and heparin-induced thrombocytopenia. Due to different preparation methods, LMWHs have diverse structures and extensive biological activities. In this review, we describe the basic preparation methods in this field and compare the main principles and advantages of these specific methods in detail. Importantly, we focus on the non-anticoagulant pharmacological effects of LMWHs and their conjugates, such as preventing glycocalyx shedding, anti-inflammatory, antiviral infection, anti-fibrosis, inhibiting angiogenesis, inhibiting cell adhesion and improving endothelial function. LMWHs are effective in various diseases at the animal level, including cancer, some viral diseases, fibrotic diseases, and obstetric diseases. Finally, we briefly summarize their usage and potential applications in the clinic to promote the development and utilization of LMWHs.

Low molecular weight heparin synergistically enhances the efficacy of adoptive and anti-PD-1-based immunotherapy by increasing lymphocyte infiltration in colorectal cancer

BACKGROUND

Immunotherapy, including adoptive cell therapy (ACT) and immune checkpoint inhibitors (ICIs), has a limited effect in most patients with colorectal cancer (CRC), and the efficacy is further limited in patients with liver metastasis. Lack of antitumor lymphocyte infiltration could be a major cause, and there remains an urgent need for more potent and safer therapies for CRC.

METHODS

In this study, the antitumoral synergism of low molecular weight heparin (LMWH) combined with immunotherapy in the microsatellite stable (MSS) highly aggressive murine model of CRC was fully evaluated.

RESULTS

Dual LMWH and ACT objectively mediated the stagnation of tumor growth and inhibition of liver metastasis, neither LMWH nor ACT alone had any antitumoral activity on them. The combination of LMWH and ACT obviously increased the infiltration of intratumor CD8+ T cells, as revealed by multiplex immunohistochemistry, purified CD8+ T-cell transfer assay, and IVIM in vivo imaging. Mechanistically, evaluation of changes in the tumor microenvironment revealed that LMWH improved tumor vascular normalization and facilitated the trafficking of activated CD8+ T cells into tumors. Similarly, LMWH combined with anti-programmed cell death protein 1 (PD-1) therapy provided superior antitumor activity as compared with the single PD-1 blockade in murine CT26 tumor models.

CONCLUSIONS

LMWH could enhance ACT and ICIs-based immunotherapy by increasing lymphocyte infiltration into tumors, especially cytotoxic CD8+ T cells. These results indicate that combining LMWH with an immunotherapy strategy presents a promising and safe approach for CRC treatment, especially in MSS tumors.

Heparin, Heparan Sulphate and Sepsis: Potential New Options for Treatment

Sepsis is a life-threatening hyperreaction to infection in which excessive inflammatory and immune responses cause damage to host tissues and organs. The glycosaminoglycan heparan sulphate (HS) is a major component of the cell surface glycocalyx. Cell surface HS modulates several of the mechanisms involved in sepsis such as pathogen interactions with the host cell and neutrophil recruitment and is a target for the pro-inflammatory enzyme heparanase. Heparin, a close structural relative of HS, is used in medicine as a powerful anticoagulant and antithrombotic. Many studies have shown that heparin can influence the course of sepsis-related processes as a result of its structural similarity to HS, including its strong negative charge. The anticoagulant activity of heparin, however, limits its potential in treatment of inflammatory conditions by introducing the risk of bleeding and other adverse side-effects. As the anticoagulant potency of heparin is largely determined by a single well-defined structural feature, it has been possible to develop heparin derivatives and mimetic compounds with reduced anticoagulant activity. Such heparin mimetics may have potential for use as therapeutic agents in the context of sepsis.

Glycosoaminoglycans in cancer therapy

Glycosaminoglycans (GAGs) are an important component of the tumor microenvironment (TME). GAGs can interact with a variety of binding partners and thereby influence cancer progression on multiple levels. GAGs can modulate growth factor and chemokine signaling, invasion and metastasis formation. Moreover, GAGs are able to change the physical property of the extracellular matrix (ECM). Abnormalities in GAG abundance and structure (e.g., sulfation patterns and molecular weight) are found across various cancer types and show biomarker potential. Targeting GAGs, as well as the usage of GAGs and their mimetics, are promising approaches to interfere with cancer progression. In addition, GAGs can be used as drug and cytokine carriers to induce an anti-tumor response. In this review, we summarize the role of GAGs in cancer and the potential use of GAGs and GAG derivatives to target cancer.

Targeting the "sweet spot" in septic shock - A perspective on the endothelial glycocalyx regulating proteins Heparanase-1 and -2

Sepsis is a life-threatening syndrome caused by a pathological host response to an infection that eventually, if uncontrolled, leads to septic shock and ultimately, death. In sepsis, a massive aggregation of pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) cause a cytokine storm. The endothelial glycocalyx (eGC) is a gel like layer on the luminal side of the endothelium that consists of proteoglycans, glycosaminoglycans (GAG) and plasma proteins. It is synthesized by endothelial cells and plays an active role in the regulation of inflammation, permeability, and coagulation. In sepsis, early and profound injury of the eGC is observed and circulating eGC components correlate directly with clinical severity and outcome. The activity of the heparan sulfate (HS) specific glucuronidase Heparanase-1 (Hpa-1) is elevated in sepsis, resulting in shedding of heparan sulfate (HS), a main GAG of the eGC. HS induces endothelial barrier breakdown and accelerates systemic inflammation. Lipopolysaccharide (LPS), a PAMP mainly found on the surface of gram-negative bacteria, activates TLR-4, which results in cytokine production and further activation of Hpa-1. Hpa-1 shed HS fragments act as DAMPs themselves, leading to a vicious cycle of inflammation and end-organ dysfunction such as septic cardiomyopathy and encephalopathy. Recently, Hpa-1's natural antagonist, Heparanase-2 (Hpa-2) has been identified. It has no intrinsic enzymatic activity but instead acts by reducing inflammation. Hpa-2 levels are reduced in septic mice and patients, leading to an acquired imbalance of Hpa-1 and Hpa-2 paving the road towards a therapeutic intervention. Recently, the synthetic antimicrobial peptide 19-2.5 was described as a promising therapy protecting the eGC by inhibition of Hpa-1 activity and HS shed fragments in animal studies. However, a recombinant Hpa-2 therapy does not exist to the present time. Therapeutic plasma exchange (TPE), a modality already tested in clinical practice, effectively removes injurious mediators, e.g., Hpa-1, while replacing depleted protective molecules, e.g., Hpa-2. In critically ill patients with septic shock, TPE restores the physiological Hpa-1/Hpa-2 ratio and attenuates eGC breakdown. TPE results in a significant improvement in hemodynamic instability including reduced vasopressor requirement. Although promising, further studies are needed to determine the therapeutic impact of TPE in septic shock.

