Glycosaminoglycans in cancer treatment

In silico approaches for better understanding cysteine cathepsin-glycosaminoglycan interactions

Cysteine cathepsins constitute the largest cathepsin family, with 11 proteases in human that are present primarily within acidic endosomal and lysosomal compartments. They are involved in the turnover of intracellular and extracellular proteins. They are synthesized as inactive procathepsins that are converted to mature active forms. Cathepsins play important roles in physiological and pathological processes and, therefore, receive increasing attention as potential therapeutic targets. Their maturation and activity can be regulated by glycosaminoglycans (GAGs), long linear negatively charged polysaccharides composed of recurring dimeric units. In this review, we summarize recent computational progress in the field of (pro)cathepsin-GAG complexes analyses.

Longitudinal Assessment of Circulating Tumor Cells and Outcome in Small Cell Lung Cancer: A Sub-Study of RASTEN-A Randomized Trial with Low Molecular Weight Heparin

Circulating tumor cells (CTCs) may provide a liquid biopsy approach to disease monitoring in small cell lung cancer (SCLC), a particularly aggressive tumor subtype. Yet, the prognostic role of CTCs during and after treatment in relation to baseline remains ill-defined. Here, we assessed the value of longitudinal CTC analysis and the potential of low-molecular-weight heparin (LMWH) to reduce CTC abundance in SCLC patients from a randomized trial (RASTEN). Blood samples were collected at baseline, before chemotherapy Cycle 3, and at 2-month follow-up from 42 patients in total, and CTCs were quantified using the FDA-approved CellSearch system. We found a gradual decline in CTC count during and after treatment, independently of the addition of LMWH to standard therapy. Detectable CTCs at baseline correlated significantly to reduced survival compared to undetectable CTCs (unadjusted hazard ratio (HR) of 2.75 (95% CI 1.05-7.20; p = 0.040)). Furthermore, a persistent CTC count at 2-month follow-up was associated with a HR of 4.22 (95% CI 1.20-14.91; p = 0.025). Our findings indicate that persistently detectable CTCs during and after completion of therapy offer further prognostic information in addition to baseline CTC, suggesting a role for CTC in the individualized management of SCLC.

Integrative Analysis Reveals the Diverse Effects of 3D Stiffness upon Stem Cell Fate

The origin of life and native tissue development are dependent on the heterogeneity of pluripotent stem cells. Bone marrow mesenchymal stem cells (BMMSCs) are located in a complicated niche with variable matrix stiffnesses, resulting in divergent stem cell fates. However, how stiffness drives stem cell fate remains unknown. For this study, we performed whole-gene transcriptomics and precise untargeted metabolomics sequencing to elucidate the complex interaction network of stem cell transcriptional and metabolic signals in extracellular matrices (ECMs) with different stiffnesses, and we propose a potential mechanism involved in stem cell fate decision. In a stiff (39~45 kPa) ECM, biosynthesis of aminoacyl-tRNA was up-regulated, and increased osteogenesis was also observed. In a soft (7~10 kPa) ECM, biosynthesis of unsaturated fatty acids and deposition of glycosaminoglycans were increased, accompanied by enhanced adipogenic/chondrogenic differentiation of BMMSCs. In addition, a panel of genes responding to the stiffness of the ECM were validated in vitro, mapping out the key signaling network that regulates stem cells' fate decisions. This finding of "stiffness-dependent manipulation of stem cell fate" provides a novel molecular biological basis for development of potential therapeutic targets within tissue engineering, from both a cellular metabolic and a biomechanical perspective.

Altered Glycosylation in Progression and Management of Bladder Cancer

Bladder cancer (BC) is the 10th most common malignancy worldwide, with an estimated 573,000 new cases and 213,000 deaths in 2020. Available therapeutic approaches are still unable to reduce the incidence of BC metastasis and the high mortality rates of BC patients. Therefore, there is a need to deepen our understanding of the molecular mechanisms underlying BC progression to develop new diagnostic and therapeutic tools. One such mechanism is protein glycosylation. Numerous studies reported changes in glycan biosynthesis during neoplastic transformation, resulting in the appearance of the so-called tumor-associated carbohydrate antigens (TACAs) on the cell surface. TACAs affect a wide range of key biological processes, including tumor cell survival and proliferation, invasion and metastasis, induction of chronic inflammation, angiogenesis, immune evasion, and insensitivity to apoptosis. The purpose of this review is to summarize the current information on how altered glycosylation of bladder cancer cells promotes disease progression and to present the potential use of glycans for diagnostic and therapeutic purposes.

Molecular Dynamics-Based Comparative Analysis of Chondroitin and Dermatan Sulfates

Glycosaminoglycans (GAGs) are a class of linear anionic periodic polysaccharides containing disaccharide repetitive units. These molecules interact with a variety of proteins in the extracellular matrix and so participate in biochemically crucial processes such as cell signalling affecting tissue regeneration as well as the onset of cancer, Alzheimer's or Parkinson's diseases. Due to their flexibility, periodicity and chemical heterogeneity, often termed "sulfation code", GAGs are challenging molecules both for experiments and computation. One of the key questions in the GAG research is the specificity of their intermolecular interactions. In this study, we make a step forward to deciphering the "sulfation code" of chondroitin sulfates-4,6 (CS4, CS6, where the numbers correspond to the position of sulfation in NAcGal residue) and dermatan sulfate (DS), which is different from CSs by the presence of IdoA acid instead of GlcA. We rigorously investigate two sets of these GAGs in dimeric, tetrameric and hexameric forms with molecular dynamics-based descriptors. Our data clearly suggest that CS4, CS6 and DS are substantially different in terms of their structural, conformational and dynamic properties, which contributes to the understanding of how these molecules can be different when they bind proteins, which could have practical implications for the GAG-based drug design strategies in the regenerative medicine.

