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Galectin-3 (Gal-3) is a carbohydrate binding protein that has been implicated in the development and progression of fibrotic diseases. Proof-of-principal animal models have demonstrated that inhibition of Gal-3 is a potentially viable pathway for the treatment of fibrosis─with small molecule Gal-3 inhibitors advanced into clinical trials. We hereby report the discovery of novel galactose-based monosaccharide Gal-3 inhibitors comprising 2-methyl-4-phenyl-2,4-dihydro-3 H -1,2,4-triazole-3-thione (compound 20 ) and 4-phenyl-4 H -1,2,4-triazole (compound 15 ). Notably, hindered rotation caused by steric interaction between the 3-thione and ortho -trifluoromethyl group of compounds 20 , 21 induced formation of thermodynamically stable atropisomers. Distinct X-ray cocrystal structures of 20 and 21 were obtained, which clearly demonstrated that the configuration of 21 proscribes a key halogen bonding σ-hole interaction of 3-chloro with carbonyl oxygen of Gly182, thereby leading to significant loss in potency. Ultimately, 20 and 15 were evaluated in mouse pharmacokinetic studies, and both compounds exhibited oral exposures suitable for further in vivo assessment.

Galectins are a family of beta-galactoside-binding proteins that are characterised by their carbohydrate recognition domain (CRD) and include galectin-1 and galectin-3. These galectins have been implicated in numerous diseases due to their pleiotropic nature, including cancer and fibrosis, with therapeutic inhibitors being clinically developed to block the CRD. One of the early methods developed to characterise these galectins was the hemagglutination of red blood cells. Although it is insightful, this approach has been hampered by a lack of sensitivity and accurate quantification of the agglutination observed. In this study, we aimed to validate a more precise and quantitative method to enable the further investigation of differences between galectins in respect to agglutination induction in different blood groups, as well as the characterisation of small molecule inhibitors. Quantification of hemagglutination was shown to be optimal using U-bottom plates imaged and analysed with FIJI ImageJ rather than flat-bottom plates read for absorbance on an optical density plate reader. Galectin-3-induced red blood cell agglutination efficacy increased significantly from blood group O to A to B. However, for both the galectin-1 monomer and concatemer, a more comparable effect was observed between blood group B and O, but with more potent effects than in blood group A. Inhibition assays for both galectin-3 and galectin-1 induced-hemagglutination were able to demonstrate clear concentration responses and expected selectivity profiles for a set of small-molecule glycomimetics, confirming the historical profiles obtained in biochemical binding and functional cellular assays.

Galectin-3 has a variety of important pathophysiological significance in the human body. Much evidence shows that the abnormal expression of galectin-3 is related to the formation and development of many diseases. Pectin is mostly obtained from processed citrus fruits and apples and is a known natural inhibitor of galactin-3. A large number of peels produced each year are discarded, and it is necessary to recycle some of the economically valuable active compounds in these by-products to reduce resource waste and environmental pollution. By binding with galectin-3, pectin can directly reduce the expression level of galectin-3 on the one hand, and regulate the expression level of cytokines by regulating certain signaling pathways on the other hand, to achieve the effect of treating diseases. This paper begins by presenting an overview of the basic structure of pectin, subsequently followed by a description of the structure of galectin-3 and its detrimental impact on human health when expressed abnormally. The health effects of pectin as a galectin-3 inhibitor were then summarized from the perspectives of anticancer, anti-inflammatory, ameliorating fibrotic diseases, and anti-diabetes. Finally, the challenges and prospects of future research on pectin are presented, which provide important references for expanding the application of pectin in the pharmaceutical industry or developing functional dietary supplements., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

As a result of our continued efforts to pursue Gal-3 inhibitors that could be used to fully evaluate the potential of Gal-3 as a therapeutic target, two novel series of benzothiazole derived monosaccharides as potent (against both human and mouse Gal-3) and orally bioavailable Gal-3 inhibitors, represented by 4 and 5, respectively, were identified. These discoveries were made based on proposals that the benzothiazole sulfur atom could interact with the carbonyl oxygen of G182/G196 in h/mGal-3, and that the anomeric triazole moiety could be modified into an N-methyl carboxamide functionality. The interaction between the benzothiazole sulfur and the carbonyl oxygen of G196 in mGal-3 was confirmed by an X-ray co-crystal structure of early lead 9, providing a rare example of using a S···O binding interaction for drug design. It was found that for both the series, methylation of 3-OH in the monosaccharides caused no loss in h & mGal-3 potencies but significantly improved permeability of the molecules., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Galectins play relevant roles in tumor development, progression and metastasis. Accordingly, galectins are certainly enticing targets for medical intervention in cancer. To date, however, clinical trials based on galectin inhibitors reported inconclusive results. This review summarizes the galectin inhibitors currently being evaluated and discusses some of the biological challenges that need to be addressed to improve these strategies for the benefit of cancer patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Laderach and Compagno.)

Toxoplasma gondii ( T. gondii ), one of the most important Apicomplexan protozoa, causes toxoplasmosis in human throughout the world. Galectin (Gal)-9 triggers a series of immune events via binding to its receptors, including T cell immunoglobulin and mucin-containing molecule 3, CD137, CD44, and protein disulfide isomerase. To examine the regulatory role of galectin-receptor interactions in anti-toxoplasmic activities, C57BL/6 mice were infected with T. gondii RH strain and intraperitoneally injected with alpha (α)-lactose to block the interactions of galectins and their receptors. Heatmaps showed upregulated values for Gal-9 and CD137 in the livers of T. gondii -infected mice and T. gondii -infected mice treated with α-lactose. Compared with T. gondii -infected mice, T. gondii -infected mice treated with α-lactose showed significantly increased survival rate, decreased tissue parasite burden, attenuated liver histopathology, increased mRNA expression levels of CD137, IFNγ, IL-4, and IL-10 in the liver, and increased Gal-9 mRNA expression level in the spleen. Correlation analysis showed that significant positive correlations existed between the mRNA expression levels of Gal-9 and CD137, Gal-9 and IFNγ, as well as between CD137 and IFNγ in the liver and spleen of T. gondii -infected mice; between CD137 and IFNγ in the liver of T. gondii -infected mice treated with α-lactose. In addition, blockage of galectin-receptor interactions showed enhanced M2 macrophage polarization in the liver of T. gondii -infected mice. Our data indicate that Gal-9-CD137 interaction may play an important role in T. gondii proliferation and liver inflammation in mice during acute T. gondii infection, through regulating T cell and macrophage immune responses., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 He, Hou and Lu.)

Immune profiling in patients with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), and multiple myeloma (MM) provides the framework for developing novel immunotherapeutic strategies. Here, we demonstrate decreased CD4 + Th cells, increased Treg and G-type MDSC, and upregulation of immune checkpoints on effector/regulatory and CD138 + cells in MM patients, compared MGUS/SMM patients or healthy individuals. Among the checkpoints profiled, LAG3 was most highly expressed on proliferating CD4 + Th and CD8 + Tc cells in MM patients BMMC and PBMC. Treatment with antibody targeting LAG3 significantly enhanced T cells proliferation and activities against MM. XBP1/CD138/CS1-specific CTL generated in vitro displayed anti-MM activity, which was further enhanced following anti-LAG3 treatment, within the antigen-specific memory T cells. Treg and G-type MDSC weakly express LAG3 and were minimally impacted by anti-LAG3. CD138 + MM cells express GAL-3, a ligand for LAG3, and anti-GAL-3 treatment increased MM-specific responses, as observed for anti-LAG3. Finally, we demonstrate checkpoint inhibitor treatment evokes non-targeted checkpoints as a cause of resistance and propose combination therapeutic strategies to overcome this resistance. These studies identify and validate blockade of LAG3/GAL-3, alone or in combination with immune strategies including XBP1/CD138/CS1 multipeptide vaccination, to enhance anti-tumor responses and improve patient outcome in MM., (© 2021. The Author(s).)

