The discovery, biology, and drug development of sialyl Lea and sialyl Lex

Differential expression of CD175 and CA19-9 in pancreatic adenocarcinoma

Alterations in protein glycosylation are observed in many solid tumor types leading to formation of tumor-associated carbohydrate antigens (TACAs). The most common TACA is the Tn antigen (CD175), which is a mucin-type O-GalNAc-Ser/Thr/Tyr glycan in membrane and secreted glycoproteins. In addition, two other TACAs are CA19-9 (sialyl-Lewis a), which is used as a prognostic serum marker for pancreatic cancer, and its isomer sialyl-Lewis x (SLex, CD15s), which is overexpressed in many cancer types and associated with metastasis. While CD175 and other TACAs may be expressed by many human carcinomas, little is known about their differential expression patterns in tumors, thus limiting their use as tissue biomarkers or therapeutic targets. Here we address the clinicopathological relevance of the expression of CA19-9, CD15s, and CD175 in pancreatic ductal adenocarcinoma (PDAC) tissues. Semi-quantitative IHC staining with well-defined monoclonal antibodies demonstrates that CD175 is expressed in all PDAC specimens analyzed. Unexpectedly, however, these TACAs are differentially expressed within PDAC specimens and their glycoproteins, but not significantly expressed in adjacent normal tissues. These data provide avenues for novel therapeutic approaches that could combine CD175- and CA19-9-targeting therapies for PDAC patients.

Sialyl Lewisx Glycomimetics as E- and P-Selectin Antagonists Targeting Hyperinflammation

Inflammatory disorders, such as sepsis, pancreatitis, and severe COVID-19, often cause immune dysfunction and high mortality. These conditions trigger excessive immune cell influx, leading to cytokine storms, organ damage, and compensatory immune suppression that results in immunoparalysis, organ dysfunction, and reinfection. Controlled and reversible immunosuppression limiting immune cell recruitment to inflammation sites could reduce hyperinflammation and prevent immune exhaustion. PSGL-1 on leukocytes binds to vascular P- and E-selectins via its sialyl Lewisx pharmacophore, triggering key features of systemic inflammatory response syndrome and sepsis. We report the discovery of two immunomodulators, sialyl Lewisx glycomimetics (12 and 13), with a tetrazole carboxyl bioisostere of 3a, which binds P- and E-selectin and blocks their interaction with PSGL-1. In an in vivo hyperinflammation model, they reduced immune cell recruitment, evidenced by decreased neutrophils, CD11b+, monocytes/macrophages, and PSGL-1-positive cells at various time points. These glycomimetics may be promising leads for managing the systemic inflammatory response syndrome.

The Past, Present, and Future of Biomarkers for the Early Diagnosis of Pancreatic Cancer

Pancreatic cancer is one of the most aggressive cancers with a very poor 5-year survival rate and reduced therapeutic options when diagnosed in an advanced stage. The dismal prognosis of pancreatic cancer has guided significant efforts to discover novel biomarkers in order to anticipate diagnosis, increasing the population of patients who can benefit from curative surgical treatment. CA 19-9 is the reference biomarker that supports the diagnosis and guides the response to treatments. However, it has significant limitations, a low specificity, and is inefficient as a screening tool. Several potential biomarkers have been discovered in the serum, urine, feces, and pancreatic juice of patients. However, most of this evidence needs further validation in larger cohorts. The advent of advanced omics sciences and liquid biopsy techniques has further enhanced this field of research. The aim of this review is to analyze the historical evolution of the research on novel biomarkers for the early diagnosis of pancreatic cancer, focusing on the current evidence for the most promising biomarkers from different body fluids and the novel trends in research, such as omics sciences and liquid biopsy, in order to favor the application of modern personalized medicine.

Targeting hematologic malignancies by inhibiting E-selectin: A sweet spot for AML therapy?

E-selectin, a cytoadhesive glycoprotein, is expressed on venular endothelial cells and mediates leukocyte localization to inflamed endothelium, the first step in inflammatory cell extravasation into tissue. Constitutive marrow endothelial E-selectin expression also supports bone marrow hematopoiesis via NF-κB-mediated signaling. Correspondingly, E-selectin interaction with E-selectin ligand (sialyl Lewisx) on acute myeloid leukemia (AML) cells leads to chemotherapy resistance in vivo. Uproleselan (GMI-1271) is a carbohydrate analog of sialyl Lewisx that blocks E-selectin binding. A Phase 2 trial of MEC chemotherapy combined with uproleselan for relapsed/refractory AML showed a median overall survival of 8.8 months and low (2%) rates of severe oral mucositis. Clinical trials seek to confirm activity in AML and mitigation of neutrophil-mediated adverse events (mucositis and diarrhea) after intensive chemotherapy. In this review we summarize E-selectin biology and the rationale for uproleselan in combination with other therapies for hematologic malignancies. We also describe uproleselan pharmacology and ongoing clinical trials.

How E-, L-, and P-Selectins Bind to sLex and PSGL-1: A Quantification of Critical Residue Interactions

Selectins and their ability to interact with specific ligands are a cornerstone in cell communication. Over the last three decades, a considerable wealth of experimental and molecular modeling insights into their structure and modus operandi were gathered. Nonetheless, explaining the role of individual selectin residues on a quantitative level remained elusive, despite its importance in understanding the structure-function relationship in these molecules and designing their inhibitors. This work explores essential interactions of selectin-ligand binding, employing a multiscale approach that combines molecular dynamics, quantum-chemical calculations, and residue interaction network models. Such an approach successfully reproduces most of the experimental findings. It proves to be helpful, with the potential for becoming an established tool for quantitative predictions of residue contribution to the binding of biomolecular complexes. The results empower us to quantify the importance of particular residues and functional groups in the protein-ligand interface and to pinpoint differences in molecular recognition by the three selectins. We show that mutations in the E-, L-, and P-selectins, e.g., different residues in positions 46, 85, 97, and 107, present a crucial difference in how the ligand is engaged. We assess the role of sulfation of tyrosine residues in PSGL-1 and suggest that TyrSO3- in position 51 interacting with Arg85 in P-selectin is a significant factor in the increased affinity of P-selectin to PSGL-1 compared to E- and L-selectins. We propose an original pharmacophore targeting five essential PSGL-binding sites based on the analysis of the selectin···PSGL-1 interactions.

P- and E- selectin in venous thrombosis and non-venous pathologies

Venous thromboembolism is a very common and costly health problem worldwide. Anticoagulant treatment for VTE is imperfect: all have the potential for significant bleeding, and none prevent the development of post thrombotic syndrome after deep vein thrombosis or chronic thromboembolic pulmonary hypertension after pulmonary embolism. For these reasons, alternate forms of therapy with improved efficacy and decreased bleeding are needed. Selectins are a family (P-selectin, E-selectin, L-selectin) of glycoproteins that facilitate and augment thrombosis, modulating neutrophil, monocyte, and platelet activity. P- and E-selectin have been investigated as potential biomarkers for thrombosis. Inhibition of P-selectin and E-selectin decrease thrombosis and vein wall fibrosis, with no increase in bleeding. Selectin inhibition is a promising avenue of future study as either a stand-alone treatment for VTE or as an adjunct to standard anticoagulation therapies.

Targeting Tumor Glycans for Cancer Therapy: Successes, Limitations, and Perspectives

Simple Summary

Aberrant glycosylation is a common feature of many cancers, and it plays crucial roles in tumor development and biology. Cancer progression can be regulated by several physiopathological processes controlled by glycosylation, such as cell–cell adhesion, cell–matrix interaction, epithelial-to-mesenchymal transition, tumor proliferation, invasion, and metastasis. Different mechanisms of aberrant glycosylation lead to the formation of tumor-associated carbohydrate antigens (TACAs), which are suitable for selective cancer targeting, as well as novel antitumor immunotherapy approaches. This review summarizes the strategies developed in cancer immunotherapy targeting TACAs, analyzing molecular and cellular mechanisms and state-of-the-art methods in clinical oncology.

