Galectin-1 inhibitors and their potential therapeutic applications: a patent review

Discovery of the Selective and Orally Available Galectin-1 Inhibitor GB1908 as a Potential Treatment for Lung Cancer

We have previously described a new series of selective and orally available galectin-1 inhibitors resulting in the thiazole-containing glycomimetic GB1490. Here, we show that the introduction of polar substituents to the thiazole ring results in galectin-1-specific compounds with low nM affinities. X-ray structural analysis of a new ligand-galectin-1 complex shows changes in the binding mode and ligand-protein hydrogen bond interactions compared to the GB1490-galectin-1 complex. These new high affinity ligands were further optimized with respect to affinity and ADME properties resulting in the galectin-1-selective GB1908 (Kd galectin-1/3 0.057/6.0 μM). In vitro GB1908 inhibited galectin-1-induced apoptosis in Jurkat cells (IC50 = 850 nM). Pharmacokinetic experiments in mice revealed that a dose of 30 mg/kg b.i.d. results in free levels of GB1908 in plasma over galectin-1 Kd for 24 h. GB1908 dosed with this regimen reduced the growth of primary lung tumor LL/2 in a syngeneic mouse model.

Metabolic profiling of galectin-1 and galectin-3: a cross-sectional, multi-omics, association study

OBJECTIVES

Experimental studies indicate a role for galectin-1 and galectin-3 in metabolic disease, but clinical evidence from larger populations is limited.

METHODS

We measured circulating levels of galectin-1 and galectin-3 in the Prospective investigation of Obesity, Energy and Metabolism (POEM) study, participants (n = 502, all aged 50 years) and characterized the individual association profiles with metabolic markers, including clinical measures, metabolomics, adipose tissue distribution (Imiomics) and proteomics.

RESULTS

Galectin-1 and galectin-3 were associated with fatty acids, lipoproteins and triglycerides including lipid measurements in the metabolomics analysis adjusted for body mass index (BMI). Galectin-1 was associated with several measurements of adiposity, insulin secretion and insulin sensitivity, while galectin-3 was associated with triglyceride-glucose index (TyG) and fasting insulin levels. Both galectins were associated with inflammatory pathways and fatty acid binding protein (FABP)4 and -5-regulated triglyceride metabolic pathways. Galectin-1 was also associated with several proteins related to adipose tissue differentiation.

CONCLUSIONS

The association profiles for galectin-1 and galectin-3 indicate overlapping metabolic effects in humans, while the distinctly different associations seen with fat mass, fat distribution, and adipose tissue differentiation markers may suggest a functional role of galectin-1 in obesity.

Integrins as the pivotal regulators of cisplatin response in tumor cells

Cisplatin (CDDP) is a widely used first-line chemotherapeutic drug in various cancers. However, CDDP resistance is frequently observed in cancer patients. Therefore, it is required to evaluate the molecular mechanisms associated with CDDP resistance to improve prognosis among cancer patients. Integrins are critical factors involved in tumor metastasis that regulate cell-matrix and cell-cell interactions. They modulate several cellular mechanisms including proliferation, invasion, angiogenesis, polarity, and chemo resistance. Modification of integrin expression levels can be associated with both tumor progression and inhibition. Integrins are also involved in drug resistance of various solid tumors through modulation of the tumor cell interactions with interstitial matrix and extracellular matrix (ECM). Therefore, in the present review we discussed the role of integrin protein family in regulation of CDDP response in tumor cells. It has been reported that integrins mainly promoted the CDDP resistance through interaction with PI3K/AKT, MAPK, and WNT signaling pathways. They also regulated the CDDP mediated apoptosis in tumor cells. This review paves the way to suggest the integrins as the reliable therapeutic targets to improve CDDP response in tumor cells.

Design and synthesis of novel coumarin-benzimidazole hybrids as human galectin-1 inhibitors

Aim: To develop novel non-carbohydrate inhibitors of human galectin-1 (GAL-1), we have designed a series of coumarin-benzimidazole hybrids. Methods: We synthesized and characterized the coumarin-benzimidazole hybrids and further evaluated them using an in vitro GAL-1 enzyme-linked immunosorbent assay and in silico methods. Results: Among all, the compounds 6p and 6q were found to be potent, with GAL-1 inhibition of 37.61 and 36.92%, respectively, at 10 μM in GAL-1-expressed cell culture supernatant of MCF-7 cells. These two compounds are feasible for fluorine-18 radiolabeling to develop GAL-1 selective PET radiotracers. Computational studies revealed strong binding interactions of GAL-1 with these novel coumarin-benzimidazole hybrids. Conclusion: Coumarin-benzimidazole hybrids can serve as potential leads to develop selective non-carbohydrate GAL-1 inhibitors for cancer therapy.

Enzymatically-derived oligo-carrageenans interact with α-Gal antibodies and Galectin-3

Carrageenans are linear sulfated galactans synthesized in the Gigartinales, Rhodophyceae species with a varied range of biological properties that are of value to the pharmaceutical and cosmetic sectors. It is unknown how the fine structure of carrageenans dictates their capacity to affect molecular and cellular responses important to wound healing, or the ability to mitigate oxidative, hemostatic and inflammatory processes. Here we use specific endo-carrageenases, from the marine bacterium Zobellia galactanivorans, to produce enzymatically defined neo-series oligosaccharides from carrageenans with 3,6-anhydro-D-galactose on the non-reducing end. Further enzymatic modification of the oligosaccharides was done by treating with the 3,6-anhydro-D-galactosidases from the same bacterium which hydrolyze non-reducing end 3,6-anhydro-D-galactose moieties from neo-carrageenan oligosaccharides. Using the enzymatically produced oligosaccharides, we demonstrate binding to natural human serum antibodies and a monoclonal anti-αGal Ab (m86). The significant interactions with the Galα(1,3)Gal reactive antibodies produced by humans makes them potential potent inducers of complement-dependent reactions and attractive for therapeutic applications. We also demonstrate modulation of the galectin selectivity for the Gal-3 Carbohydrate Recognition Domain (CRD) relative to Gal-1 which has implications to targeting specific biological pathways regulated by the galectins.

