Functions of Sialyltransferases in gynecological malignancies: A systematic review

INTRODUCTION

The biosynthesis of tumor-associated sialoglycans involves Sialyltransferases expressed in cancer cells differentially. The current review aspires to bridge the existing knowledge gaps by consolidating evidence regarding the role of Sialyltransferases in gynecological malignant tumors (ovarian, cervix, endometrial, and breast).

METHODS

In this systematic review, we searched databases, including PubMed, Embase, Web of Science, Scopus and Cochrane Library. Twenty-two high-quality articles were selected out of 559 researched studies using radiomics quality score (RQS) tools.

RESULTS

Our findings indicated that 7 articles were related to Sialyltransferases in ovarian cancer, in which 6 studies was examined only ST6Gal-I and one study examined the ST3Gal-I, ST3Gal-II, ST3Gal-III, ST3Gal-IV, ST3Gal-VI, and ST3Gal-6. In addition, 5 articles were related to Sialyltransferases in cervix cancer (ST6Gal-I), 3 articles to endometrial cancer (ST6Gal-I, ST3Gal-III, ST3Gal-IV, and ST3Gal-6), and 7 articles to breast cancer (ST6Gal-I gene in 5 studies, ST6GAL-II gene in one study, and ST8SIA1 and ST3GAL-V genes in one study).

CONCLUSION

ST6Gal-I gene expression occurs at a high speed in ovarian, cervix, endometrial, and breast cancers, leading to metastasis to distant cells, cell destruction, cell invasion, and reduced patient survival.

Selective targeting of lectins and their macropinocytosis in urothelial tumours: translation from in vitro to ex vivo

Urinary bladder cancer can be treated by intravesical application of therapeutic agents, but the specific targeting of cancer urothelial cells and the endocytotic pathways of the agents are not known. During carcinogenesis, the superficial urothelial cells exhibit changes in sugar residues on the apical plasma membranes. This can be exploited for selective targeting from the luminal side of the bladder. Here we show that the plant lectins Jacalin (from Artocarpus integrifolia), ACA (from Amaranthus caudatus) and DSA (from Datura stramonium) selectively bind to the apical plasma membrane of low- (RT4) and high-grade (T24) cancer urothelial cells in vitro and urothelial tumours ex vivo. The amount of lectin binding was significantly different between RT4 and T24 cells. Endocytosis of lectins was observed only in cancer urothelial cells and not in normal urothelial cells. Transmission electron microscopy analysis showed macropinosomes, endosome-like vesicles and multivesicular bodies filled with lectins in RT4 and T24 cells and also in cells of urothelial tumours ex vivo. Endocytosis of Jacalin and ACA in cancer cells was decreased in vitro after addition of inhibitor of macropinocytosis 5-(N-ethyl-N-isopropyl) amiloride (EIPA) and increased after stimulation of macropinocytosis with epidermal growth factor (EGF). Clathrin, caveolin and flotillin did not colocalise with lectins. These results confirm that the predominant mechanism of lectin endocytosis in cancer urothelial cells is macropinocytosis. Therefore, we propose that lectins in combination with conjugated therapeutic agents are promising tools for improved intravesical therapy by targeting cancer cells.

Recognition factors of Dolichos biflorus agglutinin (DBA) and their accommodation sites

Dolichos biflorus agglutinin (DBA) is one of the well known plant lectins that are widely used in clinical serology to differentiate human blood group A1 and A2 erythrocytes and also applied to glycobiology. However, the knowledge of recognition factors of polyvalent (super) glycotopes in glycans and the roles of functional group and epimer in monosaccharide (sub-monosaccharide recognition factor) have not been well established. The size and shape of the recognition (combining) site of DBA has not been clearly defined. In this study, many importnat recognition factors of DBA-glycan binding were characterized by our established enzyme-linked lectinosorbent (ELLSA) and inhibition assays. The results of these assays showed that the intensity profile of the recognition factors for the major combining site of DBA was expressed by Mass relative potency (Mass R.P.) and shown by decreasing order of high density of polyvalent GalNAcα1 → (super glycotopes, 3.7 × 103) >> the corresponding β anomers >> monomeric GalNAcα1 → related glycotopes (GalNAc as 1.0) >> their GalNAc β-anomers >> Gal (absence of NHCH3CO at carbon-2 of GAlNAc) and GlcNAc (different epimer of Carbon-4 in GalNAc). From the all data available, it is proposed that the combining site of DBA should consist of a small cavity shape as major site and most complementary to monomeric GalNAcα → located at both terminal reducing end (Tn) and nonreducing end of glycan chains, and with a wide and broad area as subsite to accomodate from mono- to tetra-saccharides (GalNAcβ, Galβ1 → 3/4GlcNAc, lFuc1 → 2Galβ1 → 3/4GlcNAc, GalNAcβ1 → 3Galα1 → 4Galβ1 → 4Glc) at the nonreducing side. In this study, it has provided the most (comprehensive) recognition knowledge of DBA-glycan interactions at the factors of glycotope, super glycotope/sub-monosaccharide levels. Thus, it should expand and upgrade the conventional concept of the combining (recognition) site of DBA since 1980s.