The growth of new blood vessels is a key event in many (patho) physiological processes, including embryogenesis, wound healing, inflammatory diseases, and cancer. Neovascularization requires different, well-coordinated actions of endothelial cells, i.e., the cells lining the luminal side of all blood vessels. Galectins are involved in several of these activities. In this chapter, we describe methods to study galectins in three key functions of endothelial cells during angiogenesis, i.e., endothelial cell migration, endothelial cell sprouting, and endothelial cell network formation., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature.)

Hepatopathy is frequently observed in patients with severe malaria but its pathogenesis remains unclear. Galectins are evolutionarily conserved glycan-binding proteins with pleiotropic roles in innate and adaptive immune responses, and exhibit pivotal roles during Plasmodium spp. infection. Here, we analyzed the impact of blockage of galectin-receptor interactions by treatment with alpha (α)-lactose on liver immunopathology during the erythrocytic stage of malaria in mice infected with Plasmodium berghei ANKA ( Pb ANKA). Our results found that compared with Pb ANKA-infected mice (malarial mice), blockage of galectin-receptor interactions led to decreased host survival rate and increased peripheral blood parasitemia; exacerbated liver pathology, increased numbers of CD68 + macrophages and apoptotic cells, and increased parasite burden in the livers on days 5 and 7 post infection (p.i.) as well as increased mRNA expression levels of galectin-9 (Gal-9) and its receptor, the T cell immunoglobulin domain and mucin domain protein 3 (Tim-3), interferon (IFN)α, IFNγ, and the triggering receptor expressed on myeloid cells (TREM)-1 in the livers or spleens of Pb ANKA-infected mice on day 7 p.i. Observed by transmission electron microscopy, the peritoneal macrophages isolated from malarial mice with α-lactose treatment had more pseudopodia than those from malarial mice. Measured by using quantitative real-time reverse transcription-polymerase chain reaction assay, the mRNA expression levels of Gal-9, IFNα, IFNβ, IFNγ, and TREM-1 were increased in the peritoneal macrophages isolated from malarial mice with α-lactose treatment in comparison of those from malarial mice. Furthermore, significant positive correlations existed between the mRNA levels of Gal-9 and Tim-3/IFNγ/TREM-1 in both the livers and the peritoneal macrophages, and between Gal-9 and Tim-3/TREM-1 in the spleens of malarial mice; significant positive correlations existed between the mRNA levels of Gal-9 and IFNγ in the livers and between Gal-9 and IFNα in the peritoneal macrophages from malarial mice treated with α-lactose. Our data suggest a potential role of galectin-receptor interactions in limiting liver inflammatory response and parasite proliferation by down-regulating the expressions of IFNα, IFNγ, and TREM-1 during Pb ANKA infection., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Wu, Huang, Xiao, He and Lu.)

Galectin-3 (Gal-3), a β-galactoside-binding lectin, has been implicated in a plethora of pathological disorders including fibrosis, inflammation, cancer and metabolic diseases. TD139-a thio-digalactoside inhibitor developed by Galecto Biotech as a potential therapeutic for idiopathic pulmonary fibrosis-is the most advanced small-molecule Gal-3 inhibitor in clinical studies. It binds to human Gal-3 with high affinity but has lower affinity towards mouse and rat homologs, which is also manifested in the differential inhibition of Gal-3 function. Using biophysical methods and high-resolution X-ray co-crystal structures of TD139 and Gal-3 proteins, we demonstrate that a single amino acid change corresponding to A146 in human Gal-3 is sufficient for the observed reduction in the binding affinity of TD139 in rodents. Site-directed mutagenesis of A146V (in human Gal-3) and V160A (in mouse Gal-3) was sufficient to interchange the affinities, mainly by affecting the off rates of the inhibitor binding. In addition, molecular dynamics simulations of both wild-type and mutant structures revealed the sustained favorable noncovalent interactions between the fluorophenyl ring and the active site A146 (human Gal-3 and mouse V160A) that corroborate the finding from biophysical studies. Current findings have ramifications in the context of optimization of drug candidates against Gal-3., (© The Author(s) 2021. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Galectin-7 is a soluble unglycosylated lectin that is able to bind specifically to β-galactosides. It has been described to be involved in apoptosis, proliferation and differentiation, but also in cell adhesion and migration. Several disorders and diseases are discussed by covering the aforementioned biological processes. Structural features of galectin-7 are discussed as well as targeting the protein intracellularly or extracellularly. The exact molecular mechanisms that lie behind many biological processes involving galectin-7 are not known. It is therefore useful to come up with chemical probes or tools in order to obtain knowledge of the physiological processes. The objective of this review is to summarize the roles and functions of galectin-7 in the human body, providing reasons why it is necessary to design inhibitors for galectin-7, to give the reader structural insights and describe its current inhibitors.

Lectins are a family of glycan-binding proteins, many of which have been established as key targets for therapeutic intervention. They play a central role in many physiological and cellular processes. With the advances in protein crystallography, NMR spectroscopy and computational power over the past couple of decades, the carbohydrate-receptor interactions are now well understood and characterized. Nevertheless, designing efficient carbohydrate inhibitors is a laborious endeavour. They are known to have weak affinities, unsuitable pharmacokinetic properties and highly cumbersome/complex synthetic routes. To circumvent these issues many non-carbohydrate strategies have been reported. Galectins are a sub-family of lectin proteins which have been recognized as crucial targets for a wide variety of diseases. Many candidates targeting galectins are currently in advanced stages of clinical trials. There have been a few reports of non-carbohydrate inhibitors targeting galectins which comprise of peptide-based inhibitors and a recent flourish of heterocyclic inhibitors. In this review, we have briefly highlighted the strategies like fragment-based drug-design and high-throughput screens utilized to identify non-carbohydrate based antagonists for proteins wherein the presence of a sugar was believed to be essential. Additionally, we have described the literature pertaining to non-carbohydrate inhibitors of galectins and how previous reports on rational substitution of a sugar motif could aid in design of heterocyclics that inhibit lectins/galectins. We have concluded with remarks on challenges, gap in our understanding and future perspectives concerned with rational design of non-carbohydrate molecules targeting lectins/galectins., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Oral squamous cell carcinoma (OSCC) is a cancer associated with high mortality (accounting for 3.1/100,000 deaths per year in Brazil in 2013) and a high frequency of amplification in the expression of the epidermal growth factor receptor (EGFR). Treatment with the EGFR inhibitor cetuximab leads to drug resistance in patients with OSCC due to unknown mechanisms. Galectin‑3 (Gal‑3) is a β‑galactoside binding lectin that regulates multiple signaling pathways in cells. The present study aimed to investigate the effect of Gal‑3 in cetuximab‑resistant (cet‑R) OSCC. The OSCC HSC3 cell line was selected to establish a mouse xenograft model, which was treated with cetuximab to induce resistance. Subsequently, a Gal‑3 inhibitor was used to treat cet‑R tumors, and the tumor volume was monitored. The expression of Gal‑3, phosphorylated (p)‑ERK1/2 and p‑Akt was assessed using immunohistochemistry. The combined effect of cetuximab and the Gal‑3 inhibitor on HSC3 tumor xenografts was also investigated. HSC3 cells were cultured in vitro to investigate the regulatory effects of Gal‑3 on ERK1/2 and Akt via western blotting. In addition, the effects of the Gal‑3 inhibitor on the proliferation, colony formation, invasion and apoptosis of HSC3 cells were investigated by performing Cell Counting Kit‑8, colony formation, Transwell and apoptosis assays, respectively. In cet‑R OSCC tumors, increased expression of Gal‑3, p‑ERK1/2 and p‑Akt was observed. Further research demonstrated that Gal‑3 regulated the expression of both ERK1/2 and Akt in HSC3 cells by promoting phosphorylation. Moreover, the Gal‑3 inhibitor decreased the proliferation and invasion, but increased the apoptosis of cet‑R HSC3 cells. In addition, the Gal‑3 inhibitor suppressed the growth of cet‑R tumors. Collectively, the results indicated that the Gal‑3 inhibitor and cetuximab displayed a synergistic inhibitory effect on OSCC tumors. In summary, the present study demonstrated that Gal‑3 may serve an important role in cet‑R OSCC. The combination of cetuximab and the Gal‑3 inhibitor may display a synergistic antitumor effect, thereby inhibiting the development of cetuximab resistance in OSCC.