Understanding the Role of Galectin-1 in Heart Failure: A Comprehensive Narrative Review

Heart failure (HF) is the fastest-growing cardiovascular condition worldwide. The immune system may play a role in the development of HF since this condition is associated with elevated pro-inflammatory cytokine levels. HF is a life-threatening disease, and there is an increasing demand for diagnostic biomarkers, prognostic factors, and therapeutic agents that can help treat it. Galectin-1 (Gal-1) is the prototype galectin of the lectin family. Multiple signal transduction pathways are regulated by Ras proteins, which act as a molecular switch in cells. Gal-1 regulates T and B cell activation, differentiation, and survival. Gal-1 has been linked to inflammation. Activated T cells produce Gal-1 through an autocrine apoptotic mechanism involving MEK1/ERK and p38 MAPK. In the cardiovascular system, atherosclerosis is facilitated by Gal-1. Heart disease, myocardial infarction, hypertension, and stroke can be caused by atherosclerotic plaque. HF and heart hypertrophy are caused by decreased cardiac L-type Ca2+ channel activity. Deregulation of Gal-1 and CaV1.2 in pathological cardiac hypertrophy suggests a possible target for anti-hypertrophic therapy. Rat hypertrophic cardiomyocytes express Gal-1 and CaV1.2 channels simultaneously. It has been reported that diastolic dysfunction (DD) is associated with elevated Gal-1 levels. The high Gal-1 level in subjects led to the lowest cumulative survival as a composite endpoint. Incidences of HF, DD, and serum Gal-1 levels correlated significantly. The ejection fraction was negatively correlated with Gal-1 and CRP concentrations. Based on two different approaches in mice and humans, Gal-1 was identified as a potential mediator of HF.

Galectin-9 is a target for the treatment of cancer: A patent review

Galectins, which correspond to a group of proteins capable of recognizing and reversibly binding to β-galactoside carbohydrates, have been the subject of innovation and development of technological products. Galectins play biological roles, such as cell proliferation and apoptosis, and some studies showed differences in the concentrations of galectins dispersed in serum of patients with cancer. For this reason, different studies have evaluated the biotechnological potential of these proteins as biomarkers for the prognosis and/or diagnosis of physiological disorders. Thus, this review discusses recent technological advancements in targeting galectins for the treatment of cancer and using galectins for cancer prognosis and diagnosis. Data mining was performed using the search descriptors "Galectin 9* and cancer*" and the ESPACENET and Cortellis Drug Discovery Intelligence (CDDI) databases. PRISMA guidelines were followed as a basis for literature review which aimed to conduct a systematic study of galectin-9 patents related to cancer prognosis, diagnosis and treatment. Results showed the importance of galectin-9 protein patents in furthering biomedical advancements in the global fight against cancer.

Discovery of Selective and Orally Available Galectin-1 Inhibitors

A new series of orally available α-d-galactopyranosides with high affinity and specificity toward galectin-1 have been discovered. High affinity and specificity were achieved by changing six-membered aryl-triazolyl substituents in a series of recently published galectin-3-selective α-d-thiogalactosides (e.g., GB1107 Kd galectin-1/3 3.7/0.037 μM) for five-membered heterocycles such as thiazoles. The in vitro pharmacokinetic properties were optimized, resulting in several galectin-1 inhibitors with favorable properties. One compound, GB1490 (Kd galectin-1/3 0.4/2.7 μM), was selected for further characterization toward a panel of galectins showing a selectivity of 6- to 320-fold dependent on galectin. The X-ray structure of GB1490 bound to galectin-1 reveals the compound bound in a single conformation in the carbohydrate binding site. GB1490 was shown to reverse galectin-1-induced apoptosis of Jurkat cells at low μM concentrations. No cell cytotoxicity was observed for GB1490 up to 90 μM in the A549 cells. In pharmacokinetic studies in mice, GB1490 showed high oral bioavailability (F% > 99%).

Unexpected alkyl isomerization at the silicon ligand of an unsaturated Rh complex: combined experiment and theory

The formation of dimer [(μ-Cl)Rh-(κ3(P,Si,Si)PhP(o-C6H4CH2SiiPr2)(o-C6H4CH2SiiPrnPr))]2 (Rh-3) with an n-propyl group on one of the silicon atoms as a minor product was affected by the reaction of [RhCl(COD)]2 with proligand PhP(o-C6H4CH2SiHiPr2)2, L1. The major product of the reaction was monomeric 14-electron Rh(III) complex [ClRh(κ3(P,Si,Si)PhP(o-C6H4CH2SiiPr2)2)] (Rh-1). Computations revealed that the monomer-dimer equilibrium is shifted toward the monomer with four isopropyl substituents on the two Si atoms of the ligand as in Rh-1; conversely, the dimer is favored with only one n-propyl as in Rh-3, and with less bulky alkyl substituents such as in [ClRh(κ3(P,Si,Si)PhP(o-C6H4CH2SiMe2)2]2 (Rh-2). Computations on the mechanism of formation of Rh-3 directly from [RhCl(COD)]2 are in agreement with the experimental findings and it is found to be less energetic than if stemming from Rh-1. Additionally, a Si-O-Si complex, [μ-Cl-Rh{κ3(P,Si,C)PPh(o-C6H4CH2SiiPrO SiiPr2CH-o-C6H4)}]2, Rh-4, is generated from the reaction of Rh-1 with adventitious water as a result of intramolecular C-H activation.

Glycomimetics for the inhibition and modulation of lectins

Carbohydrates are essential mediators of many processes in health and disease. They regulate self-/non-self- discrimination, are key elements of cellular communication, cancer, infection and inflammation, and determine protein folding, function and life-times. Moreover, they are integral to the cellular envelope for microorganisms and participate in biofilm formation. These diverse functions of carbohydrates are mediated by carbohydrate-binding proteins, lectins, and the more the knowledge about the biology of these proteins is advancing, the more interfering with carbohydrate recognition becomes a viable option for the development of novel therapeutics. In this respect, small molecules mimicking this recognition process become more and more available either as tools for fostering our basic understanding of glycobiology or as therapeutics. In this review, we outline the general design principles of glycomimetic inhibitors (Section 2). This section is then followed by highlighting three approaches to interfere with lectin function, i.e. with carbohydrate-derived glycomimetics (Section 3.1), novel glycomimetic scaffolds (Section 3.2) and allosteric modulators (Section 3.3). We summarize recent advances in design and application of glycomimetics for various classes of lectins of mammalian, viral and bacterial origin. Besides highlighting design principles in general, we showcase defined cases in which glycomimetics have been advanced to clinical trials or marketed. Additionally, emerging applications of glycomimetics for targeted protein degradation and targeted delivery purposes are reviewed in Section 4.

Targeting galectin-driven regulatory circuits in cancer and fibrosis

Galectins are a family of endogenous glycan-binding proteins that have crucial roles in a broad range of physiological and pathological processes. As a group, these proteins use both extracellular and intracellular mechanisms as well as glycan-dependent and independent pathways to reprogramme the fate and function of numerous cell types. Given their multifunctional roles in both tissue fibrosis and cancer, galectins have been identified as potential therapeutic targets for these disorders. Here, we focus on the therapeutic relevance of galectins, particularly galectin 1 (GAL1), GAL3 and GAL9 to tumour progression and fibrotic diseases. We consider an array of galectin-targeted strategies, including small-molecule carbohydrate inhibitors, natural polysaccharides and their derivatives, peptides, peptidomimetics and biological agents (notably, neutralizing monoclonal antibodies and truncated galectins) and discuss their mechanisms of action, selectivity and therapeutic potential in preclinical models of fibrosis and cancer. We also review the results of clinical trials that aim to evaluate the efficacy of galectin inhibitors in patients with idiopathic pulmonary fibrosis, nonalcoholic steatohepatitis and cancer. The rapid pace of glycobiology research, combined with the acute need for drugs to alleviate fibrotic inflammation and overcome resistance to anticancer therapies, will accelerate the translation of anti-galectin therapeutics into clinical practice.