Proteoglycans: a common portal for SARS-CoV-2 and extracellular vesicle uptake

As structural components of the glycocalyx, heparan sulfate proteoglycans (HSPGs) are involved in multiple pathophysiological processes at the apex of cell signaling cascades, and as endocytosis receptors for particle structures, such as lipoproteins, extracellular vesicles, and enveloped viruses, including SARS-CoV-2. Given their diversity and complex biogenesis regulation, HSPGs remain understudied. Here we compile some of the latest studies focusing on HSPGs as internalizing receptors of extracellular vesicles ("endogenous virus") and SARS-CoV-2 lipid-enclosed particles and highlight similarities in their biophysical and structural characteristics. Specifically, the similarities in their biogenesis, size, and lipid composition may explain a common dependence on HSPGs for efficient cell-surface attachment and uptake. We further discuss the relative complexity of extracellular vesicle composition and the viral mechanisms that evolve towards increased infectivity that complicate therapeutic strategies addressing blockade of their uptake.

Analysis of Extracellular Vesicle-Associated Proteoglycans

Extracellular vesicles (EVs) have emerged as a central mechanism of intercellular communication in physiology and disease. EVs participate in paracrine exchange of nucleic acids as well as lipids, proteins, and glycans to elicit a complex biological response in target cells. Proteoglycans (PGs) are widely expressed in EV-producing cells and are sorted to the membrane of secreted EVs to participate in some of the key processes in EV-mediated signaling. Most notably, PGs mainly of the heparan sulfate (HS) type are involved in EV biogenesis and cellular uptake of EVs through endocytic processes. EV-associated PGs may serve as short- and long-range chaperones of signaling molecules with potential implications for intercellular information exchange, most importantly in cancer development. This motivates the development of approaches targeting EV-HSPG interactions as a strategy in cancer treatment. Moreover, the importance of PG remodeling and alterations in their expression in cancer, together with the fact that EVs mimic their cell or tissue of origin, point at an important role of EV-associated PGs as disease biomarkers. Here, we provide methodological insights into the analysis of EV-PGs isolated from cell cultures as well as patient plasma liquid biopsy.

Pulmonary Thrombosis Promotes Tumorigenesis via Myeloid Hypoxia-Inducible Factors

Cancer patients have a greater risk of thrombosis than individuals without cancer. Conversely, thrombosis is a diagnostic predictor of cancer, but the mechanisms by which thrombosis promotes tumor propagation are incompletely understood. Our previous studies showed that hypoxia-inducible factors (HIF) 1α and HIF2α are stabilized in myeloid cells of murine thrombi. We also previously showed that pulmonary thrombosis increases the levels of HIF1α and HIF2α in murine lungs, enhances the levels of tumorigenic factors in the circulation, and promotes pulmonary tumorigenesis. In this study, we aimed to investigate the regulation of thrombosis-induced tumorigenesis by myeloid cell-specific HIFs (i.e., HIF1 and HIF2 in neutrophils and macrophages). Our in vitro studies showed that multiple tumorigenic factors are upregulated in the secretome of hypoxic versus normoxic neutrophils and macrophages, which promotes lung cancer cell proliferation and migration in a myeloid-HIF-dependent manner. Next, we used a mouse model of pulmonary microvascular occlusion to study the impact of pulmonary thrombosis and myeloid HIFs on lung tumorigenesis. Experiments on mice lacking either HIF1α or HIF2α in myeloid cells demonstrated that loss of either factor eliminates the advantage given to pulmonary tumor formation by thrombotic insult. The myeloid HIF-dependent and tumorigenic impact of pulmonary thrombosis on tumor burden may be partly driven by paracrine thymidine phosphorylase (TP), given that TP levels were increased by hypoxia in neutrophil and macrophage supernates, and that plasma TP levels were positively correlated with multiple measures of tumor progression in wild type mice but not myeloid cell-specific HIF1α or HIF2α knockout mice. These data together demonstrate the importance of thrombotic insult in a model of pulmonary tumorigenesis and the essential role of myeloid HIFs in mediating tumorigenic success.

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.

Complexation of europium(III) with exopolysaccharides from a marine bacterium envisaged as luminescent probe in a theranostic approach

Exopolysaccharide (EPS) derivatives, produced by Alteromonas infernus bacterium, showed anti-metastatic properties in osteosarcoma (bone tumor). These EPSs could be employed as new drug delivery systems for therapeutic uses. They may represent a new class of ligands to be combined in a theranostic approach with fluorescent metals, such as Eu(III), to serve as imaging probe. The goal of this work was to investigate the feasibility of such coupling by time-resolved laser-induced fluorescence spectroscopy (TRLFS). Since these EPSs are polyelectrolytes their conformation could affect the complexation properties. Thus, viscosimetric measurements were performed as a function of their concentration as well as the background electrolyte concentration. Polysaccharides conformation exhibited a lower hydrodynamic volume for the highest ionic strengths. The resulting random-coiled conformation could affect the complexation with metal for high concentration but no change was evidenced when increasing europium concentration. Two sites of complexation of Eu(III) were evidenced by TRLFS in heparin, whereas only one site was evidenced in two modified EPSs produced from Alteromonas infernus.