Galectin-3 plays a crucial role in cancerogenesis; its targeting is a prospective pathway in cancer diagnostics and therapy. Multivalent presentation of glycans was shown to strongly increase the affinity of glycoconjugates to galectin-3. Further strengthening of interaction with galectin-3 may be accomplished using artificial glycomimetics with apt aryl substitutions. We established a new, as yet undescribed chemoenzymatic method to produce selective C-3-substituted N,N'-diacetyllactosamine glycomimetics and coupled them to human serum albumin. From a library of enzymes, only β-N-acetylhexosaminidase from Talaromyces flavus was able to efficiently synthesize the C-3-propargylated disaccharide. Various aryl residues were attached to the functionalized N,N'-diacetyllactosamine via click chemistry to assess the impact of the aromatic substitution. In ELISA-type assays with galectin-3, free glycomimetics exhibited up to 43-fold stronger inhibitory potency to Gal-3 than the lactose standard. Coupling to human serum albumin afforded multivalent neo-glycoproteins with up to 4209-fold increased inhibitory potency per glycan compared to the monovalent lactose standard. Surface plasmon resonance brought further information on the kinetics of galectin-3 inhibition. The potential of prepared neo-glycoproteins to target galectin-3 was demonstrated on colorectal adenocarcinoma DLD-1 cells. We investigated the uptake of neo-glycoproteins into cells and observed limited non-specific transport into the cytoplasm. Therefore, neo-glycoproteins primarily act as efficient scavengers of exogenous galectin-3 of cancer cells, inhibiting its interaction with the cell surface, and protecting T-lymphocytes against galectin-3-induced apoptosis. The present neo-glycoproteins combine the advantage of a straightforward synthesis, selectivity, non-toxicity, and high efficiency for targeting exogenous galectin-3, with possible application in the immunomodulatory treatment of galectin-3-overexpressing cancers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Introduction: Galectins are ubiquitous in nature. They have established themselves as a protein family of high therapeutic potential and play a role in a wide variety of diseases like cancer, fibrosis, and Alzheimer's. Within the galectin family, galectin- 1 and galectin- 3 have been widely studied and their roles and functions have now been well established., Areas Covered: In this review, we discuss the important advancements in the development of galectin-1 & 3 inhibitors. All patents filed detailing the divergent strategies to inhibit galectin-1 & 3 from 2016 to present have been covered and discussed., Expert Opinion: Over the past couple of decades, distinct galectin inhibitors have been synthesized, reported and studied. Among all, the mono and disaccharide-based antagonists have been found to be considerably successful. However, the cumbersome synthetic route followed to develop this class of inhibitors, in addition to complexity involved in making selective modifications within these molecules has posed a significant challenge. Recently, there have been numerous reports on heterocyclic-based galectin inhibitors. If these are established as potent galectin inhibitors, their ease of synthesis and tunability could overcome the potential drawbacks of carbohydrate-based inhibitors and could thus be exploited to develop efficient and highly specific galectin inhibitors.

Over the past few years, tumor immunotherapy has emerged as an innovative tumor treatment and owned incomparable advantages over other tumor therapy. With unique complexity and uncertainty, immunotherapy still need helper to apply in the clinic. Galectins, modulated in tumor microenvironment, can regulate the disorders of innate and adaptive immune system resisting tumor growth. Considering the role of galectins in tumor immunosuppression, combination therapy of targeted anti-galectins and immunotherapy may be a promising tumor treatment. This brief review summarizes the expression and immune functions of different galectins in tumor microenvironment and discusses the potential value of anti-galectins in combination with checkpoint inhibitors in tumor immunotherapy., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Here, we compare the content and composition of polysaccharides derived from the mycelium (40.4 kDa intracellular polysaccharide, IPS) and culture (27.2 kDa extracellular polysaccharide, EPS) of Penicillium oxalicum. Their chemical structures investigated by IR, NMR, enzymolysis and methylation analysis indicate that both IPS and EPS are galactomannans composed of α-1,2- mannopyranose (Manp) and α-1,6-Manp in a backbone ratio of ~3:1, respectively, both decorated with β-l,5-galactofuranose (Galf) side chains. A few β-l,6-Galf residues were also detected in the IPS fraction. EPS and IPS have different molecular weights (Mw) and degrees of branching. IPS obtained by alkaline extraction of P. oxalicum have been reported to be galactofuranans, a composition different from our IPS. Up to now, there have been no reports on the fine structure of EPS. Our results of galectin-mediated hemagglutination demonstrate that IPS exhibits greater inhibitory effects on five galectins compared with EPS. In addition, we find that Galf, a five-membered ring form of galactose, can also inhibit galectins. IPS may provide a new source of galectin inhibitors. These results increase our understanding of structure-activity relationships of polysaccharides as galectin inhibitors., Competing Interests: Declaration of competing interest All authors declare that they have no conflicts of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Leukocyte recruitment to the site of injury is a crucial event in the regulation of an inflammatory response. Tight regulation of interactions between the endothelium and circulating leukocytes is necessary to ensure a protective response to injury does not result in inflammatory disease. Rising interest in the broad immunoregulatory roles displayed by members of the glycan-binding galectin family suggests that these proteins could be an attractive target for therapeutic intervention, since their expression is significantly altered in disease. The focus of this review is to summarize current knowledge on the role of galectins in leukocyte trafficking during inflammation and the clinical approaches being taken to target these interactions for treatment of inflammatory disease., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Lightfoot, McGettrick and Iqbal.)

Chemotherapy-induced peripheral neuropathy (CIPN) is a severe dose-limiting side effect of taxanes such as paclitaxel and docetaxel. Despite the high medical needs, insufficient understanding of the complex mechanism underlying CIPN pathogenesis precludes any endorsed causal therapy to prevent or relieve CIPN. In this study, we report that elevation of plasma galectin-3 level is a pathologic change common to both patients with taxane-treated breast cancer with CIPN and a mouse model of taxane-related CIPN. Following multiple intraperitoneal injections of paclitaxel in mice, galectin-3 levels were elevated in Schwann cells within the sciatic nerve but not in other peripheral organs or cells expressing galectin-3. Consistent with this, paclitaxel treatment of primary cultures of rat Schwann cells induced upregulation and secretion of galectin-3. In vitro migration assays revealed that recombinant galectin-3 induced a chemotactic response of the murine macrophage cell line RAW 264.7. In addition, perineural administration of galectin-3 to the sciatic nerve of naive mice mimicked paclitaxel-induced macrophage infiltration and mechanical hypersensitivity. By contrast, chemical depletion of macrophages by clodronate liposomes suppressed paclitaxel-induced mechanical hypersensitivity despite the higher level of plasma galectin-3. Deficiency ( Galectin-3 -/- mice) or pharmacologic inhibition of galectin-3 inhibited paclitaxel-induced macrophage infiltration and mechanical hypersensitivity. In conclusion, we propose that Schwann cell-derived galectin-3 plays a pronociceptive role via macrophage infiltration in the pathogenesis of taxane-induced peripheral neuropathy. Therapies targeting this phenomenon, which is common to patients with CIPN and mouse models, represent a novel approach to suppress taxane-related CIPN. SIGNIFICANCE: These findings demonstrate that the elevation of plasma galectin-3 is a CIPN-related pathologic change common to humans and mice, and that targeting galectin-3 is a therapeutic option to delay CIPN progression., (©2021 American Association for Cancer Research.)