Inhibition of galectins in cancer: Biological challenges for their clinical application

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.

The protective effects of Esculentoside A through AMPK in the triple transgenic mouse model of Alzheimer's disease

BACKGROUND

Neurofibrillary tangles comprising hyperphosphorylated tau are vital factors associated with the pathogenesis of Alzheimer's disease (AD). The elimination or reduction of hyperphosphorylated and abnormally aggregated tau is a valuable measure in AD therapy. Esculentoside A (EsA), isolated from Phytolacca esculenta, exhibits pharmacotherapeutic efficacy in mice with amyloid beta-induced AD. However, whether EsA affects tau pathology and its specific mechanism of action in AD mice remains unclear.

PURPOSE

To investigate the roles and mechanisms of EsA in cognitive decline and tau pathology in a triple transgenic AD (3 × Tg-AD) mouse model.

METHODS

EsA (5 and 10 mg/kg) was administered via intraperitoneal injection to 8-month-old AD mice for eight consecutive weeks. Y-maze and novel object recognition tasks were used to evaluate the cognitive abilities of mice. Potential signaling pathways and targets in EsA-treated AD mice were assessed using quantitative proteomic analysis. The NFT levels and hippocampal synapse numbers were investigated using Gallyas-Braak silver staining and transmission electron microscopy, respectively. Western blotting and immunofluorescence assays were used to measure the expression of tau-associated proteins.

RESULTS

EsA administration attenuated memory and recognition deficits and synaptic damage in AD mice. Isobaric tags for relative and absolute quantitation proteomic analysis of the mouse hippocampus revealed that EsA modulated the expression of some critical proteins, including brain-specific angiogenesis inhibitor 3, galectin-1, and Ras-related protein 24, whose biological roles are relevant to synaptic function and autophagy. Further research revealed that EsA upregulated AKT/GSK3β activity, in turn, inhibited tau hyperphosphorylation and promoted autophagy to clear abnormally phosphorylated tau. In hippocampus-derived primary neurons, inhibiting AMP-activated protein kinase (AMPK) activity through dorsomorphin could eliminate the effect of EsA, as revealed by increased tau hyperphosphorylation, downregulated activity AKT/GSK3β, and blocked autophagy.

CONCLUSIONS

To our knowledge, this study is the first to demonstrate that EsA attenuates cognitive decline by targeting the pathways of both tau hyperphosphorylation and autophagic clearance in an AMPK-dependent manner and it shows a high reference value in AD pharmacotherapy research.

Investigations on the binding specificity of β-galactoside analogues with human galectin-1 using molecular dynamics simulations

Galectin-1 (Gal-1) is the first member of galectin family, which has a carbohydrate recognition domain, specifically binds towards β-galactoside containing oligosaccharides. Owing its association with carbohydrates, Gal-1 is involved in many biological processes such as cell signaling, adhesion and pathological pathways such as metastasis, apoptosis and increased tumour cell survival. The development of β-galactoside based inhibitors would help to control the Gal-1 expression. In the current study, we carried out molecular dynamics (MD) simulations to examine the structural and dynamic behaviour Gal-1-thiodigalactoside (TDG), Gal-1-lactobionic acid (LBA) and Gal-1-beta-(1→6)-galactobiose (G16G) complexes. The analysis of glycosidic torsional angles revealed that β-galactoside analogues TDG and LBA have a single binding mode (BM1) whereas G16G has two binding modes (BM1 and BM2) for interacting with Gal-1 protein. We have computed the binding free energies for the complexes Gal-1-TDG, Gal-1-LBA and Gal-1-G16G using MM/PBSA and are -6.45, -6.22 and -3.08 kcal/mol, respectively. This trend agrees well with experiments that the binding of Gal-1 with TDG is stronger than LBA. Further analysis revealed that the interactions due to direct and water-mediated hydrogen bonds play a significant role to the structural stability of the complexes. The result obtained from this study is useful to formulate a set of rules and derive pharmacophore-based features for designing inhibitors against galectin-1.Communicated by Ramaswamy H. Sarma.

Drug repurposing against galectin-3 using simulation-based studies

The protein galectin, which binds to carbohydrates and is involved in a number of therapeutic processes including cell proliferation, inflammatory responses, apoptosis, etc., has been discovered as a potential therapeutic target. Galectin-3 is a stable biomarker that exhibits both increased and decreased expression in a variety of illnesses and infections, regardless of sex, age, or body mass index. The goal of the current study is to apply bioinformatics techniques to examine the possibility of cardiovascular medications to inhibit Galectin-3-related biological activities. Unsupervised clustering techniques, molecular docking, and guided molecular dynamics (MD) simulation were used to create a computational pipeline that was used to screen potential chemical compounds from a library of chemical compounds with related molecular fingerprints. Utilizing input factors such as gene expression, mode of action, and chemical descriptors, clustering enables prioritization of medicinal molecules. Twenty-four compounds were screened and repurposed against Galectin-3 utilizing molecular docking as part of the cluster-facilitated virtual screening technique. The polar interactions that Arg144, Glu184, Arg162, His158, and Asn174 have with Bufalin, Cymarin, and Ouabalin have the highest binding affinities, according to docking studies. Studies using MD simulations confirm the tested compounds' ability to inhibit Galectin-3. Galactin-3 targeted experimental and in vivo animal model-based validation studies using Bufalin, Cymarin, and Ouabalin are also necessary.Communicated by Ramaswamy H. Sarma.

Galectin-1 in Obesity and Type 2 Diabetes

Galectin-1 is a carbohydrate-binding protein expressed in many tissues. In recent years, increasing evidence has emerged for the role of galectin-1 in obesity, insulin resistance and type 2 diabetes. Galectin-1 has been highly conserved through evolution and is involved in key cellular functions such as tissue maturation and homeostasis. It has been shown that galectin-1 increases in obesity, both in the circulation and in the adipose tissue of human and animal models. Several proteomic studies have independently identified an increased galectin-1 expression in the adipose tissue in obesity and in insulin resistance. Large population-based cohorts have demonstrated associations for circulating galectin-1 and markers of insulin resistance and incident type 2 diabetes. Furthermore, galectin-1 is associated with key metabolic pathways including glucose and lipid metabolism, as well as insulin signalling and inflammation. Intervention studies in animal models alter animal weight and metabolic profile. Several studies have also linked galectin-1 to the progression of complications in diabetes, including kidney disease and retinopathy. Here, we review the current knowledge on the clinical potential of galectin-1 in obesity and type 2 diabetes.