Abstract

Aberrant glycosylation is a hallmark of cancer and can lead to changes that influence tumor behavior. Glycans can serve as a source of novel clinical biomarker developments, providing a set of specific targets for therapeutic intervention. Different mechanisms of aberrant glycosylation lead to the formation of tumor-associated carbohydrate antigens (TACAs) suitable for selective cancer-targeting therapy. The best characterized TACAs are truncated O-glycans (Tn, TF, and sialyl-Tn antigens), gangliosides (GD2, GD3, GM2, GM3, fucosyl-GM1), globo-serie glycans (Globo-H, SSEA-3, SSEA-4), Lewis antigens, and polysialic acid. In this review, we analyze strategies for cancer immunotherapy targeting TACAs, including different antibody developments, the production of vaccines, and the generation of CAR-T cells. Some approaches have been approved for clinical use, such as anti-GD2 antibodies. Moreover, in terms of the antitumor mechanisms against different TACAs, we show results of selected clinical trials, considering the horizons that have opened up as a result of recent developments in technologies used for cancer control.

Mixed-Up Sugars: Glycosyltransferase Cross-Reactivity in Cancerous Tissues and Their Therapeutic Targeting

The main categories of glycan changes in cancer are: (1) decreased expression of histo-blood group A and/or B antigens and increased Lewis-related antigens, (2) appearance of cryptic antigens, such as Tn and T, (3) emergence of genetically incompatible glycans, such as A antigen expressed in tumors of individuals of group B or O and heterophilic expression of Forssman antigen (FORS1), and (4) appearance of neoglycans. This review focuses on the expression of genetically incompatible A/B/FORS1 antigens in cancer. Several possible molecular mechanisms are exemplified, including missense mutations that alter the sugar specificity of A and B glycosyltransferases (AT and BT, respectively), restoration of the correct codon reading frame of O alleles, and modification of acceptor specificity of AT to synthesize the FORS1 antigen by missense mutations and/or altered splicing. Taking advantage of pre-existing natural immunity, the potential uses of these glycans for immunotherapeutic targeting will also be discussed.

Application of the Antibody-Inducing Activity of Glycosphingolipids to Human Diseases

Glycosphingolipids (GSLs) are composed of a mono-, di-, or oligosaccharide and a ceramide and function as constituents of cell membranes. Various molecular species of GSLs have been identified in mammalian cells due to differences in the structures of oligosaccharides. The oligosaccharide structure can vary depending on cell lineage, differentiation stage, and pathology; this property can be used as a cell identification marker. Furthermore, GSLs are involved in various aspects of the immune response, such as cytokine production, immune signaling, migration of immune cells, and antibody production. GSLs containing certain structures exhibit strong immunogenicity in immunized animals and promote the production of anti-GSL antibodies. By exploiting this property, it is possible to generate antibodies that recognize the fine oligosaccharide structure of specific GSLs or glycoproteins. In our study using artificially synthesized GSLs (artGSLs), we found that several structural features are correlated with the antibody-inducing activity of GSLs. Based on these findings, we designed artGSLs that efficiently induce the production of antibodies accompanied by class switching and developed several antibodies that recognize not only certain glycan structures of GSLs but also those of glycoproteins. This review comprehensively introduces the immune activities of GSLs and their application as pharmaceuticals.

Roles of CA19-9 in pancreatic cancer: Biomarker, predictor and promoter

Carbohydrate antigen 19-9 (CA19-9) is the best validated biomarker and an indicator of aberrant glycosylation in pancreatic cancer. CA19-9 functions as a biomarker, predictor, and promoter in pancreatic cancer. As a biomarker, the sensitivity is approximately 80%, and the major challenges involve false positives in conditions of inflammation and nonpancreatic cancers and false negatives in Lewis-negative Individuals. Lewis antigen status should be determined when using CA19-9 as a biomarker. CA19-9 has screening potential when combined with symptoms and/or risk factors. As a predictor, CA19-9 could be used to assess stage, prognosis, resectability, recurrence, and therapeutic efficacy. Normal baseline levels of CA19-9 are associated with long-term survival. As a promoter, CA19-9 could be used to evaluate the biology of pancreatic cancer. CA19-9 can accelerate pancreatic cancer progression by glycosylating proteins, binding to E-selectin, strengthening angiogenesis, and mediating the immunological response. CA19-9 is an attractive therapeutic target for cancer, and strategies include therapeutic antibodies and vaccines, CA19-9-guided nanoparticles, and inhibition of CA19-9 biosynthesis.

Mycobacterium tuberculosis Infection Up-Regulates Sialyl Lewis X Expression in the Lung Epithelium

Glycans display increasingly recognized roles in pathological contexts, however, their impact in the host-pathogen interplay in many infectious diseases remains largely unknown. This is the case for tuberculosis (TB), one of the ten most fatal diseases worldwide, caused by infection of the bacteria Mycobacterium tuberculosis. We have recently reported that perturbing the core-2 O-glycans biosynthetic pathway increases the host susceptibility to M. tuberculosis infection, by disrupting the neutrophil homeostasis and enhancing lung pathology. In the present study, we show an increased expression of the sialylated glycan structure Sialyl-Lewis X (SLeX) in the lung epithelium upon M. tuberculosis infection. This increase in SLeX glycan epitope is accompanied by an altered lung tissue transcriptomic signature, with up-regulation of genes codifying enzymes that are involved in the SLeX core-2 O-glycans biosynthetic pathway. This study provides novel insights into previously unappreciated molecular mechanisms involving glycosylation, which modulate the host response to M. tuberculosis infection, possibly contributing to shape TB disease outcome.

A new way to treat proximal deep venous thrombosis using E-selectin inhibition

OBJECTIVE

There is an inter-relationship between thrombosis and inflammation. Previously, we have shown the importance of P-selectin in thrombogenesis and thrombus resolution in many preclinical animal models. The role of E-selectin has been explored in rodent models and in a small pilot study of clinical calf vein deep venous thrombosis. The purpose of this study was to determine the role of E-selectin in thrombosis in a primate model of proximal iliac vein thrombosis, a model close to the human condition.

METHODS

Iliac vein thrombosis was induced with a well-characterized primate model. Through a transplant incision, the hypogastric vein and iliac vein branches were ligated. Thrombus was induced by balloon occlusion of the proximal and distal iliac vein for 6 hours. The balloons were then deflated, and the primates recovered. Starting on postocclusion day 2, animals were treated with the E-selectin inhibitor GMI-1271, 25 mg/kg subcutaneously, once daily until day 21 (n = 4). Nontreated control animals received no treatment (n = 5). All animals were evaluated by magnetic resonance venography (MRV); evaluation of vessel area by ultrasound, protein analysis, hematology (complete blood count), and coagulation tests (bleeding time, prothrombin time, activated partial thromboplastin time, fibrinogen, and thromboelastography) were performed at baseline, day 2, day 7, day 14, and day 21 with euthanasia. In addition, platelet function and CD44 expression on leukocytes were determined.