Introduction: Galectin-3 (Gal-3) is a β-galactoside binding protein associated with many disease pathologies, including chronic inflammation and fibrogenesis. It has been implicated in the disease severity of NASH, although its precise role is unknown. Inhibition of Gal-3 has shown to improve and prevent fibrosis progression and has now reached phase III clinical trial in NASH patients., Areas Covered: This discusses the role of Gal-3 in NASH. It brings together the current findings of Gal-3 in NASH and hepatic fibrosis by analyzing recent data from animal model studies and clinical trials., Expert Opinion: Gal-3 inhibitors, in particular, Belapectin (GR-MD-02), have shown promising results for NASH with advanced fibrosis. In a phase 2 trial, Belapectin did not meet the primary endpoint. However, a sub-analysis of Belapectin among a separate group of patients without esophageal varices showed 2 mg/kg of GR-MD-02 reduced HVPG and the development of new varices. A subsequent study is under way, aiming to replicate the positive findings in phase 2 and demonstrate greater efficacy. If Belapectin is shown to be effective, it will be coupled with other drugs that target steatohepatitis to maximize efficacy and disease reversal.

Fluorescent biosensors are indispensable tools for molecular imaging, detection, and drug screening. Conventionally, fluorescent biosensors were constructed by incorporating fluorophores into ligands. Here, to develop ligand-independent biosensors, we demonstrated biosensor selection from a fluorophore-modified peptide phage library. In this library, the peptides were designed to form α-helical structures, and one cysteine, the probe modification site, was located at the center of four randomized residues on the same face of the helix. By conjugation with 4-nitrobenzoxadiazole (NBD), we constructed an NBD-modified phage library. We conducted selection against galectin-3 (Gal-3), a galactose-specific lectin associated with various biological events such as tumor metastasis and insulin resistance. After biopanning, we obtained NBD-modified peptides that selectively bind to Gal-3 from the library. The fluorescence intensity of the hit biosensors increased with the concentration of Gal-3, and this fluorescent response was visually observed., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: PD-1/PD-L1 engagement and overexpression of galectin-3 (Gal-3) are critical mechanisms of tumor-induced immune suppression that contribute to immunotherapy resistance. We hypothesized that Gal-3 blockade with belapectin (GR-MD-02) plus anti-PD-1 (pembrolizumab) would enhance tumor response in patients with metastatic melanoma (MM) and head and neck squamous cell carcinoma (HNSCC)., Methods: We performed a phase I dose escalation study of belapectin+pembrolizumab in patients with advanced MM or HNSCC (NCT02575404). Belapectin was administered at 2, 4, or 8 mg/kg IV 60 min before pembrolizumab (200 mg IV every 3 weeks for five cycles). Responding patients continued pembrolizumab monotherapy for up to 17 cycles. Main eligibility requirements were a functional Eastern Cooperative Oncology Group status of 0-2, measurable or assessable disease, and no active autoimmune disease. Prior T-cell checkpoint antibody therapy was permitted., Results: Objective response was observed in 50% of MM (7/14) and and 33% of HNSCC (2/6) patients. Belapectin+pembrolizumab was associated with fewer immune-mediated adverse events than anticipated with pembrolizumab monotherapy. There were no dose-limiting toxicities for belapectin within the dose range investigated. Significantly increased effector memory T-cell activation and reduced monocytic myeloid-derived suppressor cells (M-MDSCs) were observed in responders compared with non-responders. Increased baseline expression of Gal-3+ tumor cells and PD-1+CD8+ T cells in the periphery correlated with response as did higher serum trough levels of pembrolizumab., Conclusions: Belapectin+pembrolizumab therapy has activity in MM and HNSCC. Increased Gal-3 expression, expansion of effector memory T cells, and decreased M-MDSCs correlated with clinical response. Further investigation is planned., Competing Interests: Competing interests: WLR: research support from Galectin Therapeutics, Bristol Myers Squibb (BMS), Merck, Tesaro/GlaxoSmithKline, MiNA Therapeutics, Inhibrx, Veana Therapeutics, Aeglea Biotherapeutics, Shimadzu, OncoSec, and Calibr. Patents/licensing fees: Galectin Therapeutics. Advisory boards: Nektar Therapeutics, Vesselon. BC: research support from AstraZeneca, Clinigen, and Galectin Therapeutics. Advisory Boards: Replimmune, Clinigen, BMS, and Merck. Leidner: research support from BMS. Advisory boards: Merck, Oncolys, Sanofi, and Regeneron. YW: advisory boards: Roche, Amgen, Alexion, and AstraZeneca. NI and TS: employees of Shimadzu Scientific Instruments. Traber: stockholder of Galectin Therapeutics; employee and stockholder for Selecta Biosciences. EZ, JRH, and HS: employees and stockholders of Galectin Therapeutics. All other authors had no relevant disclosures., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Larch arabinogalactan (AG), extracted from Larix gmelinii sawdust, was depolymerized by H 2 O 2 oxidation and purified by gel column to yield a novel degraded fraction (AGD2). The structural analysis indicated AGD2 had lower arabinose content and molecular weight compared with AG, in which the ratio of galactose and arabinose was changed from 7:3 to 16:1, the molecular weight was decreased from 50.2 kDa to 3.7 kDa, and the chain conformation spread from highly branched structure to flexible strand. It was one kind of β-D-(1 → 3)-galactan with fewer β-D-(1 → 6)-Galp side branches at O-6 position. Further, the results of the Gal-3 binding and immunomodulatory assay suggested that the unbinding force of AGD2 onto Gal-3 was as twice as AG to be 76 ± 11 pN at the loading rate of 0.15 μm/s. It could better promote the secretion of pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β) than AG in a dose-dependent manner., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Calix[4]arene PTX008 is an angiostatic agent that inhibits tumor growth in mice by binding to galectin-1, a β-galactoside-binding lectin. To assess the affinity profile of PTX008 for galectins, we used 15 N, 1 H HSQC NMR spectroscopy to show that PTX008 also binds to galectin-3 (Gal-3), albeit more weakly. We identified the contact site for PTX008 on the F-face of the Gal-3 carbohydrate recognition domain. STD NMR revealed that the hydrophobic phenyl ring crown of the calixarene is the binding epitope. With this information, we performed molecular modeling of the complex to assist in improving the rather low affinity of PTX008 for Gal-3. By removing the N-dimethyl alkyl chain amide groups, we produced PTX013 whose reduced alkyl chain length and polar character led to an approximately eightfold stronger binding than PTX008. PTX013 also binds Gal-1 more strongly than PTX008, whereas neither interacts strongly, if at all, with Gal-7. In addition, PTX013, like PTX008, is an allosteric inhibitor of galectin binding to the canonical ligand lactose. This study broadens the scope for galectin targeting by calixarene-based compounds and opens the perspective for selective galectin blocking., (© 2020 Wiley-VCH GmbH.)

A sequence of interconnected events known as the metastatic cascade promotes tumor progression by regulating cellular and molecular interactions between tumor, stromal, endothelial, and immune cells both locally and systemically. Recently, a new concept has emerged to better describe this process by defining four attributes that metastatic cells should undergo. Every individual hallmark represents a unique trait of a metastatic cell that impacts directly in the outcome of the metastasis process. These critical features, known as the hallmarks of metastasis, include motility and invasion, modulation of the microenvironment, cell plasticity and colonization. They are hierarchically regulated at different levels by several factors, including galectins, a highly conserved family of β-galactoside-binding proteins abundantly expressed in tumor microenvironments and sites of metastasis. In this review, we discuss the role of galectins in modulating each hallmark of metastasis, highlighting novel therapeutic opportunities for treating the metastatic disease., (© 2021 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)

The two T cell inhibitory receptors PD-1 and TIM-3 are co-expressed during exhausted T cell differentiation, and recent evidence suggests that their crosstalk regulates T cell exhaustion and immunotherapy efficacy; however, the molecular mechanism is unclear. Here we show that PD-1 contributes to the persistence of PD-1 + TIM-3 + T cells by binding to the TIM-3 ligand galectin-9 (Gal-9) and attenuates Gal-9/TIM-3-induced cell death. Anti-Gal-9 therapy selectively expands intratumoral TIM-3 + cytotoxic CD8 T cells and immunosuppressive regulatory T cells (T reg cells). The combination of anti-Gal-9 and an agonistic antibody to the co-stimulatory receptor GITR (glucocorticoid-induced tumor necrosis factor receptor-related protein) that depletes T reg cells induces synergistic antitumor activity. Gal-9 expression and secretion are promoted by interferon β and γ, and high Gal-9 expression correlates with poor prognosis in multiple human cancers. Our work uncovers a function for PD-1 in exhausted T cell survival and suggests Gal-9 as a promising target for immunotherapy.