The anti-cancer properties of heparin and its derivatives: a review and prospect

Heparin, including unfractionated heparin (UFH), low-molecular-weight heparin (LMWH) and heparin derivatives, are commonly used in venous thromboembolism treatment and reportedly have beneficial effects on cancer survival. Heparin can affect the proliferation, adhesion, angiogenesis, migration and invasion of cancer cells via multiple mechanisms. The main mechanisms involve inhibition of heparanase, P-/L-selectin, angiogenesis, and interference with the CXCL12-CXCR4 axis. Here we summarize the current experimental evidence regarding the anti-cancer role of heparin and its derivatives, and conclude that there is evidence to support heparin’s role in inhibiting cancer progression, making it a promising anti-cancer agent.

A Combined Activity of Thrombin and P-Selectin Is Essential for Platelet Activation by Pancreatic Cancer Cells

Pancreatic cancer patients have an elevated risk of suffering from venous thrombosis. Among several risk factors that contribute to hypercoagulability of this malignancy, platelets possess a key role in the initiation of clot formation. Although single mechanisms of platelet activation are well-known in principle, combinations thereof and their potential synergy to mediate platelet activation is, in the case of pancreatic cancer, far from being clear. Applying an inhibitor screening approach using light transmission aggregometry, dense granule release, and thrombin formation assays, we provide evidence that a combination of tissue factor-induced thrombin formation by cancer cells and their platelet P-selectin binding is responsible for AsPC-1 and Capan-2 pancreatic cancer cell-mediated platelet activation. While the blockade of one of these pathways leads to a pronounced inhibition of platelet aggregation and dense granule release, the simultaneous blockade of both pathways is inevitable to prevent platelet aggregation completely and minimize ATP release. In contrast, MIA PaCa-2 pancreatic cancer cells express reduced levels of tissue factor and P-selectin ligands and thus turn out to be poor platelet activators. Consequently, a simultaneous blockade of thrombin and P-selectin binding seems to be a powerful approach, as mediated by heparin to crucially reduce the hypercoagulable state of pancreatic cancer patients.

Visualizing cancer extravasation: from mechanistic studies to drug development

Metastasis is a multistep process that accounts for the majority of cancer-related death. By the end of metastasize dissemination, circulating tumor cells (CTC) need to extravasate the blood vessels at metastatic sites to form new colonization. Although cancer cell extravasation is a crucial step in cancer metastasis, it has not been successfully targeted by current anti-metastasis strategies due to the lack of a thorough understanding of the molecular mechanisms that regulate this process. This review focuses on recent progress in cancer extravasation visualization techniques, including the development of both in vitro and in vivo cancer extravasation models, that shed light on the underlying mechanisms. Specifically, multiple cancer extravasation stages, such as the adhesion to the endothelium and transendothelial migration, are successfully probed using these technologies. Moreover, the roles of different cell adhesive molecules, chemokines, and growth factors, as well as the mechanical factors in these stages are well illustrated. Deeper understandings of cancer extravasation mechanisms offer us new opportunities to escalate the discovery of anti-extravasation drugs and therapies and improve the prognosis of cancer patients.

In Vitro Study of Synergic Effect of Cisplatin and Low Molecular Weight Heparin on Oral Squamous Cell Carcinoma

Objectives

To evaluate the possible synergic effect of cisplatin and low molecular weight heparin (LMWH) on oral squamous cell carcinoma (OSCC).

Materials and Methods

Cisplatin and enoxaparin sodium, alone or in combination, were administered at doses of 1, 2, 4, 8 and 10 µM and 0.1, 0.5, 1, 5, 10, 50, and 100 µg/ml, respectively, to the H357 human OSCC line. The effects on cell viability and apoptosis were evaluated after 24, 48, and 72 h and on cell migration after 18 and 24 h.

Results

10 µM concentration of cisplatin produced the greatest decrease in cell viability, with significant differences at 24 (p=0.009), 48 (p=0.001) and 72 h (p = 0.003); the 100 µg/ml dose of enoxaparin produced the greatest decrease in cell viability but without significant differences (p>0.05). When different concentrations of cisplatin and enoxaparin were combined, it was found that 100 µg/ml enoxaparin sodium produced the greatest synergic effect on cell viability reduction. In analyses of apoptosis and cell migration, it was found that the combination of cisplatin at 8 or 10 μM and 100 μg/ml enoxaparin produced a higher rate of apoptosis at 24, 48, and 72 h and a greater reduction in cell migration at 18 and 24 h.

Conclusions

A combination of cisplatin and enoxaparin sodium shows a synergic effect that reduces cell viability and cell migration capacity and increases the apoptosis of human OSCC cells.