RESULTS

E-selectin inhibition by GMI-1271 significantly increased vein recanalization by MRV vs control animals on day 14 (P < .05) and day 21 (P < .0001). GMI-1271 significantly decreased vein wall inflammation by MRV with gadolinium vein wall enhancement vs control also on day 14 (P < .0001) and day 21 (P < .0001). The thromboelastographic measure of clot strength (maximum amplitude) showed significant decreases in animals treated with GMI-1271 vs controls at day 2 (P < .05) and day 7 (P < .05). Animals treated with GMI-1271 had significant vessel area increase by day 21 vs controls (P < .05) by ultrasound. Vein wall intimal thickening (P < .001) and intimal fibrosis (P < .05) scores were significantly decreased in GMI-1271-treated animals vs controls. Importantly, no significant differences in hematology or coagulation test results were noted between all groups, suggesting that E-selectin inhibition carries no bleeding potential. GMI-1271 did not affect platelet function or aggregation or CD44 expression on leukocytes. In addition, no episodes of bleeding were noted in either group.

CONCLUSIONS

This study suggests that E-selectin modulates venous thrombus progression and that its inhibition will increase thrombus recanalization and decrease vein wall inflammation, without affecting coagulation. The use of an E-selectin inhibitor such as GMI-1271 could potentially change how we treat deep venous thrombosis.

Sialyltransferase inhibition leads to inhibition of tumor cell interactions with E-selectin, VCAM1, and MADCAM1, and improves survival in a human multiple myeloma mouse model

Aberrant glycosylation resulting from altered expression of sialyltransferases, such as ST3 β-galactoside α2-3-sialyltransferase 6, plays an important role in disease progression in multiple myeloma (MM). Hypersialylation can lead to increased immune evasion, drug resistance, tumor invasiveness, and disseminated disease. In this study, we explore the in vitro and in vivo effects of global sialyltransferase inhibition on myeloma cells using the pan-sialyltransferase inhibitor 3F_ax-Neu5Ac delivered as a per-acetylated methyl ester pro-drug. Specifically, we show in vivo that 3F_ax-Neu5Ac improves survival by enhancing bortezomib sensitivity in an aggressive mouse model of MM. However, 3F_ax-Neu5Ac treatment of MM cells in vitro did not reverse bortezomib resistance conferred by bone marrow (BM) stromal cells. Instead, 3Fax-Neu5Ac significantly reduced interactions of myeloma cells with E-selectin, MADCAM1 and VCAM1, suggesting that reduced sialylation impairs extravasation and retention of myeloma cells in the BM. Finally, we showed that 3F_ax-Neu5Ac alters the post-translational modification of the α4 integrin, which may explain the reduced affinity of α4β1/α4β7 integrins for their counter-receptors. We propose that inhibiting sialylation may represent a valuable strategy to restrict myeloma cells from entering the protective BM microenvironment, a niche in which they are normally protected from chemotherapeutic agents such as bortezomib. Thus, our work demonstrates that targeting sialylation to increase the ratio of circulating to BM-resident MM cells represents a new avenue that could increase the efficacy of other anti-myeloma therapies and holds great promise for future clinical applications.

Receptor targeting drug delivery strategies and prospects in the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA), a chronic inflammatory disease, is characterized by cartilage damage, bone tissue destruction, morphological changes in synovial fluids, and synovial joint inflammation. The inflamed synovial tissue has potential for passive and active targeting because of enhanced permeability and retention effect and the existence of RA synovial macrophages and fibroblasts that selectively express surface receptors such as folate receptor β, CD44 and integrin αVβ. Although there are numerous interventions in RA treatment, they are not safe and effective. Therefore, it is important to develop new drug or drug delivery systems that specifically targets inflamed/swollen joints but attenuates other possible damages to healthy tissues. Recently some receptors such as toll-like receptors (TLRs), the nucleotide-binding oligomerization domain-like receptors, and Fc-γ receptor have been identified in synovial tissue and immune cells that are involved in induction or suppression of arthritis. Analysis of the TLR pathway has moreover suggested new insights into the pathogenesis of RA. In the present paper, we have reviewed drug delivery strategies based on receptor targeting with novel ligand-anchored carriers exploiting CD44, folate and integrin αVβ as well as TLRs expressed on synovial monocytes and macrophages and antigen presenting cells, for possible active targeting in RA. TLRs could not only open a new horizon for developing new drugs but also their antagonists or humanized monoclonal antibodies that block TLRS specially TLR4 and TLR9 signaling could be used as targeting agents to antigen presenting cells and dendritic cells. As a conclusion, common conventional receptors and multifunctional ligands that arte involved in targeting receptors or developing nanocarriers with appropriate ligands for TLRs can provide profoundly targeting drug delivery systems for the effective treatment of RA.

Synthesis of Sialyl LewisX Glycomimetics Bearing a Bicyclic 3- O,4- C-Fused Galactopyranoside Scaffold

Reported herein is the synthesis of sialyl Lewis^X analogues bearing a trans-bicyclo[4.4.0] dioxadecane-modified 3- O,4- C-fused galactopyranoside scaffold that locks the carboxylate pharmacophore in either the axial or equatorial position. This novel series of bicyclic galactopyranosides are prepared through a stereocontrolled intramolecular cyclization reaction that has been evaluated both experimentally and by density functional theory calculations. The cyclization precursors are obtained from β-d-galactose pentaacetate in a nine-step sequence featuring a highly diastereoselective equatorial alkynylation and Cu(I) catalyzed formation of the acetylenic α-ketoester moiety. Preliminary biological evaluations indicate improved activity as P-selectin antagonists for the axially configured analogues as compared to their equatorial counterparts.

Glycan Profiling Analysis of Equine Amniotic Progenitor Mesenchymal Cells and Their Derived Extracellular Microvesicles

Equine amniotic mesenchymal cells (eAMCs) are involved in many mechanisms in tissue regenerative processes. Their secreted vesicles are important effectors in a wide array of biological processes, and contribute to in vivo healing of equine tendon lesions and endometrial inflammation. Glycoconjugates are involved in cellular recognition and in the efficient uptake of extracellular vesicles (EVs) by recipient cells. In this study, we evaluated the surface glycosylation pattern of eAMCs and their EVs from the eAMCs released in conditioned medium. We used a microarray procedure in which eAMCs and eAMC-EVs were spotted on microarray slides, and incubated with a panel of 14 biotinylated lectins and Cy3-conjugated streptavidin. Signal intensity was detected using a microarray scanner. Both eAMC and eAMC-EV microarrays interacted with all the lectins, indicating the presence of N- and O-linked glycans. With respect to eAMCs, eAMC-EVs, were found to be (1) enriched in Galβ1,3GalNAc terminating O-glycans, α2,3-linked sialoglycans, and high-mannose N-glycans (Con A); (2) diminished in N-acetyllactosamine, GalNAc, Gal, GlcNAc, and fucose terminating glycans; and (3) unchanged in α2,6 linked sialoglycans content. These results suggest that eAMC-EVs emerge from a specific eAMC microdomain, and that the high simultaneous presence of Galβ1,3GalNAc, α2,3 sialic acid, and high-mannose N-linked glycans may constitute markers of the eAMC-EVs. The role of these sugars in equine regenerative medicine requires further investigation.

Usefulness of Carbohydrate Antigen 19-9 Test in Healthy People and Necessity of Medical Follow-up in Individuals with Elevated Carbohydrate Antigen 19-9 Level

Background

Carbohydrate antigen 19-9 (CA 19-9) is a tumor marker whose level is elevated in many types of cancers and other benign conditions. CA 19-9 levels are frequently found to be elevated in individuals during general health examinations. This study aimed to investigate the clinical characteristics of such individuals and to determine the need for medical follow-up.

Methods

We investigated individuals who underwent a health inspection, including a serum CA 19-9 test, at our center. Their CA 19-9 levels, age, sex, body mass index (BMI), and personal and past histories were investigated. Additionally, subgroup analyses were performed for those who underwent follow-up study for the elevated CA 19-9 levels.