Antiproliferative Properties of Scandium Exopolysaccharide Complexes on Several Cancer Cell Lines

Antimetastatic properties on both murine and human osteosarcoma cell lines (POS-1 and KHOS) have been evidenced using exopolysaccharide (EPS) derivatives, produced by Alteromonas infernus bacterium. These derivatives had no significant effect on the cell cycle neither a pro-apoptotic effect on osteosarcoma cells. Based on this observation, these EPSs could be employed as new drug delivery systems for therapeutic uses. A theranostic approach, i.e., combination of a predictive biomarker with a therapeutic agent, has been developed notably by combining with true pair of theranostic radionuclides, such as scandium ⁴⁷Sc/⁴⁴Sc. However, it is crucial to ensure that, once complexation is done, the biological properties of the vector remain intact, allowing the molecular tropism of the ligand to recognize its molecular target. It is important to assess if the biological properties of EPS evidenced on osteosarcoma cell lines remain when scandium is complexed to the polymers and can be extended to other cancer cell types. Scandium-EPS complexes were thus tested in vitro on human cell lines: MNNG/HOS osteosarcoma, A375 melanoma, A549 lung adenocarcinoma, U251 glioma, MDA231 breast cancer, and Caco2 colon cancer cells. An xCELLigence Real Cell Time Analysis (RTCA) technology assay was used to monitor for 160 h, the proliferation kinetics of the different cell lines. The tested complexes exhibited an anti-proliferative effect, this effect was more effective compared to EPS alone. This increase of the antiproliferative properties was explained by a change in conformation of EPS complexes due to their polyelectrolyte nature that was induced by complexation. Alterations of both growth factor-receptor signaling, and transmembrane protein interactions could be the principal cause of the antiproliferative effect. These results are very promising and reveal that EPS can be coupled to scandium for improving its biological effects and also suggesting that no major structural modification occurs on the ligand.

Glycosaminoglycans: Carriers and Targets for Tailored Anti-Cancer Therapy

The tumor microenvironment (TME) is composed of cancerous, non-cancerous, stromal, and immune cells that are surrounded by the components of the extracellular matrix (ECM). Glycosaminoglycans (GAGs), natural biomacromolecules, essential ECM, and cell membrane components are extensively altered in cancer tissues. During disease progression, the GAG fine structure changes in a manner associated with disease evolution. Thus, changes in the GAG sulfation pattern are immediately correlated to malignant transformation. Their molecular weight, distribution, composition, and fine modifications, including sulfation, exhibit distinct alterations during cancer development. GAGs and GAG-based molecules, due to their unique properties, are suggested as promising effectors for anticancer therapy. Considering their participation in tumorigenesis, their utilization in drug development has been the focus of both industry and academic research efforts. These efforts have been developing in two main directions; (i) utilizing GAGs as targets of therapeutic strategies and (ii) employing GAGs specificity and excellent physicochemical properties for targeted delivery of cancer therapeutics. This review will comprehensively discuss recent developments and the broad potential of GAG utilization for cancer therapy.

Marine Exopolysaccharide Complexed With Scandium Aimed as Theranostic Agents

(1) Background: Exopolysaccharide (EPS) derivatives, produced by Alteromonas infernus bacterium, showed anti-metastatic properties. They may represent a new class of ligands to be combined with theranostic radionuclides, such as ⁴⁷Sc/⁴⁴Sc. The goal of this work was to investigate the feasibility of such coupling. (2) Methods: EPSs, as well as heparin used as a drug reference, were characterized in terms of molar mass and dispersity using Asymmetrical Flow Field-Flow Fractionation coupled to Multi-Angle Light Scattering (AF4-MALS). The intrinsic viscosity of EPSs at different ionic strengths were measured in order to establish the conformation. To determine the stability constants of Sc with EPS and heparin, a Free-ion selective radiotracer extraction (FISRE) method has been used. (3) Results: AF4-MALS showed that radical depolymerization produces monodisperse EPSs, suitable for therapeutic use. EPS conformation exhibited a lower hydrodynamic volume for the highest ionic strengths. The resulting random-coiled conformation could affect the complexation with metal for high concentration. The LogK of Sc-EPS complexes have been determined and showing that they are comparable to the Sc-Hep. (4) Conclusions: EPSs are very promising to be coupled with the theranostic pair of scandium for Nuclear Medicine.

Heparan Sulfate Glycosaminoglycans: (Un)Expected Allies in Cancer Clinical Management

In an era when cancer glycobiology research is exponentially growing, we are witnessing a progressive translation of the major scientific findings to the clinical practice with the overarching aim of improving cancer patients' management. Many mechanistic cell biology studies have demonstrated that heparan sulfate (HS) glycosaminoglycans are key molecules responsible for several molecular and biochemical processes, impacting extracellular matrix properties and cellular functions. HS can interact with a myriad of different ligands, and therefore, hold a pleiotropic role in regulating the activity of important cellular receptors and downstream signalling pathways. The aberrant expression of HS glycan chains in tumours determines main malignant features, such as cancer cell proliferation, angiogenesis, invasion and metastasis. In this review, we devote particular attention to HS biological activities, its expression profile and modulation in cancer. Moreover, we highlight HS clinical potential to improve both diagnosis and prognosis of cancer, either as HS-based biomarkers or as therapeutic targets.

