M402, a novel heparan sulfate mimetic, targets multiple pathways implicated in tumor progression and metastasis

A Novel Drug Candidate for Sepsis Targeting Heparanase by Inhibiting Cytokine Storm

Sepsis is an infection-triggered, rapidly progressive systemic inflammatory syndrome with a high mortality rate. Currently, there are no promising therapeutic strategies for managing this disease in the clinic. Heparanase plays a crucial role in the pathology of sepsis, and its inhibition can significantly relieve related symptoms. Here, a novel heparanase inhibitor CV122 is rationally designed and synthesized, and its therapeutic potential for sepsis with Lipopolysaccharide (LPS) and Cecal Ligation and Puncture (CLP)-induced sepsis mouse models are evaluated. It is found that CV122 potently inhibits heparanase activity in vitro, protects cell surface glycocalyx structure, and reduces the expression of adhesion molecules. In vivo, CV122 significantly reduces the systemic levels of proinflammatory cytokines, prevents organ damage, improves vitality, and efficiently protects mice from sepsis-induced death. Mechanistically, CV122 inhibits the activity of heparanase, reduces its expression in the lungs, and protects glycocalyx structure of lung tissue. It is also found that CV122 provides effective protection from organ damage and death caused by Crimean-Congo hemorrhagic fever virus (CCHFV) infection. These results suggest that CV122 is a potential drug candidate for sepsis therapy targeting heparanase by inhibiting cytokine storm.

Synthesis and Detection of BODIPY-, Biotin-, and 19 F- Labeled Single-Entity Dendritic Heparan Sulfate Mimetics

Heparin and heparan sulfate (HS) are naturally occurring mammalian glycosaminoglycans, and their synthetic and semi-synthetic mimetics have attracted significant interest as potential therapeutics. However, understanding the mechanism of action by which HS, heparin, and HS mimetics have a biological effect is difficult due to their highly charged nature, broad protein interactomes, and variable structures. To address this, a library of novel single-entity dendritic mimetics conjugated to BODIPY, Fluorine-19 (19 F), and biotin was synthesized for imaging and localization studies. The novel dendritic scaffold allowed for the conjugation of labeling moieties without reducing the number of sulfated capping groups, thereby better mimicking the multivalent nature of HS-protein interactions. The 19 F labeled mimetics were assessed in phantom studies and were detected at concentrations as low as 5 mM. Flow cytometric studies using a fluorescently labeled mimetic showed that the compound associated with immune cells from tumors more readily than splenic counterparts and was directed to endosomal-lysosomal compartments within immune cells and cancer cells. Furthermore, the fluorescently labeled mimetic entered the central nervous system and was detectable in brain-infiltrating immune cells 24 hours after treatment. Here, we report the enabling methodology for rapidly preparing various labeled HS mimetics and molecular probes with diverse potential therapeutic applications.

Strategies of Helicobacter pylori in evading host innate and adaptive immunity: insights and prospects for therapeutic targeting

Helicobacter pylori (H. pylori) is the predominant pathogen causing chronic gastric mucosal infections globally. During the period from 2011 to 2022, the global prevalence of H. pylori infection was estimated at 43.1%, while in China, it was slightly higher at approximately 44.2%. Persistent colonization by H. pylori can lead to gastritis, peptic ulcers, and malignancies such as mucosa-associated lymphoid tissue (MALT) lymphomas and gastric adenocarcinomas. Despite eliciting robust immune responses from the host, H. pylori thrives in the gastric mucosa by modulating host immunity, particularly by altering the functions of innate and adaptive immune cells, and dampening inflammatory responses adverse to its survival, posing challenges to clinical management. The interaction between H. pylori and host immune defenses is intricate, involving evasion of host recognition by modifying surface molecules, manipulating macrophage functionality, and modulating T cell responses to evade immune surveillance. This review analyzes the immunopathogenic and immune evasion mechanisms of H. pylori, underscoring the importance of identifying new therapeutic targets and developing effective treatment strategies, and discusses how the development of vaccines against H. pylori offers new hope for eradicating such infections.

Discovery of a novel tetrahydroimidazo[1,2-a]pyridine-5-carboxylic acid derivative as a potent and selective heparanase-1 inhibitor utilizing an improved synthetic approach

Heparanase-1 (HPSE1) is an endo-β-d-glucuronidase that catalyzes degradation of heparan sulfate proteoglycans. Inhibition of HPSE1 appears to be a useful therapeutic target against cancer and proteinuric kidney diseases. We previously reported tetrahydroimidazo[1,2-a]pyridine 2 as a potent HPSE1 inhibitor after optimization of the synthetic reaction. However, synthesis of 2 involves a total of 19 steps, including a cyclization process that accompanies a strong odor due to the use of Lawesson's reagent and an epimerization reaction; furthermore, 2 exhibited insufficient selectivity for HPSE1 over exo-β-d-glucuronidase (GUSβ) and glucocerebrosidase (GBA), which also needed to be addressed. First, the cyclization reaction was optimized to synthesize tetrahydroimidazo[1,2-a]pyridine without using Lawesson's reagent or epimerization, with reference to previous reports. Next, 16 and 17 containing a bulkier substituent at position 6 than the 6-methoxyl group in 2 were designed and synthesized using the improved cyclization conditions, so that the synthetic route of 16 and 17 was shortened by five steps as compared with that of 2. The inhibitory activities of 16 and 17 against GUSβ and GBA were reduced as compared with those of 2, that is, the compounds showed improved selectivity for HPSE1 over GUSβ and GBA. In addition, 16 showed enhanced inhibitory activity against HPSE1 as compared with that of 2. Compound 16 appears promising as an HPSE1 inhibitor with therapeutic potential due to its highly potent inhibitory activity against HPSE1 with high selectivity for HPSE1.

Discovery and development of small-molecule heparanase inhibitors

Heparanase-1 (HPSE) is a promising yet challenging therapeutic target. It is the only known enzyme that is responsible for cleavage of heparan sulfate (HS) side chains from heparan sulfate proteoglycans (HSPGs), and is the key enzyme involved in the remodeling and degradation of the extracellular matrix (ECM). Overexpression of HPSE is found in various types of diseases, including cancers, inflammations, diabetes, and viral infections. Inhibiting HPSE can restore ECM functions and integrity, making the development of HPSE inhibitors a highly sought-after topic. So far, all HPSE inhibitors that have entered clinical trials belong to the category of HS mimetics, and no small-molecule or drug-like HPSE inhibitors have made similar progress. None of the HS mimetics have been approved as drugs, with some clinical trials discontinued due to poor bioavailability, side effects, and unfavorable pharmacokinetics characteristics. Small-molecule HPSE inhibitors are, therefore, particularly appealing due to their drug-like characteristics. Advances in the chemical spaces and drug design technologies, including the increasing use of in vitro and in silico screening methods, have provided new opportunities in drug discovery. This article aims to review the discovery and development of small-molecule HPSE inhibitors via screening strategies to shed light on the future endeavors in the development of novel HPSE inhibitors.

