Glycoproteomics-based cancer marker discovery adopting dual enrichment with Wisteria floribunda agglutinin for high specific glyco-diagnosis of cholangiocarcinoma

Lectin: A Molecular Tool in Cancer Diagnosis and Therapy with Special Reference to Reproductive Cancers

The prevalence of cancer deaths globally and domestically is higher especially due to the deferment of diagnosis and lack of facilities for women's reproductive cancers. The present review focussed to explore the application of lectins in cancer theranostics. Though there is cancer diagnostic and treatment available there is no promising early diagnostic tool and effective treatment available for the cancer which is the major concern. Lectins are cellulose-binding proteins that are strongly determined in saccharide groups of glycans, glycopeptides, or glycolipids. In the concomitance of events in cells, carbohydrates, and proteins, lectins play an important role. Lectins bind superiorly to the cancer cell membrane and their receptors induce the cytotoxic effect, which results in caspase-mediated cell death, and prohibits tumour development. Lectin snuffing also reveals polyamine stocks and impedes the growth of cancerous cells. They affect the cell cycle by non-apoptotic aggregation, seizure of the cell cycle phase G2, M, and the mediation of caspases. It can also adversely affect the action of telomerase and hinder vascularisation. They promote immunomodulation and adversely limit protein synthesis. Their easy availability and its characteristics support its use in cancer diagnosis and therapy, despite their small corollary effects. Future investigations recommend focussing more on the key applications of lectin by reducing its concurrent effects and carrying out more in-vitro investigations. However, the use of lectin formulations for cancer theranostics is a new area in cancer detection and treatment. In this review, plant lectin appears to be a potential target for cancer research in the fields of diagnosis and theranostics.

Lectin-Based Approaches to Analyze the Role of Glycans and Their Clinical Application in Disease

Lectin-based approaches remain a valuable tool for analyzing glycosylation, especially when detecting cancer-related changes. Certain glycans function as platforms for cell communication, signal transduction, and adhesion. Therefore, the functions of glycans are important considerations for clinical aspects, such as cancer, infection, and immunity. Considering that the three-dimensional structure and multivalency of glycans are important factors for their function, their binding characteristics toward lectins provide vital information. Glycans and lectins are inextricably linked, and studies on lectins have also led to research on the roles of glycans. The applications of lectins are not limited to analysis but can also be used as drug delivery tools. Moreover, mammalian lectins are potential therapeutic targets because certain lectins change their expression in cancer, and lectin regulation subsequently regulates several molecules with glycans. Herein, we review lectin-based approaches for analyzing the role of glycans and their clinical applications in diseases, as well as our recent results.

Site-specific N-glycan alterations on haptoglobin as potential biomarkers for distinguishing intrahepatic cholangiocarcinoma from hepatocellular carcinoma

Intrahepatic cholangiocellular carcinoma (ICC) is a challenging malignancy marked by subtle early symptoms and a high mortality rate, making effective diagnostic markers crucial for early detection and improved patient outcomes. Currently, the conventional diagnosis of ICC is not easily distinguishable from Hepatocellular Carcinoma (HCC) and lacks highly specific and sensitive diagnostic markers. Protein glycosylation, pivotal in biological processes, shows promise for cancer biomarkers due to its association with disease progression. This study aims to develop a novel biomarker discovery framework for ICC utilizing site-specific quantitative N-glycoproteomics to overcome the limitations of existing diagnostic approaches. Employing a tandem mass tag (TMT)-based quantitative analysis, we profiled serum glycoproteins from ICC, HCC, and control cohorts at site-specific glycosylation level. The identified markers underwent further validation in an independent cohort using label-free quantitative methods. Ultimately, we identified five site-specific N-glycans on haptoglobin (HP) as potential biomarkers (AUC > 0.9) for distinguishing ICC from HCC. This finding represents a considerable advance over traditional biomarkers, highlighting the significance of protein glycosylation alterations in ICC pathogenesis. This research, therefore, sets a new precedent for biomarker discovery in ICC, with potential applications in other cancers characterized by glycosylation abnormalities.

Differential Glycoform Analysis of MUC1 Derived from Biological Specimens Using an Antibody-Overlay Lectin Microarray

The association between altered glycosylation of MUC1 and various disease events has sparked significant interest. However, analytical technologies to investigate the disease-related glycoforms of endogenous MUC1 in blood and tissue specimens are limited. Therefore, we devised a reliable technique for differential analysis of endogenous MUC1 glycoforms based on an antibody-assisted lectin microarray. Its highly sensitive detection aids in analyzing soluble MUC1 from relatively small amounts of serum via a simple enrichment process. Micro-/macro-dissection of the MUC1-positive region is combined with glycoform analysis of the membrane-tethered MUC1. Thus, we have optimized the protocol for sample qualification using immunohistochemistry, sample pretreatment for tissue sections, protein extraction, purification via immunoprecipitation, and the antibody-overlay lectin microarray, which are sequentially essential for differential glycoform analysis of endogenous MUC1.