Glycosaminoglycans

Glycosaminoglycans (GAGs) are important constituents of human glycome. They are negatively charged unbranched polysaccharides that are usually covalently attached to proteins, forming glycan-protein conjugates, called proteoglycans. Glycosaminoglycans play critical roles in numerous biological processes throughout individual development and are also involved in the pathological processes of various diseases. Based on their remarkable bioactivities and their universal involvement in disease progression, GAGs are applied as therapeutics or are being targeted or used in treating diseases. In this chapter, we introduce the characteristics of the four classes of GAGs that constitute the glycosaminoglycan family. The pathological roles of glycosaminoglycans in major diseases including innate disease, infectious disease, and cancer are discussed. The application of GAGs and their mimetics as therapeutics is introduced, as well as those therapeutic methods developed based on GAGs' role in pathogenesis. In addition, we provide a brief and overall lookback at the history of GAG research and sort out some critical techniques that facilitated GAG and glycomics studies.

Inhibitory Effect of Topical Cartilage Acellular Matrix Suspension Treatment on Neovascularization in a Rabbit Corneal Model

BACKGROUND

The extracellular matrix (ECM) of articular cartilage has an inhibitory effect on vascularization, yet clinical utilization has been technically challenging. In this study, we aimed to fabricate a biologically functional ECM powder suspension from porcine articular cartilage that inhibits neovascularization (NV).

METHODS

The digested-cartilage acellular matrix (dg-CAM) was prepared by sequential processes of decellularization, enzymatic digestion and pulverization. Physicochemical properties of dg-CAM were compared with that of native cartilage tissue (NCT). Cellular interactions between human umbilical vein endothelial cells (HUVECs) and dg-CAM was evaluated with proliferation, migration and tube formation assays compared with that of type I collagen (COL) and bevacizumab, an anti-angiogenic drug. We then investigated the therapeutic potential of topical administration of dg-CAM suspension on the experimentally induced rabbit corneal NV model.

RESULTS

The dg-CAM released a significantly larger amount of soluble proteins than that of the NCT and showed an improved hydrophilic and dispersion properties. In contrast, the dg-CAM contained a large amount of collagen, glycosaminoglycans and anti-angiogenic molecules as much as the NCT. The inhibitory effect on NV of the dg-CAM was more prominent than that of COL and even comparable to that of bevacizumab in inhibiting the HUVECs. The therapeutic potential of the dg-CAM was comparable to that of bevacizumab in the rabbit corneal NV model by efficiently inhibiting neovessel formation of the injured cornea.

CONCLUSION

The current study developed a dg-CAM having anti-angiogenic properties, together with water-dispersible properties suitable for topical or minimally invasive application for prevention of vessel invasion.

Exploring Circulating Tumor Cells in Cholangiocarcinoma Using a Novel Glycosaminoglycan Probe on a Microfluidic Platform

The search of alternative approaches to epithelial cell adhesion molecule (EpCAM), for the isolation of circulating tumor cells (CTC), is on the rise. This work attempts at evaluating the feasibility of using a new glycosaminoglycan, SCH45, as a probe to isolate CTCs from the peripheral blood of 65 advanced/metastatic cholangiocarcinoma (CCA) patients. The positive enrichment of CTCs from 1 mL of blood using SCH45-bound magnetic beads and subsequent staining on an integrated microfluidic platform is demonstrated. Results detailing CTC concentrations averaging ≥1 CTCs mL^-1 of blood are shown, and a conventional protein biomarker, EpCAM, has been used to corroborate the finding that 100% of the patients possess CTCs in their blood. Studies detailing the use of CTCs in the prognostic monitoring and treatment effectiveness of advanced/metastatic CCA are scarce, and the isolation of CTCs from all CCA patients tested has not been reported yet. A strong correlation between CTC counts and disease progression at the time of and/or in advance of radiographic imaging in patients receiving chemotherapy is also reported. This study is one of its kind with the new probe and reduced sample volume and has potential for use in CCA diagnosis and prognosis in the near future.

Sulfated Non-Saccharide Glycosaminoglycan Mimetics as Novel Drug Discovery Platform for Various Pathologies

Glycosaminoglycans (GAGs) are very complex, natural anionic polysaccharides. They are polymers of repeating disaccharide units of uronic acid and hexosamine residues. Owing to their template-free, spatiotemporally-controlled, and enzyme-mediated biosyntheses, GAGs possess enormous polydispersity, heterogeneity, and structural diversity which often translate into multiple biological roles. It is well documented that GAGs contribute to physiological and pathological processes by binding to proteins including serine proteases, serpins, chemokines, growth factors, and microbial proteins. Despite advances in the GAG field, the GAG-protein interface remains largely unexploited by drug discovery programs. Thus, Non-Saccharide Glycosaminoglycan Mimetics (NSGMs) have been rationally developed as a novel class of sulfated molecules that modulate GAG-protein interface to promote various biological outcomes of substantial benefit to human health. In this review, we describe the chemical, biochemical, and pharmacological aspects of recently reported NSGMs and highlight their therapeutic potentials as structurally and mechanistically novel anti-coagulants, anti-cancer agents, anti-emphysema agents, and anti-viral agents. We also describe the challenges that complicate their advancement and describe ongoing efforts to overcome these challenges with the aim of advancing the novel platform of NSGMs to clinical use.