Galectins—Potential Therapeutic Targets for Neurodegenerative Disorders

Advancements in medicine have increased the longevity of humans, resulting in a higher incidence of chronic diseases. Due to the rise in the elderly population, age-dependent neurodegenerative disorders are becoming increasingly prevalent. The available treatment options only provide symptomatic relief and do not cure the underlying cause of the disease. Therefore, it has become imperative to discover new markers and therapies to modulate the course of disease progression and develop better treatment options for the affected individuals. Growing evidence indicates that neuroinflammation is a common factor and one of the main inducers of neuronal damage and degeneration. Galectins (Gals) are a class of β-galactoside-binding proteins (lectins) ubiquitously expressed in almost all vital organs. Gals modulate various cellular responses and regulate significant biological functions, including immune response, proliferation, differentiation, migration, and cell growth, through their interaction with glycoproteins and glycolipids. In recent years, extensive research has been conducted on the Gal superfamily, with Gal-1, Gal-3, and Gal-9 in prime focus. Their roles have been described in modulating neuroinflammation and neurodegenerative processes. In this review, we discuss the role of Gals in the causation and progression of neurodegenerative disorders. We describe the role of Gals in microglia and astrocyte modulation, along with their pro- and anti-inflammatory functions. In addition, we discuss the potential use of Gals as a novel therapeutic target for neuroinflammation and restoring tissue damage in neurodegenerative diseases.

In silico prediction of flavan-3-ol as a bioactive compound of Calophyllum macrophyllum as a potential drug against angiostrongylus eosinophilic meningitis

Background and Aim:

Angiostrongylus eosinophilic meningitis is caused by larvae of the rat lungworm Angiostrongylus cantonensis. It manifests as meningitis, radiculitis, cranial nerve abnormalities, and encephalitis, which can be fatal. A flavan-3-ol compound isolated from the bark of Calophyllum macrophyllum Scheff. has several medicinal properties, including antioxidant, anti-inflammatory, antidiabetic, and antibacterial activities. This compound is stronger than other types of flavan-3-ols such as catechin. This study aimed to identify the hydroxylation pattern of this flavan-3-ol compound and evaluated its potential as an anti-meningitis drug, using an in silico approach through pharmacophore and molecular docking methods.

Materials and Methods:

Pharmacokinetic and toxicological data were analyzed and supported by the server http://www.swissadme.ch/index.php and https://tox-new.charite.de/protox_II/index.php. The hydroxylation pattern of the flavan-3-ol compound was identified using shear reagents (MeOH, NaOH, NaOAc, HCl, and AlCl₃). The CviR receptor (pdb id.3QP5) was used in the in silico approach, and seven ligands were downloaded from PubChem in “SMILES” format.

Results:

The spectroscopic analysis conducted using the shear reagents confirmed that the flavan-3-ol compound has a “p-diOH” pattern on the cinnamoyl ring. Pharmacophore analysis revealed this compound “hit” with pharmacophore features, and molecular docking analysis showed that this compound has a strong affinity with both receptors.

Conclusion:

The flavan-3-ol compound is a potential drug candidate for meningitis caused by pathogenic bacteria and the worm A. cantonensis. This result was supported by the pharmacokinetic profile, which had a very low toxicity level to the host. However, further investigation is required to confirm the data in vitro and in vivo.

Oncolytic H-1 Parvovirus Hijacks Galectin-1 to Enter Cancer Cells

Clinical studies in glioblastoma and pancreatic carcinoma patients strongly support the further development of H-1 protoparvovirus (H-1PV)-based anticancer therapies. The identification of cellular factors involved in the H-1PV life cycle may provide the knowledge to improve H-1PV anticancer potential. Recently, we showed that sialylated laminins mediate H-1PV attachment at the cell membrane. In this study, we revealed that H-1PV also interacts at the cell surface with galectin-1 and uses this glycoprotein to enter cancer cells. Indeed, knockdown/out of LGALS1, the gene encoding galectin-1, strongly decreases the ability of H-1PV to infect and kill cancer cells. This ability is rescued by the re-introduction of LGALS1 into cancer cells. Pre-treatment with lactose, which is able to bind to galectins and modulate their cellular functions, decreased H-1PV infectivity in a dose dependent manner. In silico analysis reveals that LGALS1 is overexpressed in various tumours including glioblastoma and pancreatic carcinoma. We show by immunohistochemistry analysis of 122 glioblastoma biopsies that galectin-1 protein levels vary between tumours, with levels in recurrent glioblastoma higher than those in primary tumours or normal tissues. We also find a direct correlation between LGALS1 transcript levels and H-1PV oncolytic activity in 53 cancer cell lines from different tumour origins. Strikingly, the addition of purified galectin-1 sensitises poorly susceptible GBM cell lines to H-1PV killing activity by rescuing cell entry. Together, these findings demonstrate that galectin-1 is a crucial determinant of the H-1PV life cycle.

The Complex Biological Effects of Pectin: Galectin-3 Targeting as Potential Human Health Improvement?

Galectin-3 is the only chimeric representative of the galectin family. Although galectin-3 has ubiquitous regulatory and physiological effects, there is a great number of pathological environments where galectin-3 cooperatively participates. Pectin is composed of different chemical structures, such as homogalacturonans, rhamnogalacturonans, and side chains. The study of pectin's major structural aspects is fundamental to predicting the impact of pectin on human health, especially regarding distinct molecular modulation. One of the explored pectin's biological activities is the possible galectin-3 protein regulation. The present review focuses on revealing the structure/function relationship of pectins, their fragments, and their biological effects. The discussion highlighted by this review shows different effects described within in vitro and in vivo experimental models, with interesting and sometimes contradictory results, especially regarding galectin-3 interaction. The review demonstrates that pectins are promissory food-derived molecules for different bioactive functions. However, galectin-3 inhibition by pectin had been stated in literature before, although it is not a fully understood, experimentally convincing, and commonly agreed issue. It is demonstrated that more studies focusing on structural analysis and its relation to the observed beneficial effects, as well as substantial propositions of cause and effect alongside robust data, are needed for different pectin molecules' interactions with galectin-3.

Drug targeting opportunities en route to Ras nanoclusters

Disruption of the native membrane organization of Ras by the farnesyltransferase inhibitor tipifarnib in the late 1990s constituted the first indirect approach to drug target Ras. Since then, our understanding of how dynamically Ras shuttles between subcellular locations has changed significantly. Ras proteins have to arrive at the plasma membrane for efficient MAPK-signal propagation. On the plasma membrane Ras proteins are organized into isoform specific proteo-lipid assemblies called nanocluster. Recent evidence suggests that Ras nanocluster have a specific lipid composition, which supports the recruitment of effectors such as Raf. Conversely, effectors possess lipid-recognition motifs, which appear to serve as co-incidence detectors for the lipid domain of a given Ras isoform. Evidence suggests that dimeric Raf proteins then co-assemble dimeric Ras in an immobile complex, thus forming the minimal unit of an active nanocluster. Here we review established and novel trafficking chaperones and trafficking factors of Ras, along with the set of lipid and protein modulators of Ras nanoclustering. We highlight drug targeting approaches and opportunities against these determinants of functional Ras membrane organization. Finally, we reflect on implications for Ras signaling in polarized cells, such as epithelia, which are a common origin of tumorigenesis.

