The immunological effect of hyaluronan in tumor angiogenesis

Intricate relationship between cancer stemness, metastasis, and drug resistance

Cancer stem cells (CSCs) are widely acknowledged as the drivers of tumor initiation, epithelial-mesenchymal transition (EMT) progression, and metastasis. Originating from both hematologic and solid malignancies, CSCs exhibit quiescence, pluripotency, and self-renewal akin to normal stem cells, thus orchestrating tumor heterogeneity and growth. Through a dynamic interplay with the tumor microenvironment (TME) and intricate signaling cascades, CSCs undergo transitions from differentiated cancer cells, culminating in therapy resistance and disease recurrence. This review undertakes an in-depth analysis of the multifaceted mechanisms underlying cancer stemness and CSC-mediated resistance to therapy. Intrinsic factors encompassing the TME, hypoxic conditions, and oxidative stress, alongside extrinsic processes such as drug efflux mechanisms, collectively contribute to therapeutic resistance. An exploration into key signaling pathways, including JAK/STAT, WNT, NOTCH, and HEDGEHOG, sheds light on their pivotal roles in sustaining CSCs phenotypes. Insights gleaned from preclinical and clinical studies hold promise in refining drug discovery efforts and optimizing therapeutic interventions, especially chimeric antigen receptor (CAR)-T cell therapy, cytokine-induced killer (CIK) cell therapy, natural killer (NK) cell-mediated CSC-targeting and others. Ultimately use of cell sorting and single cell sequencing approaches for elucidating the fundamental characteristics and resistance mechanisms inherent in CSCs will enhance our comprehension of CSC and intratumor heterogeneity, which ultimately would inform about tailored and personalized interventions.

Role of Hyaluronic acid and its chemical derivatives in immunity during homeostasis, cancer and tissue regeneration

Over the last few decades, scientists have recognized the critical role that various components of the extracellular matrix (ECM) play in maintaining homeostatic immunity. Besides, dysregulation in the synthesis or degradation levels of these components directly impacts the mechanisms of immune response during tissue injury caused by tumor processes or the regeneration of the tissue itself in the event of damage. ECM is a complex network of protein compounds, proteoglycans and glycosaminoglycans (GAGs). Hyaluronic acid (HA) is one of the major GAGs of this network, whose metabolism is strictly physiologically regulated and quickly altered in injury processes, affecting the behavior of different cells, from stem cells to differentiated immune cells. In this revision we discuss how the native or chemically modified HA interacts with its specific receptors and modulates intra and intercellular communication of immune cells, focusing on cancer and tissue regeneration conditions.

Calycosin inhibits the proliferation and metastasis of renal cell carcinoma through the MAZ/HAS2 signaling pathway

Calycosin (Caly), a flavonoid compound, demonstrates a variety of beneficial properties. However, the specific mechanisms behind Caly's anticancer effects remain largely unexplored. Network pharmacology was used to explore the potential targets of Caly in renal cancer. Additionally, RNA-seq sequencing was used to detect changes in genes in renal cancer cells after Caly treatment. Validation was carried out through quantitative reverse transcription-PCR and Western blot analysis. The luciferase reporter assay was applied to pinpoint the interaction site between MAZ and HAS2. Furthermore, the immunoprecipitation assay was utilized to examine the ubiquitination and degradation of MAZ. In vivo experiments using cell line-derived xenograft mouse models were performed to assess Calycosin's impact on cancer growth. Network pharmacology research suggests Caly plays a role in promoting apoptosis and inhibiting cell adhesion in renal cancer. In vitro, Caly has been observed to suppress proliferation, colony formation, and metastasis of renal cancer cells while also triggering apoptosis. Additionally, it appears to diminish hyaluronic acid synthesis by downregulating HAS2 expression. MAZ is identified as a transcriptional regulator of HAS2 expression. Calycosin further facilitates the degradation of MAZ via the ubiquitin-proteasome pathway. Notably, Caly demonstrates efficacy in reducing the growth of renal cell carcinoma xenograft tumors in vivo. Our findings indicate that Caly suppresses the proliferation, metastasis, and progression of renal cell carcinoma through its action on the MAZ/HAS2 signaling pathway. Thus, Caly represents a promising therapeutic candidate for the treatment of renal cell carcinoma.

Differential expression analysis identifies a prognostically significant extracellular matrix-enriched gene signature in hyaluronan-positive clear cell renal cell carcinoma

Hyaluronan (HA) accumulation in clear cell renal cell carcinoma (ccRCC) is associated with poor prognosis; however, its biology and role in tumorigenesis are unknown. RNA sequencing of 48 HA-positive and 48 HA-negative formalin-fixed paraffin-embedded (FFPE) samples was performed to identify differentially expressed genes (DEG). The DEGs were subjected to pathway and gene enrichment analyses. The Cancer Genome Atlas Kidney Renal Clear Cell Carcinoma (TCGA-KIRC) data and DEGs were used for the cluster analysis. In total, 129 DEGs were identified. HA-positive tumors exhibited enhanced expression of genes related to extracellular matrix (ECM) organization and ECM receptor interaction pathways. Gene set enrichment analysis showed that epithelial-mesenchymal transition-associated genes were highly enriched in the HA-positive phenotype. A protein-protein interaction network was constructed, and 17 hub genes were discovered. Heatmap analysis of TCGA-KIRC data identified two prognostic clusters corresponding to HA-positive and HA-negative phenotypes. These clusters were used to verify the expression levels and conduct survival analysis of the hub genes, 11 of which were linked to poor prognosis. These findings enhance our understanding of hyaluronan in ccRCC.