Clinical relevance

Enoxaparin may be beneficial in chemotherapy for patients with OSCC; this finding requires further clinical and laboratory investigation.

Glycosaminoglycans as Tools to Decipher the Platelet Tumor Cell Interaction: A Focus on P-Selectin

Tumor cell–platelet interactions are regarded as an initial crucial step in hematogenous metastasis. Platelets protect tumor cells from immune surveillance in the blood, mediate vascular arrest, facilitate tumor extravasation, growth, and finally angiogenesis in the metastatic foci. Tumor cells aggregate platelets in the bloodstream by activation of the plasmatic coagulation cascade and by direct contact formation. Antimetastatic activities of unfractionated or low molecular weight heparin (UFH/LMWH) can undoubtedly be related to attenuated platelet activation, but molecular mechanisms and contribution of contact formation vs. coagulation remain to be elucidated. Using a set of non-anticoagulant heparin derivatives varying in size or degree of sulfation as compared with UFH, we provide insight into the relevance of contact formation for platelet activation. Light transmission aggregometry and ATP release assays confirmed that only those heparin derivatives with P-selectin blocking capacities were able to attenuate breast cancer cell-induced platelet activation, while pentasaccharide fondaparinux was without effects. Furthermore, a role of P-selectin in platelet activation and signaling could be confirmed by proteome profiler arrays detecting platelet kinases. In this study, we demonstrate that heparin blocks tumor cell-induced coagulation. Moreover, we identify platelet P-selectin, which obviously acts as molecular switch and controls aggregation and secretion of procoagulant platelets.

A systematic review on the effects of direct oral anticoagulants on cancer growth and metastasis in animal models

BACKGROUND

Direct oral anticoagulants (DOACs) are now the first choice thromboprophylaxis in cancer patients who do not have a high risk of bleeding. In addition to the anticoagulant effects, potential anti-tumor effects of DOACs have also been studied in animal cancer models. In this study, we summarize the effects of DOACs on cancer growth and metastasis in animal models through a systematic review with a qualitative analysis.

METHODS

PubMed, EMBASE and Web of Science were systematically searched for original studies that describe animal models of cancer in which one of the experimental groups received DOAC monotherapy, and which reported quantitatively on primary tumor or metastases.

RESULTS

Nine studies - reporting a total of 19 animal experiments - met the inclusion criteria. These 19 experiments included spontaneous cancer (n = 2), carcinogenicity (n = 2), xenograft (n = 7) and syngeneic (n = 8) models, encompassing orthotopic (n = 7), subcutaneous (n = 5), intraperitoneal (n = 1) and intravenous (n = 2) injection of cancer cells and included treatments with the DOACs ximelagatran (n = 4), dabigatran etexilate (n = 6) and/or rivaroxaban (n = 11). DOAC treatment decreased tumor growth at implanted and metastatic site in 18.8% (3/16) and 20.0% (3/15) of the experiments, respectively. Conversely, DOACs increased tumor growth at implanted and metastatic site in 6.3% (1/16) and 20.0% (3/15) of the experiments, respectively.

CONCLUSION

DOAC monotherapy resulted in neoplastic changes in a rat carcinogenicity study, showed a lack of effect in mouse xenograft models, while the effect on cancer growth and metastasis in mouse syngeneic models depended on the timing of DOAC treatment and type of cancer model used.

Roneparstat: Development, Preclinical and Clinical Studies

A growing interest around heparanase and its role in cancer, inflammation and other diseases prompted the identification of specific inhibitors of this enzyme and the exploration of their potential therapeutic role. Roneparstat, a 15-25 kDa N-acetylated and glycol split heparin, is one of the most potent and widely studied heparanase inhibitors. These studies generated a large body of data, which allowed to characterize Roneparstat properties and to endorse its potential therapeutic role. Multiple Myeloma represents the indication that most of the studies, including the phase I clinical trial, addressed. However, Roneparstat antitumor activity activity has been documented in other cancers, and in non-oncological conditions.In addition, assessing Roneparstat activity in different experimental models contributed to understanding heparanase role and the biological factors that may be affected by heparanase inhibition in more detail. Finally, some studies elucidated the molecular mechanisms regulating the enzyme-inhibitor kinetics, thus providing important data for the identification and design of new inhibitors.The objective of this chapter is to provide a comprehensive overview of the most significant studies involving Roneparstat and discuss its potential role in therapy.

Heparanase: A Potential Therapeutic Target in Sarcomas

Sarcomas comprise a heterogeneous group of rare malignancies of mesenchymal origin including more than 70 subtypes. They may arise in muscle, bone, cartilage and other connective tissues. Their high histological and genetic heterogeneity makes diagnosis and treatment very challenging. Deregulation of heparanase has been found in several sarcoma subtypes and high expression levels have been correlated with poor prognosis in Ewing's sarcoma and osteosarcoma. Altered expression of specific heparan sulfate proteoglycans and heparan sulfate biosynthetic enzymes has also been observed. Advances in molecular pathogenesis of sarcomas have evidenced the critical role of several heparan sulfate binding growth factors and receptor tyrosine kinases, highly interconnected with the microenvironment, in sustaining tumor growth and progression. Interference with heparanase/heparan sulfate functions represents a potential therapeutic approach in sarcoma. In this chapter, we summarize the current knowledge about the biological significance of heparanase expression and its potential as a therapeutic target in subtypes of both soft tissue and bone sarcomas. Particular emphasis is given to the involvement of heparan sulfate proteoglycans and their synthesizing and modifying enzymes in bone physiology and disorders leading up to the pathobiology of bone sarcomas. The chapter also describes the cooperation between exostin loss-of-function and heparanase upregulation in hereditary Multiple Osteochondroma syndrome as a paradigmatic example of constitutive alteration of the heparanase/heparan sulfate proteoglycan system which may contribute to progression to malignant secondary chondrosarcoma. Preclinical evidence of the role of heparanase as a promising therapeutic target in various sarcoma subtypes is finally resumed.