Results

Of 58,498 subjects, 581 (1.0%) had elevated CA 19-9 levels. Multivariate analyses revealed that older age, female sex, lower BMI, and diabetes were independent predisposing factors for elevated CA 19-9 level. A subgroup analysis revealed that the causative conditions were identified in 129 of 351 subjects (36.8%). Among them, the causative conditions in 31 subjects (8.8%, including four cases of cancer and 15 of benign tumors) were not detected at the initial check-up and were found during the follow-up period.

Conclusion

The use of CA 19-9 as a marker for cancer in healthy individuals is inappropriate. However, medical follow-up in individuals with elevated CA 19-9 levels may be useful because some causative diseases may be detected during follow-up.

Serum CA199 levels are significantly increased in patients suffering from liver, lung, and other diseases

CA199 is a sialic acid containing glycan antigen found in both glycoproteins and glycolipids, which is recognized by monoclonal antibodies generated by hybridoma technology. The increased serum CA199 levels measured by using the monoclonal antibodies have been used as diagnostic or prognostic biomarker for pancreatic cancer. Even though increased serum CA199 levels are also observed in other cancers and noncancer diseases, it is largely unknown if CA199 levels could serve as biomarkers for other diseases as well. Therefore, in our current study, serum CA199 levels from 45,645 patients with 47 clinically defined diseases and 14,783 healthy controls who attended their annual physical examination were collected and measured by the clinical laboratory in the Affiliated Hospital of Qingdao University over the past 5 years. Based on the median, mean, and -Log₁₀p values, we found that patients with pancreatic cancer, lung fibrosis, cirrhosis, liver cancer, hepatitis, and pancreatitis had the highest media and mean serum CA199 levels with statistical significance based on the -Log₁₀p values. Unexpectedly, patients suffering from gout and anemia had significantly low CA199 levels compared to that of the healthy controls. These results showed that serum CA199 levels are not only increased in pancreatic and other cancer patients but also either increased or decreased in noncancer diseases. The overall data indicated that the abnormal serum CA199 level might be an indicator of system malfunction rather than a cancer biomarker in general.

Prognostic Impact of Presurgical CA19-9 Level in Pancreatic Adenocarcinoma: A Pooled Analysis

BACKGROUND: Presurgical carbohydrate antigen 19-9 (CA19-9) level predicts overall survival (OS) in resected pancreatic adenocarcinoma (PaC). The aim of this pooled analysis was to evaluate if presurgical CA19-9 level can also predict local control (LC) and distant metastasis-free survival (DMFS). METHODS: Seven hundred patients with PaC from eight institutions who underwent surgical resection ± adjuvant treatment between 2000 and 2014 were analyzed. Patients were divided based on four presurgical CA19-9 level cutoffs (5, 37, 100, 353 U/ml). Weibull regression model to identify independent predictors of OS on 404 patients with complete information was fitted. RESULTS: Median follow-up was 17 months (range: 2-225 months). Univariate analysis showed a better prognosis in pT1-2, pN0, diameter <30 mm, or grade 1 tumors and in patients undergoing R0 resection, distal pancreatectomy, or adjuvant chemotherapy and with lower CA19-9 levels. Five-year OS, LC, and DMFS were as follows: CA19-9 <5.0: 5.7%, 47.2%, 17.0%; CA19-9 5.1-37.0: 37.9%, 63.3%, 46.0%; CA19-9 37.1-100.0: 27.1%, 59.4%, 39.0%; CA19-9 100.1-353.0: 17.4%, 43.4%, 26.7%; CA19-9 >353.1: 10.9%, 50.2%, and 23.4%, respectively. At multivariate analysis, CA19-9 >100 and <353 level (P=.002), CA19-9 ≥353.1 (P<.001) level, G3 tumor (P=.002), and tumor diameter >30 mm (P<.001) correlated with worse OS. Patients treated with postoperative chemoradiation doses >50.0 Gy showed improved OS (P<.001). CONCLUSION: Presurgical CA19-9 predicts both OS and pattern of failure. Therefore, CA19-9 should be included in predictive models in order to customize treatments based on prognostic factors. Moreover, future studies should stratify patients according to presurgical CA19-9 level.

Serum CEA and CA 19-9 Levels are Associated with the Presence and Severity of Colorectal Neoplasia

PURPOSE

Limited data are available regarding the association between circulating serum carcinoembryonic antigen (CEA) or carbohydrate antigen 19-9 (CA 19-9) concentrations and colorectal adenoma. We aimed to investigate whether elevated serum CEA and CA 19-9 levels are correlated with the presence of colorectal neoplasia (CRN) and whether the levels of these antigens vary according to CRN severity.

MATERIALS AND METHODS

A cross-sectional study was performed on asymptomatic subjects who underwent colonoscopy between 2010 and 2014 as part of a comprehensive health screening program in Korea.

RESULTS

A total of 124509 participants with measured serum CEA levels and 115833 participants with measured serum CA 19-9 levels were analyzed. Elevated CEA concentrations were associated with a higher rate of any adenoma, advanced adenoma, high-risk adenoma, advanced CRN (ACRN), overall CRN, and colorectal cancer (CRC). Elevated CA 19-9 concentrations were also associated with a higher rate of advanced adenoma, high-risk adenoma, ACRN, and CRC. Both elevated levels of CEA and CA 19-9 were identified as independent predictors of ACRN. Among patients with CRN, the proportions of elevated CEA/CA 19-9 levels were significantly higher in patients with ACRN than in those with non-ACRN, and these levels were correlated with larger lesion size and multiplicity of adenomas.

CONCLUSION

Both elevated serum CEA and CA 19-9 levels were associated with the presence of ACRN, as well as CRC. Elevated CEA levels were also associated with the presence of overall CRN. Moreover, both CEA and CA 19-9 levels were correlated with the severity of CRN.

E-selectin ligands recognised by HECA452 induce drug resistance in myeloma, which is overcome by the E-selectin antagonist, GMI-1271

Multiple myeloma (MM) is characterized by the clonal expansion and metastatic spread of malignant plasma cells to multiple sites in the bone marrow (BM). Recently, we implicated the sialyltransferase ST3Gal-6, an enzyme critical to the generation of E-selectin ligands, in MM BM homing and resistance to therapy. Since E-selectin is constitutively expressed in the BM microvasculature, we wished to establish the contribution of E-selectin ligands to MM biology. We report that functional E-selectin ligands are restricted to a minor subpopulation of MM cell lines which, upon expansion, demonstrate specific and robust interaction with recombinant E-selectin in vitro. Moreover, an increase in the mRNA levels of genes involved in the generation of E-selectin ligands was associated with inferior progression-free survival in the CoMMpass study. In vivo, E-selectin ligand-enriched cells induced a more aggressive disease and were completely insensitive to Bortezomib. Importantly, this resistance could be reverted by co-administration of GMI-1271, a specific glycomimetic antagonist of E-selectin. Finally, we report that E-selectin ligand-bearing cells are present in primary MM samples from BM and peripheral blood with a higher proportion seen in relapsed patients. This study provides a rationale for targeting E-selectin receptor/ligand interactions to overcome MM metastasis and chemoresistance.