Aberrant protein glycosylation: Implications on diagnosis and Immunotherapy

Glycosylation-mediated post-translational modification is critical for regulating many fundamental processes like cell division, differentiation, immune response, and cell-to-cell interaction. Alterations in the N-linked or O-linked glycosylation pattern of regulatory proteins like transcription factors or cellular receptors lead to many diseases, including cancer. These alterations give rise to micro- and macro-heterogeneity in tumor cells. Here, we review the role of O- and N-linked glycosylation and its regulatory function in autoimmunity and aberrant glycosylation in cancer. The change in cellular glycome could result from a change in the expression of glycosidases or glycosyltransferases like N-acetyl-glucosaminyl transferase V, FUT8, ST6Gal-I, DPAGT1, etc., impact the glycosylation of target proteins leading to transformation. Moreover, the mutations in glycogenes affect glycosylation patterns on immune cells leading to other related manifestations like pro- or anti-inflammatory effects. In recent years, understanding the glycome to cancer indicates that it can be utilized for both diagnosis/prognosis as well as immunotherapy. Studies involving mass spectrometry of proteome, site- and structure-specific glycoproteomics, or transcriptomics/genomics of patient samples and cancer models revealed the importance of glycosylation homeostasis in cancer biology. The development of emerging technologies, such as the lectin microarray, has facilitated research on the structure and function of glycans and glycosylation. Newly developed devices allow for high-throughput, high-speed, and precise research on aberrant glycosylation. This paper also discusses emerging technologies and clinical applications of glycosylation.

Diagnosis Biomarkers of Cholangiocarcinoma in Human Bile: An Evidence-Based Study

Simple Summary

A liquid biopsy has the characteristics of low trauma and easy acquisition in the diagnosis of cholangiocarcinoma. Many researchers try to find diagnostic or prognostic biomarkers of CCA through blood, urine, bile and other body fluids. Due to the close proximity of bile to the lesion and the stable nature, bile gradually comes into people’s view. The evaluation of human bile diagnostic biomarkers is not only to the benefit of screening more suitable clinical markers but also of exploring the pathological changes of the disease.

Abstract

Cholangiocarcinoma (CCA) is a multifactorial malignant tumor of the biliary tract, and the incidence of CCA is increasing in recent years. At present, the diagnosis of CCA mainly depends on imaging and invasive examination, with limited specificity and sensitivity and late detection. The early diagnosis of CCA always faces the dilemma of lacking specific diagnostic biomarkers. Non-invasive methods to assess the degree of CAA have been developed throughout the last decades. Among the many specimens looking for CCA biomarkers, bile has gotten a lot of attention lately. This paper mainly summarizes the recent developments in the current research on the diagnostic biomarkers for CCA in human bile at the levels of the gene, protein, metabolite, extracellular vesicles and volatile organic compounds.

Precision N-glycoproteomics reveals elevated LacdiNAc as a novel signature of intrahepatic cholangiocarcinoma

Primary liver cancer, mainly comprising hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC), remains a major global health problem. Although ICC is clinically different from HCC, their molecular differences are still largely unclear. In this study, precision N‐glycoproteomic analysis was performed on both ICC and HCC tumors as well as paracancer tissues to investigate their aberrant site‐specific N‐glycosylation. By using our newly developed glycoproteomic methods and novel algorithm, termed ‘StrucGP’, a total of 486 N‐glycan structures attached on 1235 glycosites were identified from 894 glycoproteins in ICC and HCC tumors. Notably, glycans with uncommon LacdiNAc (GalNAcβ1‐4GlcNAc) structures were distinguished from their isomeric glycans. In addition to several bi‐antennary and/or bisecting glycans that were commonly elevated in ICC and HCC, a number of LacdiNAc‐containing, tri‐antennary, and core‐fucosylated glycans were uniquely increased in ICC. More interestingly, almost all LacdiNAc‐containing N‐glycopeptides were enhanced in ICC tumor but not in HCC tumor, and this phenomenon was further confirmed by lectin histochemistry and the high expression of β1‐4 GalNAc transferases in ICC at both mRNA and protein expression levels. The novel N‐glycan alterations uniquely detected in ICC provide a valuable resource for future studies regarding to the discovery of ICC diagnostic biomarkers, therapeutic targets, and mechanism investigations.

N-glycan structures of Wisteria floribunda agglutinin-positive Mac2 binding protein in the serum of patients with liver fibrosis†