Non-Anticoagulant Heparins as Heparanase Inhibitors

The chapter will review early and more recent seminal contributions to the discovery and characterization of heparanase and non-anticoagulant heparins inhibiting its peculiar enzymatic activity. Indeed, heparanase displays a unique versatility in degrading heparan sulfate chains of several proteoglycans expressed in all mammalian cells. This endo-β-D-glucuronidase is overexpressed in cancer, inflammation, diabetes, atherosclerosis, nephropathies and other pathologies. Starting from known low- or non-anticoagulant heparins, the search for heparanase inhibitors evolved focusing on structure-activity relationship studies and taking advantage of new chemical-physical analytical methods which have allowed characterization and sequencing of polysaccharide chains. New methods to screen heparanase inhibitors and to evaluate their mechanism of action and in vivo activity in experimental models prompted their development. New non-anticoagulant heparin derivatives endowed with anti-heparanase activity are reported. Some leads are under clinical evaluation in the oncology field (e.g., acute myeloid leukemia, multiple myeloma, pancreatic carcinoma) and in other pathological conditions (e.g., sickle cell disease, malaria, labor arrest).

Novel N-acetyl-Glycol-split heparin biotin-conjugates endowed with anti-heparanase activity

Heparanase is regarded as a promising target for anticancer drugs and Ronepastat is one of the most promising heparanase inhibitors insert in clinical study for Multiple Myeloma Therapy. To improve its pharmacokinetic/pharmacodynamic profile, as well to have an antidote able to neutralize its activity in case of over dosages or intolerance, a new class of its derivatives was obtained inserting non-carbohydrate moieties of different length between the polysaccharide chain and biotin or its derivatives. In vitro these novel derivatives maintain the anti-heparanase activity without induced toxicity. The newly synthesized compounds retained the ability to attenuate the growth of CAG myeloma tumors in mice with potency similar, or in one case even higher than that of the reference compound Roneparstat as well as inhibited metastatic dissemination (lung colonization) of murine B16-F10 melanoma cells in vivo.

Tunicate Heparan Sulfate Enriched in 2-Sulfated β-Glucuronic Acid: Structure, Anticoagulant Activity, and Inhibitory Effect on the Binding of Human Colon Adenocarcinoma Cells to Immobilized P-Selectin

Heparin or highly sulfated heparan sulfate (HS) has been described in different invertebrates. In ascidians (Chordata-Tunicata), these glycosaminoglycans occur in intracellular granules of oocyte accessory cells and circulating basophil-like cells, resembling mammalian mast cells and basophils, respectively. HS is also a component of the basement membrane of different ascidian organs. We have analyzed an HS isolated from the internal organs of the ascidian Phallusia nigra, using solution ¹H/¹³C NMR spectroscopy, which allowed us to identify and quantify the monosaccharides found in this glycosaminoglycan. A variety of α-glucosamine units with distinct degrees of sulfation and N-acetylation were revealed. The hexuronic acid units occur both as α-iduronic acid and β-glucuronic acid, with variable sulfation at the 2-position. A peculiar structural aspect of the tunicate HS is the high content of 2-sulfated β-glucuronic acid, which accounts for one-third of the total hexuronic acid units. Another distinct aspect of this HS is the occurrence of high content of N-acetylated α-glucosamine units bearing a sulfate group at position 6. The unique ascidian HS is a potent inhibitor of the binding of human colon adenocarcinoma cells to immobilized P-selectin, being 11-fold more potent than mammalian heparin, but almost ineffective as an anticoagulant. Thus, the components of the HS structure required to inhibit coagulation and binding of tumor cells to P-selectin are distinct. Our results also suggest that the regulation of the pathway involved in the biosynthesis of glycosaminoglycans suffered variations during the evolution of chordates.

The direct oral anticoagulants rivaroxaban and dabigatran do not inhibit orthotopic growth and metastasis of human breast cancer in mice

Essentials Factor Xa (FXa)-targeting direct oral anticoagulants (DOACs) reduce venous thromboembolism (VTE) The effects of FXa-targeting DOACs on cancer progression remain to be studied In xenograft models, a FXa-targeting DOAC did not inhibit breast cancer growth and metastasis A thrombin-targeting DOAC, dabigatran, also did not inhibit breast cancer growth and metastasis ABSTRACT: Background Factor Xa-targeting DOACs were recently found to reduce recurrent VTE efficiently in cancer patients when compared to the standard treatment with low-molecular-weight heparins (LMWHs). While the anticancer effects of LMWHs have been extensively studied in preclinical cancer models, the effects of FXa-targeting DOACs on cancer progression remain to be studied. Objective We investigated whether the FXa-targeting DOAC rivaroxaban and the thrombin-targeting DOAC dabigatran etexilate (DE) affected human breast cancer growth and metastasis in orthotopic xenograft models. Methods/results Mice that were put on a custom-made chow diet supplemented with rivaroxaban (0.4 or 1.0 mg/g diet) or dabigatran etexilate (DE) (10 mg/g diet) showed prolonged ex vivo coagulation times (prothrombin time [PT] and activated partial thromboplastin time [aPTT] assay, respectively). However, rivaroxaban and DE did not inhibit MDA-MB-231 tumor growth and metastasis formation in lungs or livers of 7-week-old fully immunodeficient NOD/SCID/ƴC-/- (NSG) mice. Comparable data were obtained for rivaroxaban-treated mice when using NOD-SCID mice. Rivaroxaban and DE treatment also did not significantly inhibit tumor growth and metastasis formation when using another human triple negative breast cancer (TNBC) cell line (HCC1806) in NOD-SCID mice. The FXa and thrombin-induced gene expression of the downstream target CXCL8 in both cell lines, but FXa and thrombin, did not significantly stimulate migration, proliferation, or stemness in vitro. Conclusion Although effectively inhibiting coagulation, the DOACs rivaroxaban and DE did not inhibit orthotopic growth and metastasis of human TNBC. It remains to be investigated whether DOACs exert antitumorigenic effects in other types of cancer.