Extracellular matrix stiffness and tumor-associated macrophage polarization: new fields affecting immune exclusion

In the malignant progression of tumors, there is deposition and cross-linking of collagen, as well as an increase in hyaluronic acid content, which can lead to an increase in extracellular matrix stiffness. Recent research evidence have shown that the extracellular matrix plays an important role in angiogenesis, cell proliferation, migration, immunosuppression, apoptosis, metabolism, and resistance to chemotherapeutic by the alterations toward both secretion and degradation. The clinical importance of tumor-associated macrophage is increasingly recognized, and macrophage polarization plays a central role in a series of tumor immune processes through internal signal cascade, thus regulating tumor progression. Immunotherapy has gradually become a reliable potential treatment strategy for conventional chemotherapy resistance and advanced cancer patients, but the presence of immune exclusion has become a major obstacle to treatment effectiveness, and the reasons for their resistance to these approaches remain uncertain. Currently, there is a lack of exact mechanism on the regulation of extracellular matrix stiffness and tumor-associated macrophage polarization on immune exclusion. An in-depth understanding of the relationship between extracellular matrix stiffness, tumor-associated macrophage polarization, and immune exclusion will help reveal new therapeutic targets and guide the development of clinical treatment methods for advanced cancer patients. This review summarized the different pathways and potential molecular mechanisms of extracellular matrix stiffness and tumor-associated macrophage polarization involved in immune exclusion and provided available strategies to address immune exclusion.

Ligand binding of interleukin-8: a comparison of glycosaminoglycans and acidic peptides

Recognition and binding of regulatory proteins to glycosaminoglycans (GAGs) from the extracellular matrix is a process of high biological importance. The interaction between negatively charged sulfate or carboxyl groups of the GAGs and clusters of basic amino acids on the protein is crucial in this binding process and it is believed that electrostatics represent the key factor for this interaction. However, given the rather undirected nature of electrostatics, it is important to achieve a clear understanding of its role in protein-GAG interactions and how specificity and selectivity in these systems can be achieved, when the classical key-lock binding motif is not applicable. Here, we compare protein binding of a highly charged heparin (HP) hexasaccharide with four de novo designed decapeptides of varying negative net charge. The charge density of these peptides was comparable to typical GAGs of the extracellular matrix. We used the regulatory protein interleukin-8 (IL-8) because its interactions with GAGs are well described. All four peptide ligands bind to the same epitope of IL-8 but show much weaker binding affinity as revealed in 1H-15N HSQC NMR titration experiments. Complementary molecular docking and molecular dynamics simulations revealed further atomistic details of the interaction mode of GAG versus peptide ligands. Overall, similar contributions to the binding energy and hydrogen bond formation are determined for HP and the highly charged peptides, suggesting that the entropic loss of the peptides upon binding likely account for the remarkably different affinity of GAG versus peptide ligands to IL-8.

The molecular mechanism of Y473 phosphorylation of UGDH relieves the inhibition effect of UDP-glucose on HuR

Uridine diphosphate glucose (UDP-Glc) is able to accelerate the decay of snail family transcriptional repressor 1 (SNAI1) mRNA by inhibiting Hu antigen R (HuR, an RNA-binding protein), thereby preventing cancer invasiveness and drug resistance. Nevertheless, the phosphorylation of tyrosine 473 (Y473) of UDP-glucose dehydrogenase (UGDH is capable of converting UDP-Glc to uridine diphosphate glucuronic acid (UDP-GlcUA)) weakens the inhibition of UDP-Glc to HuR, thus initiating the epithelial-mesenchymal transformation of tumor cells and promoting tumor cell migration and metastasis. To address the mechanism, we performed molecular dynamics simulations combined with molecular mechanics generalized Born surface area (MM/GBSA) analysis on wild-type and Y473 phosphorylated UGDH and HuR, UDP-Glc, UDP-GlcUA complexes. We demonstrated that Y473 phosphorylation was able to enhance the binding between UGDH and the HuR/UDP-Glc complex. Compared with HuR, UGDH has a stronger binding ability with UDP-Glc; therefore, UDP-Glc was inclined to bind to UGDH and then was catalyzed to UDP-GlcUA by UGDH, which relieved the inhibition of UDP-Glc to HuR. In addition, the binding ability of HuR for UDP-GlcUA was lower than its affinity for UDP-Glc, significantly reducing the inhibition of HuR. Hence, HuR bound to SNAI1 mRNA more easily to increase the stability of mRNA. Our results revealed the micromolecular mechanism of Y473 phosphorylation of UGDH regulating the interaction between UGDH and HuR as well as relieving the inhibition of UDP-Glc on HuR, which contributed to understanding the role of UGDH and HuR in tumor metastasis and developing small molecule drugs targeting the interaction between UGDH and HuR.

The role of hyaluronan in renal cell carcinoma

Renal cell carcinoma (RCC) is associated with high mortality rates worldwide and survival among RCC patients has not improved significantly in the past few years. A better understanding of the pathogenesis of RCC can enable the development of more effective therapeutic strategies against RCC. Hyaluronan (HA) is a glycosaminoglycan located in the extracellular matrix (ECM) that has several roles in biology, medicine, and physiological processes, such as tissue homeostasis and angiogenesis. Dysregulated HA and its receptors play important roles in fundamental cellular and molecular biology processes such as cell signaling, immune modulation, tumor progression and angiogenesis. There is emerging evidence that alterations in the production of HA regulate RCC development, thereby acting as important biomarkers as well as specific therapeutic targets. Therefore, targeting HA or combining it with other therapies are promising therapeutic strategies. In this Review, we summarize the available data on the role of abnormal regulation of HA and speculate on its potential as a therapeutic target against RCC.

Effect of Sulfation on the Conformational Dynamics of Dermatan Sulfate Glycosaminoglycan: A Gaussian Accelerated Molecular Dynamics Study

Glycosaminoglycans (GAGs) are anionic biopolymers present on cell surfaces as a part of proteoglycans. The biological activities of GAGs depend on the sulfation pattern. In our study, we have considered three octadecasaccharide dermatan sulfate (DS) chains with increasing order of sulfation (dp6s, dp7s, and dp12s) to illuminate the role of sulfation on the GAG units and its chain conformation through 10 μs-long Gaussian accelerated molecular dynamics simulations. DS is composed of repeating disaccharide units of iduronic acid (IdoA) and N-acetylgalactosamine (N-GalNAc). Here, N-GalNAc is linked to IdoA via β(1-4), while IdoA is linked to N-GalNAc through α(1-3). With the increase in sulfation, the DS structure becomes more rigid and linear, as is evident from the distribution of root-mean-square deviations (RMSDs) and end-to-end distances. The tetrasaccharide linker region of the main chain shows a rigid conformation in terms of the glycosidic linkage. We have observed that upon sulfation (i.e., dp12s), the ring flip between two chair forms vanished for IdoA. The dynamic cross-correlation analysis reveals that the anticorrelation motions in dp12s are reduced significantly compared to dp6s or dp7s. An increase in sulfation generates relatively more stable hydrogen-bond networks, including water bridging with the neighboring monosaccharides. Despite the favorable linear structures of the GAG chains, our study also predicts few significant bendings related to the different puckering states, which may play a notable role in the function of the DS. The relation between the global conformation with the micro-level parameters such as puckering and water-mediated hydrogen bonds shapes the overall conformational space of GAGs. Overall, atomistic details of the DS chain provided in this study will help understand their functional and mechanical roles, besides developing new biomaterials.

