Development of fucosyltransferase and fucosidase inhibitors

LncRNA PART1 promotes malignant biological behaviours associated with head and neck cancer cells via synergistic action with FUT6

The aim of this study was to determine the role of lncRNA PART1 and downstream FUT6 in tumorigenesis and progression of head and neck cancer (HNC). Bioinformatics analysis and qRT-PCR revealed that lncRNA PART1 was expressed at low levels in HNC patients. The proliferation, apoptosis, migration and flow cytometry results showed that low expression of lncRNA PART1 inhibited apoptosis and promoted HNC cell migration and proliferation. In addition, animal experiments have also shown that low expression of lncRNA PART1 can promote tumor growth. LncRNA PART1 overexpression promoted apoptosis and inhibited HNC cell migration and proliferation. Through bioinformatics analysis, FUT6 was found to be expressed at low levels in HNC and to be correlated with patient survival. Immunohistochemical and qRT-PCR results revealed that FUT6 was underexpressed in tumour tissues and HNC cells. Cell and animal experiments showed that overexpression of FUT6 could inhibit tumour proliferation and migration. Bioinformatics analysis revealed that lncRNA PART1 was positively correlated with FUT6. By qRT-PCR and western blot, we observed that after knockdown of lncRNA PART1, both the mRNA and protein expression levels of FUT6 were reduced. The above results indicated that lncRNA PART1 and FUT6 play an important role in HNC, and that lncRNA PART1 affected the development of tumor by downstream FUT6.

Semi-rationally designed site-saturation mutation of Helicobacter pylori α-1,2-fucosyltransferase for improved catalytic activity and thermostability

Helicobacter pylori HpfutC, a glycosyltransferase (GT) 11 family glycoprotein, has great potential for industrial 2'-fucosyllactose (2'-FL) production. However, its limited catalytic activity, low expression, and poor thermostability hinder practical applications. Herein, a semi-rationally designed site-saturation mutation was applied to engineer the catalytic activity and thermostability of HpfutC. The 6 single point mutants (K102T, R105C, D115S, Y251F, A255G and K282E) and 6 combined mutants (V1, V2, V3, V4, V5, and V6) with enhanced enzyme activity were obtained by mutant library screening and ordered recombination mutation. The optimal mutant V6, with an optimum temperature of 40 °C, was not a metal-dependent enzyme, yet the reaction was facilitated by Mn2+. Compared to wild-type HpfutC, mutant V6 exhibited a 2.3-fold increase in specific activity and a 2.18-fold increase in half-life at 40 °C, respectively. Kinetic parameters indicated that the Km values of mutant V6 were 34.5 % (lactose) and 25.0 % (GDP-L-fucose) lower than those of the wild enzyme, whereas the kcat/Km values were 1.20 and 1.25-fold higher than those of the wild enzyme. Further, 3D-structure analysis revealed that the highly rigid structure, formation of new hydrogen bonds, increased hydrophobic residues and redistribution of electrostatic charges on the surface may be responsible for the elevated enzyme activity and thermostability. The strategy adopted in this study is of great significance to the solution of the technical bottleneck of HpfutC and the industrial application of 2'-FL.

Exogenous l-fucose attenuates neuroinflammation induced by lipopolysaccharide

α1,6-Fucosyltransferase (Fut8) catalyzes the transfer of fucose to the innermost GlcNAc residue of N-glycan to form core fucosylation. Our previous studies showed that lipopolysaccharide (LPS) treatment highly induced neuroinflammation in Fut8 homozygous KO (Fut8-/-) or heterozygous KO (Fut8+/-) mice, compared with the WT (Fut8+/+) mice. To understand the underlying mechanism, we utilized a sensitive inflammation-monitoring mouse system that contains the human interleukin-6 (hIL6) bacterial artificial chromosome transgene modified with luciferase (Luc) reporter cassette. We successfully detected LPS-induced neuroinflammation in the central nervous system by exploiting this bacterial artificial chromosome transgenic monitoring system. Then we examined the effects of l-fucose on neuroinflammation in the Fut8+/- mice. The lectin blot and mass spectrometry analysis showed that l-fucose preadministration increased the core fucosylation levels in the Fut8+/- mice. Notably, exogenous l-fucose attenuated the LPS-induced IL-6 mRNA and Luc mRNA expression in the cerebral tissues, confirmed using the hIL6-Luc bioluminescence imaging system. The activation of microglial cells, which provoke neuroinflammatory responses upon LPS stimulation, was inhibited by l-fucose preadministration. l-Fucose also suppressed the downstream intracellular signaling of IL-6, such as the phosphorylation levels of JAK2 (Janus kinase 2), Akt (protein kinase B), and STAT3 (signal transducer and activator of transcription 3). l-Fucose administration increased gp130 core fucosylation levels and decreased the association of gp130 with the IL-6 receptor in Fut8+/- mice, which was further confirmed in BV-2 cells. These results indicate that l-fucose administration ameliorates the LPS-induced neuroinflammation in the Fut8+/- mice, suggesting that core fucosylation plays a vital role in anti-inflammation and that l-fucose is a potential prophylactic compound against neuroinflammation.

α1,3-fucosylation of MEST promotes invasion potential of cytotrophoblast cells by activating translation initiation

Embryo implantation into the uterus is the gateway for successful pregnancy. Proper migration and invasion of embryonic trophoblast cells are the key for embryo implantation, and dysfunction causes pregnancy failure. Protein glycosylation plays crucial roles in reproduction. However, it remains unclear whether the glycosylation of trophoblasts is involved in trophoblast migration and invasion processes during embryo implantation failure. By Lectin array, we discovered the decreased α1,3-fucosylation, especially difucosylated Lewis Y (LeY) glycan, in the villus tissues of miscarriage patients when compared with normal pregnancy women. Downregulating LeY biosynthesis by silencing the key enzyme fucosyltransferase IV (FUT4) inhibited migration and invasion ability of trophoblast cells. Using proteomics and translatomics, the specific LeY scaffolding glycoprotein of mesoderm-specific transcript (MEST) with glycosylation site at Asn163 was identified, and its expression enhanced migration and invasion ability of trophoblast cells. The results also provided novel evidence showing that decreased LeY modification on MEST hampered the binding of MEST with translation factor eIF4E2, and inhibited implantation-related gene translation initiation, which caused pregnancy failure. The α1,3-fucosylation of MEST by FUT4 may serve as a new biomarker for evaluating the functional state of pregnancy, and a target for infertility treatment.

Drug Discovery Based on Fluorine-Containing Glycomimetics

Glycomimetics, which are synthetic molecules designed to mimic the structures and functions of natural carbohydrates, have been developed to overcome the limitations associated with natural carbohydrates. The fluorination of carbohydrates has emerged as a promising solution to dramatically enhance the metabolic stability, bioavailability, and protein-binding affinity of natural carbohydrates. In this review, the fluorination methods used to prepare the fluorinated carbohydrates, the effects of fluorination on the physical, chemical, and biological characteristics of natural sugars, and the biological activities of fluorinated sugars are presented.