Structure-activity relationship of propylene glycol alginate sodium sulfate derivatives for blockade of selectins binding to tumor cells

Selectins dominate the formation of the metastasis niche and are considered important targets for exploring antimetastatic drugs. In this study, we evaluated the effect of the marine drug propylene glycol alginate sodium sulfate (PSS) and a series of PSS derivatives on P-, L- or E-selectin-mediated binding with tumor cells. We found that PSS effectively prevented the binding of P- or L-selectin with tumor cells. Moreover, the structure-activity relationship study indicated that the activity of PSS is related to the sulfate group at the C-2/C-3 position, the propylene glycol substituent at the C-6 position, the ratio of guluronic acid to mannuronic acid, and the molecular weight. Additionally, PSS derivatives significantly suppressed lung metastasis in vivo. Our results demonstrated that PSS and its derivatives are potential antimetastatic drugs candidates.

Heparan Sulfate Mimetics in Cancer Therapy: The Challenge to Define Structural Determinants and the Relevance of Targets for Optimal Activity

Beyond anticoagulation, the therapeutic potential of heparin derivatives and heparan sulfate (HS) mimetics (functionally defined HS mimetics) in oncology is related to their ability to bind and modulate the function of a vast array of HS-binding proteins with pivotal roles in cancer growth and progression. The definition of structural/functional determinants and the introduction of chemical modifications enabled heparin derivatives to be identified with greatly reduced or absent anticoagulant activity, but conserved/enhanced anticancer activity. These studies paved the way for the disclosure of structural requirements for the inhibitory effects of HS mimetics on heparanase, selectins, and growth factor receptor signaling, as well as for the limitation of side effects. Actually, HS mimetics affect the tumor biological behavior via a multi-target mechanism of action based on their effects on tumor cells and various components of the tumor microenvironment. Emerging evidence indicates that immunomodulation can participate in the antitumor activity of these agents. Significant ability to enhance the antitumor effects of combination treatments with standard therapies was shown in several tumor models. While the first HS mimetics are undergoing early clinical evaluation, an improved understanding of the molecular contexts favoring the antitumor action in certain malignancies or subgroups is needed to fully exploit their potential.

The Low Molecular Weight Heparin Tinzaparin Attenuates Platelet Activation in Terms of Metastatic Niche Formation by Coagulation-Dependent and Independent Pathways

An intimate interplay with platelets is an initial key issue for tumor cells in terms of hematogenous metastasis. Tumor cells activate platelets by different pathways and receive, upon forming a platelet cloak, protection from immune surveillance and support in metastatic niche creation. Therapeutic intervention with this early interaction is promising to antagonize the whole metastatic cascade. Here we aimed to investigate the capability of low molecular weight heparin (LMWH), unfractionated heparin (UFH), and a non-anticoagulant heparin derivative or FXa inhibitor fondaparinux to interfere with platelet activation by tumor cells. Coagulation-dependent and independent pathways of platelet activation by three tumor cell lines, and interference therewith were analyzed by fluorigenic thrombin formation assay, platelet aggregometry, ATP and VEGF release and endothelial tube formation assay. LMWH and UFH were found to repress various routes of platelet activation, reflected by attenuated endothelial tube formation. This confirms the duality of anti-coagulative and anti-adhesive properties of heparin. While non-anticoagulative heparin (RO-heparin) depressed platelets’ ATP and VEGF release by contact inhibition sufficiently, fondaparinux just attenuated tissue factor mediated thrombin generation. Concluding, these data suggest that LMWH as a guideline-based drug for anticoagulative strategies in oncology is promising to provide additional benefit for interference with metastatic activities.

Pleiotropic Effects of Heparins: From Clinical Applications to Molecular Mechanisms in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a major health problem worldwide and most cases are incurable because of late presentation. It is the most common primary neoplasm of the liver and often arises in the context of a chronic liver disease that impairs coagulation. Portal vein thrombosis (PVT) is a common complication of HCC that is associated with a poor prognosis. Heparin derivatives are widely used in the management of venous thromboembolism (VTE). Among them low molecular weight heparin (LMWH) favorably influences the survival in patients with advanced cancer, including HCC. Due to their pleiotropic function, heparins affect tumorigenesis in many ways and may promote or hamper tumorigenic transformation depending on the cancer type and cancer stage along with their structural properties and concentration. Thus, their application as an antithrombotic along with the conventional therapy regime should be carefully planned to develop the best management strategies. In this review, we first will briefly review clinical applications of heparin derivatives in the management of cancer with a particular focus on HCC. We then summarize the state of knowledge whereby heparin can crosstalk with molecules playing a role in hepatocarcinogenesis. Lastly, we highlight new experimental and clinical research conducted with the aim of moving towards personalized therapy in cancer patients at risk of thromboembolism.