Serum protein N-glycome patterns reveal alterations associated with endometrial cancer and its phenotypes of differentiation

Background

Aberrant N-glycosylation and its involvement in pathogenesis have been reported in endometrial cancer (EC). Nevertheless, the serum N-glycomic signature of EC remains unknown. Here, we investigated serum N-glycome patterns of EC to identify candidate biomarkers.

Methods

This study enrolled 34 untreated EC patients and 34 matched healthy controls (HC) from Peking Union Medical College Hospital. State-of-the-art MS-based methods were employed for N-glycans profiling. Multivariate and univariate statistical analyses were used to identify discriminative N-glycans driving classification. Receiver operating characteristic analyses were performed to evaluate classification accuracy.

Results

EC patients displayed distinct differences in serum N-glycome and had abnormal high-mannose and hybrid-type N-glycans, fucosylation, galactosylation, and linkage-specific sialylation compared with HC. The glycan panel built with the four most discriminative and biologically important derived N-glycan traits could accurately identify EC (random forest model, the area under the curve [AUC]=0.993 [95%CI 0.955-1]). The performance was validated by two other models. Total hybrid-type N-glycans significantly associated with the differentiation types of EC could effectively stratify EC into well- or poorly-differentiated subgroups (AUC>0.8).

Conclusion

This study provides the initial evidence supporting the utility of serum N-glycomic signature as potential markers for the diagnosis and phenotyping of EC.

Glycan signatures for the identification of cisplatin‐resistant testicular cancer cell lines: Specific glycoprofiling of human chorionic gonadotropin (hCG)

Background

Testicular cancer (TC) is the most frequent type of cancer among young men aged between 15 and 34 years. TC is treated using cisplatin, but 3%–5% of TC patients fail to respond to cisplatin, with a very bad to fatal prognosis. Accordingly, it is most important to quickly and readily identify those TC patients who are resistant to cisplatin treatment.

Methods

This study seeks to investigate changes in the glycosylation associated with cisplatin resistance to TC cell lines.

Results

A specific glycoprofiling of human chorionic gonadotropin (hCG) was analysed in three TC cell lines and one cell line of female origin. A typical calibration curve for hCG glycoprofiling showed a dynamic range up to 50 ng/ml, with a limit of detection of 0.3 ng/ml and assay reproducibility represented by relative standard deviation of 3.0%. Changes in the glycan signatures on hCG were analysed in cisplatin‐sensitive cell lines and in their cisplatin‐resistant sub‐lines using an enzyme‐linked lectin assay (ELLA) protocol. An immobilised antibody was applied to a selective capture of hCG from a cytoplasmic fraction of cell lysates with final incubation using a lectin from a panel of 17 lectins.

Conclusion

The results suggest that one particular lectin Dolichos biflorus agglutinin (DBA) can selectively discriminate sensitive TC cell lines from resistant TC cell lines. Moreover, there are additional lectins which can provide useful information about the strength of cisplatin resistance.