The heparan sulfate mimetic Muparfostat aggravates steatohepatitis in obese mice due to its binding affinity to lipoprotein lipase

BACKGROUND AND PURPOSE

Heparanase is the only confirmed endoglycosidase that cleaves heparan sulfate (HS), a ubiquitous glycosaminoglycan with various essential roles in multiple pathological processes. Thus, the development of heparanase inhibitors has become an attractive strategy for drug discovery, especially in tumour therapy, in which HS mimetics are the most promising compounds. The various biological effects of heparanase also suggest a role for HS mimetics in many non-cancer indications, such as type 1 diabetes. However, the potential benefits of HS mimetics in obesity-related type 2 diabetes have not been elucidated.

EXPERIMENTAL APPROACH

In this study, we investigated muparfostat (PI-88), a developed HS mimetic currently enrolled in Phase III clinical trials, in obese mouse models and in vitro cultured murine hepatocytes.

KEY RESULTS

Daily administration of muparfostat for 4 weeks caused hyperlipidaemia and aggravated hepatic steatosis in obese mice models, but not in lean animals. In cultured hepatocytes, muparfostat did not alter lipid accumulation. Acute tests suggested that muparfostat binds to lipoprotein lipase in competition with HS on vascular endothelial cell surfaces, thereby reducing the degradation of circulating triglycerides by lipoprotein lipase and subsequent uptake of fatty acids into vascular endothelial cells and causing hyperlipidaemia. This hyperlipidaemia aggravates hepatic steatosis and causes liver injury in muparfostat-treated obese mice.

CONCLUSIONS AND IMPLICATIONS

The binding activity of HS mimetics to lipoprotein lipase should be investigated as an additional pharmacological effect during heparanase inhibitor drug discovery. This study also provides novel evidence for an increased risk of drug-induced liver injury in obese individuals.

Complex Inhibitory Mechanism of Glycomimetics with Heparanase

Heparanase (HPSE) is the only mammalian endo-β-glucuronidase known to catalyze the degradation of heparan sulfate. Dysfunction of HPSE activity has been linked to several disease states, resulting in HPSE becoming the target of numerous therapeutic programs, yet no drug has passed clinical trials to date. Pentosan polysulfate sodium (PPS) is a heterogeneous, FDA-approved drug for the treatment of interstitial cystitis and a known HPSE inhibitor. However, due to its heterogeneity, characterization of its mechanism of HPSE inhibition is challenging. Here, we show that inhibition of HPSE by PPS is complex, involving multiple overlapping binding events, each influenced by factors such as oligosaccharide length and inhibitor-induced changes in the protein secondary structure. The present work advances our molecular understanding of the inhibition of HPSE and will aid in the development of therapeutics for the treatment of a broad range of pathologies associated with enzyme dysfunction, including cancer, inflammatory disease, and viral infections.

Construction of a novel MPT-driven necrosis-related lncRNAs signature for prognosis prediction in laryngeal squamous cell carcinoma

Mitochondrial permeability transition (MPT)-driven necrosis, a type of programmed cell death, has recently gained much attention in a variety of tumor types. Few studies have been performed to explore the role of MPT-driven necrosis-related lncRNAs (MPTDNRlncRNAs) in laryngeal squamous cell carcinoma (LSCC). The purpose of our study is to screen MPTDNRlncRNAs with prognostic value and to explore their potential roles in LSCC. The RNA-sequencing data and the corresponding clinical data of LSCC patients were obtained from the TCGA database, and those MPT-driven necrosis-related genes were extracted from the Gene Set Enrichment Analysis (GSEA) database. We identified MPTDNRlncRNAs differentially expressed in LSCC. Also, we gained MPT-driven necrosis-related prognostic lncRNAs by univariate cox regression analysis. A novel MPTDNRlncRNAs signature was constructed by LASSO-COX. The accuracy and utility of the MPTDNRlncRNAs signature were evaluated via a variety of statistical methods. Multiple bioinformatics tools were used to explore the underlying difference in biological functions and signaling pathways between the different risk groups. The expressions levels of MPTDNRlncRNAs were analyzed using RT-qPCR in LSCC cell line. Finally, we identified A 5 MPTDNRlncRNAs signature in LSCC. Our prognostic model demonstrated an efficient ability to predict outcomes. The proportion difference of immune cells in the subgroups were significant, such as M0 macrophage and T follicular helper cells. The in vitro experiments suggested that our MPTDNRlncRNAs were significantly different. This 5 MPTDNRlncRNAs signature is a prognostic biomarker for LSCC. More importantly, the novel biologic prognostic model can be utilized for personalized immunotherapy in LSCC patients.

Potential roles of heparanase in cancer therapy: Current trends and future direction

Heparanase (HPSE; heparanase-1) is an endo-β-glucuronidase capable of degrading the carbohydrate moiety of heparan sulfate proteoglycans, thus modulating and facilitating the remodeling of the extracellular matrix and basement membrane. HPSE activity is strongly associated with major human pathological complications, including but not limited to tumor progress and angiogenesis. Several lines of literature have shown that overexpression of HPSE leads to enhanced tumor growth and metastatic transmission, as well as poor prognosis. Gene silencing of HPSE or treatment of tumor with compounds that block HPSE activity are shown to remarkably attenuate tumor progression. Therefore, targeting HPSE is considered as a potential therapeutical strategy for the treatment of cancer. Intriguingly, recent findings disclose that heparanase-2 (HPSE-2), a close homolog of HPSE but lacking enzymatic activity, can also regulate antitumor mechanisms. Given the pleiotropic roles of HPSE, further investigation is in demand to determine the precise mechanism of regulating action of HPSE in different cancer settings. In this review, we first summarize the current understanding of HPSE, such as its structure, subcellular localization, and tissue distribution. Furthermore, we systematically review the pro- and antitumorigenic roles and mechanisms of HPSE in cancer progress. In addition, we delineate HPSE inhibitors that have entered clinical trials and their therapeutic potential.

Heparan sulfate proteoglycans in cancer: Pathogenesis and therapeutic potential

The heparan sulfate proteoglycans (HSPGs) are glycoproteins that consist of a proteoglycan "core" protein and covalently attached heparan sulfate (HS) chain. HSPGs are ubiquitously expressed in mammalian cells on the cell surface and in the extracellular matrix (ECM) and secretory vesicles. Within HSPGs, the protein cores determine when and where HSPG expression takes place, and the HS chains mediate most of HSPG's biological roles through binding various protein ligands, including cytokines, chemokines, growth factors and receptors, morphogens, proteases, protease inhibitors, and ECM proteins. Through these interactions, HSPGs modulate cell proliferation, adhesion, migration, invasion, and angiogenesis to display essential functions in physiology and pathology. Under physiological conditions, the expression and localization of HSPGs are finely regulated to orchestrate their physiological functions, and this is disrupted in cancer. The HSPG dysregulation elicits multiple oncogenic signaling, including growth factor signaling, ECM and Integrin signaling, chemokine and immune signaling, cancer stem cell, cell differentiation, apoptosis, and senescence, to prompt cell transformation, proliferation, tumor invasion and metastasis, tumor angiogenesis and inflammation, and immunotolerance. These oncogenic roles make HSPGs an attractive pharmacological target for anti-cancer therapy. Several therapeutic strategies have been under development, including anti-HSPG antibodies, peptides and HS mimetics, synthetic xylosides, and heparinase inhibitors, and shown promising anti-cancer efficacy. Therefore, much progress has been made in this line of study. However, it needs to bear in mind that the roles of HSPGs in cancer can be either oncogenic or tumor-suppressive, depending on the HSPG and the cancer cell type with the underlying mechanisms that remain obscure. Further studies need to address these to fill the knowledge gap and rationalize more efficient therapeutic targeting.