Galectins in Glioma: Current Roles in Cancer Progression and Future Directions for Improving Treatment

Simple Summary

Glioblastomas are among the most common and aggressive brain tumors. The high rate of recurrence and mortality associated with this cancer underscores the need for the development of new therapeutical targets. Galectins are among the new targets that have attracted the attention of many scientists working in the field of cancer. They form a group of small proteins found in many tissues where they accomplish various physiological roles, including regulation of immune response and resistance to cell death. In many types of cancer, however, production of abnormally high levels of galectins by cancer cells can be detrimental to patients. Elevated levels of galectins can, for example, suppress the ability of the host’s immune system to kill cancer cells. They can also provide cancer cells with resistance to drugs-induced cell death. Here, we review the recent progress that has contributed to a better understanding of the mechanisms of actions of galectins in glioblastoma. We also discuss recent development of anti-galectin drugs and the challenges associated with their use in clinical settings, with particular attention to their role in reducing the efficacy of immunotherapy, a promising treatment that exploits the capacity of the immune system to recognize and kill cancer cells.

Abstract

Traditional wisdom suggests that galectins play pivotal roles at different steps in cancer progression. Galectins are particularly well known for their ability to increase the invasiveness of cancer cells and their resistance to drug-induced cell death. They also contribute to the development of local and systemic immunosuppression, allowing cancer cells to escape the host’s immunological defense. This is particularly true in glioma, the most common primary intracranial tumor. Abnormally high production of extracellular galectins in glioma contributes to the establishment of a strong immunosuppressive environment that favors immune escape and tumor progression. Considering the recent development and success of immunotherapy in halting cancer progression, it is logical to foresee that galectin-specific drugs may help to improve the success rate of immunotherapy for glioma. This provides a new perspective to target galectins, whose intracellular roles in cancer progression have already been investigated thoroughly. In this review, we discuss the mechanisms of action of galectins at different steps of glioma progression and the potential of galectin-specific drugs for the treatment of glioma.

Alzheimer's disease: Is there a role for galectins?

Alzheimer's disease (AD) is the world's leading cause of neurological dysfunction, cognitive decline, and neuronal loss in the elderly. The sedimentation of beta amyloid (Aβ)-containing plaque, and formation of tau-containing neurofibrillary tangles (NFTs) along with extensive neuroinflammation, are the events that characterize the pathogenesis of AD. Galectins (gal) are carbohydrate-containing-ligand molecules recognized as potential modulators of the brain microglia polarization, immunosurveillance, neuroinflammation, and neuroprotection. Galectins 1, 3, 4, 8, and 9 are amongst the 15 members of the galectin family which are expressed in the brain. These galectins possess a significant correlation with neuromodulation through the glial cell-induced cytokine production that plays either a complementary or antagonistic role in the disturbance of the CNS physiology. Therefore, elaborating the hypothesis of galectins in the development of AD is of potential interest. This review aims at discussing the interaction between galectins and the neuropathophysiology of AD. An understanding about how galectins communicate with AD progression could lead to the development of improved diagnostic and therapeutic strategies for this leading cause of dementia worldwide.

Increased Circulating Levels of Galectin Proteins in Patients with Breast, Colon, and Lung Cancer

Galectins are proteins with high-affinity β-galactoside-binding sites that function in a variety of signaling pathways through interactions with glycoproteins. The known contributions of galectins-1, -3, -7, -8, and -9 to angiogenesis, metastasis, cell division, and evasion of immune destruction led us to investigate the circulating levels of these galectins in cancer patients. This study compares galectin concentrations by enzyme-linked immunosorbent assay (ELISA) from each stage of breast, lung, and colon cancer. Galectins-1 and -7, which share a prototype structure, were found to have statistically significant increases in breast and lung cancer. Of the tandem-repeat galectins, galectin-8 showed no statistically significant change in these cancer types, but galectin-9 was increased in colon and lung cancer. Galectin-3 is the only chimera-type galectin and was increased in all stages of breast, colon, and lung cancer. In conclusion, there were significant differences in the galectin levels in patients with these cancers compared with healthy controls, and galectin levels did not significantly change from stage to stage. These findings suggest that further research on the roles of galectins early in disease pathogenesis may lead to novel indications for galectin inhibitors.

Immunosuppressive Roles of Galectin-1 in the Tumor Microenvironment

Evasion of immune surveillance is an accepted hallmark of tumor progression. The production of immune suppressive mediators by tumor cells is one of the major mechanisms of tumor immune escape. Galectin-1 (Gal-1), a pivotal immunosuppressive molecule, is expressed by many types of cancer. Tumor-secreted Gal-1 can bind to glycosylated receptors on immune cells and trigger the suppression of immune cell function in the tumor microenvironment, contributing to the immune evasion of tumors. The aim of this review is to summarize the current literature on the expression and function of Gal-1 in the human tumor microenvironment, as well as therapeutics targeting Gal-1.

Non-carbohydrate strategies to inhibit lectin proteins with special emphasis on galectins

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.

An updated patent review of galectin-1 and galectin-3 inhibitors and their potential therapeutic applications (2016-present)

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.

Polymer-Based Drug-Free Therapeutics for Anticancer, Anti-Inflammatory, and Antibacterial Treatment

This paper summarizes the area of biomedicinal polymers, which serve as nanomedicines even though they do not contain any anticancer or antiinflammatory drugs. These polymer nanomedicines with unique design are in the literature highlighted as a novel class of therapeutics called "drug-free macromolecular therapeutics." Their therapeutic efficacy is based on the tailored multiple presentations of biologically active vectors, i.e., peptides, oligopeptides, or oligosaccharides. Thus, they enable, for example, to directly induce the apoptosis of malignant cells by the crosslinking of surface slowly internalizing receptors, or to deplete the efficacy of tumor-associated proteins. The precise biorecognition of natural binding motifs by multiple vectors on the polymer construct remains the crucial part in the designing of these drug-free nanomedicines. Here, the rationales, designs, synthetic approaches, and therapeutic potential of drug-free macromolecular therapeutics consisting of various active vectors are described in detail. Recent developments and achievements for namely B-cell lymphoma treatment, Gal-3-positive tumors, inflammative liver injury, and bacterial treatment are reviewed and highlighted. Finally, a possible future prospect within this highly exciting new field of nanomedicine research is presented.

Targeting galectins in T cell-based immunotherapy within tumor microenvironment

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.