Sialic acids in gynecological cancer development and progression: Impact on diagnosis and treatment

Gynecological cancers are in the top 10 of most common cancers in women. Survival and outcome are strongly related to the stage at diagnosis. Therefore, early diagnosis is essential in reducing morbidity and mortality. The high mortality rate of gynecological cancers can mainly be attributed to ovarian cancer (OC). OC is commonly diagnosed at an advanced stage due to a lack of proper screening tools allowing early detection. Endometrial cancer (EC) on the contrary, is mostly diagnosed at an early stage and has, in general, better outcomes. The incidence of nonendometrioid EC has increased in the last decade, displaying a shared tumor biology with OC and consequently significantly worse outcome. New approaches allowing detection of gynecological cancers in an early stage are therefore desired. Recent studies on cancer biology have shown the relevance of altered glycosylation in the occurrence and progression of cancer. The aberrant expression of sialic acid, a specific carbohydrate terminating glycoproteins and glycolipids on the cell‐surface, is frequently correlated with malignancy. We aimed to determine the current understanding of sialic acid function in different gynecological cancers to identify the gaps in knowledge and its potential use for new diagnostic and therapeutic avenues. Therefore we performed a review on current literature focusing on studies where sialylation was linked to gynecological cancers. The identified studies showed elevated levels of sialic acid in serum, tissue and sialylated antigens in most patients with gynecological cancers, underlining its potential for diagnosis.

What's new?

Recent studies have shown the relevance of altered glycosylation in the occurrence and progression of cancer. In this review, the authors found elevated levels of sialic acid in serum and tissue and high levels of sialylated antigens in most patients with gynaecological cancers, underlining the potential of sialic acid for diagnosis. Elevated levels of sialylation were related with tumour growth, poor differentiation, inhibition of apoptosis, and chemoresistance. Taken together, the studies suggest that sialylation levels could be used to discriminate healthy and benign samples from cancer samples and even early and advanced stages in ovarian, cervical, and endometrial cancer.

High-precision multiclass cell classification by supervised machine learning on lectin microarray data

INTRODUCTION

Establishment of a cell classification platform for evaluation and selection of human pluripotent stem cells (hPSCs) is of great importance to assure the efficacy and safety of cell-based therapy. In our previous work, we introduced a discriminant function that evaluates pluripotency from the cells' glycome. However, it is not yet suitable for general use.

METHODS

The current study aims to establish a high-precision cell classification platform introducing supervised machine learning and test the platform on glycome analysis as a proof-of-concept study. We employed linear classification and neural network to the lectin microarray data from 1577 human cells and categorized them into five classes including hPSCs.

RESULTS

The linear-classification-based model and the neural-network-based model successfully predicted the sample type with accuracies of 89% and 97%, respectively.

CONCLUSIONS

Because of the high recognition accuracies and the small amount of computing resources required for these analyses, our platform can be a high precision conventional cell classification system for hPSCs.

Plant Lectins Targeting O-Glycans at the Cell Surface as Tools for Cancer Diagnosis, Prognosis and Therapy

Aberrant O-glycans expressed at the surface of cancer cells consist of membrane-tethered glycoproteins (T and Tn antigens) and glycolipids (Lewis a, Lewis x and Forssman antigens). All of these O-glycans have been identified as glyco-markers of interest for the diagnosis and the prognosis of cancer diseases. These epitopes are specifically detected using T/Tn-specific lectins isolated from various plants such as jacalin from Artocarpus integrifola, and fungi such as the Agaricus bisporus lectin. These lectins accommodate T/Tn antigens at the monosaccharide-binding site; residues located in the surrounding extended binding-site of the lectins often participate in the binding of more extended epitopes. Depending on the shape and size of the extended carbohydrate-binding site, their fine sugar-binding specificity towards complex O-glycans readily differs from one lectin to another, resulting in a great diversity in their sugar-recognition capacity. T/Tn-specific lectins have been extensively used for the histochemical detection of cancer cells in biopsies and for the follow up of the cancer progression and evolution. T/Tn-specific lectins also induce a caspase-dependent apoptosis in cancer cells, often associated with a more or less severe inhibition of proliferation. Moreover, they provide another potential source of molecules adapted to the building of photosensitizer-conjugates allowing a specific targeting to cancer cells, for the photodynamic treatment of tumors.