The extent of liver fibrosis predicts prognosis and is important for determining treatment strategies for chronic hepatitis. During the fibrosis progression, serum levels of Mac2 binding protein (M2BP) increase and the N-glycan structure changes to enable binding to Wisteria floribunda agglutinin (WFA) lectin. As a novel diagnostic marker, glycosylation isomer of M2BP (M2BPGi) has been developed. However, its glycan structures recognized by WFA are unclear. In this study, we analyzed site-specific N-glycan structures of serum M2BP using Glyco-RIDGE (Glycan heterogeneity-based Relational IDentification of Glycopeptide signals on Elution profile) method. We evaluated five sample types: 1) M2BP immunoprecipitated from normal healthy sera (NHS-IP(+)), 2) M2BP immunoprecipitated from sera of patients with liver cirrhosis (stage 4; F4-IP(+)), 3) M2BP captured with WFA from serum of patients with liver cirrhosis (stage 4; F4-WFA(+)), 4) recombinant M2BP produced by HEK293 cells (rM2BP), and 5) WFA-captured rM2BP (rM2BP-WFA(+)). In NHS-IP(+) M2BP, bi-antennary N-glycan was the main structure, and LacNAc extended to its branches. In F4-IP(+) M2BP, many branched structures, including tri-antennary and tetra-antennary N-glycans, were found. F4-WFA(+) showed a remarkable increase in branched structures relative to the quantity before enrichment. In recombinant M2BP, both no sialylated-LacdiNAc and -branched LacNAc structures were emerged. The LacdiNAc structure was not found in serum M2BP. Glycosidase-assisted HISCL assays suggest that, reactivity with WFA of both serum and recombinant M2BP depends on unsialylated and branched LacNAc, and in part of recombinant, depends on LacdiNAc. On M2BPGi, the highly branched LacNAc, probably dense cluster of LacNAc, would be recognized by WFA.

Databases and Bioinformatic Tools for Glycobiology and Glycoproteomics

Glycosylation plays critical roles in various biological processes and is closely related to diseases. Deciphering the glycocode in diverse cells and tissues offers opportunities to develop new disease biomarkers and more effective recombinant therapeutics. In the past few decades, with the development of glycobiology, glycomics, and glycoproteomics technologies, a large amount of glycoscience data has been generated. Subsequently, a number of glycobiology databases covering glycan structure, the glycosylation sites, the protein scaffolds, and related glycogenes have been developed to store, analyze, and integrate these data. However, these databases and tools are not well known or widely used by the public, including clinicians and other researchers who are not in the field of glycobiology, but are interested in glycoproteins. In this study, the representative databases of glycan structure, glycoprotein, glycan-protein interactions, glycogenes, and the newly developed bioinformatic tools and integrated portal for glycoproteomics are reviewed. We hope this overview could assist readers in searching for information on glycoproteins of interest, and promote further clinical application of glycobiology.

Mass spectrometry-based analysis of formalin-fixed, paraffin-embedded distal cholangiocarcinoma identifies stromal thrombospondin-2 as a potential prognostic marker

Background

Distal cholangiocarcinoma is an aggressive malignancy with a dismal prognosis. Diagnostic and prognostic biomarkers for distal cholangiocarcinoma are lacking. The aim of the present study was to identify differentially expressed proteins between distal cholangiocarcinoma and normal bile duct samples.

Methods

A workflow utilizing discovery mass spectrometry and verification by parallel reaction monitoring was used to analyze surgically resected formalin-fixed, paraffin-embedded samples from distal cholangiocarcinoma patients and normal bile duct samples. Bioinformatic analysis was used for functional annotation and pathway analysis. Immunohistochemistry was performed to validate the expression of thrombospondin-2 and investigate its association with survival.

Results

In the discovery study, a total of 3057 proteins were identified. Eighty-seven proteins were found to be differentially expressed (q < 0.05 and fold change ≥ 2 or ≤ 0.5); 31 proteins were upregulated and 56 were downregulated in the distal cholangiocarcinoma samples compared to controls. Bioinformatic analysis revealed an abundance of differentially expressed proteins associated with the tumor reactive stroma. Parallel reaction monitoring verified 28 proteins as upregulated and 18 as downregulated in distal cholangiocarcinoma samples compared to controls. Immunohistochemical validation revealed thrombospondin-2 to be upregulated in distal cholangiocarcinoma epithelial and stromal compartments. In paired lymph node metastases samples, thrombospondin-2 expression was significantly lower; however, stromal thrombospondin-2 expression was still frequent (72%). Stromal thrombospondin-2 was an independent predictor of poor disease-free survival (HR 3.95, 95% CI 1.09–14.3; P = 0.037).

Conclusion

Several proteins without prior association with distal cholangiocarcinoma biology were identified and verified as differentially expressed between distal cholangiocarcinoma and normal bile duct samples. These proteins can be further evaluated to elucidate their biomarker potential and role in distal cholangiocarcinoma carcinogenesis. Stromal thrombospondin-2 is a potential prognostic marker in distal cholangiocarcinoma.

Plant-Derived Lectins as Potential Cancer Therapeutics and Diagnostic Tools

Cancer remains a global health challenge, with high morbidity and mortality, despite the recent advances in diagnosis and treatment. Multiple compounds assessed as novel potential anticancer drugs derive from natural sources, including microorganisms, plants, and animals. Lectins, a group of highly diverse proteins of nonimmune origin with carbohydrate-binding abilities, have been detected in virtually all kingdoms of life. These proteins can interact with free and/or cell surface oligosaccharides and might differentially bind cancer cells, since malignant transformation is tightly associated with altered cell surface glycans. Therefore, lectins could represent a valuable tool for cancer diagnosis and be developed as anticancer therapeutics. Indeed, several plant lectins exert cytotoxic effects mainly by inducing apoptotic and autophagic pathways in malignant cells. This review summarizes the current knowledge regarding the basis for the use of lectins in cancer diagnosis and therapy, providing a few examples of plant-derived carbohydrate-binding proteins with demonstrated antitumor effects.