Identification of co-expressed genes associated with MLL rearrangement in pediatric acute lymphoblastic leukemia

Rearrangements involving the mixed lineage leukemia (MLL) gene are common adverse prognostic factors of pediatric acute lymphoblastic leukemia (ALL). Even allogeneic hematopoietic stem cell transplantation does not improve the outcome of ALL cases with some types of MLL rearrangements. The aim of the present study was to identify the co-expressed genes that related to MLL rearrangement (MLL-r) and elucidate the potential mechanisms of how MLL-r and their partner genes lead to leukemogenesis. Gene co-expression networks were constructed using the gene expression data and sample traits of 204 pretreated pediatric ALL patients, and co-expression modules significantly related to the MLL-r were screened out. Gene ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathway analysis of the module genes were performed. Hub genes were identified and their expression levels were analyzed in samples with or without MLL-r and the results were validated by an independent investigation. Furthermore, the relationships between the hub genes and sample traits were analyzed. In total, 21 co-expression modules were identified. The green module was positively correlated with MLL-r. PROM1, LGALS1, CD44, FUT4 and HOXA10 were identified as hub genes, which were involved in focal adhesion, calcium-dependent phospholipid binding, connective tissue development and transcriptional misregulation in cancer. The expression levels of the five hub genes were significantly increased in MLL-r samples, and the results were further validated. PROM1, LGALS1, CD44 and HOXA10 were positively related to the leukocyte count. These findings might provide novel insight regarding the mechanisms and potential therapeutic targets for pediatric ALL with MLL-r.

Intra-individual reproducibility of galectin-1, haptoglobin, and nesfatin-1 as promising new biomarkers of immunometabolism

Background

Galectin-1, haptoglobin, and nesfatin-1 have recently emerged as promising biomarkers implicated in immunometabolism. However, whether single blood measurements of these analytes could be suitable for large-scale human studies has not yet been evaluated.

Methods

The concentrations of galectin-1, haptoglobin, and nesfatin-1 were measured over a 4-month period in 207 healthy adults with median age of 56.7 years. Biomarker intra-individual reproducibility was assessed based on calculation of intraclass correlation coefficients (ICCs) and examining Bland-Altman plots.

Results

The overall ICCs were excellent for nesfatin-1 (ICC: 0.89 (95% CI: 0.86, 0.92), and good for galectin-1 and haptoglobin (ICCs: 0.70 (95% CI: 0.61, 0.77) and 0.67 (95% CI: 0.57, 0.74), respectively). Bland-Altman plots supported a high level of agreement between repeated biomarker measurements.

Conclusions

Assay measurements of galectin-1, haptoglobin, and nesfatin-1 showed good to excellent within-subject reproducibility over a 4-month period, indicating that they may serve as feasible and reliable biomarkers for assessing metabolic inflammation in population research.

Autocrine Signaling of NRP1 Ligand Galectin-1 Elicits Resistance to BRAF-Targeted Therapy in Melanoma Cells

Melanoma cells addicted to mutated BRAF oncogene activity can be targeted by specific kinase inhibitors until they develop resistance to therapy. We observed that the expression of Galectin-1 (Gal-1), a soluble ligand of Neuropilin-1 (NRP1), is upregulated in melanoma tumor samples and melanoma cells resistant to BRAF-targeted therapy. We then demonstrated that Gal-1 is a novel driver of resistance to BRAF inhibitors in melanoma and that its activity is linked to the concomitant upregulation of the NRP1 receptor observed in drug-resistant cells. Mechanistically, Gal-1 sustains increased expression of NRP1 and EGFR in drug-resistant melanoma cells. Moreover, consistent with its role as a NRP1 ligand, Gal-1 negatively controls p27 levels, a mechanism previously found to enable EGFR upregulation in cancer cells. Finally, the combined treatment with a Gal-1 inhibitor and a NRP1 blocking drug enabled resistant melanoma cell resensitization to BRAF-targeted therapy. In summary, we found that the activation of Galectin-1/NRP1 autocrine signaling is a new mechanism conferring independence from BRAF kinase activity to oncogene-addicted melanoma cells.

Targeting Galectins With Glycomimetics

Among glycan-binding proteins, galectins, β-galactoside-binding lectins, exhibit relevant biological roles and are implicated in many diseases, such as cancer and inflammation. Their involvement in crucial pathologies makes them interesting targets for drug discovery. In this review, we gather the last approaches toward the specific design of glycomimetics as potential drugs against galectins. Different approaches, either using specific glycomimetic molecules decorated with key functional groups or employing multivalent presentations of lactose and N-acetyl lactosamine analogs, have provided promising results for binding and modulating different galectins. The review highlights the results obtained with these approximations, from the employment of S-glycosyl compounds to peptidomimetics and multivalent glycopolymers, mostly employed to recognize and/or detect hGal-1 and hGal-3.

Galectins and their involvement in ocular disease and development

Galectins are carbohydrate binding proteins with high affinity to ß-galactoside containing glycoconjugates. Understanding of the functions of galectins has grown steadily over the past decade, as a result of substantial advancements in the field of glycobiology. Galectins have been shown to be versatile molecules that participate in a range of important biological systems, including inflammation, neovascularisation and fibrosis. These processes are of particular importance in ocular tissues, where a major theme of recent research has been to divert diseases away from pathways which result in loss of function into pathways of repair and regeneration. This review summarises our current understanding of galectins in the context important ocular diseases, followed by an update on current clinical studies and future directions.

Galectins in prostate and bladder cancer: tumorigenic roles and clinical opportunities

Advanced prostate and bladder cancer are two outstanding unmet medical needs for urological oncologists. The high prevalence of these tumours, lack of effective biomarkers and limited effective treatment options highlight the importance of basic research in these diseases. Galectins are a family of β-galactoside-binding proteins that are frequently altered (upregulated or downregulated) in a wide range of tumours and have roles in different stages of tumour development and progression, including immune evasion. In particular, altered expression levels of different members of the galectin family have been reported in prostate and bladder cancers, which, together with the aberrant glycosylation patterns found in tumour cells and the constituent cell types of the tumour microenvironment, can result in malignant transformation and tumour progression. Understanding the roles of galectin family proteins in the development and progression of prostate and bladder cancer could yield key insights to inform the clinical management of these diseases.

High-Affinity N-(2-Hydroxypropyl)methacrylamide Copolymers with Tailored N-Acetyllactosamine Presentation Discriminate between Galectins

N-Acetyllactosamine (LacNAc; Galβ4GlcNAc) is a typical disaccharide ligand of galectins. The most abundant members of these human lectins, galectin-1 (Gal-1) and galectin-3 (Gal-3), participate in a number of pathologies including cancerogenesis and metastatic formation. In this study, we synthesized a series of fifteen N-(2-hydroxypropyl)methacrylamide (HPMA)-based glycopolymers with varying LacNAc amounts and presentations and evaluated the impact of their architecture on the binding affinity to Gal-1 and Gal-3. The controlled radical reversible addition-fragmentation chain transfer copolymerization technique afforded linear polymer precursors with comparable molecular weight (M_n ≈ 22,000 g mol^-1) and narrow dispersity (D̵ ≈ 1.1). The precursors were conjugated with the functionalized LacNAc disaccharide (4-22 mol % content in glycopolymer) prepared by enzymatic synthesis under catalysis by β-galactosidase from Bacillus circulans. The structure-affinity relationship study based on the enzyme-linked immunosorbent assay revealed that the type of LacNAc presentation, individual or clustered on bi- or trivalent linkers, brings a clear discrimination (almost 300-fold) between Gal-1 and Gal-3, reaching avidity to Gal-1 in the nanomolar range. Whereas Gal-1 strongly preferred a dense presentation of individually distributed LacNAc epitopes, Gal-3 preferred a clustered LacNAc presentation. Such a strong galectin preference based just on the structure of a multivalent glycopolymer type is exceptional. The prepared nontoxic, nonimmunogenic, and biocompatible glycopolymers are prospective for therapeutic applications requiring selectivity for one particular galectin.