Pancreatic Cancer: Beyond Brca Mutations

Pancreatic cancer is the fourth-leading cause of cancer-related deaths worldwide. The outcomes in patients with pancreatic cancer remain unsatisfactory. In the current review, we summarize the genetic and epigenetic architecture of metastatic pancreatic cancer beyond the BRCA mutations, focusing on the genetic alterations and the molecular pathology in pancreatic cancer. This review focuses on the molecular targets for the treatment of pancreatic cancer, with a correlation to future treatments. The potential approach addressed in this review may lead to the identification of a subset of patients with specific biological behaviors and treatment responses.

Heparan Sulfate Proteoglycans in Tauopathy

Tauopathies are a class of neurodegenerative diseases, including Alzheimer's disease, and are characterized by intraneuronal tau inclusion in the brain and the patient's cognitive decline with obscure pathogenesis. Heparan sulfate proteoglycans, a major type of extracellular matrix, have been believed to involve in tauopathies. The heparan sulfate proteoglycans co-deposit with tau in Alzheimer's patient brain, directly bind to tau and modulate tau secretion, internalization, and aggregation. This review summarizes the current understanding of the functions and the modulated molecular pathways of heparan sulfate proteoglycans in tauopathies, as well as the implication of dysregulated heparan sulfate proteoglycan expression in tau pathology and the potential of targeting heparan sulfate proteoglycan-tau interaction as a novel therapeutic option.

Heparin-Superparamagnetic Iron Oxide Nanoparticles for Theranostic Applications

In this study, superparamagnetic iron oxide nanoparticles (SPIONs) were engineered with an organic coating composed of low molecular weight heparin (LMWH) and bovine serum albumin (BSA), providing heparin-based nanoparticle systems (LMWH@SPIONs). The purpose was to merge the properties of the heparin skeleton and an inorganic core to build up a targeted theranostic nanosystem, which was eventually enhanced by loading a chemotherapeutic agent. Iron oxide cores were prepared via the co-precipitation of iron salts in an alkaline environment and oleic acid (OA) capping. Dopamine (DA) was covalently linked to BSA and LMWH by amide linkages via carbodiimide coupling. The following ligand exchange reaction between the DA-BSA/DA-LMWH and OA was conducted in a biphasic system composed of water and hexane, affording LMWH@SPIONs stabilized in water by polystyrene sulfonate (PSS). Their size and morphology were investigated via dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. The LMWH@SPIONs’ cytotoxicity was tested, showing marginal or no toxicity for samples prepared with PSS at concentrations of 50 µg/mL. Their inhibitory activity on the heparanase enzyme was measured, showing an effective inhibition at concentrations comparable to G4000 (N-desulfo-N-acetyl heparin, a non-anticoagulant and antiheparanase heparin derivative; Roneparstat). The LMWH@SPION encapsulation of paclitaxel (PTX) enhanced the antitumor effect of this chemotherapeutic on breast cancer cells, likely due to an improved internalization of the nanoformulated drug with respect to the free molecule. Lastly, time-domain NMR (TD-NMR) experiments were conducted on LMWH@SPIONs obtaining relaxivity values within the same order of magnitude as currently used commercial contrast agents.

Meta-analysis of gemcitabine plus nab-paclitaxel combined with targeted agents in the treatment of metastatic pancreatic cancer

BACKGROUND

Gemcitabine plus nab-paclitaxel (GA) is a commonly used first-line treatment regimen for metastatic pancreatic cancer, and many studies will add a novel targeted agent to this regimen for improving patient survival rate. However, the clinical effectiveness of GA is the most controversial issue.

AIM

To compare the efficacy and safety of GA regimen with a targeted agent and GA regimen.

METHODS

Up to 1 December 2021, the eligible randomized controlled trials (RCTs) relating to GA and GA with a targeted agent were searched on PubMed, EMBASE and Cochrane Library for eligible data. We screened out appropriate studies for overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and toxicity, which had been pooled and finally analyzed by using Stata version 15.1. In addition, we use Reference Citation Analysis (https://www.referencecitationanalysis.com/) to collect the latest related literature to improve the latest cutting-edge research results.

RESULTS

Seven RCTs involving 1544 patients (848 men and 696 women) were included. There were no significant differences between GA with a targeted agent and GA in PFS [hazard ratio (HR): 1.18 95% confidence interval (CI): 0.91-1.53], OS (HR: 1.12 95%CI: 0.99-1.27), and ORR (HR: 0.96 95%CI: 0.71-1.29). There was no notable difference in the two groups in grade 3/4 toxicity (fatigue, anemia, vomiting and neutropenia), whereas the incidence of grade 3/4 diarrhea considerably increased in GA with a targeted drug.

CONCLUSION

Adding a novel targeted agent to the GA regimen did not improve survival rate of patients with metastatic pancreatic cancer.

Heparanase in cancer progression: Structure, substrate recognition and therapeutic potential

Heparanase, a member of the carbohydrate-active enzyme (CAZy) GH79 family, is an endo-β-glucuronidase capable of degrading the carbohydrate moiety of heparan sulphate proteoglycans, thus modulating and facilitating remodeling of the extracellular matrix. Heparanase activity is strongly associated with major human pathological complications, including but not limited to tumour progress, angiogenesis and inflammation, which make heparanase a valuable therapeutic target. Long-due crystallographic structures of human and bacterial heparanases have been recently determined. Though the overall architecture of human heparanase is generally comparable to that of bacterial glucuronidases, remarkable differences exist in their substrate recognition mode. Better understanding of regulatory mechanisms of heparanase in substrate recognition would provide novel insight into the anti-heparanase inhibitor development as well as potential clinical applications.

Mechanism-based heparanase inhibitors reduce cancer metastasis in vivo

Cancer growth is accompanied by changes to the extracellular environment of tumors, which aids the proliferation and spread of cancer cells. Cancer-associated extracellular matrix changes include excessive degradation of heparan sulfate carbohydrates, promoting metastatic spread by multiple mechanisms. Heparanase is the main human enzyme responsible for extracellular heparan sulfate breakdown and strongly drives metastasis when overexpressed. Few effective heparanase inhibitors are known, and the most effective molecules to date possess nondrug-like structures with multiple off-target effects. We have carried out structure-guided development of heparanase inhibitors, which covalently bind to the enzyme active site to cause irreversible inhibition. These inhibitors are heparanase specific and reduce metastasis in animal models with comparable efficacy to current “best-in-class” compounds.