Qualitative and quantitative alterations in intracellular and membrane glycoproteins maintain the balance between cellular senescence and human aging

Glycans are associated with and serve as biomarkers for various biological functions. We previously reported that cell surface sialylated glycoproteins of dermal fibroblasts decreased with cellular senescence and human aging. There is little information on the changes in glycoprotein expression and subcellular localization during the aging process. Here, we examined intracellular glycan profiles of fibroblasts undergoing cellular senescence and those derived from aging human subjects using lectin microarray analysis. We found a sequential change of the intracellular glycan profiles was little during cellular senescence. The intracellular glycans of cells derived from aged fetus and from elderly subjects showed similar localized patterns while repeating unsteady changes. The ratio of α2-3/2-6sialylated intracellular glycoproteins in total cell extracts increased, except for a part of α2-3sialylated O-glycans. These findings are in contrast to those for membrane glycoprotein, which decreased with aging. Interestingly, the ratio of increasing sialylated glycoproteins in the fetus-derived cells showing cellular senescence was similar to that in cells derived from the elderly. Thus, intracellular glycans may maintain cellular functions such as ubiquitin/proteasome-mediated degradation and/or autophagy during aging by contributing to the accumulation of intracellular glycosylated proteins. Our findings provide novel mechanistic insight into the molecular changes that occur during aging.

Meta-analysis of the diagnostic value of Wisteria floribunda agglutinin-sialylated mucin1 and the prognostic role of mucin1 in human cholangiocarcinoma

OBJECTIVE

Serum carbohydrate antigen 19-9 (CA19-9) is a widely used tumour marker for cholangiocarcinoma (CCA). However, it is not a necessarily good CCA marker in terms of diagnostic accuracy. The purpose of this study is to evaluate the diagnostic value of Wisteria floribundaagglutinin-sialylated Mucin1 (WFA-MUC1) and the prognostic role of Mucin1 (MUC1) in human CCA.

DESIGN

Meta-analysis.

DATA SOURCES

Studies published in PubMed, Web of Science, The Cochrane Library and the China National Knowledge Infrastructure up to 11 October 2017.

ELIGIBILITY CRITERIA

We included reports assessing the diagnostic capacity of WFA-MUC1 and the prognostic role of MUC1 in CCA. The receiver operating characteristic curve (ROC) of WFA-MUC1 and/or CA19-9 was described, and the HRs including 95% CI and the corresponding p value for MUC1 can be extracted.

DATA EXTRACTION AND SYNTHESIS

Two independent researchers extracted data and assessed risk of bias. The diagnostic sensitivity and specificity data of WFA-MUC1 were extracted and analysed as bivariate data. Pooled HRs and its 95% CI for MUC1 were calculated with a random-effects meta-analysis model on overall survival of resectable CCA.

RESULTS

Sixteen reports were included in this study. The pooled sensitivity and specificity of WFA-MUC1 were 0.76 (95% CI 0.71 to 0.81) and 0.72 (95% CI 0.59 to 0.83) in serum, 0.85 (95% CI 0.81 to 0.89) and 0.72 (95% CI 0.64 to 0.80) in bile and 0.72 (95% CI 0.50 to 0.87) and 0.85 (95% CI 0.70 to 0.93) in tissue, respectively. The summary ROC (SROC) were 0.77 (95% CI 0.73 to 0.81) in serum, 0.88 (95% CI 0.85 to 0.90) in bile and 0.86 (95% CI 0.83 to 0.89) in tissue, respectively. Furthermore, the pooled sensitivity and specificity and the SROC of CA19-9 in serum were 0.67 (95% CI 0.61 to 0.72), 0.86 (95% CI 0.75 to 0.93) and 0.75 (95% CI 0.71 to 0.79), respectively. The pooled HRs for MUC1 was 2.20 (95% CI 1.57 to 3.01) in CCA and 4.17 (95% CI 1.71 to 10.17) in mass-forming intrahepatic CCA.

CONCLUSIONS

Compared with CA19-9, WFA-MUC1 was shown to possess stronger diagnostic capability. MUC1 could serve as a prognosis factor for poor outcomes of CCA, particularly, mass-forming intrahepatic CCA.

Fucosyl-Agalactosyl IgG₁ Induces Cholangiocarcinoma Metastasis and Early Recurrence by Activating Tumor-Associated Macrophage

Concern over roles of serum IgG agalactosylation in chronic inflammatory diseases has been mounting for years but less touched in cancers. The present study addressed the underlying role of agalactosylated IgG beyond tumorigenesis. Liquid-chromatography-tandem mass spectrometry was leveraged for the analysis of IgG₁ and IgG₂N-glycomes. We found that a high percentage of serum fucosyl-agalactosyl IgG₁ (IgG₁-G0F) in patients with cholangiocarcinoma was associated with poor tumor differentiation and tumor metastasis. Results from Kaplan–Meier analyses and a stepwise Cox regression analysis showed that patients with serum IgG₁-G0F ≥40% were highly correlated with poor recurrence-free survivals and overall survivals. Interestingly, patients with cholangiocarcinoma whose serum IgG₁-G0F ≥40% had more CD163+ tumor-associated macrophages in cancerous tissues than adjacent non-cancerous counterparts. In vitro assays revealed that agalactosylated IgG upregulated tumor-associated macrophage markers CD163 and CD204 in human U-937 cells and peripheral macrophages. Moreover, a positive and a negative feedback loop of transforming growth factor-β1 and interferon-γ, respectively, on IgG agalactosylation was identified using hybridoma cells and verified in sera of the patients. In conclusion, agalactosylated IgG activates tumor-associated macrophages, thereby promoting tumor metastasis and recurrence of cholangiocarcinoma.