Antitumor efficacy of the heparan sulfate mimic roneparstat (SST0001) against sarcoma models involves multi-target inhibition of receptor tyrosine kinases

The heparan sulfate (HS) mimic/heparanase inhibitor roneparstat (SST0001) shows antitumor activity in preclinical sarcoma models. We hypothesized that this 100% N-acetylated and glycol-split heparin could interfere with the functions of several receptor tyrosine kinases (RTK) coexpressed in sarcomas and activated by heparin-binding growth factors. Using a phospho-proteomic approach, we investigated the drug effects on RTK activation in human cell lines representative of different sarcoma subtypes. Inhibition of FGF, IGF, ERBB and PDGF receptors by the drug was biochemically and functionally validated. Roneparstat counteracted the autocrine loop induced by the COL1A1/PDGFB fusion oncogene, expressed in a human dermatofibrosarcoma protuberans primary culture and in NIH3T3^COL1A1/PDGFB transfectants, inhibiting cell anchorage-independent growth and invasion. In addition, roneparstat inhibited the activation of cell surface PDGFR and PDGFR-associated FAK, likely contributing to the reversion of NIH3T3^COL1A1/PDGFB cell transformed and pro-invasive phenotype. Biochemical and histological/immunohistochemical ex vivo analyses confirmed a reduced activation of ERBB4, EGFR, INSR, IGF1R, associated with apoptosis induction and angiogenesis inhibition in a drug-treated Ewing's sarcoma family tumor xenograft. The combination of roneparstat with irinotecan significantly improved the antitumor effect against A204 rhabdoid xenografts resulting in a high rate of complete responses and cures. These findings reveal that roneparstat exerts a multi-target inhibition of RTKs relevant in the pathobiology of different sarcoma subtypes. These effects, likely cooperating with heparanase inhibition, contribute to the antitumor efficacy of the drug. The study supports heparanase/HS axis targeting as a valuable approach in combination therapies of different sarcoma subtypes providing a preclinical rationale for clinical investigation.

Supersulfated low-molecular weight heparin synergizes with IGF1R/IR inhibitor to suppress synovial sarcoma growth and metastases

Synovial sarcoma (SS) is an aggressive tumor with propensity for lung metastases which significantly impact patients' prognosis. New therapeutic approaches are needed to improve treatment outcome. Targeting the heparanase/heparan sulfate proteoglycan system by heparin derivatives which act as heparanase inhibitors/heparan sulfate mimetics is emerging as a therapeutic approach that can sensitize the tumor response to chemotherapy. We investigated the therapeutic potential of a supersulfated low molecular weight heparin (ssLMWH) in preclinical models of SS. ssLMWH showed a potent anti-heparanase activity, dose-dependently inhibited SS colony growth and cell invasion, and downregulated the activation of receptor tyrosine kinases including IGF1R and IR. The combination of ssLMWH and the IGF1R/IR inhibitor BMS754807 synergistically inhibited proliferation of cells exhibiting IGF1R hyperactivation, also abrogating cell motility and promoting apoptosis in association with PI3K/AKT pathway inhibition. The drug combination strongly enhanced the antitumor effect against the CME-1 model, as compared to single agent treatment, abrogating orthotopic tumor growth and significantly repressing spontaneous lung metastatic dissemination in treated mice. These findings provide a strong preclinical rationale for developing drug regimens combining heparanase inhibitors/HS mimetics with IGF1R antagonists for treatment of metastatic SS.

Old and new applications of non-anticoagulant heparin

The aim of this chapter is to provide an overview of non-anticoagulant effects of heparins and their potential use in new therapeutic applications. Heparin and heparin derivatives have been tested in inflammatory, pulmonary and reproductive diseases, in cardiovascular, nephro- and neuro-tissue protection and repair, but also as agents against angiogenesis, atheroschlerosis, metastasis, protozoa and viruses. Targeting and inhibition of specific mediators involved in the inflammatory process, promoting some of the above mentioned pathologies, are reported along with recent studies of heparin conjugates and oral delivery systems. Some reports from the institute of the authors, such as those devoted to glycol-split heparins are also included. Among the members and derivatives of this class, several are undergoing clinical trials as antimetastatic and antimalarial agents and for the treatment of labour pain and severe hereditary anaemia. Other heparins, whose therapeutic targets are non-anticoagulant such as nephropathies, retinopathies and cystic fibrosis are also under investigation.

Hypercoagulation and complement: Connected players in tumor development and metastases

Hypercoagulation is a common feature of several tumors to the extent that individuals with coagulation defects often present with occult visceral cancers. Recent evidence has shown that hypercoagulation is not just a mere secondary effect due to the presence of the tumor, rather it actively contributes to tumor development and dissemination. Among the numerous mechanisms that can contribute to cancer-associated hypercoagulation, the ones involving immune-mediated processes are gaining increasing attention. In particular, complement cascade and hypercoagulation are one inducing the other in a vicious circle that involves neutrophil extracellular traps (NETs) formation. Together, in this feedback loop, they can promote the protumorigenic phenotype of immune cells and the protection of tumor cells from immune attack, ultimately favouring tumor development, progression and metastases formation. In this review, we summarize the role of these processes in cancer development and highlight new possible intervention strategies based on anticoagulants that can arrest this vicious circle.

Low molecular weight heparin and cancer survival: clinical trials and experimental mechanisms

INTRODUCTION

The relationship between cancer and thrombosis is complex, as the hemostatic system is inextricably linked to the mechanisms of cancer growth and metastasis. The coagulation system thus appears to be a site for oncogenic events and necessary for the survival and spread of malignant cells. Although several meta-analyses on the effectiveness of unfractionated heparin and low molecular weight heparin (LMWH) in the treatment of venous thromboembolism (VTE) have suggested a lower mortality risk in cancer patients receiving LMWH, this contention has not received general acceptance. In fact, there exist no sufficiently powered studies to date supporting the routine use of LMWH to improve cancer survival. Meanwhile, the molecular mechanism underlying the anti-neoplastic effect of LMWH which is independent of its anti-coagulant function is largely unexplored and is a topic of active investigation.

MATERIALS AND METHODS

In this communication, we aimed to review comprehensively evidences from clinical trials, meta-analysis as well as experimental molecular research and to identify future research areas of importance so as to stimulate future research on the potential anti-tumor action of LMWH.