Heparan sulfate proteoglycans (HSPGs) mediate essential interactions throughout the extracellular matrix (ECM), providing signals that regulate cellular growth and development. Altered HSPG composition during tumorigenesis strongly aids cancer progression. Heparanase (HPSE) is the principal enzyme responsible for extracellular heparan sulfate catabolism and is markedly up-regulated in aggressive cancers. HPSE overactivity degrades HSPGs within the ECM, facilitating metastatic dissemination and releasing mitogens that drive cellular proliferation. Reducing extracellular HPSE activity reduces cancer growth, but few effective inhibitors are known, and none are clinically approved. Inspired by the natural glycosidase inhibitor cyclophellitol, we developed nanomolar mechanism-based, irreversible HPSE inhibitors that are effective within physiological environments. Application of cyclophellitol-derived HPSE inhibitors reduces cancer aggression in cellulo and significantly ameliorates murine metastasis. Mechanism-based irreversible HPSE inhibition is an unexplored anticancer strategy. We demonstrate the feasibility of such compounds to control pathological HPSE-driven malignancies.

Harnessing Human Papillomavirus’ Natural Tropism to Target Tumors

Human papillomaviruses (HPV) are small non-enveloped DNA tumor viruses established as the primary etiological agent for the development of cervical cancer. Decades of research have elucidated HPV’s primary attachment factor to be heparan sulfate proteoglycans (HSPG). Importantly, wounding and exposure of the epithelial basement membrane was found to be pivotal for efficient attachment and infection of HPV in vivo. Sulfation patterns on HSPG’s become modified at the site of wounds as they serve an important role promoting tissue healing, cell proliferation and neovascularization and it is these modifications recognized by HPV. Analogous HSPG modification patterns can be found on tumor cells as they too require the aforementioned processes to grow and metastasize. Although targeting tumor associated HSPG is not a novel concept, the use of HPV to target and treat tumors has only been realized in recent years. The work herein describes how decades of basic HPV research has culminated in the rational design of an HPV-based virus-like infrared light activated dye conjugate for the treatment of choroidal melanoma.

Identification of Novel Potential Heparanase Inhibitors Using Virtual Screening

Heparanase (HPSE) is a mammalian endo-β-D-glucuronidase that cleaves heparan sulphate (HS) side chains of heparin sulphate proteoglycans (HSPG), a class of molecules composed of repeating polysulfated disaccharide units of glucosamine and hexuronic acid residues. HPSE controls the availability of growth factors, chemokines, lipoproteins and other bioactive molecules by degrading HS into smaller fractions, allowing the release of saccharide fragments that activate a plethora of signaling processes. HPSE overexpression has been correlated with tumor survival and metastasis as well as several diseases associated with chronic inflammation, including the ongoing COVID-19 pandemic caused by SARS-CoV-2. Thus, the search for molecules that could potentially inhibit HPSE has become increasingly relevant in the clinic. In this study, we have integrated a strategy that combines virtual screening and molecular docking of publicly available chemical databases to identify small compounds that can be developed into novel HPSE inhibitors. Structural rationalization of the interactions previously reported compounds led us to identify promising unexplored chemotypes. Here we show that these novel potential HPSE inhibitors present optimized in silico druggability and docking properties and may serve as pharmacological tools for the treatment of chronic and infectious diseases associated with chronic inflammation.

Synthesis of novel glycolipid mimetics of heparan sulfate and their application in colorectal cancer treatment in a mouse model

Heparan sulfate (HS) is a highly sulfated natural carbohydrate that plays crucial roles in cancer, inflammation, and angiogenesis. Heparanase (HPSE) is the sole HS degrading endoglycosidase that cleaves HS at structure‐dependent sites along the polysaccharide chain. Overexpression of HPSE by cancer cells correlates with increased tumor size and enhanced metastasis. Previously we have shown that a tetramer HS mimetic is a potent HPSE inhibitor displaying remarkable anticancer activity in vivo. Building on that work, we report the synthesis and testing of a novel library of single entity trimer glycolipid mimetics that effectively inhibit HPSE at low nanomolar concentrations. A lipophilic arm was introduced to assess whether an improvement of pharmacokinetics and plasma residence time would offset the reduction in charge and multivalency. Preclinical tests in a mouse syngeneic model showed effective tumor growth inhibition by the tetramer but not the trimer glycomimetic.

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.

The Role and Therapeutic Value of Syndecan-1 in Cancer Metastasis and Drug Resistance

Metastasis and relapse are major causes of cancer-related fatalities. The elucidation of relevant pathomechanisms and adoption of appropriate countermeasures are thus crucial for the development of clinical strategies that inhibit malignancy progression as well as metastasis. An integral component of the extracellular matrix, the type 1 transmembrane glycoprotein syndecan-1 (SDC-1) binds cytokines and growth factors involved in tumor microenvironment modulation. Alterations in its localization have been implicated in both cancer metastasis and drug resistance. In this review, available data regarding the structural characteristics, shedding process, and nuclear translocation of SDC-1 are detailed with the aim of highlighting strategies directly targeting SDC-1 as well as SDC-1-mediated carcinogenesis.

Anticancer opportunities at every stage of chemokine function

The chemokine system, comprising 48 chemokines and 23 receptors, is critically involved in several hallmarks of cancer. Yet, despite extensive efforts from the pharmaceutical sector, only two drugs aimed at this system are currently approved for clinical use against cancer. To date, numerous pharmacological approaches have been developed to successfully intervene at different stages of chemokine function: (i) chemokine availability; (ii) chemokine-glycosaminoglycan binding; and (iii) chemokine receptor binding. Many of these strategies have been tested in preclinical cancer models, and some have advanced to clinical trials as potential anticancer therapies. Here we will review the strategies and growing pharmacological toolbox for manipulating the chemokine system in cancer, and address novel methods poised for future (pre)clinical testing.

Metastasis Prevention: Focus on Metastatic Circulating Tumor Cells

Metastasis is the main cause of cancer death. Metastatic foci are derived from tumor cells that detach from the primary tumor and then enter the circulation. Circulating tumor cells (CTCs) are generally associated with a high probability of distant metastasis and a negative prognosis. Most CTCs die in the bloodstream, and only a few cells form metastases. Such metastatic CTCs have a stem-like and hybrid epithelial-mesenchymal phenotype, can avoid immune surveillance, and show increased therapy resistance. Targeting metastatic CTCs and their progenitors in primary tumors and their descendants, particularly disseminated tumor cells, represents an attractive strategy for metastasis prevention. However, current therapeutic strategies mainly target the primary tumor and only indirectly affect metastasis-initiating cells. Here, we consider potential methods for preventing metastasis based on targeting molecular and cellular features of metastatic CTCs, including CTC clusters. Also, we emphasize current knowledge gaps in CTC biology that should be addressed to develop highly effective therapeutics and strategies for metastasis suppression.