Current Technologies for Complex Glycoproteomics and Their Applications to Biology/Disease-Driven Glycoproteomics

Glycoproteomics is an important recent advance in the field of glycoscience. In glycomics, glycan structures are comprehensively analyzed after glycans are released from glycoproteins. However, a major limitation of glycomics is the lack of insight into glycoprotein functions. The Biology/Disease-driven Human Proteome Project has a particular focus on biological and medical applications. Glycoproteomics technologies aimed at obtaining a comprehensive understanding of intact glycoproteins, i.e., the kind of glycan structures that are attached to particular amino acids and proteins, have been developed. This Review focuses on the recent progress of the technologies and their applications. First, the methods for large-scale identification of both N- and O-glycosylated proteins are summarized. Next, the progress of analytical methods for intact glycopeptides is outlined. MS/MS-based methods were developed for improving the sensitivity and speed of the mass spectrometer, in parallel with the software for complex spectrum assignment. In addition, a unique approach to identify intact glycopeptides using MS1-based accurate masses is introduced. Finally, as an advance of glycomics, two approaches to provide the spatial distribution of glycans in cells are described, i.e., MS imaging and lectin microarray. These methods allow rapid glycomic profiling of different types of biological samples and thus facilitate glycoproteomics.

Lectin-Based Assay for Glycoform-Specific Detection of α2,6-sialylated Transferrin and Carcinoembryonic Antigen in Tissue and Body Fluid

Antibodies are useful for detecting glycoprotein antigens, but a conventional antibody recognizes only a protein epitope rather than a glycan. Thus, glycan isoform detection generally requires time- and labor-consuming processes such as lectin affinity column chromatography followed by sandwich ELISA. We recently found antigen-antibody reactions that were inhibited by lectin binding to glycans on the glycoprotein antigen, leading to a convenient glycoform-specific assay. Indeed, Sambucus sieboldiana agglutinin (SSA) lectin, a binder to sialylα2,6galactose residue, inhibited antibody binding to α2,6-sialylated transferrin (Tf) (SSA inhibition). SSA inhibition was not observed with other glycoforms, such as periodate-treated, sialidase-treated and sialidase/galactosidase-treated Tf, suggesting that the assay was glycoform-specific. SSA inhibition was also applicable for visualizing localization of α2,6-sialylated-Tf in a liver section. This is the first immunohistochemical demonstration of glycoform localization in a tissue section. SSA inhibition was utilized for establishing ELISA to quantify α2,6-sialylated carcinoembryonic antigen (CEA), a marker for various cancers. In addition, α2,6-sialylated-CEA was visualized in a colonic adenocarcinoma section by SSA inhibition. The method would further be applicable to a simple and rapid estimation of other α2,6-sialylated glycoproteins and have a potential aid to histopathological diagnosis.

Biomarkers for the Diagnosis of Cholangiocarcinoma: A Systematic Review

Cholangiocarcinoma (CCA), a malignant tumor of the bile duct, is a major public health problem in many Southeast Asian countries, particularly Thailand. The slow progression makes it difficult for early diagnosis and most patients are detected in advanced stages. This study aimed to review all relevant articles related to the biomarkers for the diagnosis of CCA and point out potential biomarkers. A thorough search was performed in PubMed and ScienceDirect for CCA biomarker articles. Required data were extracted. A total of 46 articles that fulfilled the inclusion and had none of the exclusion criteria were included in the analysis (17, 22, 3, 4, and 1 articles on blood, tissue, bile, both blood and tissue, and urine biomarkers, respectively). Carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA), either alone or in combination with other biomarkers, are the most commonly studied biomarkers in the serum. Their sensitivity and specificity ranged from 47.2% to 98.2% and 89.7% to 100%, respectively. However, in the tissue, gene methylations and DNA-related markers were the most studied CCA biomarkers. Their sensitivity and specificity ranged from 58% to 87% and 98% to 100%, respectively. Some articles investigated biomarkers both in blood and tissues, particularly CA19-9 and CEA, with sensitivity and specificity ranging from 33% to 100% and 50% to 97.7%, respectively. Although quite a number of biomarkers with a potential role in the early detection of CCA have been established, it is difficult to single out any particular marker that could be used in the routine clinical settings.