Metabolic gene alterations impact the clinical aggressiveness and drug responses of 32 human cancers

Malignant cells reconfigure their metabolism to support oncogenic processes such as accelerated growth and proliferation. The mechanisms by which this occurs likely involve alterations to genes that encode metabolic enzymes. Here, using genomics data for 10,528 tumours of 32 different cancer types, we characterise the alterations of genes involved in various metabolic pathways. We find that mutations and copy number variations of metabolic genes are pervasive across all human cancers. Based on the frequencies of metabolic gene alterations, we further find that there are two distinct cancer supertypes that tend to be associated with different clinical outcomes. By utilising the known dose-response profiles of 825 cancer cell lines, we infer that cancers belonging to these supertypes are likely to respond differently to various anticancer drugs. Collectively our analyses define the foundational metabolic features of different cancer supertypes and subtypes upon which discriminatory strategies for treating particular tumours could be constructed.

Virus-Receptor Interactions: Structural Insights For Oncolytic Virus Development

Recent advancements in oncolytic virotherapy commend a special attention to developing new strategies for targeting cancer cells with oncolytic viruses (OVs). Modifications of the viral envelope or coat proteins serve as a logical mean of repurposing viruses for cancer treatment. In this review, we discuss how detailed structural knowledge of the interactions between OVs and their natural receptors provide valuable insights into tumor specificity of some viruses and re-targeting of alternate receptors for broad tumor tropism or improved tumor selectivity.

Engineering Controlled Peritumoral Inflammation to Constrain Brain Tumor Growth

Brain tumors remain a great clinical challenge, in part due to their capacity to invade into eloquent, inoperable regions of the brain. In contrast, inflammation in the central nervous system (CNS) due to injuries activates microglia and astrocytes culminating in an astroglial scar that typically "walls-off" the injury site. Here, the hypothesis is tested that targeting peritumoral cells surrounding tumors to activate them via an inflammatory stimulus that recapitulates the sequelae of a traumatic CNS injury, could generate an environment that would wall-off and contain invasive tumors in the brain. Gold nanoparticles coated with inflammatory polypeptides to target stromal cells in close vicinity to glioblastoma (GBM) tumors, in order to activate these cells and stimulate stromal CNS inflammation, are engineered. It is reported that this approach significantly contains tumors in rodent models of GBM relative to control treatments (reduction in tumor volume by over 300% in comparison to controls), by the activation of the innate and adaptive immune response, and by triggering pathways related to cell clustering. Overall, this report outlines an approach to contain invasive tumors that can complement adjuvant interventions for invasive GBM such as radiation and chemotherapy.

Coagulation biomarkers and prediction of venous thromboembolism and survival in small cell lung cancer: A sub-study of RASTEN - A randomized trial with low molecular weight heparin

Coagulation activation and venous thromboembolism (VTE) are hallmarks of cancer; however, there is an unmet need of improved biomarkers for individualized anticoagulant treatment. The present sub-study of the RASTEN trial was designed to explore the role of coagulation biomarkers in predicting VTE risk and outcome in a homogenous cancer patient population. RASTEN is a multicenter, randomized phase-3 trial investigating the survival effect of low molecular weight heparin enoxaparin when added to standard treatment in newly diagnosed small cell lung cancer (SCLC) patients. Plasma collected at baseline, during treatment, and at follow-up was used in this ad hoc sub-study (N = 242). Systemic coagulation was assessed using four assays reflecting various facets of the coagulation system: Total tissue factor (TF); extracellular vesicle associated TF (EV-TF); procoagulant phospholipids (PPL); and thrombin generation (TG). We found small variations of biomarker levels between baseline, during treatment and at follow-up, and appeared independent on low molecular weight heparin treatment. Overall, none of the measured biomarkers at any time-point did significantly associate with VTE incidence, although increased total TF at baseline showed significant association in control patients not receiving low molecular weight heparin (P = 0.03). Increased TG-Peak was significantly associated with decreased overall survival (OS; P = 0.03), especially in patients with extensive disease. Low baseline EV-TF predicted a worse survival in the low molecular weight heparin as compared with the control group (HR 1.42; 95% CI 1.04–1.95; P = 0.03; P for interaction = 0.12). We conclude that the value of the analyzed coagulation biomarkers for the prediction of VTE risk was very limited in SCLC patients. The associations between TG-Peak and EV-TF with patient survival and response to low molecular weight heparin therapy, respectively, warrant further studies on the role of coagulation activation in SCLC aggressiveness.

Conventional Anti-glioblastoma Chemotherapy Affects Proteoglycan Composition of Brain Extracellular Matrix in Rat Experimental Model in vivo

Temozolomide (TMZ) is a conventional chemotherapy drug for adjuvant treatment of glioblastoma multiforme (GBM), often accompanied by dexamethasone (DXM) to prevent brain oedema and alleviate clinical side effects. Here, we aimed to investigate an ability of the drugs to affect normal brain tissue in terms of proteoglycan (PG) composition/content in experimental rat model in vivo. Age- and brain zone-specific transcriptional patterns of PGs were demonstrated for 8, 60, and 120 days old rats, and syndecan-1, glypican-1, decorin, biglycan, and lumican were identified as the most expressed PGs. DXM treatment affected both PG core proteins expression (mainly syndecan-1, glypican-1, decorin, biglycan, lumican, versican, brevican, and NG2) and heparan sulphate (HS)/chondroitin sulphate (CS) content in organotypic brain slice culture ex vivo and experimental animals in vivo in a dose-dependent manner. TMZ treatment did not result in the significant changes in PG core proteins expression both in normal rat brain hippocampus and cortex in vivo (although generics did), but demonstrated significant effects onto polysaccharide HS/CS content in the brain tissue. The effects were age- and brain zone-specific and similar with the age-related PGs expression changes in rat brain. Combination of TMZ with DXM resulted in the most profound deterioration in PGs composition and content in the brain tissue both at core protein and glycosaminoglycan levels. Taken together, the obtained results demonstrate that conventional anti-glioblastoma therapy affects proteoglycan structure and composition in normal brain tissue, potentially resulting in deterioration of brain extracellular matrix and formation of the favourable tumorigenic niche for the expansion of the residual glioma cells. During the TMZ chemotherapy, dose and regimen of DXM treatment matter, and repetitive low DXM doses seem to be more sparing treatment compared with high DXM dose(s), which should be avoided where possible, especially in combination with TMZ.