Helicobacter pylori-Induced Heparanase Promotes H. pylori Colonization and Gastritis

Chronic gastritis caused by Helicobacter pylori (H. pylori) infection has been widely recognized as the most important risk factor for gastric cancer. Analysis of the interaction between the key participants in gastric mucosal immunity and H. pylori infection is expected to provide important insights for the treatment of chronic gastritis and the prevention of gastric cancer. Heparanase is an endoglycosidase that degrades heparan sulfate, resulting in remodeling of the extracellular matrix thereby facilitating the extravasation and migration of immune cells towards sites of inflammation. Heparanase also releases heparan sulfate-bound cytokines and chemokines that further promote directed motility and recruitment of immune cells. Heparanase is highly expressed in a variety of inflammatory conditions and diseases, but its role in chronic gastritis has not been sufficiently explored. In this study, we report that H. pylori infection promotes up-regulation of heparanase in gastritis, which in turn facilitates the colonization of H. pylori in the gastric mucosa, thereby aggravating gastritis. By sustaining continuous activation, polarization and recruitment of macrophages that supply pro-inflammatory and pro-tumorigenic cytokines (i.e., IL-1, IL-6, IL-1β, TNF-α, MIP-2, iNOS), heparanase participates in the generation of a vicious circle, driven by enhanced NFκB and p38-MAPK signaling, that supports the development and progression of gastric cancer. These results suggest that inhibition of heparanase may block this self-sustaining cycle, and thereby reduce the risk of gastritis and gastric cancer.

Computational Investigation Identified Potential Chemical Scaffolds for Heparanase as Anticancer Therapeutics

Heparanase (Hpse) is an endo-β-D-glucuronidase capable of cleaving heparan sulfate side chains. Its upregulated expression is implicated in tumor growth, metastasis and angiogenesis, thus making it an attractive target in cancer therapeutics. Currently, a few small molecule inhibitors have been reported to inhibit Hpse, with promising oral administration and pharmacokinetic (PK) properties. In the present study, a ligand-based pharmacophore model was generated from a dataset of well-known active small molecule Hpse inhibitors which were observed to display favorable PK properties. The compounds from the InterBioScreen database of natural (69,034) and synthetic (195,469) molecules were first filtered for their drug-likeness and the pharmacophore model was used to screen the drug-like database. The compounds acquired from screening were subjected to molecular docking with Heparanase, where two molecules used in pharmacophore generation were used as reference. From the docking analysis, 33 compounds displayed higher docking scores than the reference and favorable interactions with the catalytic residues. Complex interactions were further evaluated by molecular dynamics simulations to assess their stability over a period of 50 ns. Furthermore, the binding free energies of the 33 compounds revealed 2 natural and 2 synthetic compounds, with better binding affinities than reference molecules, and were, therefore, deemed as hits. The hit compounds presented from this in silico investigation could act as potent Heparanase inhibitors and further serve as lead scaffolds to develop compounds targeting Heparanase upregulation in cancer.

Synthesis and Cell Growth Inhibitory Activity of Six Non-glycosaminoglycan-Type Heparin-Analogue Trisaccharides

The design and synthesis of heparin mimetics with high anticancer activity but no anticoagulant activity is an important task in medicinal chemistry. Herein, we present the efficient synthesis of five Glc-GlcA-Glc-sequenced and one Glc-IdoA-Glc-sequenced non-glycosaminoglycan, heparin-related trisaccharides with various sulfation/sulfonylation and methylation patterns. The cell growth inhibitory effects of the compounds were tested against four cancerous human cell lines and two non-cancerous cell lines. Two d-glucuronate-containing tetra-O-sulfated, partially methylated trisaccharides displayed remarkable and selective inhibitory effects on the growth of ovary carcinoma (A2780) and melanoma (WM35) cells. Methyl substituents on the glucuronide unit proved to be detrimental, whereas acetyl substituents were beneficial to the cytostatic activity of the sulfated derivatives.

Heparanase Inhibitors in Cancer Progression: Recent Advances

BACKGROUND

An endo-β-glucuronidase enzyme, Heparanase (HPSE), degrades the side chains of polymeric heparan sulfate (HS), a glycosaminoglycan formed by alternate repetitive units of D-glucosamine and D-glucuronic acid/L-iduronic acid. HS is a major component of the extracellular matrix and basement membranes and has been implicated in processes of the tissue's integrity and functional state. The degradation of HS by HPSE enzyme leads to conditions like inflammation, angiogenesis, and metastasis. An elevated HPSE expression with a poor prognosis and its multiple roles in tumor growth and metastasis has attracted significant interest for its inhibition as a potential anti-neoplastic target.

METHODS

We reviewed the literature from journal publication websites and electronic databases such as Bentham, Science Direct, PubMed, Scopus, USFDA, etc., about HPSE, its structure, functions, and role in cancer.

RESULTS

The present review is focused on Heparanase inhibitors (HPIns) that have been isolated from natural resources or chemically synthesized as new therapeutics for metastatic tumors and chronic inflammatory diseases in recent years. The recent developments made in the HPSE structure and function are also discussed, which can lead to the future design of HPIns with more potency and specificity for the target.

CONCLUSION

HPIns can be a better target to be explored against various cancers.

Development of Molecules Antagonizing Heparan Sulfate Proteoglycans

Heparan sulfate proteoglycans (HSPGs) occur in almost every tissue of the human body and consist of a protein core, with covalently attached glycosaminoglycan polysaccharide chains. These glycosaminoglycans are characterized by their polyanionic nature, due to sulfate and carboxyl groups, which are distributed along the chain. These chains can be modified by different enzymes at varying positions, which leads to huge diversity of possible structures with the complexity further increased by varying chain lengths. According to their location, HSPGs are divided into different families, the membrane bound, the secreted extracellular matrix, and the secretory vesicle family. As members of the extracellular matrix, they take part in cell-cell communication processes on many levels and with different degrees of involvement. Of particular therapeutic interest is their role in cancer and inflammation as well as in infectious diseases. In this review, we give an overview of the current status of medical approaches to antagonize HSPG function in pathology.

Glycosylation of Cancer Extracellular Vesicles: Capture Strategies, Functional Roles and Potential Clinical Applications

Glycans are major constituents of extracellular vesicles (EVs). Alterations in the glycosylation pathway are a common feature of cancer cells, which gives rise to de novo or increased synthesis of particular glycans. Therefore, glycans and glycoproteins have been widely used in the clinic as both stratification and prognosis cancer biomarkers. Interestingly, several of the known tumor-associated glycans have already been identified in cancer EVs, highlighting EV glycosylation as a potential source of circulating cancer biomarkers. These particles are crucial vehicles of cell–cell communication, being able to transfer molecular information and to modulate the recipient cell behavior. The presence of particular glycoconjugates has been described to be important for EV protein sorting, uptake and organ-tropism. Furthermore, specific EV glycans or glycoproteins have been described to be able to distinguish tumor EVs from benign EVs. In this review, the application of EV glycosylation in the development of novel EV detection and capture methodologies is discussed. In addition, we highlight the potential of EV glycosylation in the clinical setting for both cancer biomarker discovery and EV therapeutic delivery strategies.