The effects of sulfated hyaluronan in breast, lung and colorectal carcinoma and monocytes/macrophages cells: Its role in angiogenesis and tumor progression

Hyaluronan (HA) is a component of the extracellular matrix (ECM) it is the main non-sulfated glycosaminoglycan able to modulate cell behavior in the healthy and tumor context. Sulfated hyaluronan (sHA) is a biomaterial derived from chemical modifications of HA, since this molecule is not naturally sulfated. The HA sulfation modifies several properties of the native molecule, acquiring antitumor properties in different cancers. In this study, we evaluated the action of sHA of ~30-60 kDa with different degrees of sulfation (0.7 sHA1 and 2.5 sHA3) on tumor cells of a breast, lung, and colorectal cancer model and its action on other cells of the tumor microenvironment, such as endothelial and monocytes/macrophage cells. Our data showed that in breast and lung tumor cells, sHA3 is able to modulate cell viability, cytotoxicity, and proliferation, but no effects were observed on colorectal cancer cells. In 3D cultures of breast and lung cancer cells, sHA3 diminished the size of the tumorsphere and modulated total HA levels. In these tumor models, treatment of monocytes/macrophages with sHA3 showed a downregulation of the expression of angiogenic factors. We also observed a decrease in endothelial cell migration and modulation of the hyaluronan-binding protein TSG-6. In the breast in vivo xenograft model, monocytes/macrophages preincubated with sHA1 or sHA3 decreased tumor vasculature, TSG-6 and HA levels. Besides, in silico analysis showed an association of TSG-6, HAS2, and IL-8 with biological processes implicated in the progression of the tumor. Taken together, our data indicate that sHA in a breast and lung tumor context is able to induce an antiangiogenic action on tumor cells as well as in monocytes/macrophages (Mo/MØ) by modulation of endothelial migration, angiogenic factors, and vessel formation.

Comorbidity-associated glutamine deficiency is a predisposition to severe COVID-19

SARS-CoV-2 vaccinations have greatly reduced COVID-19 cases, but we must continue to develop our understanding of the nature of the disease and its effects on human immunity. Previously, we suggested that a dysregulated STAT3 pathway following SARS-Co-2 infection ultimately leads to PAI-1 activation and cascades of pathologies. The major COVID-19-associated metabolic risks (old age, hypertension, cardiovascular diseases, diabetes, and obesity) share high PAI-1 levels and could predispose certain groups to severe COVID-19 complications. In this review article, we describe the common metabolic profile that is shared between all of these high-risk groups and COVID-19. This profile not only involves high levels of PAI-1 and STAT3 as previously described, but also includes low levels of glutamine and NAD+, coupled with overproduction of hyaluronan (HA). SARS-CoV-2 infection exacerbates this metabolic imbalance and predisposes these patients to the severe pathophysiologies of COVID-19, including the involvement of NETs (neutrophil extracellular traps) and HA overproduction in the lung. While hyperinflammation due to proinflammatory cytokine overproduction has been frequently documented, it is recently recognized that the immune response is markedly suppressed in some cases by the expansion and activity of MDSCs (myeloid-derived suppressor cells) and FoxP3+ Tregs (regulatory T cells). The metabolomics profiles of severe COVID-19 patients and patients with advanced cancer are similar, and in high-risk patients, SARS-CoV-2 infection leads to aberrant STAT3 activation, which promotes a cancer-like metabolism. We propose that glutamine deficiency and overproduced HA is the central metabolic characteristic of COVID-19 and its high-risk groups. We suggest the usage of glutamine supplementation and the repurposing of cancer drugs to prevent the development of severe COVID-19 pneumonia.

Interfering with hyaluronic acid metabolism suppresses glioma cell proliferation by regulating autophagy

The tumor microenvironment plays an important role in tumor progression. Hyaluronic acid (HA), an important component of the extracellular matrix in the tumor microenvironment, abnormally accumulates in a variety of tumors. However, the role of abnormal HA accumulation in glioma remains unclear. The present study indicated that HA, hyaluronic acid synthase 3 (HAS3), and a receptor of HA named CD44 were expressed at high levels in human glioma tissues and negatively correlated with the prognosis of patients with glioma. Silencing HAS3 expression or blocking CD44 inhibited glioma cell proliferation in vitro and in vivo. The underlying mechanism was attributed to the inhibition of autophagy flux and maintaining glioma cell cycle arrest in G1 phase. More importantly, 4-methylumbelliferone (4-MU), a small competitive inhibitor of Uridine diphosphate (UDP) with the ability to penetrate the blood-brain barrier (BBB), also inhibited glioma cell proliferation in vitro and in vivo. Thus, approaches that interfere with HA metabolism by altering the expression of HAS3 and CD44 and the administration of 4-MU potentially represent effective strategies for glioma treatment.