Fucosyltransferase 5 Promotes the Proliferative and Migratory Properties of Intrahepatic Cholangiocarcinoma Cells via Regulating Protein Glycosylation Profiles

Background

The incidence of intrahepatic cholangiocarcinoma (ICC) is increasing globally, and its prognosis has not improved substantially in recent years. Understanding the pathogenesis of ICC may provide a theoretical basis for its treatment. In this study, we investigated the effects and underlying mechanisms of fucosyltransferase 5 (FUT5) on the malignant progression of ICC.

Methods

FUT5 expression in ICC samples and adjacent nontumor tissues was compared using quantitative real-time polymerase chain reaction and immunohistochemical assays. We performed cell counting kit-8, colony formation, and migration assays to determine whether FUT5 influenced the proliferation and mobility of ICC cells. Finally, mass spectrometry was performed to identify the glycoproteins regulated by FUT5.

Results

FUT5 mRNA was significantly upregulated in most ICC samples compared with corresponding adjacent nontumor tissues. The ectopic expression of FUT5 promoted the proliferation and migration of ICC cells, whereas FUT5 knockdown significantly suppressed these cellular properties. Mechanistically, we demonstrated that FUT5 is essential for the synthesis and glycosylation of several proteins, including versican, β3 integrin, and cystatin 7, which may serve key roles in the precancer effects of FUT5.

Conclusions

FUT5 is upregulated in ICC and promotes ICC development by promoting glycosylation of several proteins. Therefore, FUT5 may serve as a therapeutic target for the treatment of ICC.

Applications and continued evolution of glycan imaging mass spectrometry

Glycosylation is an important posttranslational modifier of proteins and lipid conjugates critical for the stability and function of these macromolecules. Particularly important are N-linked glycans attached to asparagine residues in proteins. N-glycans have well-defined roles in protein folding, cellular trafficking and signal transduction, and alterations to them are implicated in a variety of diseases. However, the non-template driven biosynthesis of these N-glycans leads to significant structural diversity, making it challenging to identify the most biologically and clinically relevant species using conventional analyses. Advances in mass spectrometry instrumentation and data acquisition, as well as in enzymatic and chemical sample preparation strategies, have positioned mass spectrometry approaches as powerful analytical tools for the characterization of glycosylation in health and disease. Imaging mass spectrometry expands upon these strategies by capturing the spatial component of a glycan's distribution in-situ, lending additional insight into the organization and function of these molecules. Herein we review the ongoing evolution of glycan imaging mass spectrometry beginning with widely adopted tissue imaging approaches and expanding to other matrices and sample types with potential research and clinical implications. Adaptations of these techniques, along with their applications to various states of disease, are discussed. Collectively, glycan imaging mass spectrometry analyses broaden our understanding of the biological and clinical relevance of N-glycosylation to human disease.

Biological properties of exopolysaccharides produced by Bacillus spp

There is currently a constant search for ecofriendly bioproducts, which could contribute to various biomedical applications. Among bioproducts, exopolysaccharides are prominent contemporary extracellular biopolymers that are produced by a great variety of bacterial species. These homo- or heteropolymers are composed of monomeric sugar units linked by glycosidic bonds, which are secreted to the external medium. Bacillus spp. are reported to be present in different ecosystems and produce exopolysaccharides with different biological properties such as antioxidant, antibacterial, antiviral anti-inflammatory, among others. Since a great diversity of bacterial strains are able to produce exopolysaccharides, a great variation in the molecular composition is observed, which is indeed present in some of the chemical structures predicted until date. These molecular characteristics and their relations with different biological functions are discussed in order to visualize future applications in biomedical section.

Identification of gene profiles related to the development of oral cancer using a deep learning technique

BACKGROUND

Oral cancer (OC) is a debilitating disease that can affect the quality of life of these patients adversely. Oral premalignant lesion patients have a high risk of developing OC. Therefore, identifying robust survival subgroups among them may significantly improve patient therapy and care. This study aimed to identify prognostic biomarkers that predict the time-to-development of OC and survival stratification for patients using state-of-the-art machine learning and deep learning.

METHODS

Gene expression profiles (29,096 probes) related to 86 patients from the GSE26549 dataset from the GEO repository were used. An autoencoder deep learning neural network model was used to extract features. We also used a univariate Cox regression model to select significant features obtained from the deep learning method (P < 0.05). High-risk and low-risk groups were then identified using a hierarchical clustering technique based on 100 encoded features (the number of units of the encoding layer, i.e., bottleneck of the network) from autoencoder and selected by Cox proportional hazards model and a supervised random forest (RF) classifier was used to identify gene profiles related to subtypes of OC from the original 29,096 probes.

RESULTS

Among 100 encoded features extracted by autoencoder, seventy features were significantly related to time-to-OC-development, based on the univariate Cox model, which was used as the inputs for the clustering of patients. Two survival risk groups were identified (P value of log-rank test = 0.003) and were used as the labels for supervised classification. The overall accuracy of the RF classifier was 0.916 over the test set, yielded 21 top genes (FUT8-DDR2-ATM-CD247-ETS1-ZEB2-COL5A2-GMAP7-CDH1-COL11A2-COL3A1-AHR-COL2A1-CHORDC1-PTP4A3-COL1A2-CCR2-PDGFRB-COL1A1-FERMT2-PIK3CB) associated with time to developing OC, selected among the original 29,096 probes.

CONCLUSIONS

Using deep learning, our study identified prominent transcriptional biomarkers in determining high-risk patients for developing oral cancer, which may be prognostic as significant targets for OC therapy. The identified genes may serve as potential targets for oral cancer chemoprevention. Additional validation of these biomarkers in experimental prospective and retrospective studies will launch them in OC clinics.

A universal glycoenzyme biosynthesis pipeline that enables efficient cell-free remodeling of glycans

The ability to reconstitute natural glycosylation pathways or prototype entirely new ones from scratch is hampered by the limited availability of functional glycoenzymes, many of which are membrane proteins that fail to express in heterologous hosts. Here, we describe a strategy for topologically converting membrane-bound glycosyltransferases (GTs) into water soluble biocatalysts, which are expressed at high levels in the cytoplasm of living cells with retention of biological activity. We demonstrate the universality of the approach through facile production of 98 difficult-to-express GTs, predominantly of human origin, across several commonly used expression platforms. Using a subset of these water-soluble enzymes, we perform structural remodeling of both free and protein-linked glycans including those found on the monoclonal antibody therapeutic trastuzumab. Overall, our strategy for rationally redesigning GTs provides an effective and versatile biosynthetic route to large quantities of diverse, enzymatically active GTs, which should find use in structure-function studies as well as in biochemical and biomedical applications involving complex glycomolecules.