E-selectin inhibition with GMI-1271 decreases venous thrombosis without profoundly affecting tail vein bleeding in a mouse model

Selectins, such as E-selectin (CD62E), function in venous thrombosis by binding and activating immune cells to initiate the coagulation cascade. GMI-1271 is a small molecule antagonist that inhibits E-selectin activity. Here we determine whether inhibition of E-selectin is sufficient to decrease acute venous thrombosis and associated inflammatory events in both prophylactic and treatment protocols without significantly affecting haemostasis. Male C57BL/6 mice underwent surgery for experimental thrombosis induction and were harvested at peak thrombus formation in our animal model, two days post induction. Groups included non-thrombosed true controls, shams, controls, and prophylactic or treatment groups of GMI-1271 (10 mg/kg intraperitoneal BID (twice a day) and low-molecular-weight heparin (LMWH, Lovenox 6 mg/kg subcutaneously (SC), once a day (SID). Compared with control animals, prophylaxis or treatment with LMWH and GMI-1271 in a dose-dependent manner significantly decreased thrombosis. GMI-1271 significantly lowered tail bleeding times when compared to LMWH. GMI-1271 and LMWH prophylactically administered significantly decreased vein wall neutrophil cell extravasation. However, all treatment and prophylactic therapies significantly decreased vein wall monocyte extravasation versus controls. GMI-1271 prophylactic therapy significantly decreased intra-thrombus cell counts versus control animals and other treatment groups. Immunohistochemistry confirmed that both treatments with GMI-1271 and LMWH significantly decreased activated leukocyte migration. GMI-1271 therapy significantly decreased thrombus weight and resulted in significantly lower bleeding times than LMWH. GMI-1271 treated mice showed decreased local and systemic inflammatory effects while modulating neutrophil activation, suggesting that GMI-1271 is a viable therapeutic candidate for venous thrombosis prophylaxis and treatment.

Influence of prognostic nutritional index and tumor markers on survival in gastric cancer surgery patients

PURPOSE

Blood analytes are easily used in routine clinical practice. Tumor markers (TMs) are useful in diagnosing, treating, and predicting prognosis of gastric cancer (GC). The prognostic nutritional index (PNI) was also recently found to be useful in predicting GC prognosis.

METHODS

The PNI and serum levels of CEA and CA19-9 of 453 patients with GC were measured to examine correlations between those levels and patients' prognoses.

RESULTS

Of the 453 patients, 84 (18.5%) were positive for CEA and/or CA19-9 and therefore considered positive for TMs. Prognosis of patients who were TM+ was significantly worse than for those who were TM-. Mean PNI was 48.2 (range 27.7-63.6). ROC analysis indicated that 46.7 was the optimal PNI cutoff value. Prognosis of patients in the PNI^Low group (<46.7) was significantly worse than in the PNI^High group (≥46.7). Prognosis of patients who were both TM+ and PNI^Low was significantly worse than that of patients who were either TM+ or PNI^Low and those who were both TM- and PNI^High. Multivariate analysis indicated that combination of TM and PNI was an independent prognostic indicator.

CONCLUSIONS

The combination of TM and PNI offers accurate information about a patient's prognosis.

Serum CA 19-9 and risk of incident diabetes in middle-aged and elderly Chinese: a prospective cohort study

AIMS

Carbohydrate antigen (CA) 19-9 is a tumor marker for gastrointestinal and pancreatic cancers. Previous studies found that CA 19-9 was elevated in patients with diabetes, but little is known about its relationship with diabetes risk in prospective studies. Our objective was to evaluate the association between serum CA 19-9 and the risk of incident diabetes in Chinese population.

METHODS

Data were obtained from a prospective cohort study among 2391 middle-aged and elderly Chinese with a median follow-up of 3.8 years. The measurement for the study outcome was incident diabetes.

RESULTS

Compared with individuals in the lowest quartile, those in the highest quartile of CA 19-9 had significantly higher incidence of diabetes (12.54 vs. 8.86%, P = 0.04). In the fully adjusted logistic regression model, compared with the lowest quartile, the highest quartile of CA 19-9 was significantly associated with 58% increased risk of incident diabetes [odds ratio (OR), 95% confidence interval (CI) 1.58, 1.02-2.44]. Stratified analysis suggested that the increased risk was seen only in women (OR, 95% CI 1.96, 1.10-3.48), or participants aged ≥65 (OR, 95% CI 2.32, 1.03-5.19), or those with body mass index ≥24 (OR, 95% CI 2.09, 1.20-3.63), or current nondrinkers (OR, 95% CI 1.79, 1.09-2.92), or those with impaired glucose regulation (IGR) (OR, 95% CI 2.49, 1.33-4.67). Significant interaction was detected between IGR and serum CA 19-9 (P for interaction <0.0001).

CONCLUSIONS

Serum CA 19-9 is associated with a significantly increased risk of diabetes among the middle-aged and elderly Chinese population. Further investigations are needed to confirm this association and disclose potential mechanisms.

Endotoxaemia-augmented murine venous thrombosis is dependent on TLR-4 and ICAM-1, and potentiated by neutropenia

Venous thromboembolism is a major cause of death during and immediately post-sepsis. Venous thrombosis (VT) is mediated by cell adhesion molecules and leukocytes, including neutrophil extracellular traps (NETs). Sepsis, or experimentally, endotoxaemia, shares similar characteristics and is modulated via toll like receptor 4 (TLR4). This study was undertaken to determine if endotoxaemia potentiates early stasis thrombogenesis, and secondarily to determine the role of VT TLR4, ICAM-1 and neutrophils (PMNs). Wild-type (WT), ICAM-1^-/- and TLR4^-/- mice underwent treatment with saline or LPS (10 mg/kg i. p.) alone, or followed by inferior vena cava (IVC) ligation to generate stasis VT. In vivo microscopy of leukocyte trafficking was performed in non-thrombosed mice, and tissue and plasma were harvested during early VT formation. Pre-thrombosis, circulating ICAM-1 was elevated and increased leukocyte adhesion and rolling occurred on the IVC of LPS-treated mice. Post-thrombosis, endotoxaemic mice formed larger, platelet-poor thrombi. Endotoxaemic TLR4^-/- mice did not have an augmented thrombotic response and exhibited significantly decreased circulating ICAM-1 compared to endotoxaemic WT controls. Endotoxaemic ICAM-1^-/- mice had significantly smaller thrombi compared to controls. Hypothesising that PMNs localised to the inflamed endothelium were promoting thrombosis, PMN depletion using anti-Ly6G antibody was performed. Paradoxically, VT formed without PMNs was amplified, potentially related to endotoxaemia induced elevation of PAI-1 and circulating FXIII, and decreased uPA. Endotoxaemia enhanced early VT occurs in a TLR-4 and ICAM-1 dependent fashion, and is potentiated by neutropenia. ICAM-1 and/or TLR-4 inhibition may be a unique strategy to prevent sepsis-associated VT.

Gram-Negative Pneumonia Alters Large-Vein Cell-Adhesion Molecule Profile and Potentiates Experimental Stasis Venous Thrombosis

BACKGROUND/AIMS

Pneumonia is a significant risk factor for the development of venous thrombosis (VT). Cell-adhesion molecules (CAMs) are linked to the pathogenesis of both pneumonia and VT. We hypothesized that remote infection would confer a prothrombogenic milieu via systemic elevation of CAMs.

METHODS

Lung injury was induced in wild-type (C57BL/6) mice by lung contusion or intratracheal inoculation with Klebsiella pneumoniae or saline controls. K. pneumoniae-treated mice and controls additionally underwent inferior vena cava (IVC) ligation to generate VT.

RESULTS

Lung-contusion mice demonstrated no increase in E-selectin or P-selectin whereas mice infected with K. pneumoniae demonstrated increased circulating P-selectin, ICAM-1, VCAM-1 and thrombin-antithrombin (TAT) complexes. Mice with pneumonia formed VT 3 times larger than controls, demonstrated significantly more upregulation of vein-wall and systemic CAMs, and formed erythrocyte-rich thrombi.