The role of Galectin-1 in HIV associated preeclampsia

OBJECTIVE

In this study, the role of Gal1, a regulatory protein involved in receptor binding and gene transcription within trophoblast cells, in the pathophysiology of HIV associated preeclampsia was determined by immunolocalizing its expression in the placenta of a South African cohort.

STUDY DESIGN

this is an analytical study carried out at the Optics and Imaging Center, Neslon R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa. A hundred and twenty HIV negative or positive, Black African primigrad or multigravid women with pre-eclamptic and normotensive pregnancies were involved in the study. Post-delivery, full thickness of centrally located placental tissue obtained was fixed for immunohistochemistry. The expression of Gal1 was immunolocalized using immunohistochemical assay kit and further quantified with using AxioVision Image analysis software package. Student t-test was used to compare the levels of the analytes while One-way ANOVA was used for comparison across the groups.

RESULTS

Gal1 immunoreactivity was observed within the Hofbauer cells, cytotrophoblast, syncytial knots and in the endothelial cells lining blood vessels in both exchange and conducting villi of both normotensive and preeclamptic pregnancies regardless of HIV status. There was a down regulation in Gal1 immunoreactivity in both the exchange and conducting villi of preeclamptic compared to normotensive pregnancies. However, there was no significant effect of HIV infection on Gal1 immunostaining in both villi types.

CONCLUSION

The down regulation of Gal1 in preeclampsia may be due to the inhibition of the MAPK pathway. Since Gal1 influences differentiation and migration, the defective trophoblast invasion in preeclampsia may emanate from its decreased immunoexpression. This highlights the role of Gal1 in angiogenesis and placentation.

Shikonin induces colorectal carcinoma cells apoptosis and autophagy by targeting galectin-1/JNK signaling axis

Colorectal carcinoma (CRC) is the third most common malignant tumor pathology worldwide. Despite progress in surgical procedures and therapy options, CRC is still a considerable cause of cancer-related mortality. In this study, we tested the antitumor effects of shikonin in CRC and tried to identify its potential mechanism. The potential target, molecular mechanism as well as in vitro and in vivo antitumor effects of shikonin in CRC cells were determined by an integrative protocol including quantitative proteomics, RT-PCR, western blotting, RNA interference and overexpression, apoptosis and autophagy assays, etc. Galectin-1 was a potential target of shikonin from the iTRAQ-based proteomic analysis in shikonin-treated SW620 cell. The overexpression and RNA silencing of galectin-1 in two CRC cells suggested that the shikonin sensitivity was correlation to galectin-1 levels. The ROS accumulation induced by shikonin was important to the formation of galectin-1 dimers. Dimer galectin-1 was found to be associated with the activation of JNK and downstream apoptosis or autophagy. Moreover, through functional in vitro studies, we showed that differences in galectin-1 level affected tumor cell proliferation, migration, and invasion. In summary, shikonin induced CRC cells apoptosis and autophagy by targeting galectin-1 and JNK signaling pathway both in vitro and in vivo, which suggested a potential novel therapy target for CRC.

The Structural Biology of Galectin-Ligand Recognition: Current Advances in Modeling Tools, Protein Engineering, and Inhibitor Design

Galectins (formerly known as “S-type lectins”) are a subfamily of soluble proteins that typically bind β-galactoside carbohydrates with high specificity. They are present in many forms of life, from nematodes and fungi to animals, where they perform a wide range of functions. Particularly in humans, different types of galectins have been described differing not only in their tissue expression but also in their cellular location, oligomerization, fold architecture and carbohydrate-binding affinity. This distinct yet sometimes overlapping distributions and physicochemical attributes make them responsible for a wide variety of both intra- and extracellular functions, including tremendous importance in immunity and disease. In this review, we aim to provide a general description of galectins most important structural features, with a special focus on the molecular determinants of their carbohydrate-recognition ability. For that purpose, we structurally compare the human galectins, in light of recent mutagenesis studies and novel X-ray structures. We also offer a detailed description on how to use the solvent structure surrounding the protein as a tool to get better predictions of galectin-carbohydrate complexes, with a potential application to the rational design of glycomimetic inhibitory compounds. Finally, using Gal-1 and Gal-3 as paramount examples, we review a series of recent advances in the development of engineered galectins and galectin inhibitors, aiming to dissect the structure-activity relationship through the description of their interaction at the molecular level.

Human Galectin-1 and Its Inhibitors: Privileged Target for Cancer and HIV

Galectin 1(Gal-1), a β-galactoside binding mammalian lectin of 14KDa, is implicated in many signalling pathways, immune responses associated with cancer progression and immune disorders. Inhibition of human Gal-1 has been regarded as one of the potential therapeutic approaches for the treatment of cancer, as it plays a major role in tumour development and metastasis by modulating various biological functions viz. apoptosis, angiogenesis, migration, cell immune escape. Gal-1 is considered as a biomarker in diagnosis, prognosis and treatment condition. The overexpression of Gal-1 is well established and seen in many types of cancer progression like osteosarcoma, breast, lung, prostate, melanoma, etc. Gal-1 greatly accelerates the binding kinetics of HIV-1 to susceptible cells, leading to faster viral entry and a more robust viral replication by specific binding of CD4 cells. Hence, the Gal-1 is considered a promising molecular target for the development of new therapeutic drugs for cancer and HIV. The present review laid emphasis on structural insights and functional role of Gal-1 in the disease, current Gal-1 inhibitors and future prospects in the design of specific Gal-1 inhibitors.