Removal of human pathogenic viruses in a down-flow hanging sponge (DHS) reactor treating municipal wastewater and health risks associated with utilization of the effluent for agricultural irrigation

A down-flow hanging sponge (DHS) reactor has been developed as a cost-effective wastewater treatment system that is adaptable to local conditions in low-income countries. A pilot-scale DHS reactor previously demonstrated stable reduction efficiencies for chemical oxygen demand (COD) and ammonium nitrogen over a year at ambient temperature, but the pathogen reduction efficiency of the DHS reactor has yet to be investigated. In the present study, the reduction efficiency of a pilot-scale DHS reactor fed with municipal wastewater was investigated for 10 types of human pathogenic viruses (norovirus GI, GII and GIV, aichivirus, astrovirus, enterovirus, hepatitis A and E viruses, rotavirus, and sapovirus). DHS influent and effluent were collected weekly or biweekly for 337 days, and concentrations of viral genomes were determined by microfluidic quantitative PCR. Aichivirus, norovirus GI and GII, enterovirus, and sapovirus were frequently detected in DHS influent, and the log₁₀ reduction (LR) of these viruses ranged from 1.5 to 3.7. The LR values for aichivirus and norovirus GII were also calculated using a Bayesian estimation model, and the average LR (±standard deviation) values for aichivirus and norovirus GII were estimated to be 1.4 (±1.5) and 1.8 (±2.5), respectively. Quantitative microbial risk assessment was conducted to calculate a threshold reduction level for norovirus GII that would be required for the use of DHS effluent for agricultural irrigation, and it was found that LRs of 2.6 and 3.7 for norovirus GII in the DHS effluent were required in order to not exceed the tolerable burden of disease at 10^-4 and 10^-6 disability-adjusted life years loss per person per year, respectively, for 95% of the exposed population during wastewater reuse for irrigation.

Role of lectin microarrays in cancer diagnosis

The majority of cell differentiation associated tumor markers reported to date are either glycoproteins or glycolipids. Despite there being a large number of glycoproteins reported as candidate markers for various cancers, only a handful are approved by the US Food and Drug Administration. Lectins, which bind to the glycan part of the glycoproteins, can be exploited to identify aberrant glycosylation patterns, which in turn would help in enhancing the specificity of cancer diagnosis. Although conventional techniques such as HPLC and MS have been instrumental in performing the glycomic analyses, these techniques lack multiplexity. Lectin microarrays have proved to be useful in studying multiple lectin-glycan interactions in a single experiment and, with the advances made in the field, hold a promise of enabling glycomic profiling of cancers in a fast and efficient manner.

Glycolipid dynamics in generation and differentiation of induced pluripotent stem cells

Glycosphingolipids (GSLs) are glycoconjugates that function as mediators of cell adhesion and modulators of signal transduction. Some well-defined markers of undifferentiated human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) are glycoconjugates, such as SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81. However, Comprehensive GSL profiles of hiPSCs have not yet been elucidated. The global images of GSLs from the parental cells, hiPSCs, and differentiated cells revealed that there are parental cell-independent specific glycolipids, including Globo H (fucosyl-Gb5Cer) and H type1 antigen (fucosyl-Lc4Cer) that are novel markers for undifferentiated hiPSCs. Interestingly, undifferentiated hiPSCs expressed H type 1 antigen, specific for blood type O, regardless of the cells’ genotypes. Thus, in this study, we defined the dynamics of GSL remodeling during reprogramming from parental cell sets to iPSC sets and thence to iPSC-neural cells.

Decreased expression of Bauhinia purpurea lectin is a predictor of gastric cancer recurrence

PURPOSE

Molecular markers as indicators for gastric cancer recurrence are urgently required. The aim of this study was to identify lectins that can be used to predict gastric cancer recurrence after gastrectomy.

METHODS

We created lectin expression profiles by microarray analysis for 60 patients, who underwent surgery for gastric cancer at the Oita University Hospital between January, 2005 and December, 2007. Lectin expression and clinicopathological factors in patients who suffered gastric cancer recurrence and those who did not were compared by univariate and multivariate analyses.

RESULTS

Thirteen lectins showed a significant increase in binding to cancer tissues, whereas 11 lectins showed a significant decrease in binding to cancer tissues, when compared with binding to normal epithelia. Multivariate analysis revealed that lymph node metastasis and low Bauhinia purpurea lectin (BPL)-binding signals were independent predictive factors for recurrence. All patients with low BPL expression had significantly worse relapse-free survival than those with high BPL expression.

CONCLUSIONS

Our results using a novel lectin microarray system provide the first solid evidence that BPL expression is a predictor of gastric cancer recurrence.