CONCLUSION

Elevated CAM expression was identified in mice with pneumonia, but not lung contusion, indicating that the type of inflammatory stimulus and the presence of infection drive the vein-wall response. Elevation of CAMs was associated with amplified VT and may represent an alternate mechanism by which to target the prevention of VT.

Unexpected distribution of CA19.9 and other type 1 chain Lewis antigens in normal and cancer tissues of colon and pancreas: Importance of the detection method and role of glycosyltransferase regulation

BACKGROUND

CA19.9 antigen has been assumed as an abundant product of cancer cells, due to the reactivity found by immunohistochemical staining of cancer tissues with anti-CA19.9 antibody.

METHODS

Expression and biosynthesis of type 1 chain Lewis antigens in the colon and the pancreas were studied by immunodetection in tissue sections and lysates, quantification of glycosyltransferase transcripts, bisulfite sequencing, and chromatin immunoprecipitation assays.

RESULTS

CA19.9 was poorly detectable in normal colon mucosa and almost undetectable in colon cancer, while it was easily detected in the pancreatic ducts, together with Lewis b antigen, under both normal and cancer conditions. B3GALT5 transcripts were down-regulated in colon cancer, while they remained expressed in pancreatic cancer. Even ST3GAL3 transcript appeared well expressed in the pancreas but poorly in the colon, irrespective of normal or cancer conditions. CpG islands flanking B3GALT5 native promoter presented an extremely low degree of methylation in pancreatic cancer with respect to colon cancer. In a DNA region about 1kb away from the B3GALT5 retroviral promoter, a stretch of CG dinucleotides presented a methylation pattern potentially associated with transcription. Such a DNA region and the transcription factor binding site provided overlapping results by chromatin immunoprecipitation assays, corroborating the hypothesis.

CONCLUSIONS

CA19.9 appears as a physiological product whose synthesis strongly depends on the tissue specific and epigenetically-regulated expression of B3GALT5 and ST3GAL3.

GENERAL SIGNIFICANCE

CA19.9 and other Lewis antigens acquire tumor marker properties in the pancreas due to mechanisms giving rise to reabsorption into vessels and elevation in circulating levels.

Linkage-Specific in Situ Sialic Acid Derivatization for N-Glycan Mass Spectrometry Imaging of Formalin-Fixed Paraffin-Embedded Tissues

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging is a rapidly evolving field in which mass spectrometry techniques are applied directly on tissues to characterize the spatial distribution of various molecules such as lipids, protein/peptides, and recently also N-glycans. Glycans are involved in many biological processes and several glycan changes have been associated with different kinds of cancer, making them an interesting target group to study. An important analytical challenge for the study of glycans by MALDI mass spectrometry is the labile character of sialic acid groups which are prone to in-source/postsource decay, thereby biasing the recorded glycan profile. We therefore developed a linkage-specific sialic acid derivatization by dimethylamidation and subsequent amidation and transferred this onto formalin-fixed paraffin-embedded (FFPE) tissues for MALDI imaging of N-glycans. Our results show (i) the successful stabilization of sialic acids in a linkage specific manner, thereby not only increasing the detection range, but also adding biological meaning, (ii) that no noticeable lateral diffusion is induced during to sample preparation, (iii) the potential of mass spectrometry imaging to spatially characterize the N-glycan expression within heterogeneous tissues.

The glycobiology of the CD system: a dictionary for translating marker designations into glycan/lectin structure and function

The profile of cell surface molecules, the biochemical platform for cellular communication, can be likened to a molecular fingerprint. Historically, raising monoclonal antibodies by immunization with cells has been instrumental in obtaining tools suited for phenotyping and functional analysis. Initially for leukocyte antigens, the resulting cluster of differentiation (CD) nomenclature has become a popular system for classification. Glycans presented on proteins or lipids and receptors for carbohydrate structures (lectins) are part of the CD list. Our review presents biochemical and biomedical highlights of the respective CD entries.

Glycosylation characteristics of colorectal cancer

Glycans on proteins and lipids are known to alter with malignant transformation. The study of these may contribute to the discovery of biomarkers and treatment targets as well as understanding of cancer biology. We here describe the change of glycosylation specifically defining colorectal cancer with view on N-glycans, O-glycans, and glycosphingolipid glycans in colorectal cancer cells and tissues as well as patient sera. Glycan alterations observed in colon cancer include increased β1,6-branching and correlating higher abundance of (poly-)N-acetyllactosamine extensions of N-glycans as well as an increase in (truncated) high-mannose type glycans, while bisected structures decrease. Colorectal cancer-associated O-glycan changes are predominated by reduced expression of core 3 and 4 glycans, whereas higher levels of core 1 glycans, (sialyl) T-antigen, (sialyl) Tn-antigen, and a generally higher density of O-glycans are observed. Specific changes for glycosphingolipid glycans are lower abundances of disialylated structures as well as globo-type glycosphingolipid glycans with exception of Gb3. In general, alterations affecting all discussed glycan types are increased sialylation, fucosylation as well as (sialyl) Lewis-type antigens and type-2 chain glycans. As a consequence, interactions with glycan-binding proteins can be affected and the biological function and cellular consequences of the altered glycosylation with regard to tumorigenesis, metastasis, modulation of immunity, and resistance to antitumor therapy will be discussed. Finally, analytical approaches aiding in the field of glycomics will be reviewed with focus on binding assays and mass spectrometry.

Diagnostic value of serum carbohydrate antigen 19-9 in pancreatic cancer: a meta-analysis

Pancreatic cancer is a highly malignant cancer with increasing incidence and mortality worldwide. Carbohydrate antigen 19-9 (CA19-9) has been widely reported to play a role in the diagnosis of pancreatic cancer patients. However, published data on this subject are inconclusive. There was no meta-analysis that has been previously performed to evaluate critically the diagnostic accuracy of CA19-9 for pancreatic cancer. Therefore, we performed a meta-analysis to evaluate the sensitivity and specificity of CA19-9 in the diagnosis of pancreatic cancer. We conducted a comprehensive search to identify studies in which the pooled sensitivity, specificity, diagnostic odds ratio (DOR), and summary receiver operating curves (SROC) could be determined. A total of 11 studies that included 2,316 individuals who fulfilled all of the inclusion criteria were considered for analysis. The summary estimates for serum CA19-9 in the diagnosis of pancreatic cancer in these studies were pooled sensitivity 0.80 (95 % confidence interval [CI] 0.77-0.82), specificity 0.80 (95 % CI 0.77-0.82), and DOR 14.79 (95 % CI 8.55-25.59), and the area under the curve was 0.87. Our meta-analysis showed that serum CA19-9 plays important role in the diagnosis of pancreatic cancer.

High expression of sLex associated with poor survival in Argentinian colorectal cancer patients

AIM

Colorectal cancer (CRC) is one of the most prevalent malignancies in Argentina with 11,043 new cases and 6,596 deaths estimated to have occurred in 2008. The present study was developed to clarify the differential expression of MUC1, MUC2, sLex, and sLea in colorectal cancer patients and their relationship with survival and clinical and histological features.

METHODS

Ninety primary tumor samples and 43 metastatic lymph nodes from CRC patients were studied; follow-up was documented. Twenty-six adenoma and 68 histological normal mucosa specimens were analyzed. An immunohistochemical approach was applied and statistical analysis was performed.

RESULTS

In tumor samples, MUC1, sLea, and sLex were highly expressed (94%, 67%, and 91%, respectively); also, we found a significantly increased expression of the 3 antigens in primary tumors and metastatic lymph nodes compared with normal mucosa and adenomas. MUC2 was expressed in 52% of both normal mucosa and CRC samples; this reactivity significantly decreased in metastatic lymph nodes (p<0.05). A multiple comparison analysis showed that MUC1 and sLex discriminated among 3 groups: normal, adenoma, and CRC tissues. The increase of sLex expression showed an association with recurrence, and survival analysis showed that a high sLex staining was significantly associated with a poor survival. By multivariate analysis MUC1 inmunoreactivity correlated positively and significantly with tumor size, while MUC2 expression showed the opposite correlation.