CONCLUSION

Although benefit of LMWH on cancer patients' survival is controversial depending on the tumor type, cancer stage as well as LMWH type, it appears to be associated with a reduction in VTE and increased bleeding is minor and controllable; thus, randomized controlled trials targeting the survival benefit of certain specific LWMH are needed and justified, and more in-depth experimental researches are imperative to elucidate the anti-tumor effect of anticoagulants.

Turning-Off Signaling by Siglecs, Selectins, and Galectins: Chemical Inhibition of Glycan-Dependent Interactions in Cancer

Aberrant glycosylation, a common feature associated with malignancy, has been implicated in important events during cancer progression. Our understanding of the role of glycans in cancer has grown exponentially in the last few years, concurrent with important advances in glycomics and glycoproteomic technologies, paving the way for the validation of a number of glycan structures as potential glycobiomarkers. However, the molecular bases underlying cancer-associated glycan modifications are still far from understood. Glycans exhibit a natural heterogeneity, crucial for their diverse functional roles as specific carriers of biologically relevant information. This information is decoded by families of proteins named lectins, including sialic acid-binding immunoglobulin (Ig)-like lectins (siglecs), C-type lectin receptors (CLRs), and galectins. Siglecs are primarily expressed on the surface of immune cells and differentially control innate and adaptive immune responses. Among CLRs, selectins are a family of cell adhesion molecules that mediate interactions between cancer cells and platelets, leukocytes, and endothelial cells, thus facilitating tumor cell invasion and metastasis. Galectins, a family of soluble proteins that bind β-galactoside-containing glycans, have been implicated in diverse events associated with cancer biology such as apoptosis, homotypic cell aggregation, angiogenesis, cell migration, and tumor-immune escape. Consequently, individual members of these lectin families have become promising targets for the design of novel anticancer therapies. During the past decade, a number of inhibitors of lectin–glycan interactions have been developed including small-molecule inhibitors, multivalent saccharide ligands, and more recently peptides and peptidomimetics have offered alternatives for tackling tumor progression. In this article, we review the current status of the discovery and development of chemical lectin inhibitors and discuss novel strategies to limit cancer progression by targeting lectin–glycan interactions.

Holothurian glycosaminoglycan inhibits metastasis via inhibition of P-selectin in B16F10 melanoma cells

P-selectin-mediated tumor cell adhesion to platelets is a well-established stage in the process of tumor metastasis. Through computerized structural analysis, we found a marine-derived polysaccharide, holothurian glycosaminoglycan (hGAG), behaved as a ligand-competitive inhibitor of P-selectin, indicating its potential to disrupt the binding of P-selectin to cell surface receptor and activation of downstream regulators of tumor cell migration. Our experimental data demonstrated that hGAG significantly inhibited P-selectin-mediated adhesion of tumor cells to platelets and tumor cell migration in vitro and reduced subsequent pulmonary metastasis in vivo. Furthermore, abrogation of the P-selectin-mediated adhesion of tumor cells led to down-regulation of protein levels of integrins, FAK and MMP-2/9 in B16F10 cells, which is a crucial molecular mechanism of hGAG to inhibit tumor metastasis. In conclusion, hGAG has emerged as a novel anti-cancer agent via blocking P-selectin-mediated malignant events of tumor metastasis.

Low molecular weight heparin tinzaparin antagonizes cisplatin resistance of ovarian cancer cells

Low molecular weight heparin (LMWH) is routinely used for antithrombotic treatment of cancer patients. Preclinical- and clinical data suggest that LMWH has beneficial effects for cancer patients beyond the prevention of thrombosis, i.e. by inhibiting metastasis. It is, however, unclear whether heparin has an impact on the efficiency of chemotherapy in cancer patients. Here we show that a therapeutic dosage of LMWH tinzaparin reverses cisplatin resistance of A2780cis human ovarian cancer cells to the level of sensitive cells. This novel activity of tinzaparin is associated with intense transcriptional reprogramming. Our gene expression profiling experiments revealed that 3776 genes responded to tinzaparin treatment. For this reason tinzaparin has a complex impact on diverse biological processes. We discovered that tinzaparin inhibits the expression of genes that mediate cisplatin resistance of A2780cis cells. In contrast tinzaparin induced the expression of genes that antagonize drug resistance. This activity of tinzaparin is mediated by cell surface proteoglycans, since enzymatic cleavage of heparan sulfates prevented the reversal of cisplatin resistance. These data indicate that cell surface heparan sulfate proteoglycans play an important role for chemotherapy resistance. The results of this study shed a new light on LMWH application in cancer therapy and suggest tinzaparin as promising treatment option of ovarian cancer patients in combination with anticancer drugs. Future clinical trials are needed to validate these findings.

Nuclear heparanase-1 activity suppresses melanoma progression via its DNA-binding affinity

Heparanase-1 (HPSE) plays a pivotal role in structural remodeling of the ECM and the glycocalyx, thus conferring protumorigenic, proangiogenic and prometastatic properties to many cancer entities. In addition to its extracellular function, recent studies suggest an intracellular activity of HPSE with a largely unknown significance during tumor progression. Therefore, we investigated the relevance of the dual functions of HPSE to malignant melanoma in vitro, as well as in different mouse melanoma models based on the intradermal or intravenous injection of melanoma cells. Consistent with its extracellular action, an HPSE deficiency led to a reduced shedding of the glycocalyx accompanied by a reduced availability of vascular endothelial growth factor, affecting tumor growth and vascularization. In contrast, we measured an elevated expression of the protumorigenic factors pentraxin-3, tissue factor, TNF-α and most prominently, MMP-9, upon HPSE knockdown. In vivo, an HPSE deficiency was related to increased lymph node metastasis. Since the inhibition of its extracellular function with heparin was unable to block the gene regulatory impact of HPSE, we proposed an intracellular mechanism. Immunostaining revealed a counter-staining of HPSE and NF-κB in the nucleus, suggesting a close relationship between both proteins. This finding was further supported by the discovery of a direct charge-driven molecular interaction between HPSE and DNA by using atomic force microscopy and a co-precipitation approach. Our findings are novel and point towards a dual function for HPSE in malignant melanoma with a protumorigenic extracellular activity and a tumor-suppressive nuclear action. The identification of molecular strategies to shuttle extracellular HPSE into the nuclei of cancer cells could provide new therapeutic options.