Designation of fingerprint glycopeptides for targeted glycoproteomic analysis of serum haptoglobin: insights into gastric cancer biomarker discovery

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide, largely because of difficulties in early diagnosis. Despite accumulating evidence indicating that aberrant glycosylation is associated with GC, site-specific localization of the glycosylation to increase specificity and sensitivity for clinical use is still an analytical challenge. Here, we created an analytical platform with a targeted glycoproteomic approach for GC biomarker discovery. Unlike the conventional glycomic approach with untargeted mass spectrometric profiling of released glycan, our platform is characterized by three key features: it is a target-protein-specific, glycosylation-site-specific, and structure-specific platform with a one-shot enzyme reaction. Serum haptoglobin enriched by immunoaffinity chromatography was subjected to multispecific proteolysis to generate site-specific glycopeptides and to investigate the macroheterogeneity and microheterogeneity. Glycopeptides were identified and quantified by nano liquid chromatography-mass spectrometry and nano liquid chromatography-tandem mass spectrometry. Ninety-six glycopeptides, each corresponding to a unique glycan/glycosite pairing, were tracked across all cancer and control samples. Differences in abundance between the two groups were marked by particularly high magnitudes. Three glycopeptides exhibited exceptionally high control-to-cancer fold changes along with receiver operating characteristic curve areas of 1.0, indicating perfect discrimination between the two groups. From the results taken together, our platform, which provides biological information as well as high sensitivity and reproducibility, may be useful for GC biomarker discovery. Graphical abstract ᅟ.

Clinical significance of GalNAcylated glycans in cholangiocarcinoma: Values for diagnosis and prognosis

Cancer cells exhibited the aberrant cancer-associated glycans that are potential biomarkers for diagnosis and monitoring of the cancer. In this study, Sophora japonica agglutinin (SJA) was used to detect SJA-specific N-acetylgalactosamine-associated glycans (SNAG) in liver tissues and sera from cholangiocarcinoma (CCA) patients. Whether SNAG could be the diagnostic and prognostic markers for CCA was evaluated. SJA-histochemistry revealed that SNAG was undetec2 in normal bile ducts but was highly expressed in hyperplastic/dysplastic bile ducts and CCA. SNAG was negative in hepatocytes and hepatoma tissues indicating SNAG as a differential marker of CCA and hepatoma. SJA-histochemistry of CCA hamster tissues revealed the involvement of SNAG in the early pathogenesis of bile duct epithelia and CCA development. A SJA-based ELISA was successfully developed to determine SNAG in serum. Serum-SNAG from CCA patients was significantly higher than those of non-CCA control groups with the diagnostic values of 59.5% sensitivity and 73.6% specificity, comparable to those of serum CA19-9. High levels of serum SNAG (≥69AU/ml) indicated poor survival of CCA patients. Taken together, SNAG was first demonstrated here to be a glycobiomarker for diagnosis and prognosis of CCA. Association of SNAG with pathogenesis of bile ducts and CCA development were suggested. (198).

Glycomic profiling of targeted serum haptoglobin for gastric cancer using nano LC/MS and LC/MS/MS

Gastric cancer has one of the highest cancer mortality rates worldwide, largely because of difficulties in early-stage detection. Aberrant glycosylation in serum proteins is associated with many human diseases including inflammation and various types of cancer. Serum-based global glycan profiling using mass spectrometry has been explored and has already led to several potential glycan markers for several disease states. However, localization of the aberrant glycosylation is desirable in order to improve the specificity and sensitivity for clinical use. Here, we combined protein-specific immunoaffinity purification, glycan release, and MS analysis to examine haptoglobin glycosylation of gastric cancer patients for glyco-markers. Age- and sex-matched 60 serum samples (30 cancer patients and 30 healthy controls) were used to profile and quantify haptoglobin N-glycans. A T-test based statistical analysis was performed to identify potential glyco-markers for gastric cancer. Interestingly, abundances of several tri- and tetra-antennary fucosylated N-glycans were increased in gastric cancer patients. Additionally, structural analysis via LC/MS/MS indicated that the fucosylated complex type N-glycans were primarily decorated with antenna fucose, which can be categorized as sialyl-Le^a or sialyl-Le^x type structures. This platform demonstrates quantitative, structure-specific profiling of haptoglobin glycosylation for the purposes of biomarker discovery for gastric cancer.

Engineering of recombinant Wisteria floribunda agglutinin specifically binding to GalNAcβ1,4GlcNAc (LacdiNAc)

Wisteria floribunda agglutinin (WFA) is a useful probe for distinguishing glycan structural alterations in diseases such as intrahepatic bile duct carcinoma and hepatic fibrosis; however, the gene encoding WFA has not been identified. Here, we identified the gene encoding WFA, and recombinant WFA (rWFA) was expressed in Escherichia coli and purified. The natural complementary DNA sequence obtained from wisteria seeds contained an open reading frame of 861 nucleotides encoding a WFA precursor, which included a hydrophobic signal peptide at the N-terminus, a propeptide at the C-terminus and a single cysteine (Cys) residue for dimer formation. We characterized the natural and rWFA by the glycoconjugate microarray and frontal affinity chromatography. rWFA exhibited glycan binding specificity similar to that of natural WFA: both bound to Gal- and N-acetylgalactosamine (GalNAc)-terminated glycans. Moreover, the engineered WFA with an amino acid substitution in Cys-272 yielded a recombinant monomeric lectin with limited binding specificity but wild-type affinity for GalNAc-terminated glycans, specifically GalNAcβ1,4GlcNAc. Thus, this engineered lectin may be applied to highly sensitive biomarker detection.