Ange K, Han X, Edsinger E, Sohn J, Linhardt RJ. Structural and Functional Components of the Skate Sensory Organ Ampullae of Lorenzini

The skate, a cartilaginous fish related to sharks and rays, possesses a unique electrosensitive sensory organ known as the ampullae of Lorenzini (AoL). This organ is responsible for the detection of weak electric field changes caused by the muscle contractions of their prey. While keratan sulfate (KS) is believed to be a component of a jelly that fills this sensory organ and has been credited with its high proton conductivity, modern analytical methods have not been applied to its characterization. Surprisingly, total glycosaminoglycan (GAG) analysis demonstrates that the KS from skate jelly is extraordinarily pure, containing no other GAGs. This KS had a molecular weight of 20 to 30 kDa, consisting primarily of N-linked KS comprised mostly of a monosulfated disaccharide repeating unit, →3) Gal (1→4) GlcNAc6S (1→. Proteomic analysis of AoL jelly suggests that transferrin, keratin, and mucin serve as KS core proteins. Actin and tropomyosin are responsible for assembling the macrostructure of the jelly, and parvalbumin α-like protein and calreticulin regulate calcium and potassium channels involved in the transduction of the electrical signal, once conducted down the AoL by the jelly, serving as the molecular basis for electroreception.

Functional role of extracellular vesicles and lipoproteins in the tumour microenvironment

Cancer can be regarded as an invasive organ that exhibits unique plasticity provided by coordinated, cancer cell-stromal cell communication in the tumour microenvironment. Typical stress factors in the tumour niche, such as hypoxia and acidosis, are major drivers and modulators of these events. Recent findings reveal an important role of extracellular vesicles and lipoproteins in cancer cell adaption to exogenous stress. Adaptive mechanisms include stimulation of angiogenesis and increased metastasis. Here, we will discuss the similarities and distinct features of these endogenous nanoparticles and their roles as signalosomes and nutrient sources in cancer. We will focus on the accumulating evidence for a central role of cell-surface heparan sulphate proteoglycans in the uptake of extracellular vesicles and lipoproteins.This article is part of the discussion meeting issue 'Extracellular vesicles and the tumour microenvironment'.

Tumor target amplification: Implications for nano drug delivery systems

Tumor cells overexpress surface markers which are absent from normal cells. These tumor-restricted antigenic signatures are a fundamental basis for distinguishing on-target from off-target cells for ligand-directed targeting of cancer cells. Unfortunately, tumor heterogeneity impedes the establishment of a solid expression pattern for a given target marker, leading to drastic changes in quality (availability) and quantity (number) of the target. Consequently, a subset of cancer cells remains untargeted during the course of treatment, which subsequently promotes drug-resistance and cancer relapse. Since target inefficiency is only problematic for cancer treatment and not for treatment of other pathological conditions such as viral/bacterial infections, target amplification or the generation of novel targets is key to providing eligible antigenic markers for effective targeted therapy. This review summarizes the limitations of current ligand-directed targeting strategies and provides a comprehensive overview of tumor target amplification strategies, including self-amplifying systems, dual targeting, artificial markers and peptide modification. We also discuss the therapeutic and diagnostic potential of these approaches, the underlying mechanism(s) and established methodologies, mostly in the context of different nanodelivery systems, to facilitate more effective ligand-directed cancer cell monitoring and targeting.

Randomized phase III trial of low-molecular-weight heparin enoxaparin in addition to standard treatment in small-cell lung cancer: the RASTEN trial

Background

Coagulation activation and venous thromboembolism (VTE) are hallmarks of malignant disease and represent a major cause of morbidity and mortality in cancer. Coagulation inhibition with low-molecular-weight heparin (LMWH) may improve survival specifically in small-cell lung cancer (SCLC) patients by preventing VTE and tumor progression; however, randomized trials with well-defined patient populations are needed to obtain conclusive data. The aim of RASTEN was to investigate the survival effect of LMWH enoxaparin in a homogenous population of SCLC patients.

Patients and methods

We carried out a randomized, multicenter, open-label trial to investigate the addition of enoxaparin at a supraprophylactic dose (1 mg/kg) to standard treatment in patients with newly diagnosed SCLC. The primary outcome was overall survival (OS), and secondary outcomes were progression-free survival (PFS), incidence of VTE and hemorrhagic events.

Results

In RASTEN, 390 patients were randomized over an 8-year period (2008-2016), of whom 186 and 191 were included in the final analysis in the LMWH and control arm, respectively. We found no evidence of a difference in OS or PFS by the addition of enoxaparin [hazard ratio (HR), 1.11; 95% confidence interval (CI) 0.89-1.38; P = 0.36 and HR, 1.18; 95% CI 0.95-1.46; P = 0.14, respectively]. Subgroup analysis of patients with limited and extensive disease did not show reduced mortality by enoxaparin. The incidence of VTE was significantly reduced in the LMWH arm (HR, 0.31; 95% CI 0.11-0.84; P = 0.02). Hemorrhagic events were more frequent in the LMWH-treated group but fatal bleedings occurred in both arms.