Proteomic Analysis of Chicken Chorioallantoic Membrane (CAM) during Embryonic Development Provides Functional Insight

In oviparous animals, the egg contains all resources required for embryonic development. The chorioallantoic membrane (CAM) is a placenta-like structure produced by the embryo for acid-base balance, respiration, and calcium solubilization from the eggshell for bone mineralization. The CAM is a valuable in vivo model in cancer research for development of drug delivery systems and has been used to study tissue grafts, tumor metastasis, toxicology, angiogenesis, and assessment of bacterial invasion. However, the protein constituents involved in different CAM functions are poorly understood. Therefore, we have characterized the CAM proteome at two stages of development (ED12 and ED19) and assessed the contribution of the embryonic blood serum (EBS) proteome to identify CAM-unique proteins. LC/MS/MS-based proteomics allowed the identification of 1470, 1445, and 791 proteins in CAM (ED12), CAM (ED19), and EBS, respectively. In total, 1796 unique proteins were identified. Of these, 175 (ED12), 177 (ED19), and 105 (EBS) were specific to these stages/compartments. This study attributed specific CAM protein constituents to functions such as calcium ion transport, gas exchange, vasculature development, and chemical protection against invading pathogens. Defining the complex nature of the CAM proteome provides a crucial basis to expand its biomedical applications for pharmaceutical and cancer research.

Comparing different machine learning techniques for predicting COVID-19 severity

Background

Coronavirus disease 2019 (COVID-19) is still ongoing spreading globally, machine learning techniques were used in disease diagnosis and to predict treatment outcomes, which showed favorable performance. The present study aims to predict COVID-19 severity at admission by different machine learning techniques including random forest (RF), support vector machine (SVM), and logistic regression (LR). Feature importance to COVID-19 severity were further identified.

Methods

A retrospective design was adopted in the JinYinTan Hospital from January 26 to March 28, 2020, eighty-six demographic, clinical, and laboratory features were selected with LassoCV method, Spearman’s rank correlation, experts’ opinions, and literature evaluation. RF, SVM, and LR were performed to predict severe COVID-19, the performance of the models was compared by the area under curve (AUC). Additionally, feature importance to COVID-19 severity were analyzed by the best performance model.

Results

A total of 287 patients were enrolled with 36.6% severe cases and 63.4% non-severe cases. The median age was 60.0 years (interquartile range: 49.0–68.0 years). Three models were established using 23 features including 1 clinical, 1 chest computed tomography (CT) and 21 laboratory features. Among three models, RF yielded better overall performance with the highest AUC of 0.970 than SVM of 0.948 and LR of 0.928, RF also achieved a favorable sensitivity of 96.7%, specificity of 69.5%, and accuracy of 84.5%. SVM had sensitivity of 93.9%, specificity of 79.0%, and accuracy of 88.5%. LR also achieved a favorable sensitivity of 92.3%, specificity of 72.3%, and accuracy of 85.2%. Additionally, chest-CT had highest importance to illness severity, and the following features were neutrophil to lymphocyte ratio, lactate dehydrogenase, and D-dimer, respectively.

Conclusions

Our results indicated that RF could be a useful predictive tool to identify patients with severe COVID-19, which may facilitate effective care and further optimize resources.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40249-022-00946-4.

Fluorinated rhamnosides inhibit cellular fucosylation

The sugar fucose is expressed on mammalian cell membranes as part of glycoconjugates and mediates essential physiological processes. The aberrant expression of fucosylated glycans has been linked to pathologies such as cancer, inflammation, infection, and genetic disorders. Tools to modulate fucose expression on living cells are needed to elucidate the biological role of fucose sugars and the development of potential therapeutics. Herein, we report a class of fucosylation inhibitors directly targeting de novo GDP-fucose biosynthesis via competitive GMDS inhibition. We demonstrate that cell permeable fluorinated rhamnose 1-phosphate derivatives (Fucotrim I & II) are metabolic prodrugs that are metabolized to their respective GDP-mannose derivatives and efficiently inhibit cellular fucosylation.

Fucosyltransferase 2 inhibitors: Identification via docking and STD-NMR studies

Fucosyltransferase 2 (FUT2) catalyzes the biosynthesis of A, B, and H antigens and other important glycans, such as (Sialyl Lewisx) sLex, and (Sialyl Lewisy) sLey. The production of these glycans is increased in various cancers, hence to design and develop specific inhibitors of FUT2 is a therapeutic strategy. The current study was designed to identify the inhibitors for FUT2. In silico screening of 300 synthetic compounds was performed. Molecular docking studies highlighted the interactions of ligands with critical amino acid residues, present in the active site of FUT2. The epitope mapping in ligands was performed using the STD-NMR experiments to identify the interactions between ligands, and receptor protein. Finally, we have identified 5 lead compounds 4, 5, 26, 27, and 28 that can be studied for further development as cancer therapeutic agents.

Overexpression of a Novel ERF-X-Type Transcription Factor, OsERF106MZ, Reduces Shoot Growth and Tolerance to Salinity Stress in Rice

Transcription factors (TFs) such as ethylene-responsive factors (ERFs) are important for regulating plant growth, development, and responses to abiotic stress. Notably, more than half of the rice ERF-X group members, including ethylene-responsive factor 106 (OsERF106), are abiotic stress-responsive genes. However, their regulatory roles in abiotic stress responses remain poorly understood. OsERF106, a salinity-induced gene of unknown function, is annotated differently in RAP-DB and MSU RGAP. In this study, we isolated a novel (i.e., previously unannotated) OsERF106 gene, designated OsERF106MZ (GenBank accession No. MZ561461), and investigated its role in regulating growth and the response to salinity stress in rice. OsERF106MZ is expressed in germinating seeds, primary roots, and developing flowers. Overexpression of OsERF106MZ led to retardation of growth, relatively high levels of both malondialdehyde (MDA) and reactive oxygen species (ROS), reduced catalase (CAT) activity, and overaccumulation of both sodium (Na⁺) and potassium (K⁺) ions in transgenic rice shoots. Additionally, the expression of OsHKT1.3 was downregulated in the shoots of transgenic seedlings grown under both normal and NaCl-treated conditions, while the expression of OsAKT1 was upregulated in the same tissues grown under NaCl-treated conditions. Further microarray and qPCR analyses indicated that the expression of several abiotic stress-responsive genes such as OsABI5 and OsSRO1c was also altered in the shoots of transgenic rice grown under either normal or NaCl-treated conditions. The novel transcription factor OsERF106MZ negatively regulates shoot growth and salinity tolerance in rice through the disruption of ion homeostasis and modulation of stress-responsive gene expression.