Heparin derivatives for the targeting of multiple activities in the inflammatory response

An attractive strategy for ameliorating symptoms arising from the multi-faceted processes of excessive and/or continual inflammation would be to identify compounds able to interfere with multiple effectors of inflammation. The well-tolerated pharmaceutical, heparin, is capable of acting through several proteins in the inflammatory cascade, but its use is prevented by strong anticoagulant activity. Derivatives of heparin involving the periodate cleavage of 2,3 vicinal diols in non-sulfated uronate residues (glycol-split) and replacement of N-sulphamido- with N-acetamido- groups in glucosamine residues, capable of inhibiting neutrophil elastase activity in vitro, while exhibiting attenuated anticoagulant properties, have been identified and characterised. These also interact with two other important modulators of the inflammatory response, IL-8 and TNF-alpha. It is therefore feasible in principle to modulate several activities, while minimising anticoagulant side effects, providing a platform from which improved anti-inflammatory agents might be developed.

Cancer and venous thromboembolic disease: from molecular mechanisms to clinical management

Venous thromboembolism (vte) represents a major challenge in the management of patients with cancer. The malignant phenotype is associated with derangements in the coagulation cascade that can manifest as thrombosis, hemorrhage, or disseminated intravascular coagulation. The risk of vte is increased by a factor of approximately 6 in patients with cancer compared with non-cancer patients, and cancer patients account for approximately 20% of all newly diagnosed cases of vte. Postmortem studies have demonstrated rates of vte in patients with cancer to be as high as 50%. Despite that prevalence, vte prophylaxis is underused in hospitalized patients with cancer. Studies have demonstrated that hospitalized patients with cancer are less likely than their non-cancer counterparts to receive vte prophylaxis. Consensus guidelines address the aforementioned issues and emerging concepts in the area, including the use of risk-assessment models, biomarkers to identify patients at highest risk of vte, and use of anticoagulants as anticancer therapy. Despite those guidelines, a gulf exists between current recommendations and clinical practice; greater efforts are thus required to ensure effective implementation of strategies to reduce the incidence of vte in patients with cancer.

Recent advances toward the development of inhibitors to attenuate tumor metastasis via the interruption of lectin-ligand interactions

Aberrant glycosylation is a well-recognized phenomenon that occurs on the surface of tumor cells, and the overexpression of a number of ligands (such as TF, sialyl Tn, and sialyl Lewis X) has been correlated to a worse prognosis for the patient. These unique carbohydrate structures play an integral role in cell-cell communication and have also been associated with more metastatic cancer phenotypes, which can result from binding to lectins present on cell surfaces. The most well studied metastasis-associated lectins are the galectins and selectins, which have been correlated to adhesion, neoangiogenesis, and immune-cell evasion processes. In order to slow the rate of metastatic lesion formation, a number of approaches have been successfully developed which involve interfering with the tumor lectin-substrate binding event. Through the generation of inhibitors, or by attenuating lectin and/or carbohydrate expression, promising results have been observed both in vitro and in vivo. This article briefly summarizes the involvement of lectins in the metastatic process and also describes different approaches used to prevent these undesirable carbohydrate-lectin binding events, which should ultimately lead to improvement in current cancer therapies.

Synthesis and biological evaluation of a unique heparin mimetic hexasaccharide for structure-activity relationship studies

To date, the structure-activity relationship studies of heparin/heparan sulfate with their diverse binding partners such as growth factors, cytokines, chemokines, and extracellular matrix proteins have been limited yet provide early insight that specific sequences contribute to this manifold biological role. This has led to an impetus for the chemical synthesis of oligosaccharide fragments of these complex polysaccharides, which can provide an effective tool for this goal. The synthesis of three heparin mimetic hexasaccharides with distinct structural patterns is described herein, and the influence of the targeted substitution on their bioactivity profiles is studied using in vitro affinity and/or inhibition toward different growth factors and proteins. Additionally, the particularly challenging synthesis of an irregular hexasaccharide is reported, which, interestingly, in spite of being considerably structurally similar with its two counterparts, displayed a unique and remarkably distinct profile in the test assays.

Heparan sulfate signaling in cancer

Heparan sulfate (HS) is a biopolymer consisting of variably sulfated repeating disaccharide units. The anticoagulant heparin is a highly sulfated intracellular variant of HS. HS has demonstrated roles in embryonic development, homeostasis, and human disease via non-covalent interactions with numerous cellular proteins, including growth factors and their receptors. HS can function as a co-receptor by enhancing receptor-complex formation. In other contexts, HS disrupts signaling complexes or serves as a ligand sink. The effects of HS on growth factor signaling are tightly regulated by the actions of sulfyltransferases, sulfatases, and heparanases. HS has important emerging roles in oncogenesis, and heparin derivatives represent potential therapeutic strategies for human cancers. Here we review recent insights into HS signaling in tumor proliferation, angiogenesis, metastasis, and differentiation. A cancer-specific understanding of HS signaling could uncover potential therapeutic targets in this highly actionable signaling network.