Aims: To utilize in silico-based approach for investigating the ability of PEGylated rapamycin as a competitive inhibitor to Galectin-3 for curing various diseases or that may provide an attractive strategy for treatment of a wide variety of tumors., Background: Galectin-3 (Gal-3) signaling protein is a unique member of lectin family present at the cell surface, intracellularly in both the nucleus and cytoplasm and extracellularly in the general circulation. Circulating Gal-3 is present in both normal and cancer cells. High levels of circulating Gal-3 have been proven to be associated with inflammation and fibrosis in several acute and chronic conditions, which include neurological degeneration, inflammatory and immune responses, autoimmune diseases, diabetes, heart failure, atherosclerosis, response to infection, wound healing, liver, lung, and kidney disease. Gal-3 is known to regulate many biological activities including cell adhesion, angiogenesis, growth, apoptosis, migration, and metastasis. Rapamycin has been examined alone or in combination with other drugs for treatment of various cancers in clinical studies. Although it has shown promising therapeutic effects, its clinical development was interrupted by poor aqueous solubility and limited preferential distribution. To overcome these limitations, RA has been chemically modified to hydrophilic analogues, such as everolimus (EV). However, all these approaches can only partially increase the solubility, but has little effect on the blood distribution and pharmacokinetics. Therefore, it is necessary to explore other RA conjugates to improve aqueous solubility and tissue distribution profile. Recently we reported that RP-MPEG inhibits the growth of various cancer cell lines by acting on mammalian target of RP (mTOR) receptor site and it can be used for gastric cancer., Objective: To construct various molecular weight RP-MPEG by replacing MPEG chain in 40-O-(2- hydroxyethyl) position of the EV and analyze their binding affinity to Gal-3., Methods: The chemical structures of various molecular weight RP-MPEG were built using ChemSketch software. The molecular docking study was performed to find the best probable structure of RP-MPEG for competitive inhibition of the CRD, based on the interaction score. For that purpose, the 3D structures of RP and EV were obtained from NCBI PubChem compound database, where the structural protein-co-crystallized ligand complex of Gal-3 (TD2, as a native ligand) was retrieved from RCSB Protein Data Bank. All structures of the selected compounds, served as molecules for molecular modeling, were optimized through MOE.2014 software before docking. Hydrogen atoms and partial charges were added to the protein. Protein minimization was performed in gas solvation with the side chains, keeping it rigid and the ligand flexible. The selected site was isolated and minimized, followed by protonating the protein. The 3D ligands were minimized using MMFF94x with cutoffs of 10 to 12 Å. The hydrogens and charges were fixed, and the RMS gradient was set to 0.001 kcal/mol. The docking results were analyzed to identify and assess the binding affinity of these compounds to CRD using drug discovery software., Results: Our results indicated that RP-MPEG with MW 1178.51 g/mol has a logP value of 3.79 and has possessed the strongest binding affinity toward CRD of Gal-3 with a docking score of -6.87. Compared with TD2, there were additional close contacts for RP-MPEG (MW 1178.51 g/mol), coming from three hydrogen bonds with Asp148, Arg162, and Arg144 which suggest that this ligand is a strong competitive inhibitor among the other molecules for Gal-3., Conclusion: RP-MPEG with the MW 1178.51 g/mol could be a promising blocker for various biological action of Gal-3 includes profibrotic activity, modulation of immune responses and inflammatory responses to cancer that contributes to neoplastic transformation, angiogenesis and metastasis. Other: The 95% confidence intervals (CIs) of the binding affinity (according to their mean and standard errors) were estimated with 2.5 and 97.5 percentile as the lower and upper bounds., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Galectin-3 (gal-3), a member of the galectin family, is a glycoprotein with high affinity for β-galactoside. Gal-3 is a cytoplasmically synthesized protein that can shuttle between the cytoplasm and nucleus and can even be transported to the membrane and secreted into the extracellular environment. Cardio/cerebrovascular diseases generally refer to ischemic or hemorrhagic diseases occurring in the heart, brain and systemic tissues, which are characterized by high morbidity, high disability rates and high mortality rates. To date, considerable research has demonstrated that gal-3 expression is aberrantly increased and plays important roles in cardio/cerebrovascular diseases, such as acute ischemic stroke (AIS), myocardial fibrosis, acute coronary syndrome (ACS), and heart failure (HF). Hence, understanding the biological roles of gal-3 in these diseases may be essential for cardio/cerebrovascular disease treatment and diagnosis to improve patient quality of life. In this review, we summarize current research on the roles of gal-3 in human cardiovascular diseases and potential inhibitors of gal-3, which may provide new strategies for disease therapies., (Copyright © 2020 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Galectin-3 is a beta-galactoside-binding mammalian lectin and part of the 15 member galectin family that are evolutionarily highly conserved. It is the only chimeric protein with a C-terminal carbohydrate recognition domain (CRD) linked to a proline, glycine, and tyrosine rich additional N-terminal domain. Galectin-3 binds several cell surface glycoproteins via its CRD domain as well as undergoing oligomerization, via binding at the N-terminal or the CRD, resulting in the formation of a galectin-3 lattice on the cell surface. The galectin-3 lattice has been regarded as being a crucial mechanism whereby extracellular galectin-3 modulates cellular signalling by prolonging retention time or retarding lateral movement of cell surface receptors in the plasma membrane. As such galectin-3 can regulate various cellular functions such as diffusion, compartmentalization and endocytosis of plasma membrane glycoproteins and glycolipids and the functionality of membrane receptors. In multiple models of organ fibrosis, it has been demonstrated that galectin-3 is potently pro-fibrotic and modulates the activity of fibroblasts and macrophages in chronically inflamed organs. Increased galectin-3 expression also activates myofibroblasts resulting in scar formation and may therefore impact common fibrotic pathways leading to fibrosis in multiple organs. Over the last decade there has been a marked increase in the scientific literature investigating galectin-3 in a range of fibrotic diseases as well as the clinical development of new galectin-3 inhibitors. In this review we will examine the role of galectin-3 in fibrosis, the therapeutic strategies for inhibiting galectin-3 in fibrotic disease and the clinical landscape to date., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Vanillin-based lactoside derivatives were synthetized using phase-transfer catalyzed reactions from per- O -acetylated lactosyl bromide. The aldehyde group of the vanillin moiety was then modified to generate a series of related analogs having variable functionalities in the para- position of the aromatic residue. The corresponding unprotected lactosides, obtained by Zemplén transesterification, were regioselectively 3'- O -sulfated using tin chemistry activation followed by treatment with sulfur trioxide-trimethylamine complex (Men 3 N-SO 3 ). Additional derivatives were also prepared from the vanillin's aldehyde using a Knoevenagel reaction to provide extended α, β-unsaturated carboxylic acid which was next reduced to the saturated counterpart.