N-Glycomic Analysis of the Cell Shows Specific Effects of Glycosyl Transferase Inhibitors

Glycomic profiling methods were used to determine the effect of metabolic inhibitors on glycan production. These inhibitors are commonly used to alter the cell surface glycosylation. However, structural analysis of the released glycans has been limited. In this research, the cell membranes were enriched and the glycans were released to obtain the N-glycans of the glycocalyx. Glycomic analysis using liquid chromatography–mass spectrometry (LC–MS) with a PGC chip column was used to profile the structures in the cell membrane. Glycans of untreated cells were compared to glycans of cells treated with inhibitors, including kifunensine, which inhibits the formation of complex- and hybrid-type structures, 2,4,7,8,9-Penta-O-acetyl-N-acetyl-3-fluoro-b-d-neuraminic acid methyl ester for sialylated glycans, 2-deoxy-2-fluorofucose, and 6-alkynyl fucose for fucosylated glycans. Kifunensine was the most effective, converting nearly 95% of glycans to high mannose types. The compound 6-alkynyl fucose inhibited some fucosylation but also incorporated into the glycan structure. Proteomic analysis of the enriched membrane for the four inhibitors showed only small changes in the proteome accompanied by large changes in the N-glycome for Caco-2. Future works may use these inhibitors to study the cellular behavior associated with the alteration of glycosylation in various biological systems, e.g., viral and bacterial infection, drug binding, and cell–cell interactions.

Structural Insights in Mammalian Sialyltransferases and Fucosyltransferases: We Have Come a Long Way, but It Is Still a Long Way Down

Mammalian cell surfaces are modified with complex arrays of glycans that play major roles in health and disease. Abnormal glycosylation is a hallmark of cancer; terminal sialic acid and fucose in particular have high levels in tumor cells, with positive implications for malignancy. Increased sialylation and fucosylation are due to the upregulation of a set of sialyltransferases (STs) and fucosyltransferases (FUTs), which are potential drug targets in cancer. In the past, several advances in glycostructural biology have been made with the determination of crystal structures of several important STs and FUTs in mammals. Additionally, how the independent evolution of STs and FUTs occurred with a limited set of global folds and the diverse modular ability of catalytic domains toward substrates has been elucidated. This review highlights advances in the understanding of the structural architecture, substrate binding interactions, and catalysis of STs and FUTs in mammals. While this general understanding is emerging, use of this information to design inhibitors of STs and FUTs will be helpful in providing further insights into their role in the manifestation of cancer and developing targeted therapeutics in cancer.

FUT8 and Protein Core Fucosylation in Tumours: From Diagnosis to Treatment

Glycosylation changes are key molecular events in tumorigenesis, progression and glycosyltransferases play a vital role in the this process. FUT8 belongs to the fucosyltransferase family and is the key enzyme involved in N-glycan core fucosylation. FUT8 and/or core fucosylated proteins are frequently upregulated in liver, lung, colorectal, pancreas, prostate,breast, oral cavity, oesophagus, and thyroid tumours, diffuse large B-cell lymphoma, ependymoma, medulloblastoma and glioblastoma multiforme and downregulated in gastric cancer. They can be used as markers of cancer diagnosis, occurrence, progression and prognosis. Core fucosylated EGFR, TGFBR, E-cadherin, PD1/PD-L1 and α3β1 integrin are potential targets for tumour therapy. In addition, IGg1 antibody defucosylation can improve antibody affinity, which is another aspect of FUT8 that could be applied to tumour therapy.

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.

Fucosyltransferase-specific inhibition via next generation of fucose mimetics

The ability to custom-modify cell surface glycans holds great promise for treatment of a variety of diseases. We propose a glycomimetic of l-fucose that markedly inhibits the creation of sLe^X by FTVI and FTVII, but has no effect on creation of Le^X by FTIX. Our findings thus indicate that selective suppression of sLex display can be achieved, and STD-NMR studies surprisingly reveal that the mimetic does not compete with GDP-fucose at the enzymatic binding site.

Synthesis and Evaluation of Novel Iminosugars Prepared from Natural Amino Acids

Cyclopropanated iminosugars have a locked conformation that may enhance the inhibitory activity and selectivity against different glycosidases. We show the synthesis of new cyclopropane-containing piperidines bearing five stereogenic centers from natural amino acids l-serine and l-alanine. Those prepared from the latter amino acid may mimic l-fucose, a natural-occurring monosaccharide involved in many molecular recognition events. Final compounds prepared from l-serine bear S configurations on the C5 position. The synthesis involved a stereoselective cyclopropanation reaction of an α,β-unsaturated piperidone, which was prepared through a ring-closing metathesis. The final compounds were tested as possible inhibitors of different glycosidases. The results, although, in general, with low inhibition activity, showed selectivity, depending on the compound and enzyme, and in some cases, an unexpected activity enhancement was observed.

Fluorinated carbohydrates as chemical probes for molecular recognition studies. Current status and perspectives

This review provides an extensive summary of the effects of carbohydrate fluorination with regard to changes in physical, chemical and biological properties with respect to regular saccharides. The specific structural, conformational, stability, reactivity and interaction features of fluorinated sugars are described, as well as their applications as probes and in chemical biology.

Computational classification of core and outer fucosylation of N-glycoproteins in human plasma using collision-induced dissociation in mass spectrometry

RATIONALE

Glycoprotein fucosylation, one of the major posttranslational modifications, is known to be highly involved in proteins related to various cancers. Fucosylation occurs in the core and/or outer sites of N-glycopeptides. Elucidation of the fucosylation type of N-glycoproteins is therefore important. However, it has remained a challenge to classify the fucosylation types of N-glycopeptides using collision-induced dissociation (CID) tandem mass (MS/MS) spectra.

METHODS

The relative intensities of the Y₁ F, Y₂ F, Y₃ F, and Y₄ F product ions in the CID-MS/MS spectra of the IgG N-glycopeptides were measured for core fucosylation. The Core Fucose Index (CFI) was then calculated by multiplication of the relative intensities with a weight factor from logistic regression to differentiate between the core and none fucosylation. From the relative intensities of the B₂ F and B₃ SF ions of the MS/MS spectra of the AGP N-glycopeptides for outer fucosylation, the Outer Fucose Index (OFI) was calculated to differentiate between the outer and none fucosylation.

RESULTS

In order to classify core and/or outer fucosylation of N-glycoproteins, we defined the fucosylation score (F-score) by a sigmoidal equation using a combination of the CFI and the OFI. For application, we classified the fucosylation types of N-glycoproteins in human plasma with 99.7% accuracy from the F-score. Human plasma samples showed 54.4%, 33.3%, 10.3%, and 1.6% for none, core, outer, and dual fucosylated N-glycopeptides, respectively. Core fucosylation was abundant at mono- and bi-antennary N-glycopeptides. Outer fucosylation was abundant at tri- and tetra-antennary N-glycopeptides. In total, 113 N-glycopeptides of 29 glycoproteins from 3365 glycopeptide spectral matches (GPSMs) were classified for different types of fucosylation.