Evaluation of replica exchange with repulsive scaling approach for docking glycosaminoglycans

Glycosaminoglycans (GAGs), long linear periodic anionic polysaccharides, are key molecules in the extracellular matrix (ECM). Therefore, deciphering their role in the biologically relevant context is important for fundamental understanding of the processes ongoing in ECM and for establishing new strategies in the regenerative medicine. Although GAGs represent a number of computational challenges, molecular docking is a powerful tool for analysis of their interactions. Despite the recent development of GAG-specific docking approaches, there is plenty of room for improvement. Here, replica exchange molecular dynamics with repulsive scaling (REMD-RS) recently proved to be a successful approach for protein-protein complexes, was applied to dock GAGs. In this method, effective pairwise radii are increased in different Hamiltonian replicas. REMD-RS is shown to be an attractive alternative to classical docking approaches for GAGs. This work contributes to setting up of GAG-specific computational protocols and provides new insights into the nature of these biological systems.

Wound Matrix Stiffness Imposes on Macrophage Activation

The immune system depends on two major paths-the innate and the adaptive immunity. Macrophage, with its unique features as the first line of immune defense to engulf and digest invaders, serves as the key effector cells integrating those two paths. The dynamic plasticity of macrophage activation during wound repair, inflammation resolution, and tissue remodeling are emerging biomedical and bioengineering hot topics in immune function studies such as the various secretions of cytokines and chemokines and the signaling pathways with ligands and their cognate receptors. Better knowledge on how physical/mechanical and multicellular microenvironment on the modulation of macrophage functions will create innovative therapies to boost host defense mechanism and assist wound healing. In this, we describe an easy method to measure functions (gene expressions) of human and mouse macrophages in response to mechanical microenvironment changes by embedding isolated macrophages in polymerized hyaluronan gel with different wound matrix stiffness.

Initial Identification of UDP-Glucose Dehydrogenase as a Prognostic Marker in Breast Cancer Patients, Which Facilitates Epirubicin Resistance and Regulates Hyaluronan Synthesis in MDA-MB-231 Cells

UDP-glucose-dehydrogenase (UGDH) synthesizes UDP-glucuronic acid. It is involved in epirubicin detoxification and hyaluronan synthesis. This work aimed to evaluate the effect of UGDH knockdown on epirubicin response and hyaluronan metabolism in MDA-MB-231 breast cancer cells. Additionally, the aim was to determine UGDH as a possible prognosis marker in breast cancer. We studied UGDH expression in tumors and adjacent tissue from breast cancer patients. The prognostic value of UGDH was studied using a public Kaplan–Meier plotter. MDA-MB-231 cells were knocked-down for UGDH and treated with epirubicin. Epirubicin-accumulation and apoptosis were analyzed by flow cytometry. Hyaluronan-coated matrix and metabolism were determined. Autophagic-LC3-II was studied by Western blot and confocal microscopy. Epirubicin accumulation increased and apoptosis decreased during UGDH knockdown. Hyaluronan-coated matrix increased and a positive modulation of autophagy was detected. Higher levels of UGDH were correlated with worse prognosis in triple-negative breast cancer patients that received chemotherapy. High expression of UGDH was found in tumoral tissue from HER2^--patients. However, UGDH knockdown contributes to epirubicin resistance, which might be associated with increases in the expression, deposition and catabolism of hyaluronan. The results obtained allowed us to propose UGDH as a new prognostic marker in breast cancer, positively associated with development of epirubicin resistance and modulation of extracellular matrix.

A modular, injectable, non-covalently assembled hydrogel system features widescale tunable degradability for controlled release and tissue integration

Biomaterials with attenuated adverse host tissue reactions, and meanwhile, combining biocompatibility with mimicry of mechanical and biochemical cues of native extracellular matrices (ECM) to promote integration and regeneration of tissues are important for many biomedical applications. Further, the materials should also be tailorable to feature desired application-related functions, like tunable degradability, injectability, or controlled release of bioactive molecules. Herein, a non-covalently assembled, injectable hydrogel system based on oligopeptides interacting with sulphated polysaccharides is reported, showing high tolerability and biocompatibility in immunocompetent hairless mice. Altering the peptide or polysaccharide component considerably varies the in vivo degradation rate of the hydrogels, ranging from a half-life of three weeks to no detectable degradation after three months. The hydrogel with sulphated low molecular weight hyaluronic acid exhibits sustained degradation-mediated release of heparin-binding molecules in vivo, as shown by small animal magnetic resonance imaging and fluorescence imaging, and enhances the expression of vascular endothelial growth factor in hydrogel surrounding. In vitro investigations indicate that M2-macrophages could be responsible for the moderate difference in pro-angiogenic effects. The ECM-mimetic and injectable hydrogels represent tunable bioactive scaffolds for tissue engineering, also enabling controlled release of heparin-binding signalling molecules including many growth factors.

High molecular weight form of hyaluronic acid reduces neuroinflammatory response in injured sciatic nerve via the intracellular domain of CD44

Inflammatory response after peripheral nerve injury is required for clearance of tissue debris and effective regeneration. Studies have revealed that hyaluronic acid (HA) may exert different properties depending on their molecular size. High molecular weight HA (>>1,000 kDa; HMW-HA) displays immunosuppressive properties, whereas low molecular weight HA (<800 kDa; LMW-HA) induces proinflammatory responses. The role of HMW-HA interaction with CD44, a major HA receptor, in neuroinflammatory responses has not been fully elucidated. The purpose of this experimental study was to investigate the effects of topical applications of HMW-HA on the sciatic nerve injury in an adult rat model. At the crush site on the sciatic nerve, the recordings of compound muscle action potential (CMAP) and the levels of several proteins related to inflammatory response were assessed at time intervals of 2, 4, and 6 weeks postsurgery. Here, we show that the recovery effect of HMW-HA treatment had significantly shortened latency and increased amplitude of CMAP compared with crushed alone, crushed plus γ-secretase inhibitor with or without HA treatment at 6 weeks after surgery. Our data reveal that HMW-HA could downregulate the expression of IL1-β, TLR4, and MMP-9, whereas these proteins expression were increased when the CD44-ICD activity was inhibited using γ-secretase inhibitor. Our findings demonstrated a novel role of CD44-ICD in HA-mediated recovery of peripheral nerve injury. Clinical relevance: an alternative for the regeneration of peripheral nerve injury.