Galectin-3 (Gal-3) is a β-galactoside-binding protein belonging to the lectin family with pleiotropic regulatory activities and several physiological cellular functions, such as cellular growth, proliferation, apoptosis, differentiation, cellular adhesion, and tissue repair. Inflammation, tissue fibrosis and angiogenesis are the main processes in which Gal-3 is involved. It is implicated in the pathogenesis of several diseases, including organ fibrosis, chronic inflammation, cancer, atherosclerosis and other cardiovascular diseases (CVDs). This review aims to explore the connections of Gal-3 with cardiovascular diseases since they represent a major cause of morbidity and mortality. We herein discuss the evidence on the pro-inflammatory role of Gal-3 in the atherogenic process as well as the association with plaque features linked to lesion stability. We report the biological role and molecular mechanisms of Gal-3 in other CVDs, highlighting its involvement in the development of cardiac fibrosis and impaired myocardium remodelling, resulting in heart failure and atrial fibrillation. The role of Gal-3 as a prognostic marker of heart failure is described together with possible diagnostic applications to other CVDs. Finally, we report the tentative use of Gal-3 inhibition as a therapeutic approach to prevent cardiac inflammation and fibrosis.

Galectins are an endogenous family of β-galactoside-binding proteins that play complex and multifaceted roles at various stages of cancer progression, including modulation of tumor cell proliferation, signaling, adhesion, migration, invasion, epithelial-mesenchymal transition, angiogenesis, and immune escape. Recently, galectins have been implicated as major therapeutic determinants that confer sensitivity or resistance to a wide range of anticancer modalities including chemotherapy, radiotherapy, targeted therapies, antiangiogenic therapies, and immunotherapies. Here, we present an integrated approach to the pleiotropic functions of galectins and discuss their emerging roles with respect to mechanisms of resistance or sensitivity to anticancer therapies. Taken together, these findings suggest that targeting galectins and/or their glycosylated ligands may help to overcome resistance and to increase the clinical efficacy of anticancer strategies., (©2020 American Association for Cancer Research.)

Galectin-8 is a β-galactoside-recognizing protein having an important role in the regulation of bone remodeling and cancer progression and metastasis. Methyl β-d-galactopyranoside malonyl aromatic esters have been designed to target and engage with particular amino acid residues of the galectin-8 N extended carbohydrate-binding site. The chemically synthesized compounds had in vitro binding affinity toward galectin-8 N in the range of 5-33 μM, as evaluated by isothermal titration calorimetry. This affinity directly correlated with the compounds' ability to inhibit galectin-8-induced expression of chemokines and proinflammatory cytokines in the SUM159 breast cancer cell line. X-ray crystallographic structure determination revealed that these monosaccharide-based compounds bind galectin-8 N by engaging its unique arginine (Arg59) and simultaneously cross-linking to another arginine (Arg45) located across the carbohydrate-binding site. This structure-based drug design approach has led to the discovery of novel monosaccharide galactose-based antagonists, with the strongest-binding compound ( K d 5.72 μM) holding 7-fold tighter than the disaccharide lactose.

Galectins play key roles in numerous biological processes. Their mode of action depends on their localization which can be extracellular, cytoplasmic, or nuclear and is partly mediated through interactions with β-galactose containing glycans. Galectins have emerged as novel therapeutic targets notably for the treatment of inflammatory disorders and cancers. This has stimulated the design of carbohydrate-based inhibitors targeting the carbohydrate recognition domains (CRDs) of the galectins. Pursuing this approach, we reasoned that linear oligogalactosides obtained by straightforward iterative click chemistry could mimic poly-lactosamine motifs expressed at eukaryote cell surfaces which the extracellular form of galectin-3, a prominent member of the galectin family, specifically recognizes. Affinities toward galectin-3 consistently increased with the length of the representative oligogalactosides but without reaching that of oligo-lactosamines. Elucidation of the X-ray crystal structures of the galectin-3 CRD in complex with a synthesized di- and tri-galactoside confirmed that the compounds bind within the carbohydrate-binding site. The atomic structures revealed that binding interactions mainly occur with the galactose moiety at the non-reducing end, primarily with subsites C and D of the CRD, differing from oligo-lactosamine which bind more consistently across the whole groove formed by the five subsites (A-E) of the galectin-3 CRD., (© 2020 John Wiley & Sons A/S.)

Rhamnogalacturonan I (RG-I) pectin are regarded as strong galectin-3 (Gal-3) antagonist because of galactan sidechains. The present study focused on discussing the effects of more structural regions in pectin on the anti-Gal-3 activity. The water-soluble pectin (WSP) recovered from citrus canning processing water was categorized as RG-I pectin. The controlled enzymatic hydrolysis was employed to sequentially remove the α-1,5-arabinan, homogalaturonan and β-1,4-galactan in WSP. The Gal-3-binding affinity KD (kd/ka) of WSP and debranched pectins were calculated to be 0.32 μM, 0.48 μM, 0.56 μM and 1.93 μM. Moreover, based on the more sensitive cell line (MCF-7) model, the IC 30 value of WSP was lower than these of modified pectins, indicating decreased anti-Gal-3 activity. Our results suggested that the total amount of neutral sugar sidechains, the length of arabinan and cooperation between HG and RG-I played important roles in the anti-Gal-3 activity of WSP, not the Gal/Ara ratio or RG-I/HG ratio. These results provided a new insight into structure-activity relationship of citrus segment membrane RG-I as a galectin-3 antagonist and a new functional food., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest., (Copyright © 2020. Published by Elsevier Ltd.)

Non-steroidal anti-inflammatory drugs (NSAIDs) induce ulcers in the gastrointestinal tract, including the stomach and small intestine. NSAID-induced gastric ulcers can be prevented by taking acid-neutralizing/inhibitory drugs and cytoprotective agents. In contrast, there are no medicines to control NSAID-induced small intestinal ulcers, which are accompanied by a mucosal invasion of bacteria and subsequent activation of immune cells. Galectin-3 (Gal3), an endogenous lectin, has anti-microbial and pro-inflammatory functions. In the small intestine, since Gal3 is highly expressed in epithelial cells constitutively and macrophages inducibly, the Gal3 level can affect microbiota composition and macrophage activation. We hypothesized that the modulation of Gal3 expression could be beneficial in NSAID-induced intestinal ulcers. Using Gal3 knockout (Gal3KO) mice, we determined whether Gal3 could be a therapeutic target in NSAID-induced intestinal ulcers. Following the administration of indomethacin, an NSAID, we found that small intestinal ulcers were less severe in Gal3KO mice than in wild-type (WT) mice. We also found that the composition of intestinal microbiota was different between WT and Gal3KO mice and that bactericidal antibiotic polymyxin B treatment significantly suppressed NSAID-induced ulcers. Furthermore, clodronate, a macrophage modulator, attenuated NSAID-induced ulcers. Therefore, Gal3 could be an exacerbating factor in NSAID-induced intestinal ulcers by affecting the intestinal microbiota population and macrophage activity. Inhibition of Gal3 may be a therapeutic strategy in NSAID-induced intestinal ulcers., Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT03832946., (Copyright © 2020 Park, Khadka, Sato, Omura, Fujita, Hsu, Liu and Tsunoda.)

Galectins are carbohydrate-binding proteins, and their importance in renal diseases of diverse etiology has been documented. Amongst different galectins, the role of galectin-3 in the pathophysiology of renal diseases has been well documented. There is an increase in galectin-3 in the circulation as well as on the kidneys in chronic kidney disease patients. The increase in galectin-3 is negatively correlated with a decrease in renal function and overall survival rate. The preclinical studies also correlate the increase in galectin-3 levels with renal dysfunction. Accordingly, scientists have exploited galectin-3 as a potential pharmacological target to improve renal functions in different preclinical models of renal injury. Apart from galectin-3, there have been few studies documenting the role of galectin-1, 8, and 9 in renal diseases. The role of galectin-1 is not clearly identified, and there have been conflicting reports regarding its role in renal diseases. Galectin-8 and 9 impart renoprotective effects as per clinical and preclinical studies, respectively. The present review discusses the role of different galectins in renal diseases of diverse etiology., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Selective galectin inhibitors are valuable research tools and could also be used as drug candidates. In that context, TD139, a thiodigalactoside galectin-3 inhibitor, is currently being evaluated clinically for the treatment of idiopathic pulmonary fibrosis. Herein, we describe a new strategy for the preparation of TD139. Starting from inexpensive levoglucosan, we used a rarely employed reaction cascade: Payne rearrangement/azidation process leading to 3-azido-galactopyranose. The latter intermediate was efficiently converted into TD139 in a few simple and practical steps.