CONCLUSIONS

We established an F-score to classify three different fucosylation types: core, outer, and dual types of N-glycopeptides. The fucosylation types of 20 new N-glycopeptides from 11 glycoproteins in human plasma were classified using the F-score. Therefore, the F-score can be useful for the automatic classification of different types of fucosylation in N-glycoproteins of biological fluids including plasma, serum, and urine.

Synthetic Fluorinated l-Fucose Analogs Inhibit Proliferation of Cancer Cells and Primary Endothelial Cells

Fucosylation is one of the most prevalent modifications on N- and O-glycans of glycoproteins, and it plays an important role in various cellular processes and diseases. Small molecule inhibitors of fucosylation have shown promise as therapeutic agents for sickle cell disease, arthritis, and cancer. We describe here the design and synthesis of a panel of fluorinated l-fucose analogs bearing fluorine atoms at the C2 and/or C6 positions of l-fucose as metabolic fucosylation inhibitors. Preliminary study of their effects on cell proliferation revealed that the 6,6-difluoro-l-fucose (3) and 6,6,6-trifluoro-l-fucose (6) showed significant inhibitory activity against proliferation of human colon cancer cells and human umbilical vein endothelial cells. In contrast, the previously reported 2-deoxy-2-fluoro-l-fucose (1) had no apparent effects on proliferations of all the cell lines tested. To understand the mechanism of cell proliferation inhibition by the fluorinated l-fucose analogs, we performed chemoenzymatic synthesis of the corresponding GDP-fluorinated l-fucose analogs and tested their inhibitory activities against the mammalian α1,6-fucosyltransferase (FUT8). Interestingly, the corresponding GDP derivatives of 6,6-difluoro-l-fucose (3) and 6,6,6-trifluoro-l-fucose (6), which are the stronger proliferation inhibitors, showed much weaker inhibitory activity against FUT8 than that of the 2-deoxy-2-fluoro-l-fucose (1). These results suggest that FUT8 is not the major target of the 6-fluorinated fucose analogs (3 and 6). Instead, other factors, such as the key enzymes involved in the de novo GDP-fucose biosynthetic pathway and/or other fucosyltransferases involved in the biosynthesis of tumor-associated glyco-epitopes are most likely the targets of the fluorinated l-fucose analogs to achieve cell proliferation inhibition. To our knowledge, this is the first comparative study of various fluorinated l-fucose analogs for suppressing the proliferation of human cancer and primary endothelial cells required for angiogenesis.

Dissecting the conformation of glycans and their interactions with proteins

The use of in silico strategies to develop the structural basis for a rational optimization of glycan-protein interactions remains a great challenge. This problem derives, in part, from the lack of technologies to quantitatively and qualitatively assess the complex assembling between a glycan and the targeted protein molecule. Since there is an unmet need for developing new sugar-targeted therapeutics, many investigators are searching for technology platforms to elucidate various types of molecular interactions within glycan-protein complexes and aid in the development of glycan-targeted therapies. Here we discuss three important technology platforms commonly used in the assessment of the complex assembly of glycosylated biomolecules, such as glycoproteins or glycosphingolipids: Biacore analysis, molecular docking, and molecular dynamics simulations. We will also discuss the structural investigation of glycosylated biomolecules, including conformational changes of glycans and their impact on molecular interactions within the glycan-protein complex. For glycoproteins, secreted protein acidic and rich in cysteine (SPARC), which is associated with various lung disorders, such as chronic obstructive pulmonary disease (COPD) and lung cancer, will be taken as an example showing that the core fucosylation of N-glycan in SPARC regulates protein-binding affinity with extracellular matrix collagen. For glycosphingolipids (GSLs), Globo H ceramide, an important tumor-associated GSL which is being actively investigated as a target for new cancer immunotherapies, will be used to demonstrate how glycan structure plays a significant role in enhancing angiogenesis in tumor microenvironments.

In Silico Evaluation of the Binding Site of Fucosyltransferase 8 and First Attempts to Synthesize an Inhibitor with Drug-Like Properties

Core fucosylation of N-glycans is catalyzed by fucosyltransferase 8 and is associated with various types of cancer. Most reported fucosyltransferase inhibitors contain non-drug-like features, such as charged groups. New starting points for the development of inhibitors of fucosyltransferase 8 using a fragment-based strategy are presented. Firstly, we discuss the potential of a new putative binding site of fucosyltransferase 8 that, according to a molecular dynamics (MD) simulation, is made accessible by a significant motion of the SH3 domain. This might enable the design of completely new inhibitor types for fucosyltransferase 8. Secondly, we have performed a docking study targeting the donor binding site of fucosyltransferase 8, and this yielded two fragments that were linked and trimmed in silico. The resulting ligand was synthesized. Saturation transfer difference (STD) NMR confirmed binding of the ligand featuring a pyrazole core that mimics the guanine moiety. This ligand represents the first low-molecular-weight compound for the development of inhibitors of fucosyltransferase 8 with drug-like properties.

Selectins-The Two Dr. Jekyll and Mr. Hyde Faces of Adhesion Molecules-A Review

Selectins belong to a group of adhesion molecules that fulfill an essential role in immune and inflammatory responses and tissue healing. Selectins are glycoproteins that decode the information carried by glycan structures, and non-covalent interactions of selectins with these glycan structures mediate biological processes. The sialylated and fucosylated tetrasaccharide sLe^x is an essential glycan recognized by selectins. Several glycosyltransferases are responsible for the biosynthesis of the sLe^x tetrasaccharide. Selectins are involved in a sequence of interactions of circulated leukocytes with endothelial cells in the blood called the adhesion cascade. Recently, it has become evident that cancer cells utilize a similar adhesion cascade to promote metastases. However, like Dr. Jekyll and Mr. Hyde’s two faces, selectins also contribute to tissue destruction during some infections and inflammatory diseases. The most prominent function of selectins is associated with the initial stage of the leukocyte adhesion cascade, in which selectin binding enables tethering and rolling. The first adhesive event occurs through specific non-covalent interactions between selectins and their ligands, with glycans functioning as an interface between leukocytes or cancer cells and the endothelium. Targeting these interactions remains a principal strategy aimed at developing new therapies for the treatment of immune and inflammatory disorders and cancer. In this review, we will survey the significant contributions to and the current status of the understanding of the structure of selectins and the role of selectins in various biological processes. The potential of selectins and their ligands as therapeutic targets in chronic and acute inflammatory diseases and cancer will also be discussed. We will emphasize the structural characteristic of selectins and the catalytic mechanisms of glycosyltransferases involved in the biosynthesis of glycan recognition determinants. Furthermore, recent achievements in the synthesis of selectin inhibitors will be reviewed with a focus on the various strategies used for the development of glycosyltransferase inhibitors, including substrate analog inhibitors and transition state analog inhibitors, which are based on knowledge of the catalytic mechanism.