Glycosaminoglycan-Protein Interactions: The First Draft of the Glycosaminoglycan Interactome

The six mammalian glycosaminoglycans (GAGs), chondroitin sulfate, dermatan sulfate, heparin, heparan sulfate, hyaluronan, and keratan sulfate, are linear polysaccharides. Except for hyaluronan, they are sulfated to various extent, and covalently attached to proteins to form proteoglycans. GAGs interact with growth factors, morphogens, chemokines, extracellular matrix proteins and their bioactive fragments, receptors, lipoproteins, and pathogens. These interactions mediate their functions, from embryonic development to extracellular matrix assembly and regulation of cell signaling in various physiological and pathological contexts such as angiogenesis, cancer, neurodegenerative diseases, and infections. We give an overview of GAG-protein interactions (i.e., specificity and chemical features of GAG- and protein-binding sequences), and review the available GAG-protein interaction networks. We also provide the first comprehensive draft of the GAG interactome composed of 832 biomolecules (827 proteins and five GAGs) and 932 protein-GAG interactions. This network is a scaffold, which in the future should integrate structures of GAG-protein complexes, quantitative data of the abundance of GAGs in tissues to build tissue-specific interactomes, and GAG interactions with metal ions such as calcium, which plays a major role in the assembly of the extracellular matrix and its interactions with cells. This contextualized interactome will be useful to identify druggable GAG-protein interactions for therapeutic purpose.

Hyaluronan in the Tumor Microenvironment

The extracellular matrix is part of the microenvironment and its functions are associated with the physical and chemical properties of the tissue. Among the extracellular components, the glycosaminoglycan hyaluronan is a key component, defining both the physical and biochemical characteristics of the healthy matrices. The hyaluronan metabolism is strictly regulated in physiological conditions, but in the tumoral tissues, its expression, size and binding proteins interaction are dysregulated. Hyaluronan from the tumor microenvironment promotes tumor cell proliferation, invasion, immune evasion, stemness alterations as well as drug resistance. This chapter describes data regarding novel concepts of hyaluronan functions in the tumor. Additionally, we discuss potential clinical applications of targeting HA metabolism in cancer therapy.

Spatial Distribution of Macrophages During Callus Formation and Maturation Reveals Close Crosstalk Between Macrophages and Newly Forming Vessels

Macrophages are essential players in the process of fracture healing, acting by remodeling of the extracellular matrix and enabling vascularization. Whilst activated macrophages of M1-like phenotype are present in the initial pro-inflammatory phase of hours to days of fracture healing, an anti-inflammatory M2-like macrophage phenotype is supposed to be crucial for the induction of downstream cascades of healing, especially the initiation of vascularization. In a mouse-osteotomy model, we provide a comprehensive characterization of vessel (CD31⁺, Emcn⁺) and macrophage phenotypes (F4/80, CD206, CD80, Mac-2) during the process of fracture healing. To this end, we phenotype the phases of vascular regeneration-the expansion phase (d1-d7 after injury) and the remodeling phase of the endothelial network, until tissue integrity is restored (d14-d21 after injury). Vessels which appear during the bone formation process resemble type H endothelium (CD31^hiEmcn^hi), and are closely connected to osteoprogenitors (Runx2⁺, Osx⁺) and F4/80⁺ macrophages. M1-like macrophages are present in the initial phase of vascularization until day 3 post osteotomy, but they are rare during later regeneration phases. M2-like macrophages localize mainly extramedullary, and CD206⁺ macrophages are found to express Mac-2⁺ during the expansion phase. VEGFA expression is initiated by CD80⁺ cells, including F4/80⁺ macrophages, until day 3, while subsequently osteoblasts and chondrocytes are main contributors to VEGFA production at the fracture site. Using Longitudinal Intravital Microendoscopy of the Bone (LIMB) we observe changes in the motility and organization of CX3CR1⁺ cells, which infiltrate the injury site after an osteotomy. A transient accumulation, resulting in spatial polarization of both, endothelial cells and macrophages, in regions distal to the fracture site, is evident. Immunofluorescence histology followed by histocytometric analysis reveals that F4/80⁺CX3CR1⁺ myeloid cells precede vascularization.

Clinical value of serum hyaluronan and propeptide of type III collagen in patients with pancreatic cancer

Hyaluronan (HA) and collagen are highly expressed in pancreatic cancer (PC) stroma. HA and collagen accumulation increase tumor interstitial fluid pressure, compromising blood flow and drug penetration. The aim of this biomarker study was to determine the clinical utility of serum HA and the propeptide of type III collagen (PRO-C3) in patients with PC. A cohort from the Danish BIOPAC study (NCT03311776) including patients with histologically confirmed pancreatic ductal adenocarcinoma (n = 809), ampullary carcinoma (n = 44), distal biliary tract cancer (n = 31), chronic pancreatitis (n = 15), intraductal papillary mucinous neoplasm (n = 41), duodenal adenoma (n = 7) and no cancer (n = 25). Healthy controls were available for serum HA (n = 141) and PRO-C3 (n = 8). The main outcome was overall survival (OS) of patients with PC in relation to pretreatment serum HA and PRO-C3 levels. Patients with PC had higher baseline serum HA and PRO-C3 than healthy subjects and patients with benign conditions. Pretreatment serum baseline HA and PRO-C3 in patients with PC were associated with poorer survival and PRO-C3 remained prognostic also after adjusting for age, performance status, stage, the presence of liver and peritoneum metastasis, and CA19-9. Detection of HA and PRO-C3 may be useful in differentiating between malignant and benign pancreatic conditions. Serum HA and PRO-C3 were prognostic for OS in patients with PC.