Conclusion

LMWH enoxaparin in addition to standard therapy did not improve OS in SCLC patients despite being administered at a supraprophylactic dose and despite resulting in a significant reduction in VTE incidence. Addition of LMWH cannot be generally recommended in the management of SCLC patients, and predictive biomarkers of VTE and LMWH-associated bleeding in cancer patients are warranted.

Glycosaminoglycans from fish swim bladder: isolation, structural characterization and bioactive potential

The swim bladder of fish is an internal gas-filled organ that allows fish to control their buoyancy and swimming depth. Fish maws (the dried swim bladders of fish) have been used over many centuries as traditional medicines, tonics and a luxurious gourmet food in China and Southeast Asia. Little is known about the structural information of polysaccharides comprising this important functional material of fish tissue. In the present study, the total glycosaminoglycan (GAG) from fish maw was characterized. Two GAGs were identified, chondroitin sulfate (CS, having a molecular weight of 18-40 kDa) and heparan sulfate (HS), corresponding to 95% and 5% of the total GAG, respectively. Chondroitinase digestion showed that the major CS GAG was composed of ΔUA-1 → 3-GalNAc4S (59.7%), ΔUA-1 → 3-GalNAc4,6S (36.5%), ΔUA-1 → 3-GalNAc6S (2.2%) and ΔUA-1 → 3-GalNAc (1.6%) disaccharide units. ¹H-NMR analysis and degradation with specific chondroitinases, both CS-type A/C and CS-type B were present in a ratio of 1.4:1. Analysis using surface plasmon resonance showed that fibroblast growth factor (FGF)-2 bound to the CS fraction (K_D = 136 nM). These results suggest that this CS may be involved in FGF-signal pathway, mediating tissue repair, regeneration and wound healing. The CS, as the major GAG in fish maw, may have potential pharmacological activity in accelerating wound healing.

Modelling pulmonary microthrombosis coupled to metastasis: distinct effects of thrombogenesis on tumorigenesis

Thrombosis can cause localized ischemia and tissue hypoxia, and both of these are linked to cancer metastasis. Vascular micro-occlusion can occur as a result of arrest of circulating tumour cells in small capillaries, giving rise to microthrombotic events that affect flow, creating localized hypoxic regions. To better understand the association between metastasis and thrombotic events, we generated an experimental strategy whereby we modelled the effect of microvascular occlusion in metastatic efficiency by using inert microbeads to obstruct lung microvasculature before, during and after intravenous tumour cell injection. We found that controlled induction of a specific number of these microthrombotic insults in the lungs caused an increase in expression of the hypoxia-inducible transcription factors (HIFs), a pro-angiogenic and pro-tumorigenic environment, as well as an increase in myeloid cell infiltration. Induction of pulmonary microthrombosis prior to introduction of tumour cells to the lungs had no effect on tumorigenic success, but thrombosis at the time of tumour cell seeding increased number and size of tumours in the lung, and this effect was strikingly more pronounced when the micro-occlusion occurred on the day following introduction of tumour cells. The tumorigenic effect of microbead treatment was seen even when thrombosis was induced five days after tumour cell injection. We also found positive correlations between thrombotic factors and expression of HIF2α in human tumours. The model system described here demonstrates the importance of thrombotic insult in metastatic success and can be used to improve understanding of thrombosis-associated tumorigenesis and its treatment.

Summary: Induction of pulmonary microthrombosis by three distinct methods enhances HIF-a expression and tumour formation; increases in tumorigenesis that are induced by these thrombotic insults occur in a time- and mode-dependent manner.

Mucopolysaccharide from cuttlefish: Purification, chemical characterization and bioactive potential

The sulfated mucopolysaccharide (GAG) was isolated from S. pharonis and the carbohydrate and protein content was found to be 62.4% and 3.9%. The disaccharide profile of sulfated GAG composed glucuronic acid, N-acetyl glucosamine and sulfate content by contributing 50.11%, 38.00% and 27.69% respectively. The carbon, hydrogen and nitrogen content of the sulfated GAG showed 14.80%, 1.68% and 2.99% respectively. The molecular weight of sulfated GAG was calculated as 27kDa and the structural characterization was done by Fourier Transform Infrared (FT-IR) and NMR Spectroscopy. The Activated Partial Thromboplastin Time (APTT) and Prothrombin Time (PT) of sulfated GAG were determined as 91 IU and 39.55 IU at 25μg/ml respectively. Further the sulfated GAG reported the cytotoxic effect (CC₅₀) of 1100μg/ml concentration on Vero cell line. The sulfated GAG reported the anticancer activity against HeLa cell line with an inhibition rate of 18.65%-66.13% at 50-250μg/ml concentration. The sulfated GAG can be considered as a potent anticoagulant and anticancer drug in future.