Although cancer is a leading cause of death, significant breakthroughs have been made in its treatment in recent years. In particular, increasingly effective cancer vaccines are being developed, including some for colorectal cancer. There are also currently a variety of compounds that can act as adjuvants, such as signalling molecules called cytokines. Other adjuvants target and inhibit the specific mechanisms by which cancers evade the immune system. One of them is a galectin inhibitor, which targets galectins-proteins produced by cancer cells that can cause the death of immune cells. Likewise, immune checkpoint inhibitors affect immune checkpoints-natural host proteins that usually control inflammation but can be exploited by cancers to weaken the body's defences. Equally, regulatory T cells may contribute to the progression of cancer by inhibiting the functions of other T cells. The main advantages of cancer vaccines include their low toxicity and their ability to strengthen the immune system. Nevertheless, significant limitations include their slow effects and their inability to treat cancer at times due to immunosuppression. Ultimately, ongoing trials provide hope for the development of more effective methods of immunotherapeutic inoculation that can target a greater variety of cancers.

Galectins are a family of carbohydrate-recognizing proteins that by interacting with specific glycoepitopes can mediate important biological processes, including immune cell homeostasis and activation of tolerogenic circuits. Among the different members of this family, Galectin 1 and 3 have shown pro-tumorigenic effects, being overexpressed in numerous neoplasic diseases, proving to be relevant in tumor immune escape, tumor progression and resistance to drug-induced apoptosis. Thus, generation of specific glycosides that could inhibit their pro-tumorigenic ability by blocking their carbohydrate recognition domain is one of the current major challenges in the field. Considering that galectin-ligand binding strength is closely related to the ligand structure, analysis of this relationship provides valuable information for rational design of high-affinity ligands that could work as effective galectin inhibitors. Taking profit of the ability of glycosidases to catalyze transglycosylation reactions we achieved the enzymatic synthesis of β-d-Galp-(1 → 6)-β-d-Galp-(1 → 4)-d-Glcp(2), a mixture of β-d-Galp-(1 → 6)-β-d-Glcp-(1 → 4)-d-Glcp(5) and β-d-Galp-(1 → 3)-β-d-Glcp-(1 → 4)-d-Glcp(6), and finally benzyl β-d-galactopyranoside (9), with reaction yields between 16 and 27%. All the galactosides were purified, and characterized using 1 H and 13 C nuclear magnetic resonance spectroscopy. Docking results performed between the synthesized compounds and human Galectin 1 (hGal-1) and human Galectin 3 (hGal-3) showed that the replacement of a glucose moiety linked to the terminal galactose with a galactose moiety, decreases the affinity for these galectins. Moreover, regarding the interglycosidic bond the most favorable β-Gal linkage seems to be β(1 → 4) followed by β(1 → 3) and β(1 → 6) for hGal-1, and β(1 → 4) followed by β(1 → 6) and β(1 → 3) for hGal-3. These results were in accordance with the IC50 values obtained with in vitro solid phase inhibition assays. Therefore, docking results obtained in this work proved to be a very good approximation for predicting binding affinity of novel galactosides., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The process of wound healing in response to chronic liver injury leads to the development of liver fibrosis. Regardless of etiology, the profound impact of the degree of liver fibrosis on the prognosis of chronic liver diseases has been well demonstrated. While disease-specific therapy, such as treatments for viral hepatitis, has been shown to reverse liver fibrosis and cirrhosis in both clinical trials and real-life practice, subsets of patients do not demonstrate fibrosis regression. Moreover, where disease-specific therapies are not available, the need for antifibrotics exists. Increased understanding into the pathogenesis of liver fibrosis sets the stage to focus on antifibrotic therapies attempting to: (1) Minimize liver injury and inflammation; (2) Inhibit liver fibrogenesis by enhancing or inhibiting target receptor-ligand interactions or intracellular signaling pathways; and (3) Promote fibrosis resolution. While no antifibrotic therapies are currently available, a number are now being evaluated in clinical trials, and their use is becoming closer to reality for select subsets of patients.

Human tumorous imaginal disc (Tid1), a DnaJ co-chaperone protein, is classified as a tumor suppressor. Previously, we demonstrated that Tid1 reduces head and neck squamous cell carcinoma (HNSCC) malignancy. However, the molecular details of Tid1-mediated anti-metastasis remain elusive. Methods: We used affinity chromatography and systemic mass spectrometry to identify Tid1-interacting client proteins. Immunohistochemical staining of Tid1 in HNSCC patient tissues was examined to evaluate the association between the expression profile of Tid1-interacting client proteins with pathologic features and prognosis. The roles of Tid1-interacting client proteins in metastasis were validated both in vitro and in vivo . The interacting partner and downstream target of Tid1-interacting client protein were determined. Results: Herein, we first revealed that Galectin-7 was one of the Tid1-interacting client proteins. An inverse association of protein expression profile between Tid1 and Galectin-7 was determined in HNSCC patients. Low Tid1 and high Galectin-7 expression predicted poor overall survival in HNSCC. Furthermore, Tid1 abolished the nuclear translocation of Galectin-7 and suppressed Galectin-7-induced tumorigenesis and metastasis. Keratinocyte-specific Tid1-deficient mice with 4-nitroquinoline-1-oxide (4NQO) treatment exhibited increased protein levels of Galectin-7 and had a poor survival rate. Tid1 interacted with Galectin-7 through its N-linked glycosylation to promote Tid1-mediated ubiquitination and proteasomal degradation of Galectin-7. Additionally, Galectin-7 played a critical role in promoting tumorigenesis and metastatic progression by enhancing the transcriptional activity of TCF3 transcription factor through elevating MMP-9 expression. Conclusions: Overall, future treatments through activating Tid1 expression or inversely repressing the oncogenic function of Galectin-7 may exhibit great potential in targeting HNSCC progression., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

Galectins are glycan-binding proteins that contain one or two carbohydrate domains and mediate multiple biological functions. By analyzing clinical tumor samples, the abnormal expression of galectins is known to be linked to the development, progression and metastasis of cancers. Galectins also have diverse functions on different immune cells that either promote inflammation or dampen T cell-mediated immune responses, depending on cognate receptors on target cells. Thus, tumor-derived galectins can have bifunctional effects on tumor and immune cells. This review focuses on the biological effects of galectin-1, galectin-3 and galectin-9 in various cancers and discusses anticancer therapies that target these molecules., Competing Interests: The authors declare no conflicts of interest.

Galectins are β-galactoside-binding proteins. As carbohydrate-binding proteins, they participate in intracellular trafficking, cell adhesion, and cell-cell signaling. Accumulating evidence indicates that they play a pivotal role in numerous physiological and pathological activities, such as the regulation on cancer progression, inflammation, immune response, and bacterial and viral infections. Galectins have drawn much attention as targets for therapeutic interventions. Several molecules have been developed as galectin inhibitors. In particular, TD139, a thiodigalactoside derivative, is currently examined in clinical trials for the treatment of idiopathic pulmonary fibrosis. Herein, we provide an in-depth review on the development of galectin inhibitors, aiming at the dissection of the structure-activity relationship to demonstrate how inhibitors interact with galectin(s). We especially integrate the structural information established by X-ray crystallography with several biophysical methods to offer, not only in-depth understanding at the molecular level, but also insights to tackle the existing challenges., Competing Interests: The authors declare no competing financial interests.