Proteoglycans and glycosaminoglycans as regulators of cancer stem cell function and therapeutic resistance

In contrast to the bulk of the tumor, a subset of cancer cells called cancer stem cells (CSC; or tumor-initiating cells) is characterized by self-renewal, unlimited proliferative potential, expression of multidrug resistance proteins, active DNA repair capacity, apoptosis resistance, and a considerable developmental plasticity. Due to these properties, CSCs display increased resistance to chemo- and radiotherapy. Recent findings indicate that aberrant functions of proteoglycans (PGs) and glycosaminoglycans (GAGs) contribute substantially to the CSC phenotype and therapeutic resistance. In this review, we summarize how the diverse functions of the glycoproteins and carbohydrates facilitate acquisition and maintenance of the CSC phenotype, and how this knowledge can be exploited to develop novel anticancer therapies. For example, the large transmembrane chondroitin sulfate PG NG2/CSPG4 marks stem cell (SC) populations in brain tumors. Cell surface heparan sulfate PGs of the syndecan and glypican families modulate the stemness-associated Wnt, hedgehog, and notch signaling pathways, whereas the interplay of hyaluronan in the SC niche with CSC CD44 determines the maintenance of stemness and promotes therapeutic resistance. A better understanding of the molecular mechanisms by which PGs and GAGs regulate CSC function will aid the development of targeted therapeutic approaches which could avoid relapse after an otherwise successful conventional therapy. Chimeric antigen receptor T cells, PG-primed dendritic cells, PG-targeted antibody-drug conjugates, and inhibitory peptides and glycans have already shown highly promising results in preclinical models.

Glycosylation in the Tumor Microenvironment: Implications for Tumor Angiogenesis and Metastasis

Just as oncogene activation and tumor suppressor loss are hallmarks of tumor development, emerging evidence indicates that tumor microenvironment-mediated changes in glycosylation play a crucial functional role in tumor progression and metastasis. Hypoxia and inflammatory events regulate protein glycosylation in tumor cells and associated stromal cells in the tumor microenvironment, which facilitates tumor progression and also modulates a patient's response to anti-cancer therapeutics. In this review, we highlight the impact of altered glycosylation on angiogenic signaling and endothelial cell adhesion, and the critical consequences of these changes in tumor behavior.

Hyaluronan preconditioning of monocytes/macrophages affects their angiogenic behavior and regulation of TSG-6 expression in a tumor type-specific manner

Hyaluronan is a glycosaminoglycan normally present in the extracellular matrix in most tissues. Hyaluronan is a crucial player in many processes associated with cancer, such as angiogenesis, invasion, and metastasis. However, little has been reported regarding the action of hyaluronan on monocytes/macrophages (Mo/MØ) in tumor angiogenesis and its consequences on tumor development. In the present study, we investigated the effects of hyaluronan of different sizes on human Mo/MØ angiogenic behavior in colorectal and breast carcinoma. In vitro, the treatment of Mo/MØ with lysates and conditioned media from a breast but not from colorectal carcinoma cell line plus high-molecular weight hyaluronan induced: (a) an increased expression of angiogenic factors VEGF, IL-8, FGF-2, and MMP-2, (b) an increased endothelial cell migration, and (c) a differential expression of hyaluronan-binding protein TSG-6. Similar results were observed in Mo/MØ derived from breast cancer patients treated with tumor lysates. Besides, macrophages primed with high-molecular weight hyaluronan and inoculated in human breast cancer xenograft tumor increased blood vessel formation and diminished TSG-6 levels. In contrast, the effects triggered by high-molecular weight hyaluronan on Mo/MØ in breast cancer context were not observed in the context of colorectal carcinoma. Taken together, these results indicate that the effect of high-molecular weight hyaluronan as an inductor of the angiogenic behavior of macrophages in breast tumor context is in part consequence of the presence of TSG-6.

INT-HA induces M2-like macrophage differentiation of human monocytes via TLR4-miR-935 pathway

As a major component of the microenvironment of solid tumors, tumor-associated macrophages (TAMs) facilitate tumor progression. Intermediate-sized hyaluronan (INT-HA) fragments have an immunological function in cell differentiation; however, their role in promoting the polarization of non-activated macrophages to an M2-like TAM phenotype has not been characterized, and the underlying mechanisms remain unclear. Here, we used a miRNA microarray to find that some miRNAs (especially miR-935) were differentially regulated in INT-HA-induced M2-like macrophages. According to RT-qPCR and Western blot, there was an association between miR-935 and C/EBPβ, that control the polarization of macrophages. Moreover, we found that INT-HA induced an M2-like phenotype via the TLR4 receptor. In our study, there was a negative correlation between plasma HA and miR-935 in monocytes from the peripheral blood of patients with solid tumors. There was also a negative correlation between miR-935 and M2-like macrophage markers in monocytes. These findings suggest that HA fragments interact with TLR4 and educate macrophage polarization to an M2-like phenotype via miR-935. Therefore, this study provides new insight into the role of miR-935 in INT-HA-induced M2-like polarization, and suggests a potential therapeutic target for antitumor treatment.

The Complex Interplay Between Extracellular Matrix and Cells in Tissues

Extracellular matrix (ECM) maintains the structural integrity of tissues and regulates cell and tissue functions. ECM is comprised of fibrillar proteins, proteoglycans (PGs), glycosaminoglycans, and glycoproteins, creating a heterogeneous but well-orchestrated network. This network communicates with resident cells via cell-surface receptors. In particular, integrins, CD44, discoidin domain receptors, and cell-surface PGs and additionally voltage-gated ion channels can interact with ECM components, regulating signaling cascades as well as cytoskeleton configuration. The interplay of ECM with recipient cells is enriched by the extracellular vesicles, as they accommodate ECM, signaling, and cytoskeleton molecules in their cargo. Along with the numerous biological properties that ECM can modify, autophagy and angiogenesis, which are critical for tissue homeostasis, are included. Throughout development and disease onset and progression, ECM endures rearrangement to fulfill cellular requirements. The main responsible molecules for tissue remodeling are ECM-degrading enzymes including matrix metalloproteinases, plasminogen activators, cathepsins, and hyaluronidases, which can modify the ECM structure and function in a dynamic mode. A brief summary of the complex interplay between ECM macromolecules and cells in tissues and the contribution of ECM in tissue homeostasis and diseases is given.