The role of heparins and nano-heparins as therapeutic tool in breast cancer

Glycosaminoglycans are integral part of the dynamic extracellular matrix (ECM) network that control crucial biochemical and biomechanical signals required for tissue morphogenesis, differentiation, homeostasis and cancer development. Breast cancer cells communicate with stromal ones to modulate ECM mainly through release of soluble effectors during cancer progression. The intracellular cross-talk between cell surface receptors and estrogen receptors is important for the regulation of breast cancer cell properties and production of ECM molecules. In turn, reorganized ECM-cell surface interface modulates signaling cascades, which regulate almost all aspects of breast cell behavior. Heparan sulfate chains present on cell surface and matrix proteoglycans are involved in regulation of breast cancer functions since they are capable of binding numerous matrix molecules, growth factors and inflammatory mediators thus modulating their signaling. In addition to its anticoagulant activity, there is accumulating evidence highlighting various anticancer activities of heparin and nano-heparin derivatives in numerous types of cancer. Importantly, heparin derivatives significantly reduce breast cancer cell proliferation and metastasis in vitro and in vivo models as well as regulates the expression profile of major ECM macromolecules, providing strong evidence for therapeutic targeting. Nano-formulations of the glycosaminoglycan heparin are possibly novel tools for targeting tumor microenvironment. In this review, the role of heparan sulfate/heparin and its nano-formulations in breast cancer biology are presented and discussed in terms of future pharmacological targeting.

Glycosaminoglycans from chicken muscular stomach or gizzard

Glycosaminoglycans (GAGs) were prepared from the muscular stomach or gizzard of the chicken. The content of GAGs on a dry weight basis contains 0.4 wt.% a typical value observed for a muscle tissue. The major GAG components were chondroitin-6-sulfate and chondroitin-4-sulfate (~64 %) of molecular weight 21-22 kDa. Hyaluronan (~24 %) had a molecular weight 120 kDa. Smaller amounts (12 %) of heparan sulfate was also present which was made of more highly sulfated chains of molecular weight of 21-22 kDa and a less sulfated low molecular weight (< 10 kDa) heterogeneous partially degraded heparan sulfate. Chicken gizzard represents an inexpensive and readily available source of muscle tissue-derived GAGs.

Glycosaminoglycan-Based Biohybrid Hydrogels: A Sweet and Smart Choice for Multifunctional Biomaterials

Glycosaminoglycans (GAGs) govern important functional characteristics of the extracellular matrix (ECM) in living tissues. Incorporation of GAGs into biomaterials opens up new routes for the presentation of signaling molecules, providing control over development, homeostasis, inflammation, and tumor formation and progression. Recent approaches to GAG-based materials are reviewed, highlighting the formation of modular, tunable biohybrid hydrogels by covalent and non-covalent conjugation schemes, including both theory-driven design concepts and advanced processing technologies. Examples of the application of the resulting materials in biomedical studies are provided. For perspective, solid-phase and chemoenzymatic oligosaccharide synthesis methods for GAG-derived motifs, rational and high-throughput design strategies for GAG-based materials, and the utilization of the factor-scavenging characteristics of GAGs are highlighted.

Development of a Biomimetic Chondroitin Sulfate-modified Hydrogel to Enhance the Metastasis of Tumor Cells

Tumor metastasis with resistance to anticancer therapies is the main cause of death in cancer patients. It is necessary to develop reliable tumor metastasis models that can closely recapitulate the pathophysiological features of the native tumor tissue. In this study, chondroitin sulfate (CS)-modified alginate hydrogel beads (ALG-CS) are developed to mimic the in vivo tumor microenvironment with an abnormally increased expression of CS for the promotion of tumor cell metastasis. The modification mechanism of CS on alginate hydrogel is due to the cross-linking between CS and alginate molecules via coordination of calcium ions, which enables ALG-CS to possess significantly different physical characteristics than the traditional alginate beads (ALG). And quantum chemistry calculations show that in addition to the traditional egg-box structure, novel asymmetric egg-box-like structures based on the interaction between these two kinds of polymers are also formed within ALG-CS. Moreover, tumor cell metastasis is significantly enhanced in ALG-CS compared with that in ALG, as confirmed by the increased expression of MMP genes and proteins and greater in vitro invasion ability. Therefore, ALG-CS could be a convenient and effective 3D biomimetic scaffold that would be used to construct standardized tumor metastasis models for tumor research and anticancer drug screening.

Potential signaling pathway involved in sphingosine-1-phosphate-induced epithelial-mesenchymal transition in cancer

The developmental process of epithelial-mesenchymal transition (EMT) occurs when epithelial cells acquire invasive mesenchymal cell characteristics, and the activation of this process has been indicated to be involved in tumor progression. EMT could be induced by growth factors, cytokines and matrix metalloproteinases (MMPs). sphingosine-1-phosphate (S1P) is a biologically-active lipid that plays an important role in cancer metastasis. S1P also contributes to the activation of EMT. However, the mechanism underlying S1P-induced EMT is unclear. Increased evidence has demonstrated that the cell surface glycocalyx is closed associated with S1P and plays an important role in tumor progression, suggesting that S1P-induced EMT could be Snail-MMP signaling-dependent. Thus, we hypothesize that an S1P-glycocalyx-Snail-MMP signaling axis mediates S1P-induced EMT. This is an essential step towards improved understanding of the underlying mechanism involved in S1P-regulted EMT, and the development of novel diagnostic and anticancer therapeutic strategies.

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.

Glycosylated Notch and Cancer

Glycosylation is one of the key components influencing several signaling pathways implicated in cell survival and growth. The Notch signaling pathway plays a pivotal role in numerous cell fate specifications during metazoan development. Both Notch and its ligands are repeatedly glycosylated by the addition of sugar moieties, such as O-fucose, O-glucose, or O-xylose, to bring about structural and functional changes. Disruption to glycosylation processes of Notch proteins result in developmental disorders and disease, including cancer. This review summarizes the importance and recent updates on the role of glycosylated Notch proteins in tumorigenesis and tumor metastasis.