The Impact of Dietary Fucosylated Oligosaccharides and Glycoproteins of Human Milk on Infant Well-Being

Apart from optimal nutritional value, human milk is the feeding strategy to support the immature immunological system of developing newborns and infants. The most beneficial dietary carbohydrate components of breast milk are human milk oligosaccharides (HMOs) and glycoproteins (HMGs), involved in both specific and nonspecific immunity. Fucosylated oligosaccharides represent the largest fraction of human milk oligosaccharides, with the simplest and the most abundant being 2'-fucosyllactose (2'FL). Fucosylated oligosaccharides, as well as glycans of glycoproteins, as beneficial dietary sugars, elicit anti-adhesive properties against fucose-dependent pathogens, and on the other hand are crucial for growth and metabolism of beneficial bacteria, and in this aspect participate in shaping a healthy microbiome. Well-documented secretor status related differences in the fucosylation profile of HMOs and HMGs may play a key but underestimated role in assessment of susceptibility to fucose-dependent pathogen infections, with a potential impact on applied clinical procedures. Nevertheless, due to genetic factors, about 20% of mothers do not provide their infants with beneficial dietary carbohydrates such as 2'-FL and other α1,2-fucosylated oligosaccharides and glycans of glycoproteins, despite breastfeeding them. The lack of such structures may have important implications for a wide range of aspects of infant well-being and healthcare. In light of the above, some artificial mixtures used in infant nutrition are supplemented with 2'-FL to more closely approximate the unique composition of maternal milk, including dietary-derived fucosylated oligosaccharides and glycoproteins.

Machine Learning Classifies Core and Outer Fucosylation of N-Glycoproteins Using Mass Spectrometry

Protein glycosylation is known to be involved in biological progresses such as cell recognition, growth, differentiation, and apoptosis. Fucosylation of glycoproteins plays an important role for structural stability and function of N-linked glycoproteins. Although many of biological and clinical studies of protein fucosylation by fucosyltransferases has been reported, structural classification of fucosylated N-glycoproteins such as core or outer isoforms remains a challenge. Here, we report for the first time the classification of N-glycopeptides as core- and outer-fucosylated types using tandem mass spectrometry (MS/MS) and machine learning algorithms such as the deep neural network (DNN) and support vector machine (SVM). Training and test sets of more than 800 MS/MS spectra of N-glycopeptides from the immunoglobulin gamma and alpha 1-acid-glycoprotein standards were selected for classification of the fucosylation types using supervised learning models. The best-performing model had an accuracy of more than 99% against manual characterization and area under the curve values greater than 0.99, which were calculated by probability scores from target and decoy datasets. Finally, this model was applied to classify fucosylated N-glycoproteins from human plasma. A total of 82N-glycopeptides, with 54 core-, 24 outer-, and 4 dual-fucosylation types derived from 54 glycoproteins, were commonly classified as the same type in both the DNN and SVM. Specifically, outer fucosylation was dominant in tri- and tetra-antennary N-glycopeptides, while core fucosylation was dominant in the mono-, bi-antennary and hybrid types of N-glycoproteins in human plasma. Thus, the machine learning methods can be combined with MS/MS to distinguish between different isoforms of fucosylated N-glycopeptides.

Chemoenzymatic synthesis of 3-deoxy-3-fluoro-l-fucose and its enzymatic incorporation into glycoconjugates

A chemoenzymatic synthesis of 3-deoxy-3-fluoro-l-fucose, using a d- to l-sugar translation strategy, and its enzymatic activation and glycosylation, is reported.

Altered expression of fucosylation pathway genes is associated with poor prognosis and tumor metastasis in non‑small cell lung cancer

Fucosylation is a post‑translational modification that attaches fucose residues to protein‑ or lipid‑bound oligosaccharides. Certain fucosylation pathway genes are aberrantly expressed in several types of cancer, including non‑small cell lung cancer (NSCLC), and this aberrant expression is associated with poor prognosis in patients with cancer. However, the molecular mechanism by which these fucosylation pathway genes promote tumor progression has not been well‑characterized. The present study analyzed public microarray data obtained from NSCLC samples. Multivariate analysis revealed that altered expression of fucosylation pathway genes, including fucosyltransferase 1 (FUT1), FUT2, FUT3, FUT6, FUT8 and GDP‑L‑fucose synthase (TSTA3), correlated with poor survival in patients with NSCLC. Inhibition of FUTs by 2F‑peracetyl‑fucose (2F‑PAF) suppressed transforming growth factor β (TGFβ)‑mediated Smad3 phosphorylation and nuclear translocation in NSCLC cells. In addition, wound‑healing and Transwell migration assays demonstrated that 2F‑PAF inhibited TGFβ‑induced NSCLC cell migration and invasion. Furthermore, in vivo bioluminescence imaging analysis revealed that 2F‑PAF attenuated the metastatic capacity of NSCLC cells. These results may help characterize the oncogenic role of fucosylation in NSCLC biology and highlight its potential for developing cancer therapeutics.

Development of Fluorogenic Substrates of α-l-Fucosidase Useful for Inhibitor Screening and Gene-expression Profiling

Inhibitors of human α-l-fucosidases, tissue α-l-fucosidase (tFuc), and plasma α-l-fucosidase reportedly play roles in multiple diseases, suggesting their therapeutic potential for gastric disease associated with Helicobacter pylori and fucosidosis. Terminal fucose linkages on glycoproteins and glycolipids are a natural substrate for both enzymes; however, there are currently no fluorogenic substrates allowing their cellular evaluation. Here, we described the development of novel three-color fluorogenic substrates for lysosome-localized tFuc that exhibited excellent specificity and sensitivity in three human cell lines. Additionally, we developed a cell-based high-throughput inhibitor screening system in a 96-well format and a cell-based inhibitory activity evaluation system in a 6-well format for tFuc inhibitors using this substrate, which allowed accurate quantification of the inhibition rate. Moreover, analysis of significant changes in gene expression resulting from 30% inhibition of tFuc in HeLa cells revealed potential roles in gastric disease.

The Diverse Contributions of Fucose Linkages in Cancer

Fucosylation is a post-translational modification of glycans, proteins, and lipids that is responsible for many biological processes. Fucose conjugation via α(1,2), α(1,3), α(1,4), α(1,6), and O'- linkages to glycans, and variations in fucosylation linkages, has important implications for cancer biology. This review focuses on the roles that fucosylation plays in cancer, specifically through modulation of cell surface proteins and signaling pathways. How L-fucose and serum fucosylation patterns might be used for future clinical diagnostic, prognostic, and therapeutic approaches will be discussed.