The incidence and mortality of cancer have increased over the past decades. Significant progress has been made in understanding the underpinnings of this disease and developing therapies. Despite this, cancer still remains a major therapeutic challenge. Current therapeutic research has targeted several aspects of the disease such as cancer development, growth, angiogenesis and metastases. Many molecular and cellular mechanisms remain unknown and current therapies have so far failed to meet their intended potential. Recent studies show that glycans, especially oligosaccharide chains, may play a role in carcinogenesis as recognition patterns for galectins. Galectins are members of the lectin family, which show high affinity for β-galactosides. The galectin-glycan conjugate plays a fundamental role in metastasis, angiogenesis, tumor immunity, proliferation and apoptosis. Galectins' action is mediated by a structure containing at least one carbohydrate recognition domain (CRD). The potential prognostic value of galectins has been described in several neoplasms and helps clinicians predict disease outcome and determine therapeutic interventions. Currently, new therapeutic strategies involve the use of inhibitors such as competitive carbohydrates, small non-carbohydrate binding molecules and antibodies. This review outlines our current knowledge regarding the mechanism of action and potential therapy implications of galectins in cancer., Competing Interests: The authors declare no conflict of interest.

Glycan microarrays are useful tools for lectin glycan profiling. The use of a glycan microarray based on evanescent-field fluorescence detection was herein further extended to the screening of lectin inhibitors in competitive experiments. The efficacy of this approach was tested with 2/3'-mono- and 2,3'-diaromatic type II lactosamine derivatives and galectins as targets and was validated by comparison with fluorescence anisotropy proposed as an orthogonal protein interaction measurement technique. We showed that subtle differences in the architecture of the inhibitor could be sensed that pointed out the preference of galectin-3 for 2'-arylamido derivatives over ureas, thioureas, and amines and that of galectin-7 for derivatives bearing an α substituent at the anomeric position of glucosamine. We eventually identified a diaromatic oxazoline as a highly specific inhibitor of galectin-3 versus galectin-1 and galectin-7., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Re-epithelialisation of wounded epidermis is ensured by collective cell migration of keratinocytes. Efficient collective migration requires the maintenance of intercellular adhesion, notably through adherens junctions, to favour cell communication, support tension forces and coordinated movement . Galectin-7, a soluble lectin expressed in stratified epithelia, has been previously implicated in cell migration and intercellular adhesion. Here, we revealed a new function of galectin-7 in the control of directionality and collective behaviour in migrating keratinocytes. Consistently, we identified galectin-7 as a direct partner of E-cadherin, a key component of adherens junctions. Unexpectedly, this interaction does not require glycosylation motifs. Focusing on the underlying mechanisms, we showed that galectin-7 stabilizes E-cadherin at the plasma membrane, restraining its endocytosis. Interestingly, galectin-7 silencing decreases E-cadherin-mediated intercellular adhesion. Consequently, this study not only identifies a new stabilizer of adherens junctions but also emphasises the importance of the interplay between E-cadherin turnover and intercellular adhesion strength.

Changes in the T cell surface redox environment regulate critical cell functions, such as cell migration, viral entry and cytokine production. Cell surface protein disulfide isomerase (PDI) contributes to the regulation of T cell surface redox status. Cell surface PDI can be released into the extracellular milieu or can be internalized by T cells. We have found that galectin-9, a soluble lectin expressed by T cells, endothelial cells and dendritic cells, binds to and retains PDI on the cell surface. While endogenous galectin-9 is not required for basal cell surface PDI expression, exogenous galectin-9 mediated retention of cell surface PDI shifted the disulfide/thiol equilibrium on the T cell surface. O-glycans on PDI are required for galectin-9 binding, and PDI recognition appears to be specific for galectin-9, as galectin-1 and galectin-3 do not bind PDI. Galectin-9 is widely expressed by immune and endothelial cells in inflamed tissues, suggesting that T cells would be exposed to abundant galectin-9, in cis and in trans, in infectious or autoimmune conditions., (© The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Liver metastasis from gastrointestinal cancer defines a patient's prognosis. Despite medical developments, pancreatic cancer with liver metastasis confers a very poor prognosis. Galectin-9 (Gal‑9) is a tandem-repeat-type galectin that has recently been demonstrated to exert antitumor effects on various types of cancer cells by inducing apoptosis. However, the apoptotic pathway of Gal‑9 in solid tumors is unclear. The aim of the present study was to evaluate the effects of Gal‑9 on human liver metastasis from pancreatic cancer. Gal‑9 suppressed cell proliferation in metastatic liver cancer cell lines derived from pancreatic cancer (KMP2, KMP7, and KMP8) and increased the levels of caspase-cleaved keratin 18 and fluorescein isothiocyanate (FITC)-conjugated Annexin V. Furthermore, expression of apoptosis-related molecules such as caspase-7, cleaved caspase-3, cleaved PARP, cytochrome c, Smac/Diablo and HtrA2/Omi was enhanced. However, Gal‑9 did not affect expression of various cell cycle-related proteins. The microRNA (miRNA) expression profile was markedly altered by Gal‑9, and various miRNAs might contribute to tumor growth suppression. Our data reveal that Gal‑9 suppresses the growth of liver metastasis, possibly by inducing apoptosis through a mechanism involving mitochondria and changes in miRNA expression. Thus, Gal‑9 might serve as a therapeutic agent for the treatment of liver metastasis from pancreatic cancer.

Group A streptococcus (GAS) is an important human pathogen that causes a wide variety of cutaneous and systemic infections. Although originally thought to be an extracellular bacterium, numerous studies have demonstrated that GAS can trigger internalization into nonimmune cells to escape from immune surveillance or antibiotic-mediated killing. Epithelial cells possess a defense mechanism involving autophagy-mediated targeting and killing of GAS within lysosome-fused autophagosomes. In endothelial cells, in contrast, we previously showed that autophagy is not sufficient for GAS killing. In the present study, we showed higher galectin-3 (Gal-3) expression and lower Gal-8 expression in endothelial cells than in epithelial cells. The recruitment of Gal-3 to GAS is higher and the recruitment of Gal-8 to GAS is lower in endothelial cells than in epithelial cells. We further showed that Gal-3 promotes GAS replication and diminishes the recruitment of Gal-8 and ubiquitin, the latter of which is a critical protein for autophagy sequestration. After knockdown of Gal-3 in endothelial cells, the colocalization of Gal-8, parkin, and ubiquitin-decorated GAS is significantly increased, as is the interaction of Gal-8 and parkin, an E3 ligase. Furthermore, inhibition of Gal-8 in epithelial cells attenuates recruitment of parkin; both Gal-8 and parkin contribute to ubiquitin recruitment and GAS elimination. Animal studies confirmed that Gal-3-knockout mice develop less-severe skin damage and that GAS replication can be detected only in the air pouch and not in organs and endothelial cells. These results demonstrate that Gal-3 inhibits ubiquitin recruitment by blocking Gal-8 and parkin recruitment, resulting in GAS replication in endothelial cells. IMPORTANCE In epithelial cells, GAS can be efficiently killed within the lysosome-fused autophaosome compartment. However, we previously showed that, in spite of LC-3 recruitment, the autophagic machinery is not sufficient for GAS killing in endothelial cells. In this report, we provide the first evidence that Gal-3, highly expressed in endothelial cells, blocks the tagging of ubiquitin to GAS by inhibiting recruitment of Gal-8 and parkin, leading to an enhancement of GAS replication. We also provide the first demonstration that Gal-8 can interact with parkin, the critical E3 ligase, for resistance to intracellular bacteria by facilitating the decoration of bacteria with ubiquitin chains. Our findings reveal that differential levels of Gal-3 and Gal-8 expression and recruitment to GAS between epithelial cells and endothelial cells may contribute to the different outcomes of GAS elimination or survival and growth of GAS in these two types of cells., (Copyright © 2017 Cheng et al.)