On the trail of the glycan codes stored in cancer-related cell adhesion proteins

Changes in the profile of protein glycosylation are a hallmark of ongoing neoplastic transformation. A unique set of tumor-associated carbohydrate antigens expressed on the surface of malignant cells may serve as powerful diagnostic and therapeutic targets. Cell-surface proteins with altered glycosylation affect the growth, proliferation and survival of those cells, and contribute to their acquisition of the ability to migrate and invade. They may also facilitate tumor-induced immunosuppression and the formation of distant metastases. Deciphering the information encoded in these particular glycan portions of glycoconjugates may shed light on the mechanisms of cancer progression and metastasis. A majority of the related review papers have focused on overall changes in the patterns of cell-surface glycans in various cancers, without pinpointing the molecular carriers of these glycan structures. The present review highlights the ways in which particular tumor-associated glycan(s) coupled with a given membrane-bound protein influence neoplastic cell behavior during the development and progression of cancer. We focus on altered glycosylated cell-adhesion molecules belonging to the cadherin, integrin and immunoglobulin-like superfamilies, examined in the context of molecular interactions.

Clinicopathological characteristics and diagnostic performance of Wisteria floribunda agglutinin positive Mac-2-binding protein as a preoperative serum marker of liver fibrosis in hepatocellular carcinoma

BACKGROUND

Wisteria floribunda agglutinin positive Mac-2-binding protein (WFA(+)-M2BP) is a novel serum marker of liver fibrosis identified in glycoproteomic biomarker screening studies, and its clinicopathological characteristics have yet to be elucidated sufficiently for clinical utilization.

METHODS

We retrospectively analyzed the clinicopathology data and serum WFA(+)-M2BP levels in 376 hepatocellular carcinoma patients undergoing liver surgery. WFA(+)-M2BP was quantified in frozen serum samples collected at the time of surgery using the FastLec-Hepa method.

RESULTS

Significant independent determinants of serum WFA(+)-M2BP levels included pathological diagnosis of cirrhosis, female gender, hepatitis C virus (HCV) infection, and liver dysfunction characteristics, such as abnormal indocyanine green retention rate at 15 min, platelet counts, albumin levels, alanine aminotransferase levels, and total bilirubin levels. Serum WFA(+)-M2BP levels increased with the pathological fibrosis stage and liver dysfunction severity. HCV infection significantly affected serum WFA(+)-M2BP levels throughout the pathological and functional progression of liver fibrosis, and the effect of gender was significant only in F4 stage patients with severe liver dysfunction. The diagnostic thresholds for cutoff index values for cirrhosis were 1.435 and 4.615 in HCV-negative and HCV-positive patients, respectively. Serum WFA(+)-M2BP levels at the time of operation were a significant predictor of hepatocellular carcinoma recurrence and overall survival in both HCV-negative and HCV-positive patients.

CONCLUSIONS

Serum WFA(+)-M2BP levels reflected both the pathological and functional progression of liver fibrosis comprehensively and continuously. Elevated WFA(+)-M2BP levels were a significant risk factor for tumor recurrence and decreased overall survival after liver surgery independent of HCV infection.

Lectin Microarray-Based Sero-Biomarker Verification Targeting Aberrant O-Linked Glycosylation on Mucin 1

Glycoform of mucin 1 (MUC1) in cancerous cells changes markedly with cell differentiation, and thus, qualitative detection and verification of the MUC1 glycosylation changes have potential diagnostic value. We have developed an ultrasensitive method to detect the changes in cholangiocarcinoma (CC), which produces MUC1, and applied it in the diagnostics development. The focused glycan analysis using 43-lectin-immobilized microarray could obtain the glycan profiles of sialylated MUC1 in 5 μL of sera. The high-throughput analysis detected disease-specific alterations of glycosylation, and the statistical analysis confirmed that use of Wisteria floribunda agglutinin (WFA) alone produced a diagnostic score sufficient for discriminating 33 CC cases from 40 hepatolithiasis patients and 48 normal controls (p < 0.0001). The CC-related glycosylation change was verified by the lectin-antibody sandwich ELISA with WFA in two cohorts: (1) 78 Opisthorchis viverrini infected patients without CC and 78 with CC, (2) 33 CC patients and 40 hepatolithiasis patients (the same cohort used for the above lectin microarray). The WFA positivity distinguished patients with CC (opisthorchiasis: p < 0.0001, odds ratio = 1.047; hepatolithiasis: p = 0.0002, odds ratio = 1.018). Sensitive detection of qualitative alterations of sialylated MUC1 glycosylation is indispensable for the development of our glycodiagnostic test for CC.