Establishment of new predictive markers for distant recurrence of colorectal cancer using lectin microarray analysis

We evaluated the clinical benefits of novel predictive markers for distant recurrence with colorectal cancer using lectin microarray analysis of cell surface glycan modifications. Glycoproteins were extracted from formalin-fixed, paraffin-embedded tumor specimens and normal epithelium from 53 consecutive curatively resected stage I–III colorectal cancer cases and then subjected to lectin microarray to obtain lectin–glycan interaction (LGI) values. In addition, clinicopathological factors associated with distant recurrence were identified. LGI values that were associated with distant recurrence were validated with an additional 55 curatively resected stage II colorectal cancer cases. LGI values for Agaricus bisporus (ABA) lectin, prominent in cancer tissues, were statistically associated with distant recurrence. ABA lectin staining exhibited strikingly intense signals in the cytoplasm and apical surfaces of cancer cells, while weak staining was observed in the supranuclear regions of normal epithelium. This ABA tumor/normal LGI ratio may be a new predictive biomarker for distant recurrence of curatively resected colorectal cancer.

Comprehensive profiling of accessible surface glycans of mammalian sperm using a lectin microarray

It is well known that cell surface glycans or glycocalyx play important roles in sperm motility, maturation and fertilization. A comprehensive profile of the sperm surface glycans will greatly facilitate both basic research (sperm glycobiology) and clinical studies, such as diagnostics of infertility. As a group of natural glycan binders, lectin is an ideal tool for cell surface glycan profiling. However, because of the lack of effective technology, only a few lectins have been tested for lectin-sperm binding profiles. To address this challenge, we have developed a procedure for high-throughput probing of mammalian sperm with 91 lectins on lectin microarrays. Normal sperm from human, boar, bull, goat and rabbit were collected and analyzed on the lectin microarrays. Positive bindings of a set of ~50 lectins were observed for all the sperm of 5 species, which indicated a wide range of glycans are on the surface of mammalian sperm. Species specific lectin bindings were also observed. Clustering analysis revealed that the distances of the five species according to the lectin binding profiles are consistent with that of the genome sequence based phylogenetic tree except for rabbit. The procedure that we established in this study could be generally applicable for sperm from other species or defect sperm from the same species. We believe the lectin binding profiles of the mammalian sperm that we established in this study are valuable for both basic research and clinical studies.

Cadmium-free sugar-chain-immobilized fluorescent nanoparticles containing low-toxicity ZnS-AgInS2 cores for probing lectin and cells

Sugar chains play a significant role in various biological processes through sugar chain-protein and sugar chain-sugar chain interactions. To date, various tools for analyzing sugar chains biofunctions have been developed. Fluorescent nanoparticles (FNPs) functionalized with carbohydrate, such as quantum dots (QDs), are an attractive imaging tool for analyzing carbohydrate biofunctions in vitro and in vivo. Most FNPs, however, consist of highly toxic elements such as cadmium, tellurium, selenium, and so on, causing problems in long-term bioimaging because of their cytotoxicity. In this study, we developed cadmium-free sugar-chain-immobilized fluorescent nanoparticles (SFNPs) using ZnS-AgInS2 (ZAIS) solid solution nanoparticles (NPs) of low or negligible toxicity as core components, and investigated their bioavailability and cytotoxicity. SFNPs were prepared by mixing our originally developed sugar-chain-ligand conjugates with ZAIS/ZnS core/shell NPs. In binding experiments with lectin, the obtained ZAIS/ZnS SFNPs interacted with an appropriate lectin to give specific aggregates, and their binding interaction was visually and/or spectroscopically detected. In addition, these SFNPs were successfully utilized for cytometry analysis and cellular imaging in which the cell was found to possess different sugar-binding properties. The results of the cytotoxicity assay indicated that SFNPs containing ZAIS/ZnS have much lower toxicity than those containing cadmium. These data strongly suggest that our designed SFNPs can be widely utilized in various biosensing applications involved in carbohydrates.