Heparan sulfate proteoglycans as targets for cancer therapy: a review

Heparan sulfate proteoglycans (HSPGs) play important roles in cancer initiation and progression, by interacting with the signaling pathways that affect proliferation, adhesion, invasion and angiogenesis. These roles suggest the possibility of various strategies of regulation of these molecules. In this review, we demonstrated that the anticancer drugs can regulate the heparan sulfate proteoglycans activity in different ways: some act directly in core protein, and can bind to a specific type of HSPG. Others drugs interact with glycosaminoglycans chains, and others can act directly in enzymes that regulate HSPGs levels. We also demonstrated that the HSPGs drug targets can be divided into four groups: monoclonal antibodies, antitumor antibiotic, natural products, and mimetics peptide. Interestingly, many drugs demonstrated in this review are approved by FDA and is used in cancer therapy (Food and Drug Administration) like trastuzumab, panitumumab, bleomycin and bisphosphonate zoledronic acid (ASCO) or are in clinical trials like codrituzumab and genistein. This review should help researchers to understand the mechanism of action of anticancer drugs existing and also may inspire the discovery of new drugs that regulate the heparan sulfate proteoglycans activity.

Heparan Sulfate Proteoglycan Signaling in Tumor Microenvironment

In the last few decades, heparan sulfate (HS) proteoglycans (HSPGs) have been an intriguing subject of study for their complex structural characteristics, their finely regulated biosynthetic machinery, and the wide range of functions they perform in living organisms from development to adulthood. From these studies, key roles of HSPGs in tumor initiation and progression have emerged, so that they are currently being explored as potential biomarkers and therapeutic targets for cancers. The multifaceted nature of HSPG structure/activity translates in their capacity to act either as inhibitors or promoters of tumor growth and invasion depending on the tumor type. Deregulation of HSPGs resulting in malignancy may be due to either their abnormal expression levels or changes in their structure and functions as a result of the altered activity of their biosynthetic or remodeling enzymes. Indeed, in the tumor microenvironment, HSPGs undergo structural alterations, through the shedding of proteoglycan ectodomain from the cell surface or the fragmentation and/or desulfation of HS chains, affecting HSPG function with significant impact on the molecular interactions between cancer cells and their microenvironment, and tumor cell behavior. Here, we overview the structural and functional features of HSPGs and their signaling in the tumor environment which contributes to tumorigenesis and cancer progression.

Heparanase: Cloning, Function and Regulation

In 2019, we mark the 20th anniversary of the cloning of the human heparanase gene. Heparanase remains the only known enzyme to cleave heparan sulfate, which is an abundant component of the extracellular matrix. Thus, elucidating the mechanisms underlying heparanase expression and activity is critical to understanding its role in healthy and pathological settings. This chapter provides a historical account of the race to clone the human heparanase gene, describes the intracellular and extracellular function of the enzyme, and explores the various mechanisms regulating heparanase expression and activity at the gene, transcript, and protein level.

A 2,5-Dihydroxybenzoic Acid-Gelatin Conjugate Inhibits the Basal and Hsp90-Stimulated Migration and Invasion of Tumor Cells

The extracellular cell surface-associated and soluble heat shock protein 90 (Hsp90) is known to participate in the migration and invasion of tumor cells. Earlier, we demonstrated that plasma membrane-associated heparan sulfate proteoglycans (HSPGs) bind the extracellular Hsp90 and thereby promote the Hsp90-mediated motility of tumor cells. Here, we showed that a conjugate of 2,5-dihydroxybenzoic acid with gelatin (2,5-DHBA–gelatin), a synthetic polymer with heparin-like properties, suppressed the basal (unstimulated) migration and invasion of human glioblastoma A-172 and fibrosarcoma HT1080 cells, which was accompanied by the detachment of a fraction of Hsp90 from cell surface HSPGs. The polymeric conjugate also inhibited the migration/invasion of cells stimulated by exogenous soluble native Hsp90, which correlated with the inhibition of the attachment of soluble Hsp90 to cell surface HSPGs. The action of the 2,5-DHBA–gelatin conjugate on the motility of A-172 and HT1080 cells was similar to that of heparin. The results demonstrate a potential of the 2,5-DHBA–gelatin polymer for the development of antimetastatic drugs targeting cell motility and a possible role of extracellular Hsp90 in the suppression of the migration and invasion of tumor cells mediated by the 2,5-DHBA–gelatin conjugate and heparin.

Randomised phase II trial of gemcitabine and nab-paclitaxel with necuparanib or placebo in untreated metastatic pancreas ductal adenocarcinoma

BACKGROUND

Necuparanib, a rationally engineered low-molecular-weight heparin, combined with gemcitabine/nab-paclitaxel showed an encouraging safety and oncologic signal in a phase Ib trial. This randomised multicentre phase II trial evaluates the addition of necuparanib or placebo to gemcitabine/nab-paclitaxel in untreated metastatic pancreatic ductal adenocarcinoma (PDAC).

PATIENTS AND METHODS

Eligibility included 18 years, histologically or cytologically confirmed metastatic PDAC, measurable disease and Eastern Co-Operative Oncology Group performance status of 0-1. Patients were randomly assigned to necuparanib (5 mg/kg subcutaneous injection once daily) or placebo (subcutaneous injection once daily) and gemcitabine/nab-paclitaxel on days 1, 8 and 15 of 28-day cycles. The primary end-point was median overall survival (OS), and secondary end-points included median progression-free survival, response rates and safety.

RESULTS

One-hundred ten patients were randomised, 62 to necuparanib arm and 58 to placebo arm. The futility boundary was crossed at a planned interim analysis, and the study was terminated by the Data Safety Monitoring Board. The median OS was 10.71 months (95% confidence interval [CI]: 7.95-11.96) for necuparanib arm and 9.99 months (95% CI: 7.85-12.85) for placebo arm (hazard ratio: 1.12, 95% CI: 0.66-1.89, P-value: 0.671). The necuparanib arm had a higher incidence of haematologic toxicity relative to placebo patients (83% and 70%).

CONCLUSION

The addition of necuparanib to standard of care treatment for advanced PDAC did not improve OS. Safety was acceptable. No further development of necuparanib is planned although targeting the coagulation cascade pathway remains relevant in PDAC. NCT01621243.