CONCLUSIONS

The correlation of sLex overexpression in primary tumors and metastatic lymph nodes, the discrimination among the normal, adenoma, and CRC groups based on sLex expression, as well as its association with recurrence and survival, all suggest a prognostic role of sLex in Argentinian CRC patients.

Shaping up for structural glycomics: a predictive protocol for oligosaccharide conformational analysis applied to N-linked glycans

•

Aqueous 10 μs simulations of N-linked mannosyl cores and sialyl Lewis (sLe) antennae are validated.

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Sequence dependent glycosidic linkage and pyranose ring μs motions are implicated in bioactivity.

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Stacked pyranoses in sLe^a and sLe^x are predicted to be atypically rigid on μs timescales.

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In a 25 μs simulation of sLe^x, all known conformers were sampled within the initial 10 μs of dynamics.

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Unbiased 10 μs simulations are proposed as a route to systematic and accurate glycomic 3D-analysis.

The human glycome comprises a vast untapped repository of 3D-structural information that holds the key to glycan recognition and a new era of rationally designed mimetic chemical probes, drugs, and biomaterials. Toward routine prediction of oligosaccharide conformational populations and exchange rates at thermodynamic equilibrium, we apply hardware-accelerated aqueous molecular dynamics to model μs motions in N-glycans that underpin inflammation and immunity. In 10 μs simulations, conformational equilibria of mannosyl cores, sialyl Lewis (sLe) antennae, and constituent sub-sequences agreed with prior refinements (X-ray and NMR). Glycosidic linkage and pyranose ring flexing were affected by branching, linkage position, and secondary structure, implicating sequence dependent motions in glycomic functional diversity. Linkage and ring conformational transitions that have eluded precise quantification by experiment and conventional (ns) simulations were predicted to occur on μs timescales. All rings populated non-chair shapes and the stacked galactose and fucose pyranoses of sLe^a and sLe^x were rigidified, suggesting an exploitable 3D-signature of cell adhesion protein binding. Analyses of sLe^x dynamics over 25 μs revealed that only 10 μs were sufficient to explore all aqueous conformers. This simulation protocol, which yields conformational ensembles that are independent of initial 3D-structure, is proposed as a route to understanding oligosaccharide recognition and structure–activity relationships, toward development of carbohydrate-based novel chemical entities.

CD10 and CA19.9 immunohistochemical expression in transitional cell carcinoma of the urinary bladder

Background:

Transitional cell carcinoma of the bladder is the most common malignancy affecting the urinary tract ranking the 5^th among males and the 9^th among females’ cancers in Iraq. The prognosis depends largely on the histological grade and stage of the tumor at diagnosis; however, there is no reliable parameter predicting the risk of recurrence or progression; molecular and immunological markers may be required to estimate the individual prognosis of patients as well as for effective diagnosis and treatment.

Objectives:

To evaluate CD10 and CA19.9 immunohistochemical expression in transitional cell carcinoma of the urinary bladder and to correlate this expression with the grade and stage of the tumor.

Materials and Methods:

This study was retrospectively designed. Forty-nine cystoscopy specimens of urothelial carcinoma of the bladder were retrieved from the archival materials of the Specialized Surgical Hospital and Al-Khadhmiya Teaching Hospital in Baghdad for the period from January 2010 to June 2011. Three sections of 5-μm thickness were taken from each case. One section was stained with Hematoxylin and Eosin; the other two were stained immunohistochemically with CA19.9 and CD10.

Results:

Immunohistochemical expression of CA19.9 and CD10 had a significant correlation with WHO 2004 grade of urothelial carcinoma. There was no significant correlation between CA19.9 and CD10 immunohistochemical expression with stage.

Conclusions:

CA19.9 and CD10 immunohistochemical expression could be of value in assisting the differentiation between high and low-grade urothelial carcinoma cases and consequently in determining the prognosis in such cases.

FX enzyme and GDP-L-Fuc transporter expression in colorectal cancer

AIMS

Fucosylation is regulated by fucosyltransferases, the guanosine diphosphate-L-fucose (GDP-L-Fuc) synthetic pathway, and the GDP-L-fucose transporter (GDP-L-Fuc Tr). We have reported previously an increased level of α(1,6)fucosyltransferase activity and expression in colorectal cancer (CRC). The present study aimed to analyse the expression profiles of the FX enzyme and GDP-L-Fuc Tr in a cohort of operated CRC patients to elucidate their role in α(1,6)fucosylation in this neoplasm.

METHODS AND RESULTS

We assessed the immunohistochemical expression of FX and GDP-L-Fuc Tr in a series of tumour samples and healthy tissues from CRC specimens. FX expression was observed in 58 of 91 (63.7%) tumours and 23 of 28 (82.1%) corresponding healthy samples. GDP-L-Fuc Tr expression was detected in 86 of 102 (84.3%) colorectal tumours, and 13 of 27 (48.1%) healthy tissue specimens. The expression of GDP-L-Fuc Tr was statistically higher in tumours than in healthy tissues (P < 0.001). A correlation was found between FX and GDP-L-Fuc Tr expression in tumour samples (P = 0.003).

CONCLUSION

GDP-L-Fuc Tr overexpression in the tumour tissue of CRC patients suggests that GDP-L-Fuc transport to the Golgi apparatus may be an important factor associated with increased α(1,6)fucosylation in CRC.

α2,3-Sialyltransferase ST3Gal IV promotes migration and metastasis in pancreatic adenocarcinoma cells and tends to be highly expressed in pancreatic adenocarcinoma tissues

Sialyltransferases have received much attention recently as they are frequently up-regulated in cancer cells. However, the role played by each sialyltransferase in tumour progression is still unknown. α2,3-Sialyltransferases ST3Gal III and ST3Gal IV are involved in sialyl-Lewis(x) (SLe(x)) synthesis. Given that the role of ST3Gal III in pancreatic adenocarcinoma cells has been previously reported, in this study we have focused on investigating the role of ST3Gal IV in the acquisition of adhesive, migratory and metastatic capabilities and, secondly, in analyzing the expression of ST3Gal III and ST3Gal IV in pancreatic adenocarcinoma tissues versus control tissues. ST3Gal IV overexpressing pancreatic adenocarcinoma MDAPanc-28 cell lines were generated. They showed a heterogeneous increase in SLe(x), and enhanced E-selectin adhesion and migration. Furthermore, when injected into nude mice, increased metastasis and decreased survival were found in comparison with controls. The behaviour of MDAPanc-28 ST3Gal IV overexpressing cells in these processes was similar to the already reported MDAPanc-28 ST3Gal III overexpressing cells. Furthermore, pancreatic adenocarcinoma tissues tended to express high levels of ST3Gal III and ST3Gal IV together with other fucosyltransferase genes FUT3 and FUT6, all involved in the last steps of sialyl-Lewis(x) biosynthesis. In conclusion, both α2,3-sialyltransferases are involved in key steps of pancreatic tumour progression processes and are highly expressed in most pancreatic adenocarcinoma tissues.