UDP-glucose Dehydrogenase: The First-step Oxidation Is an NAD+-dependent Bimolecular Nucleophilic Substitution Reaction (SN2)

UDP-glucose dehydrogenase (UGDH) catalyzes the conversion of UDP-glucose to UDP-glucuronic acid by NAD⁺-dependent two-fold oxidation. Despite extensive investigation into the catalytic mechanism of UGDH, the previously proposed mechanisms regarding the first-step oxidation are somewhat controversial and inconsistent with some biochemical evidence, which instead supports a mechanism involving an NAD⁺-dependent bimolecular nucleophilic substitution (S_N2) reaction. To verify this speculation, the essential Cys residue of Streptococcus zooepidemicus UGDH (SzUGDH) was changed to an Ala residue, and the resulting Cys260Ala mutant and SzUGDH were then co-expressed in vivo via a single-crossover homologous recombination method. Contrary to the previously proposed mechanisms, which predict the formation of the capsular polysaccharide hyaluronan, the resulting strain instead produced an amide derivative of hyaluronan, as validated via proteinase K digestion, ninhydrin reaction, FT-IR and NMR. This result is compatible with the NAD⁺-dependent S_N2 mechanism.

Co-treatment of tumor cells with hyaluronan plus doxorubicin affects endothelial cell behavior independently of VEGF expression

Hyaluronan, the main glycosaminoglycan of extracellular matrices, is concentrated in tissues with high cell proliferation and migration rates. In cancer, hyaluronan expression is altered and it becomes fragmented into low-molecular-weight forms, affecting mechanisms associated with cell proliferation, invasion, angiogenesis and multidrug resistance. Here, we analyzed the effect of low-molecular-weight hyaluronan on the response of T lymphoma, osteosarcoma, and mammary adenocarcinoma cell lines to the antineoplastic drug doxorubicin, and whether co-treatment with hyaluronan and doxorubicin modified the behavior of endothelial cells. Our aim was to associate the hyaluronan-doxorubicin response with angiogenic alterations in these tumors. After hyaluronan and doxorubicin co-treatment, hyaluronan altered drug accumulation and modulated the expression of ATP-binding cassette transporters in T-cell lymphoma cells. In contrast, no changes in drug accumulation were observed in cells from solid tumors, indicating that hyaluronan might not affect drug efflux. However, when we evaluated the effect on angiogenic mechanisms, the supernatant from tumor cells treated with doxorubicin exhibited a pro-angiogenic effect on endothelial cells. Hyaluronan-doxorubicin co-treatment increased migration and vessel formation in endothelial cells. This effect was independent of vascular endothelial growth factor but related to fibroblast growth factor-2 expression. Besides, we observed a pro-angiogenic effect on endothelial cells during hyaluronan and doxorubicin co-treatment in the in vivo murine model of T-cell lymphoma. Our results demonstrate for the first time that hyaluronan is a potential modulator of doxorubicin response by mechanisms that involve not only drug efflux but also angiogenic processes, providing an adverse tumor stroma during chemotherapy.

Cancer Cell Glycocalyx and Its Significance in Cancer Progression

Cancer is a malignant tumor that threatens the health of human beings, and has become the leading cause of death in urban and rural residents in China. The glycocalyx is a layer of multifunctional glycans that covers the surfaces of a variety of cells, including vascular endothelial cells, smooth muscle cells, stem cells, epithelial, osteocytes, as well as cancer cells. The glycosylation and syndecan of cancer cell glycocalyx are unique. However, heparan sulfate (HS), hyaluronic acid (HA), and syndecan are all closely associated with the processes of cancer progression, including cell migration and metastasis, tumor cell adhesion, tumorigenesis, and tumor growth. The possible underlying mechanisms may be the interruption of its barrier function, its radical role in growth factor storage, signaling, and mechanotransduction. In the later sections, we discuss glycocalyx targeting therapeutic approaches reported in animal and clinical experiments. The study concludes that cancer cells’ glycocalyx and its role in cancer progression are beginning to be known by more groups, and future studies should pay more attention to its mechanotransduction of interstitial flow-induced shear stress, seeking promising therapeutic targets with less toxicity but more specificity.

Neutrophils: Beneficial and Harmful Cells in Septic Arthritis

Septic arthritis is an inflammatory joint disease that is induced by pathogens such as Staphylococcus aureus. Infection of the joint triggers an acute inflammatory response directed by inflammatory mediators including microbial danger signals and cytokines and is accompanied by an influx of leukocytes. The recruitment of these inflammatory cells depends on gradients of chemoattractants including formylated peptides from the infectious agent or dying cells, host-derived leukotrienes, complement proteins and chemokines. Neutrophils are of major importance and play a dual role in the pathogenesis of septic arthritis. On the one hand, these leukocytes are indispensable in the first-line defense to kill invading pathogens in the early stage of disease. However, on the other hand, neutrophils act as mediators of tissue destruction. Since the elimination of inflammatory neutrophils from the site of inflammation is a prerequisite for resolution of the acute inflammatory response, the prolonged stay of these leukocytes at the inflammatory site can lead to irreversible damage to the infected joint, which is known as an important complication in septic arthritis patients. Thus, timely reduction of the recruitment of inflammatory neutrophils to infected joints may be an efficient therapy to reduce tissue damage in septic arthritis.

Biomimetic tumor microenvironments based on collagen matrices

This review provides an overview of the current approaches to engineer defined 3D matrices for the investigation of tumor cell behaviorin vitro, with a focus on collagen-based fibrillar systems.

Signaling at the Crossroads: Matrix-Derived Proteoglycan and Reactive Oxygen Species Signaling

SIGNIFICANCE

Proteoglycans (PGs), besides their structural contribution, have emerged as dynamic components that mediate a multitude of cellular events. The various roles of PGs are attributed to their structure, spatial localization, and ability to act as ligands and receptors. Reactive oxygen species (ROS) are small mediators that are generated in physiological and pathological conditions. Besides their reactivity and ability to induce oxidative stress, a growing body of data suggests that ROS signaling is more relevant than direct radical damage in development of human pathologies. Recent Advances: Cell surface transmembrane PGs (syndecans, cluster of differentiation 44) represent receptors in diverse and complex transduction networks, which involve redox signaling with implications in cancer, fibrosis, renal dysfunction, or Alzheimer's disease. Through NADPH oxidase (NOX)-dependent ROS, the extracellular PG, hyaluronan is involved in osteoclastogenesis and cancer. The ROS sources, NOX1 and NOX4, increase biglycan-induced inflammation, while NOX2 is a negative regulator.