A fucosyltransferase inhibition assay using image-analysis and digital microfluidics

Sialyl-LewisX and LewisX are cell-surface glycans that influence cell-cell adhesion behaviors. These glycans are assembled by α(1,3)-fucosyltransferase enzymes. Their increased expression plays a role in inflammatory disease, viral and microbial infections, and cancer. Efficient screens for specific glycan modifications such as those catalyzed by fucosyltransferases are tended toward costly materials and large instrumentation. We demonstrate for the first time a fucosylation inhibition assay on a digital microfluidic system with the integration of image-based techniques. Specifically, we report a novel lab-on-a-chip approach to perform a fluorescence-based inhibition assay for the fucosylation of a labeled synthetic disaccharide, 4-methylumbelliferyl β-N-acetyllactosaminide. As a proof-of-concept, guanosine 5'-diphosphate has been used to inhibit Helicobacter pylori α(1,3)-fucosyltransferase. An electrode shape (termed "skewed wave") is designed to minimize electrode density and improve droplet movement compared to conventional square-based electrodes. The device is used to generate a 10 000-fold serial dilution of the inhibitor and to perform fucosylation reactions in aqueous droplets surrounded by an oil shell. Using an image-based method of calculating dilutions, referred to as "pixel count," inhibition curves along with IC₅₀ values are obtained on-device. We propose the combination of integrating image analysis and digital microfluidics is suitable for automating a wide range of enzymatic assays.

Impact of Acetylated and Non-Acetylated Fucose Analogues on IgG Glycosylation

The biological activity of therapeutic antibodies is highly influenced by their glycosylation profile. A valuable method for increasing the cytotoxic efficacy of antibodies, which are used, for example, in cancer treatment, is the reduction of core fucosylation, as this enhances the elimination of target cells through antibody-dependent cell-mediated cytotoxicity. Development of fucose analogues is currently the most promising strategy to reduce core fucosylation without cell line engineering. Since peracetylated sugars display enhanced cell permeability over the highly polar free hydroxy sugars, this work sought to compare the efficacy of peracetylated sugars to their unprotected forms. Two potent fucose analogues, 2-deoxy-2-fluorofucose and 5-alkynylfucose, and their acetylated forms were compared for their effects on fucosylation. 5-alkynylfucose proved to be more potent than 2-deoxy-2-fluorofucose at reducing core fucosylation but was associated with a significant higher incorporation of the alkynylated fucose analogue. Acetylation of the sugar yielded only slightly lower fucosylation levels suggesting that acetylation has a minor impact on cellular entry. Even though the efficacy of all tested components was confirmed, results presented in this study also show a significant incorporation of unnatural fucose analogues into the glycosylation pattern of the produced IgG, with unknown effect on safety and potency of the monoclonal antibody.

Lewis acid promoted anomerisation of alkyl O- and S-xylo-, arabino- and fucopyranosides

Pentopyranoside and 6-deoxyhexopyranosides, such as those from d-xylose, l-arabinose and l-fucose are components of natural products, oligosaccharides or polysaccharides. Lewis acid promoted anomerisation of some of their alkyl O- and S-glycopyranosides is reported here. SnCl₄ was more successful than TiCl₄, with the latter giving the glycosyl chloride by-product in some cases, and both were superior to BF₃OEt₂. Kinetics study using ¹H NMR spectroscopy showed an order of reactivity: O-xylopyranoside > O-arabinopyranoside > O-fucopyranoside. Benzoylated glycosides were more reactive than acetylated glycosides. The reactivity of S-glycosides was greater than that of O-glycosides for both arabinose and fucose derivatives; the reactivity of O- and S-xylopyranosides was similar. The highest stereoselectivities were observed for fucopyranosides. The β-d-xylopyranoside and α-l-arabinopyranoside reactants are conformationally more flexible than β-l-fucopyranosides.

N-Alkyl-1,5-dideoxy-1,5-imino-l-fucitols as fucosidase inhibitors: Synthesis, molecular modelling and activity against cancer cell lines

1,5-Dideoxy-1,5-imino-l-fucitol (1-deoxyfuconojirimycin, DFJ) is an iminosugar that inhibits fucosidases. Herein, N-alkyl DFJs have been synthesised and tested against the α-fucosidases of T. maritima (bacterial origin) and B. taurus (bovine origin). The N-alkyl derivatives were inactive against the bacterial fucosidase, while inhibiting the bovine enzyme. Docking of inhibitors to homology models, generated for the bovine and human fucosidases, was carried out. N-Decyl-DFJ was toxic to cancer cell lines and was more potent than the other N-alkyl DFJs studied.

POFUT1 promotes colorectal cancer development through the activation of Notch1 signaling

Copy number variations (CNVs) are key drivers of colorectal cancer (CRC). Our previous studies revealed that protein O-fucosyltransferase 1 (POFUT1) overexpression is driven by CNVs during CRC development. The potential role and underlying mechanisms of POFUT1 in CRC were not investigated. In this study, we analyzed the expression of POFUT1 in CRC from cosmic and TCGA databases and confirmed that POFUT1 is highly expressed in CRC. We used well characterized CRC cell lines, including SW620 and HCT116 to establish a model POFUT1 knockdown cell line. Using these cells, we investigated the role of POFUT1 in CRC. Our data revealed that silencing POFUT1 in CRC cells inhibits cell proliferation, decreases cell invasion and migration, arrests cell cycle progression, and stimulates CRC cell apoptosis in vitro. We further demonstrate that POFUT1 silencing dramatically suppresses CRC tumor growth and transplantation in vivo. We additionally reveal new mechanistic insights into the role of POFUT1 during CRC, through demonstrating that POFUT1 silencing inhibits Notch1 signaling. Taken together, our findings demonstrate that POFUT1 is a tumor activating gene during CRC development, which positively regulates CRC tumor progression through activating Notch1.

Lewis-antigen-containing ICAM-2/3 on Jurkat leukemia cells interact with DC-SIGN to regulate DC functions

Dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) is an important C-type lectin and plays a critical role in the recognition of pathogens and self-antigens. It has recently been shown that DC-SIGN directly interacts with acute T lymphoblastic leukemia cells. However, the mechanism regulating DC-SIGN-dependent DC association as well as related functions is still elusive. Here we showed that DC-SIGN preferentially bound to a set of malignant T lymphocytes, including Jurkat, CCRF-HSB2 and CCRF-CEM. ICAM-2/3 on Jurkat cells appeared to be the responsible ligands and the block of ICAM-2/3 dramatically impaired DC-SIGN association. We also found that ICAM-2/3 bear a considerable amount of Lewis X, Lewis Y and Lewis A residues, which are important for DC-SIGN recognition. Furthermore, transcriptome analysis revealed an upregulation of fucosyltransferase 4 (FUT4) in Jurkat cells and downregulating FUT4 limited DC-SIGN binding, indicating a previously unappreciated role of FUT4 in the control of Lewis antigens on malignant T lymphocytes. In addition, the presence of Jurkat cells impaired DC maturation and the block of DC-SIGN improved Jurkat cell-mediated effects on DC function and T cell differentiation. Together, we provide evidence that DC-SIGN orients DC association with acute T lymphoblastic leukemia cells and orchestrates DC functions.