Sialic acid capture-and-release and LC-MS(n) analysis of glycopeptides

Extracellular glycoproteins frequently carry terminal sialic acids on their N-linked and/or O-linked glycan structures. In this chapter a sialic acid specific capture-and-release protocol for the enrichment of N- and O-glycopeptides originating from glycoproteins in complex biological samples is described. The enriched glycopeptides are subjected to reversed phase liquid chromatography (LC) interfaced with electrospray ionization and multistage tandem mass spectrometry (MS(n)). The glycopeptide precursor ions are fragmented by collision-induced dissociation (CID) for analysis of the glycan parts in the MS(2) spectra. Further fragmentation (i.e., MS(3)) of deglycosylated peptide ions results in peptide backbone fragmentation, which is used in protein database searches to identify protein sequences. For O-glycopeptides the use of both CID and electron capture dissociation (ECD) fragmentation of the peptide backbone with intact glycans still attached are used to pinpoint the glycosylation sites of glycopeptides containing several Ser/Thr residues. The step-by-step protocols for fragmentation analyses of O- and N-glycopeptides enriched from human cerebrospinal fluid are described.

Glycan array analysis of the antigen repertoire targeted by tumor-binding antibodies

Immunization with whole cells has been used extensively to generate monoclonal antibodies, produce protective immune responses, and discover new disease antigens. While glycans are abundant on cell surfaces, anti-glycan immune responses have not been well-characterized. We used glycan microarrays to profile 49 tumor-binding monoclonal antibodies generated by immunizing mice with whole cancer cells. A substantial proportion (41%) of the tumor binding antibodies bound carbohydrate antigens. The antibodies primarily recognize a group of 5 glycan antigens: Sialyl Lewis A (SLeA), Lewis A (LeA), Lewis X (LeX), blood group A (BG-A), and blood group H on a type 2 chain (BG-H2). The results have important implications for monoclonal antibody production and cancer vaccine development.

Transfection of miRNAs targeting the FUT3 gene inhibits cell proliferation in human gastric cancer cell line KATO-III

AIM: To investigate the effect of inhibition of FUT3 gene expression with miRNAs on the proliferation of gastric cancer cells (KATO-Ⅲ).

METHODS: Vectors carrying two miRNAs targeting the FUT3 gene were constructed and transiently transfected into KATO-III cells using lipidosome-mediated method. RT-PCR was performed to detect the expression of FUT3 mRNA, and immunocytochemistry and flow cytometry analysis were carried out to test expression variation of sLeA antigen. MTT assay and colony-forming assay were used to analyze cell proliferation and to detect the effect of decreased FUT3 expression on cell growth.

RESULTS: Compared to non-transfected cells and cells transfected with empty vector, the relative expression levels of FUT3 mRNA were significantly decreased (0.41 ± 0.01 vs 0.71 ± 0.05, 0.65 ± 0.03, both P < 0.05; 0.36 ± 0.02 vs 0.71 ± 0.05, 0.65 ± 0.03, both P < 0.05); the sLeA antigen expression levels were also significantly reduced (35.51% ± 0.36% vs 52.79% ± 2.62%, 49.75% ± 1.29%, both P < 0.05; 26.05% ± 1.14% vs 52.79% ± 2.62%, 49.75% ± 1.29%, both P < 0.05); cell growth was significantly inhibited (38.10% ± 1.96% vs 5.6% ± 0.63%, 8.9% ± 0.91%, both P < 0.05; 49.04% ± 2.37% vs 5.6% ± 0.63%, 8.9% ± 0.91%, both P < 0.05); and colony-forming ability was significantly reduced (14.10% ± 1.70% vs 29.79% ± 3.05%, 28.92% ± 2.10%, both P < 0.05; 12.50% ± 1.96% vs 29.79% ± 3.05%, 28.92% ± 2.10%, both P < 0.05) in FUT3-miRNA and FUT3-miRNA2 transfeced cells.

CONCLUSION: Transfection of miRNAs targeting the FUT3 gene can effectively inhibit the proliferation of KATO-Ⅲ cells.

Involvement of viral glycoprotein gC-1 in expression of the selectin ligand sialyl-Lewis X induced after infection with herpes simplex virus type 1

Several herpesviruses induce expression of the selectin receptor sialyl-Lewis X (sLe(x) ) by activating transcription of one or more of silent host FUT genes, each one encoding a fucosyltransferase that catalyses the rate-limiting step of sLe(x) synthesis. The aim here was to identify the identity of the glycoconjugate associated with sLe(x) glycoepitope in herpes simplex virus type 1 (HSV-1) infected human diploid fibroblasts, using immunofluorescence confocal microscopy. Cells infected with all tested HSV-1 strains analysed demonstrated bright sLe(x) fluorescence, except for two mutant viruses that were unable to induce proper expression of viral glycoprotein gC-1: One gC-1 null mutant and another mutant expressing gC-1 devoid of its major O-glycan-containing region (aa 33-116). The sLe(x) reactivity of HSV-1 infected cells was abolished by mild alkali treatment. Altogether the results indicated that the detectable sLe(x) was associated with O-linked glycans, situated in the mucin region of gC-1. No evidence for sLe(x) (i) in other HSV-1 glycoproteins with mucin domains such as gI-1 or (ii) in host cell glycoproteins/glycolipids was found. Thus, the mucin domain of HSV-1 gC-1 may support expression of selectin ligands such as sLe(x) and other larger O-linked glycans in cell types lacking endogenous mucin domain-containing glycoproteins, optimized for O-glycan expression, provided that the adequate host glycosyltransferase genes are activated.

One-pot multienzyme synthesis of Lewis x and sialyl Lewis x antigens

L-Fucose has been found abundantly in human milk oligosaccharides, bacterial lipopolysaccharides, glycolipids, and many N- and O-linked glycans produced by mammalian cells. Fucose-containing carbohydrates have important biological functions. Alterations in the expression of fucosylated oligosaccharides have been observed in several pathological processes such as cancer and atherosclerosis. Chemical formation of fucosidic bonds is challenging due to its acid lability. Enzymatic construction of fucosidic bonds by fucosyltransferases is highly efficient and selective but requires the expensive sugar nucleotide donor guanosine 5'- diphosphate-L-fucose (GDP-Fuc). Here, we describe a protocol for applying a one-pot three-enzyme system in synthesizing structurally defined fucose-containing oligosaccharides from free L-fucose. In this system, GDP-Fuc is generated from L-fucose, adenosine 5'-triphosphate (ATP), and guanosine 5'-triphosphate (GTP) by a bifunctional L-fucokinase/GDP-fucose pyrophosphorylase (FKP). An inorganic pyrophosphatase (PpA) is used to degrade the by-product pyrophosphate (PPi) to drive the reaction towards the formation of GDP-Fuc. In situ generated GDP-Fuc is then used by a suitable fucosyltransferase for the formation of fucosides. The three-enzyme reactions are carried out in one pot without the need for high cost sugar nucleotide or isolation of intermediates. The time for the synthesis is 4-24 hours. Purification and characterization of products can be completed in 2-3 days.

Heparin mimetics

Explorations of the therapeutic potential of heparin mimetics, anionic compounds that are analogues of glycosaminoglycans (GAGs), have gone hand-in-hand with the emergence of understanding as to the role of GAGs in many essential biological processes. A myriad of structurally different heparin mimetics have been prepared and examined in many diverse applications. They range in complexity from heterogeneous polysaccharides that have been chemically sulphated to well-defined compounds, designed in part to mimic the natural ligand, but with binding specificity and potency increased by conjugation to non-carbohydrate pharmacophores. The maturity of the field is illustrated by the seven heparin mimetics that have achieved marketing approval and there are several more in late-stage clinical development. An overview of the structural determinants of heparin mimetics is presented together with an indication of their activities. The challenges in developing heparin mimetics as drugs, specificity and potential toxicity issues, are highlighted. Finally, the development path of three structurally very different mimetics, PI-88(®), GMI-1070 and RGTAs, each of which is in clinical trials, is described.