Glycan profiling of gestational choriocarcinoma using a lectin microarray

Glycosylation is an important post-translational modification, in which attachment of glycans to proteins has effects on biological functions and carcinogenesis. Analysis of human chorionic gonadotropin, a glycoprotein hormone produced by placental trophoblasts and trophoblastic tumors, has contributed to the diagnosis and treatment of trophoblastic disease, resulting in reduced incidence and mortality. However, alterations of the glycan structure itself in choriocarcinoma have not been characterized. We established a new choriocarcinoma cell line, induced choriocarcinoma cell-1 (iC3-1), which mimics the clinical pathohistology in vivo, to examine the tumorigenesis and pathogenesis of choriocarcinoma. In this study, the alterations of glycan structures in the development of choriocarcinoma were examined by performance of comprehensive glycan profiling in clinical samples and in iC3-1 cells using a conventional microarray and the recently introduced lectin microarray. Microarray comparison showed significant upregulation of several characteristic glycogenes in the iC3-1 cells as compared to the parental HTR8/SVneo cells. The lectin array showed increased α-2-6-sialic acid, Galβ1-4GlcNAc, GlcNAcβ1-3GalNAc, and decreased α-1-6 core fucose, high mannose, GalNacβ1-4Gal, GALNAc (Tn antigen) and Galβ1-3Gal in choriocarcinoma tissue compared to normal villi. This is the first report of a lectin array analysis in choriocarcinoma and provides useful information for understanding of the disease.

Dot by dot: analyzing the glycome using lectin microarrays

The glycome, that is, the cohort of carbohydrates within a cell or tissue, plays a key part in diverse biological interactions involved in health and disease. Glycans are structurally complex and notoriously difficult to analyze. Lectin microarrays, a sensitive and high-throughput method for glycomic profiling, provide a global view of the glycome. In recent work, this technology has been successfully applied to a wide range of studies, from identification of glycan-based stem cell markers to the detection of pathogens and early diagnosis of disease. This review focuses on advances in the field of lectin microarrays.

Age- and sex-associated differences in the glycopatterns of human salivary glycoproteins and their roles against influenza A virus

Recent studies have elucidated that expression of certain glycoproteins in human saliva is increased or decreased according to age; meanwhile, human saliva may inhibit viral infection and prevent viral transmission. However, little is known about the age- and sex-associated differences in the glycopatterns of human salivary glycoproteins and their significant roles against influenza A virus (IVA). Here, we investigate the glycopatterns of human salivary glycoproteins with 180 healthy saliva samples divided into six age/sex groups using lectin microarrays and fabricate saliva microarrays to validate the terminal carbohydrate moieties of glycoproteins in individual saliva samples. Furthermore, we assess the inhibiting and neutralizing activity of saliva against two strains of influenza A (H9N2) virus. We find that seven lectins (e.g., MAL-II and SNA) show significant age differences in both females and males, and seven lectins (e.g., WFA and STL) show significant sex differences in children, adults and elderly people. Interestingly, we observe that elderly individuals have strongest resistance to IVA partly by presenting more terminal α2-3/6-linked sialic acid residues in their saliva, which bind with the influenza viral hemagglutinations. We conclude that age- and sex-associated differences in the glycopatterns of human salivary glycoproteins may provide pivotal information to help understand some age related diseases and physiological phenomena.

Lectin microarrays: concept, principle and applications

The lectin microarray is a novel platform for glycan analysis, having emerged only in recent years. Unlike other conventional methods, e.g., liquid chromatography and mass spectrometry, it enables rapid and high-sensitivity profiling of complex glycan features without the need for liberation of glycans. Target samples include an extensive range of glycoconjugates involved in cells, tissues, body fluids, as well as synthetic glycans and their mimics. Various procedures for rapid differential glycan profiling have been developed for glycan-related biomarkers. Such glycoproteomics targeting allows precise diagnosis of chronic diseases potentially related to cancer. Application of this method to evaluation of various types of stem cells resulted in the discovery of a new pluripotent cell-specific glycan marker. To explore this technology a more fundamental and extensive understanding of lectins is necessary in relation to the structural uniqueness of glycans. In this chapter, the essence of the lectin microarray is described with some focus on an evanescent-field-activated fluorescence detection principle as a system to achieve in situ (i.e., washing free) aqueous-phase observation under equilibrium conditions. The developed lectin microarray system allows even researchers with poor experience in glycan profiling to perform extensive high-throughput analysis targeting various forms of glycans and even cells.