AP1 mediates uPA/uPAR induced FUT4 expression and trophoblast invasion

Trophoblast invasion is crucial for embryo implantation and successful pregnancy. Urokinase-type plasminogen activator (uPA)/urokinase-type plasminogen activator receptor (uPAR) are expressed on trophoblasts and involved in trophoblast invasion. The transcription factor activator protein 1 (AP1) (c-Fos and cJun) and fucosyltransferase IV (FUT4) have been found to be involved in this process. However, the relationship of uPA/uPAR, AP1 and FUT4 is unclear. The current study aimed to investigate the role of AP1 in uPA/uPAR induced FUT4 expression and trophoblast invasion. We found that p-c-Fos and p-c-Jun were decreased in abortion patients compared to that in normal pregnant women. Employing human trophoblastic cells, we then demonstrated that uPA/uPAR induced the expression of p-c-Fos and p-c-Jun. Applying an electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP), we further proved that transcription factor AP1 bound to FUT4 promoter that could increase FUT4 transcriptional activity, further promoting trophoblast cell migration and invasion through JNK MAPK signaling pathway. Taken together, these results suggest that uPA/uPAR induces FUT4 expression, and trophoblast cell invasion mediated by AP1 transcription factor (c-Fos and c-Jun). Our findings provide novel insights into the relationship between AP1 and abortion.

Inhibition of fucosylation by 2-fluorofucose suppresses human liver cancer HepG2 cell proliferation and migration as well as tumor formation

Core fucosylation is one of the most important glycosylation events in the progression of liver cancer. For this study, we used an easily handled L-fucose analog, 2-fluoro-L-fucose (2FF), which interferes with the normal synthesis of GDP-fucose, and verified its potential roles in regulating core fucosylation and cell behavior in the HepG2 liver cancer cell line. Results obtained from lectin blot and flow cytometry analysis clearly showed that 2FF treatment dramatically inhibited core fucosylation, which was also confirmed via mass spectrometry analysis. Cell proliferation and integrin-mediated cell migration were significantly suppressed in cells treated with 2FF. We further analyzed cell colony formation in soft agar and tumor xenograft efficacy, and found that both were greatly suppressed in the 2FF-treated cells, compared with the control cells. Moreover, the treatment with 2FF decreased the core fucosylation levels of membrane glycoproteins such as EGF receptor and integrin β1, which in turn suppressed downstream signals that included phospho-EGFR, -AKT, -ERK, and -FAK. These results clearly described the roles of 2FF and the importance of core fucosylation in liver cancer progression, suggesting 2FF shows promise for use in the treatment of hepatoma.

Conditioned Medium from Malignant Breast Cancer Cells Induces an EMT-Like Phenotype and an Altered N-Glycan Profile in Normal Epithelial MCF10A Cells

Epithelial-mesenchymal transition (EMT) is a key process in cancer development and progression. Communication (crosstalk) between cancer cells and normal (nonmalignant) cells may facilitate cancer progression. Conditioned medium (CM) obtained from cultured cancer cells contains secreted factors capable of affecting phenotypes and the behaviors of normal cells. In this study, a culture of normal breast epithelial MCF10A cells with CM from malignant breast cancer cells (termed 231-CM and 453-CM) resulted in an alteration of morphology. CM-treated MCF10A, in comparison with control cells, showed a reduced expression of the epithelial marker E-cadherin, increased expression of the mesenchymal markers fibronectin, vimentin, N-cadherin, and TWIST1, meanwhile cell proliferation and migration were enhanced while cell apoptosis was decreased. N-glycan profiles of 231-CM-treated and control MCF10A cells were compared by MALDI-TOF/TOF-MS (Matrix-Assisted Laser Desorption/ Ionization Time of Flight Mass Spectrometry) and a lectin microarray analysis. The treated cells showed lower levels of high-mannose-type N-glycan structures, and higher levels of complex-type and hybrid-type structures. Altered N-glycan profiles were also detected in 453-CM-treated and non-treated MCF10A cells by MALDI-TOF/TOF-MS, and we found that the expression of five fucosylated N-glycan structures (m/z 1406.663, 1590.471, 1668.782, 2421.141, and 2988.342) and one high-mannose structure m/z 1743.722 have the same pattern as 231-CM-treated MCF10A cells. Our findings, taken together, show that CM derived from breast cancer cells induced an EMT-like process in normal epithelial cells and altered their N-glycan profile.

Protein O-fucosyltransferase 1 promotes trophoblast cell proliferation through activation of MAPK and PI3K/Akt signaling pathways

Protein O-fucosylation is an important glycosylation modification and plays an important role in embryonic development. Protein O-fucosyltransferase 1 (poFUT1) is an essential enzyme that catalyzes the synthesis of protein O-fucosylation. Our previous studies showed that poFUT1 promoted trophoblast cell migration and invasion at the fetal-maternal interface, but the role of poFUT1 in trophoblast cells proliferation remains unclear. Here, immunohistochemistry data showed that poFUT1 and PCNA levels were decreased in abortion patient's trophoblasts compared with women with normal pregnancies. Our results also showed that poFUT1 promoted trophoblast cell proliferation by CCK-8 assay and cell cycle analysis. PoFUT1 increased the phosphorylation of ERK1/2, p38 MAPK, and PI3K/Akt, while inhibitors of ERK1/2(PD98059), p38 MAPK(SB203580), and PI3K (LY294002) prevented ERK1/2, p38 MAPK, and Akt phosphorylation. Moreover, poFUT1 stimulation of trophoblast cells proliferation correlated with increased cell cycle progression by promoting cells into S-phase. The underlying mechanism involved increased cyclin D1, cyclin E, CDK 2, CDK 4, and pRb expression and decreased levels of the cyclin-dependent kinase inhibitors p21 and p27, which were blocked by inhibitors of the upstream signaling molecules MAPK and PI3K/Akt. In conclusion, poFUT1 promotes trophoblast cell proliferation by activating MAPK and PI3K/Akt signaling pathways.

Development of α1,6-fucosyltransferase inhibitors through the diversity-oriented syntheses of GDP-fucose mimics using the coupling between alkyne and sulfonyl azide

We developed α1,6-fucosyltransferase (FUT8) inhibitors through a diversity-oriented synthesis. The coupling reaction between the fucose unit containing alkyne and the guanine unit containing sulfonyl azide under various conditions afforded a series of Guanosine 5'-diphospho-β-l-fucose (GDP-fucose) analogs. The synthesized compounds displayed FUT8 inhibition activity. A docking study revealed that the binding mode of the inhibitor synthesized with FUT8 was similar to that of GDP-fucose.