Antitumor activity and structure-activity relationship of heparanase inhibitors: Recent advances

Heparanase (HPSE)-directed tumor progression plays a crucial role in mediating tumor-host crosstalk and priming the tumor microenvironment, leading to tumor growth, metastasis and chemo-resistance. HPSE-mediated breakdown of structural heparan sulfate (HS) networks in the extracellular matrix (ECM) and basement membranes (BM) directly facilitates tumor growth and metastasis. Lysosome HPSE also induces multi-drug resistance via enhanced autophagy. Therefore, HPSE inhibitors development has become an attractive topic to block tumor growth and metastasis or eliminate drug resistance. In this review, we summarize HPSE inhibitors applied experimentally and clinically according to interaction with the binding sites of HPSE and participation of growth factors. The antitumor activity and structure-activity relationship (SAR) are also emphasized.

Involvement of Heparan Sulfate and Heparanase in Neural Development and Pathogenesis of Brain Tumors

Brain tumors are aggressive and devastating diseases. The most common type of brain tumor, glioblastoma (GBM), is incurable and has one of the worst five-year survival rates of all human cancers. GBMs are invasive and infiltrate healthy brain tissue, which is one main reason they remain fatal despite resection, since cells that have already migrated away lead to rapid regrowth of the tumor. Curative therapy for medulloblastoma (MB), the most common pediatric brain tumor, has improved, but the outcome is still poor for many patients, and treatment causes long-term complications. Recent advances in the classification of pediatric brain tumors reveal distinct subgroups, allowing more targeted therapy for the most aggressive forms, and sparing children with less malignant tumors the side-effects of massive treatment. Heparan sulfate proteoglycans (HSPGs), main components of the neurogenic niche, interact specifically with a large number of physiologically important molecules and vital roles for HS biosynthesis and degradation in neural stem cell differentiation have been presented. HSPGs are composed of a core protein with attached highly charged, sulfated disaccharide chains. The major enzyme that degrades HS is heparanase (HPSE), an important regulator of extracellular matrix (ECM) remodeling which has been suggested to promote the growth and invasion of other types of tumors. This is of clinical interest because GBM are highly invasive and children with metastatic MB at the time of diagnosis exhibit a worse outcome. Here we review the involvement of HS and HPSE in development of the nervous system and some of its most malignant brain tumors, glioblastoma and medulloblastoma.

Immunomodulatory Activities of the Heparan Sulfate Mimetic PG545

Heparanase regulates multiple biological activities that enhance tumor growth and metastatic spread. Heparanase cleaves and degrades heparan sulfate (HS), a key structural component of the extracellular matrix that serves as a barrier to cell invasion and also as a reservoir for cytokines and growth factors critical for tumor growth and metastasis. For this reason, heparanase is an attractive target for the development of novel anti-cancer therapies. Pixatimod (PG545), a heparanase inhibitor, has shown promising results in the treatment of multiple tumor types. PG545 offers a diversity of mechanisms of action in tumor therapy that include angiogenic inhibition, inhibition of growth factor release, inhibition of tumor cell migration, tumor cell apoptosis, activation of ER stress response, dysregulation of autophagy, and NK cell activation. Further investigation into the role that heparanase and its inhibitors play in tumor therapy can lead to the development of effective tumor therapies.

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).

Forty Years of Basic and Translational Heparanase Research

This review summarizes key developments in the heparanase field obtained 20 years prior to cloning of the HPSE gene and nearly 20 years after its cloning. Of the numerous publications and review articles focusing on heparanase, we have selected those that best reflect the progression in the field as well as those we regard important accomplishments with preference to studies performed by scientists and groups that contributed to this book. Apart from a general 'introduction' and 'concluding remarks', the abstracts of these studies are presented essentially as published along the years. We apologize for not being objective and not being able to include some of the most relevant abstracts and references, due to space limitation. Heparanase research can be divided into two eras. The first, initiated around 1975, dealt with identifying the enzyme, establishing the relevant assay systems and investigating its biological activities and significance in cancer and other pathologies. Studies performed during the first area are briefly introduced in a layman style followed by the relevant abstracts presented chronologically, essentially as appears in PubMed. The second era started in 1999 when the heparanase gene was independently cloned by 4 research groups [1-4]. As expected, cloning of the heparanase gene boosted heparanase research by virtue of the readily available recombinant enzyme, molecular probes, and anti-heparanase antibodies. Studies performed during the second area are briefly introduced followed by selected abstracts of key findings, arranged according to specific topics.

An Overview of the Structure, Mechanism and Specificity of Human Heparanase

The retaining endo-β-D-glucuronidase Heparanase (HPSE) is the primary mammalian enzyme responsible for breakdown of the glycosaminoglycan heparan sulfate (HS). HPSE activity is essential for regulation and turnover of HS in the extracellular matrix, and its activity affects diverse processes such as inflammation, angiogenesis and cell migration. Aberrant heparanase activity is strongly linked to cancer metastasis, due to structural breakdown of extracellular HS networks and concomitant release of sequestered HS-binding growth factors. A full appreciation of HPSE activity in health and disease requires a structural understanding of the enzyme, and how it engages with its HS substrates. This chapter summarizes key findings from the recent crystal structures of human HPSE and its proenzyme. We present details regarding the 3-dimensional protein structure of HPSE and the molecular basis for its interaction with HS substrates of varying sulfation states. We also examine HPSE in a wider context against related β-D-glucuronidases from other species, highlighting the structural features that control exo/endo - glycosidase selectivity in this family of enzymes.

Heparan sulfate chains contribute to the anticoagulant milieu in malignant pleural effusion

Background

While malignant pleural effusion (MPE) is a common and significant cause of morbidity in patients with cancer, current treatment options are limited. Human heparanase, involved in angiogenesis and metastasis, cleaves heparan sulfate (HS) side chains on the cell surface.

Aims

To explore the coagulation milieu in MPE and infectious pleural effusion (IPE) focusing on the involvement of heparanase.

Methods

Samples of 30 patients with MPE and 44 patients with IPE were evaluated in comparison to those of 33 patients with transudate pleural effusions, using heparanase ELISA, heparanase procoagulant activity assay, thrombin and factor Xa chromogenic assays and thromboelastography. A cell proliferation assay was performed. EMT-6 breast cancer cells were injected to the pleural cavity of mice. A peptide inhibiting heparanase activity was administered subcutaneously.

Results

Levels of heparanase, factor Xa and thrombin were significantly higher in exudate than transudate. Thromboelastography detected almost no thrombus formation in the whole blood, mainly on MPE addition. This effect was completely reversed by bacterial heparinase. Direct measurement revealed high levels of HS chains in pleural effusions. Higher proliferation was observed in tumour cell lines incubated with exudate than with transudate and it was reduced when bacterial heparinase was added. The tumour size in the pleural cavity of mice treated with the heparanase inhibitor were significantly smaller compared with control (p=0.005).

Conclusions

HS chains released by heparanase form an anticoagulant milieu in MPE, preventing local thrombosis and enabling tumour cell proliferation. Inhibition of heparanase might provide a therapeutic option for patients with recurrent MPE.