CRITICAL ISSUES

The complexity of the mechanisms that bring ROS into the light of PG biology might be the foundation of a new research area with significant promise for understanding health and disease. Important aspects need to be investigated in PG/ROS signaling: the discovery of specific targets of ROS, the precise ROS-induced chemical modifications of these targets, and the study of their pathological relevance.

FUTURE DIRECTIONS

As we become more and more aware of the interactions between PG and ROS signaling underlying intracellular communication and cell fate decisions, it is quite conceivable that this field will allow to identify new therapeutic targets.-Antioxid. Redox Signal. 27, 855-873.

A Trickster in Disguise: Hyaluronan's Ambivalent Roles in the Matrix

Hyaluronan (HA) is a simple but diverse glycosaminoglycan. It plays a major role in aging, cellular senescence, cancer, and tissue homeostasis. In which way HA affects the surrounding tissues greatly depends on the molecular weight of HA. Whereas high molecular weight HA is associated with homeostasis and protective effects, HA fragments tend to be linked to the pathologic state. Furthermore, the interaction of HA with its binding partners, the hyaladherins, such as CD44, is essential for sustaining tissue integrity and is likewise related to cancer. The naked mole rat, a rodent species, possesses a special form of very high molecular weight (vHMW) HA, which is associated with the extraordinary cancer resistance and longevity of those animals. This review addresses HA and its diverse facets: from HA synthesis to degradation, from oligomeric HA to vHMW-HA and from its beneficial properties to the involvement in pathologies. We further discuss the functions of HA in the naked mole rat and compare them to human conditions. Though intensively researched, this simple polymer bears some secrets that may hold the key for a better understanding of cellular processes and the development of diseases, such as cancer.

Sequential one-pot multienzyme synthesis of hyaluronan and its derivative

Hyaluronan (HA) is a linear polysaccharide composed of repeating disaccharide units. It has been well documented to play an array of biological functions in cancer events. Here, we reported a sequential one-pot multienzyme (OPME) strategy for in vitro synthesis of HA and its derivatives. The strategy, which combined in situ sugar nucleotides generation with HA chain polymerization, could convert cheap monosaccharides into HA polymers without consuming exogenous sugar nucleotide donors. HA polymers (number-average molecular weight ranged from 1.5×10⁴ to 5.5×10⁵Da) with over 70% yields were efficiently synthesized and purified from this one-pot system. More importantly, partial labeled HA derivative was further synthesized by metabolic incorporation of unnatural monosaccharide analogues into the sequential OPME system. Cross-linked HA hydrogel was achieved via copper (I)-catalyzed azide-alkyne cycloaddition and exhibited novel networks consisting of both inter- and intra-connected HA chains, which could facilitate the potential applications of this unique polysaccharide.

Molecular weight specific impact of soluble and immobilized hyaluronan on CD44 expressing melanoma cells in 3D collagen matrices

Hyaluronan (HA) and its principal receptor CD44 are known to be involved in regulating tumor cell dissemination and metastasis. The direct correlation of CD44-HA interaction on proliferation and invasion of tumor cells in dependence on the molecular weight and the presentation form of HA is not fully understood because of lack of appropriate matrix models. To address this issue, we reconstituted 3D collagen (Coll I) matrices and functionalized them with HA of molecular weight of 30-50kDa (low molecular weight; LMW-HA) and 500-750kDa (high molecular weight; HMW-HA). A post-modification strategy was applied to covalently immobilize HA to reconstituted fibrillar Coll I matrices, resulting in a non-altered Coll I network microstructure and stable immobilization over days. Functionalized Coll I matrices were characterized regarding topological and mechanical characteristics as well as HA amount using confocal laser scanning microscopy, colloidal probe force spectroscopy and quantitative Alcian blue assay, respectively. To elucidate HA dependent tumor cell behavior, BRO melanoma cell lines with and without CD44 receptor expression were used for in vitro cell experiments. We demonstrated that only soluble LMW-HA promoted cell proliferation in a CD44 dependent manner, while HMW-HA and immobilized LMW-HA did not. Furthermore, an enhanced cell invasion was found only for immobilized LMW-HA. Both findings correlated with a very strong and specific adhesive interaction of LMW-HA and CD44+ cells quantified in single cell adhesion measurements using soft colloidal force spectroscopy. Overall, our results introduce an in vitro biomaterials model allowing to test presentation mode and molecular weight specificity of HA in a 3D fibrillar matrix thus mimicking important in vivo features of tumor microenvironments.

STATEMENT OF SIGNIFICANCE

Molecular weight and presentation form (bound vs. soluble) of hyaluronan (HA) are intensively discussed as key regulators in tumor progression and inflammation. We introduce 3D fibrillar collagen matrices with defined microstructure and stiffness allowing the presentation of specific molecular weight forms of HA in soluble and bound manner. Mimicking in that way important in vivo features of tumor microenvironments, we found that only low molecular weight HA (LMW-HA) in soluble form promoted proliferation of a melanoma cell line (BRO), while it enhanced cell invasion in bound form. The molecular weight specificity of LMW-HA was verified to be CD44 receptor dependent and was correlated to adhesive ligand-receptor interactions in quantitative colloidal force spectroscopy at single cell level.

Provisional matrix: A role for versican and hyaluronan

Hyaluronan and versican are extracellular matrix (ECM) components that are enriched in the provisional matrices that form during the early stages of development and disease. These two molecules interact to create pericellular "coats" and "open space" that facilitate cell sorting, proliferation, migration, and survival. Such complexes also impact the recruitment of leukocytes during development and in the early stages of disease. Once thought to be inert components of the ECM that help hold cells together, it is now quite clear that they play important roles in controlling cell phenotype, shaping tissue response to injury and maintaining tissue homeostasis. Conversion of hyaluronan-/versican-enriched provisional matrix to collagen-rich matrix is a "hallmark" of tissue fibrosis. Targeting the hyaluronan and versican content of provisional matrices in a variety of diseases including, cardiovascular disease and cancer, is becoming an attractive strategy for intervention.