Galectin-1 protein modified gold (III)-PEGylated complex-nanoparticles: Proof of concept of alternative probe in colorimetric glucose detection

Galectins (Gal) are a family of dimeric lectins, composed by two galactoside-binding sites implicated in the regulation of cancer progression and immune responses. In this study, we report for the first time the synthesis and the physical-chemical characterization of galectin-1-complex-gold COOH-terminated polyethlenglicole (PEG)-coated NPs (Gal-1 IN PEG-AuNPs) and their ability to recognize glucose in an aqueous solution with a concentration varying from 10 mM to 100 pM. The chemical protocol consistsof three steps: (i) complexation between galectin-1Gal-1 and tetrachloroauric acid (HAuCl₄) to form gold-protein grains; (ii) staking process of COOH-terminated polyethlenglicole molecules (PEG) onto Gal-1-Au complex and (iii) reduction of hybrid metal ions to obtain a colloidal stable solution. During the complexation, the spectral signatures related to the Gal-1 orientation on the gold surface have been found to change due to its protonation state. The effective glucose monitoring was detected by UV-vis, Raman spectroscopy and Transmission Electron Microscopy (TEM). Overall, we observed that the interaction is strongly dependent on the Gal-1 conformation at the surface of gold nanoparticles.

Hybrid ligands with calixarene and thiodigalactoside groups: galectin binding and cytotoxicity

Galectins have diverse functions and are involved in many biological processes because of their complex intra- and extracellular activities. Selective and potent inhibitors for galectins will be valuable tools to investigate the biological functions of these proteins. Therefore, we describe here the synthesis of galectin inhibitors with a potential "chelate effect". These compounds are designed to bind to two different binding sites on galectins simultaneously. In this paper a series of asymmetric "hybrid" compounds are prepared, which combine two galectin ligands (1) a substituted thiodigalactoside derivative and (2) an antagonist calixarene-based therapeutic agent. NMR spectroscopy was used to evaluate the interactions of these compounds with Galectin-1 and -3. In addition, cellular experiments were conducted to compare the cytotoxic effects of the hybrids with those of a calixarene derivative. While only the thiodigalactoside part of the hybrids showed strong binding, the calixarene part was responsible for observed cytoxoxicity effects, suggesting that the calixarene moiety may also be addressing a non-galectin target.

Targeting Myeloid Cells in Combination Treatments for Glioma and Other Tumors

Myeloid cells constitute a significant part of the immune system in the context of cancer, exhibiting both immunostimulatory effects, through their role as antigen presenting cells, and immunosuppressive effects, through their polarization to myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages. While they are rarely sufficient to generate potent anti-tumor effects on their own, myeloid cells have the ability to interact with a variety of immune populations to aid in mounting an appropriate anti-tumor immune response. Therefore, myeloid therapies have gained momentum as a potential adjunct to current therapies such as immune checkpoint inhibitors (ICIs), dendritic cell vaccines, oncolytic viruses, and traditional chemoradiation to enhance therapeutic response. In this review, we outline critical pathways involved in the recruitment of the myeloid population to the tumor microenvironment and in their polarization to immunostimulatory or immunosuppressive phenotypes. We also emphasize existing strategies of modulating myeloid recruitment and polarization to improve anti-tumor immune responses. We then summarize current preclinical and clinical studies that highlight treatment outcomes of combining myeloid targeted therapies with other immune-based and traditional therapies. Despite promising results from reports of limited clinical trials thus far, there remain challenges in optimally harnessing the myeloid compartment as an adjunct to enhancing anti-tumor immune responses. Further large Phase II and ultimately Phase III clinical trials are needed to elucidate the treatment benefit of combination therapies in the fight against cancer.

Galectin-1, -4, and -7 Were Associated with High Activity of Disease in Patients with Rheumatoid Arthritis

Background

Due to the variety of functions that galectins (Gal) possess, it is clear that they participate in the pathogenesis of rheumatoid arthritis (RA). Although some studies demonstrate their functions, there is still no correlation with the clinical data of the disease, having the physiological meaning still unknown.

Objectives

To compare serum levels of Gal-1, -4, and -7 in patients with RA and healthy controls and to correlate them with clinical parameters.

Methods

Serum samples were collected from patients with RA and healthy donors to determine the serum levels of Gal-1, -4, and -7.

Results

Serum levels of Gal-1, -4, and -7 were significantly higher in RA patients compared to controls. We evaluated disease activity (CDAI) with serum levels of galectins and found that patients who were high in disease activity had high levels of galectin compared to the moderate activity group. Galectin-4 had higher levels in patients who were in high activity when compared to the group in remission or low activity. Evaluating the activity of the individual disease (DAS28), patients in high individual activity had high levels of Gal-4 when compared to the group in remission or low activity. We also found an association between positive rheumatoid factor and Gal-1 and Gal-4 levels.

Conclusion

Our results show for the first time the relationship between serum levels of galectin and the clinical parameters of patients with RA. Demonstrating their role in pathogenesis, new studies with galectins are needed to assess how they function as a biomarker in RA.

Synthesis of 1-benzyl-1H-benzimidazoles as galectin-1 mediated anticancer agents

In our pursuit to develop novel non-carbohydrate small molecule Galectin-1 Inhibitors, we have designed a series of 1-benzyl-1H-benzimidazole derivatives and demonstrated their anticancer activity. The compound 6g, 4-(1-benzyl-5-chloro-1H-benzo[d]imidazol-2-yl)-N-(4-hydroxyphenyl) benzamide was found to be most potent with an IC₅₀ of 7.01 ± 0.20 µM and arresting MCF-7 cell growth at G2/M phase and S phase. Induction of apoptosis was confirmed by morphological changes like cell shrinkage, blebbing and cell wall deformation, dose dependent increase in the mitochondrial membrane potential (ΔΨm) and ROS levels. Further, dose dependent decrease in Gal-1 protein levels proves Gal-1 mediated apoptosis by 6g. Molecular docking studies were performed to understand the Gal-1 interaction with compound 6g. In addition, RP-HPLC studies showed 85.44% of 6g binding to Gal-1. Binding affinity studies by fluorescence spectroscopy and Surface Plasmon Resonance (SPR) showed that 6g binds to Gal-1 with binding constant (K_a) of 1.2 × 10⁴ M^-1 and equilibrium constant K_D value of 5.76 × 10^-4 M respectively.

Effects of linker and liposome anchoring on lactose-functionalized glycomacromolecules as multivalent ligands for binding galectin-3

We combine multivalent presentation of glycan ligands on sequence-defined oligo(amidoamines) and liposomes to achieve high avidity ligands targeting galectin-3.

Galectin-Carbohydrate Interactions in Biomedicine and Biotechnology

Cellular communication events are mediated by interactions between cell-surface sugars and lectins, which are carbohydrate-binding proteins. Galectins are β-galactosyl-binding lectins that bridge molecules by their sugar moieties, forming a signaling and adhesion network. Severe changes in glycosylation and galectin expression accompany major processes in oncogenesis, cardiovascular disorders, and other pathologies, making galectins attractive therapeutic targets. Here we discuss advanced strategies of chemo-enzymatic carbohydrate synthesis for creating lead glycomimetics and (neo-)glycoconjugates for galectin-1 and -3 targeting in biomedicine and biotechnology. We will describe the challenges and bottlenecks on the route into biomedical and biotechnological practice and present the first clinical candidates. The coming era will see an exciting translation of selective well-defined high-affinity galectin ligands from bench to bedside.