Heparanase: A Challenging Cancer Drug Target

Heparanase has been viewed as a promising anti-cancer drug target for almost two decades, but no anti-heparanase therapy has yet reached the clinic. This endoglycosidase is highly expressed in a variety of malignancies, and its high expression is associated with greater tumor size, more metastases, and a poor prognosis. It was first described as an enzyme cleaving heparan sulfate chains of proteoglycans located in extracellular matrices and on cell surfaces, but this is not its only function. It is a multi-functional protein with activities that are enzymatic and non-enzymatic and which take place both outside of the cell and intracellularly. Knowledge of the crystal structure of heparanase has assisted the interpretation of earlier structure-function studies as well as in the design of potential anti-heparanase agents. This review re-examines the various functions of heparanase in light of the structural data. The functions of the heparanase variant, T5, and structure and functions of heparanase-2 are also examined as these heparanase related, but non-enzymatic, proteins are likely to influence the in vivo efficacy of anti-heparanase drugs. The anti-heparanase drugs currently under development predominately focus on inhibiting the enzymatic activity of heparanase, which, in the absence of inhibitors with high clinical efficacy, prompts a discussion of whether this is the best approach. The diversity of outcomes attributed to heparanase and the difficulties of unequivocally determining which of these are due to its enzymatic activity is also discussed and leads us to the conclusion that heparanase is a valid, but challenging drug target for cancer.

Role of heparanase in tumor progression: Molecular aspects and therapeutic options

Heparanase (HPSE) is an endoglycosidase that catalyses the cutting of the side chains of heparan-sulphate proteoglycans (HS), thus determining the remodelling of the extracellular matrix and basement membranes, as well as promoting the release of different HS-related molecules as growth factors, cytokines and enzymes. Ever since the HPSE was identified in the late 1980s, several experimental studies have shown that its overexpression was instrumental in increasing tumor growth, metastatic dissemination, angiogenesis and inflammation. More recently, HPSE involvment has also been demonstrated in mediating tumor-host crosstalk, in inducing gene transcription, in the activation of signaling pathways and in the formation of exosomes and in autophagy. All of these activities (enzymatic and non-enzymatic) together make heparanase a multifunctional molecule that increases the aggressiveness and chemo-resistance of tumor cells. Conversely, heparanase gene-silencing or tumor treatment with compounds that inhibit heparanase activity have been shown to significantly attenuate tumor progression in different animal models of tumorigenesis, further emphasizing the therapeutic potential of anti-heparanase therapy for several types of neoplasms. This review focuses on present knowledge and recent development in the study of heparanase in cancer progression as well as on novel mechanisms by which heparanase regulates tumor metastasis and chemo-resistance. Moreover, recent advances in strategies for its inhibition as a potential therapeutic option will be discussed.

Targeting Heparanase in Cancer: Inhibition by Synthetic, Chemically Modified, and Natural Compounds

Heparanase is an endoglycosidase involved in remodeling the extracellular matrix and thereby in regulating multiple cellular processes and biological activities. It cleaves heparan sulfate (HS) side chains of HS proteoglycans into smaller fragments and hence regulates tissue morphogenesis, differentiation, and homeostasis. Heparanase is overexpressed in various carcinomas, sarcomas, and hematological malignancies, and its upregulation correlates with increased tumor size, tumor angiogenesis, enhanced metastasis, and poor prognosis. In contrast, knockdown or inhibition of heparanase markedly attenuates tumor progression, further underscoring the potential of anti-heparanase therapy. Heparanase inhibitors were employed to interfere with tumor progression in preclinical studies, and selected heparin mimetics are being examined in clinical trials. However, despite tremendous efforts, the discovery of heparanase inhibitors with high clinical benefit and minimal adverse effects remains a therapeutic challenge. This review discusses the key roles of heparanase in cancer progression focusing on the status of natural, chemically modified, and synthetic heparanase inhibitors in various types of malignancies.

Glycosaminoglycans and Glycosaminoglycan Mimetics in Cancer and Inflammation

Glycosaminoglycans (GAGs) are a class of biomolecules expressed virtually on all mammalian cells and usually covalently attached to proteins, forming proteoglycans. They are present not only on the cell surface, but also in the intracellular milieu and extracellular matrix. GAGs interact with multiple ligands, both soluble and insoluble, and modulate an important role in various physiological and pathological processes including cancer, bacterial and viral infections, inflammation, Alzheimer’s disease, and many more. Considering their involvement in multiple diseases, their use in the development of drugs has been of significant interest in both academia and industry. Many GAG-based drugs are being developed with encouraging results in animal models and clinical trials, showcasing their potential for development as therapeutics. In this review, the role GAGs play in both the development and inhibition of cancer and inflammation is presented. Further, advancements in the development of GAGs and their mimetics as anti-cancer and anti-inflammatory agents are discussed.

Glycosaminoglycans and Glycosaminoglycan Mimetics in Cancer and Inflammation

Glycosaminoglycans (GAGs) are a class of biomolecules expressed virtually on all mammalian cells and usually covalently attached to proteins, forming proteoglycans. They are present not only on the cell surface, but also in the intracellular milieu and extracellular matrix. GAGs interact with multiple ligands, both soluble and insoluble, and modulate an important role in various physiological and pathological processes including cancer, bacterial and viral infections, inflammation, Alzheimer's disease, and many more. Considering their involvement in multiple diseases, their use in the development of drugs has been of significant interest in both academia and industry. Many GAG-based drugs are being developed with encouraging results in animal models and clinical trials, showcasing their potential for development as therapeutics. In this review, the role GAGs play in both the development and inhibition of cancer and inflammation is presented. Further, advancements in the development of GAGs and their mimetics as anti-cancer and anti-inflammatory agents are discussed.

λ-Carrageenan Oligosaccharides of Distinct Anti-Heparanase and Anticoagulant Activities Inhibit MDA-MB-231 Breast Cancer Cell Migration

In tumor development, the degradation of heparan sulfate (HS) by heparanase (HPSE) is associated with cell-surface and extracellular matrix remodeling as well as the release of HS-bound signaling molecules, allowing cancer cell migration, invasion and angiogenesis. Because of their structural similarity with HS, sulfated polysaccharides are considered a promising source of molecules to control these activities. In this study, we used a depolymerisation method for producing λ-carrageenan oligosaccharides (λ-CO), with progressive desulfation over time. These were then used to investigate the influence of polymeric chain length and degree of sulfation (DS) on their anti-HPSE activity. The effects of these two features on λ-CO anticoagulant properties were also investigated to eliminate a potential limitation on the use of a candidate λ-CO as a chemotherapeutic agent. HPSE inhibition was mainly related to the DS of λ-CO, however this correlation was not complete. On the other hand, both chain length and DS modulated λ-CO activity for factor Xa and thrombin IIa inhibition, two enzymes that are involved in the coagulation cascade, and different mechanisms of inhibition were observed. A λ-carrageenan oligosaccharide of 5.9 KDa was identified as a suitable anticancer candidate because it displayed one of the lowest anticoagulant properties among the λ-CO produced, while showing a remarkable inhibitory effect on MDA-MB-231 breast cancer cell migration.