Cell surface nucleolin facilitates enterovirus 71 binding and infection

Because the pathogenesis of enterovirus 71 (EV71) remains mostly ambiguous, identifying the factors that mediate viral binding and entry to host cells is indispensable to ultimately uncover the mechanisms that underlie virus infection and pathogenesis. Despite the identification of several receptors/attachment molecules for EV71, the binding, entry, and infection mechanisms of EV71 remain unclear. Herein, we employed glycoproteomic approaches to identify human nucleolin as a novel binding receptor for EV71. Glycoproteins purified by lectin chromatography from the membrane extraction of human cells were treated with sialidase, followed by immunoprecipitation with EV71 particles. Among the 16 proteins identified by tandem mass spectrometry analysis, cell surface nucleolin attracted our attention. We found that EV71 interacted directly with nucleolin via the VP1 capsid protein and that an antinucleolin antibody reduced the binding of EV71 to human cells. In addition, the knockdown of cell surface nucleolin decreased EV71 binding, infection, and production in human cells. Furthermore, the expression of human nucleolin on the cell surface of a mouse cell line increased EV71 binding and conferred EV71 infection and production in the cells. These results strongly indicate that human nucleolin can mediate EV71 binding to and infection of cells. Our findings also demonstrate that the use of glycoproteomic approaches is a reliable methodology to discover novel receptors for pathogens.

IMPORTANCE

Outbreaks of EV71 have been reported in Asia-Pacific countries and have caused thousands of deaths in young children during the last 2 decades. The discovery of new EV71-interacting molecules to understand the infection mechanism has become an emergent issue. Hence, this study uses glycoproteomic approaches to comprehensively investigate the EV71-interacting glycoproteins. Several EV71-interacting glycoproteins are identified, and the role of cell surface nucleolin in mediating the attachment and entry of EV71 is characterized and validated. Our findings not only indicate a novel target for uncovering the EV71 infection mechanism and anti-EV71 drug discovery but also provide a new strategy for virus receptor identification.

Genetic and environmental determinants of risk for cholangiocarcinoma in Thailand

Cholangiocarcinoma (CCA) is a difficult cancer to diagnose in the early stage and to treat by curative resection. The incidence of CCA in the northeast of Thailand is the highest in the world. To make progress in detecting a high risk group and in the prevention and detection of CCA, we have been analyzing the risk factors for CCA. Although liver fluke infection is known to be a risk factor, there are patients who are not infected with the liver fluke and not all people infected with the liver fluke will suffer from the disease. Therefore, it is of the utmost importance to analyze the risk factors and the mechanism to prevent the disease and also to detect the disease in its early stage to save patients’ lives. Through collaboration among Thai and Japanese researchers, we analyzed the genetic and environmental determinants of risks for CCA. Also, we have been trying to develop methods to detect the disease in a non-invasive way. Without repeating findings reported in various reviews on CCA, we will first discuss the environmental and genetic determinants of the risks for CCA. Second, we will discuss the properties of CCA, including the etiological agents and the mechanism of cholangiocarcinogenesis, and finally, we will discuss future approaches to prevent and cure CCA from the standpoint of evidence-based medicine. We will discuss these points by including the data from our laboratories. We would like to emphasize the importance of the genetic data, especially whole genome approaches, to understand the properties of CCA, to find a high risk population for CCA and to develop effective preventative methods to stop the carcinogenic steps toward CCA in the near future. In addition, it is of the upmost importance to develop a non-invasive, specific and sensitive method to detect CCA in its early stage for the application of modern medical approaches to help patients with CCA.

Molecular diagnosis of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinomas (iCCA) are primary intrahepatic malignancies originating from biliary epithelia. While both hepatocellular cancer and iCCA can present as mass lesions within the liver, these cancers are distinct in their morphology, etiology, pathology, natural history and response to therapy. There is a need for accurate and sensitive molecular markers for the diagnosis of iCCA. Recent advances in elucidating molecular and genetic characteristics of iCCA offer the potential of molecular-based diagnosis of iCCA. Specific genetic mutations of IDH1/2, BAP1, p53, and KRAS, FGFR gene fusions and alterations in microRNA have all been described in iCCA. Although there are no accurate serum or biliary biomarkers currently available for diagnosis of iCCA, several potential candidates have been identified. Knowledge of specific genetic or molecular abnormalities offers potential for individualized approaches for the treatment of patients with iCCA in the future.

Multilectin-assisted fractionation for improved single-dot tissue glycome profiling in clinical glycoproteomics

To survey the glycome shift in cancer, single-dot tissue glycome profiling was improved by incorporating a lectin-assisted fractionation. The differential analysis of tissue specimens from colorectal cancer patients (n = 45) revealed that unfucosylated/α2,6-sialylated glycoproteins significantly increased in patients with poor prognoses. The detailed annotation will be an indispensable supplement for cancer-related glyco-biomarker discovery.

Serum tumor markers in bile duct cancer--a review

CONTEXT

Bile duct cancer (BDC) is a disease with a very grave prognosis, often diagnosed too late.

OBJECTIVE

The aim of this review is to evaluate available literature on tumor markers in serum from patients with BDC.

METHODS

Using the search words "serum markers", "bile duct cancer", "cholangiocarcinoma", "biomarker" and "tumor marker", a search was carried out.

RESULTS

Seventy-five studies were included in the review.

CONCLUSION

CA19-9 is by far the most studied and most promising diagnostic and/or prognostic marker in BDC. But also the different mucins are interesting as new markers of BDC in serum.

Mass spectrometry-based N-glycoproteomics for cancer biomarker discovery

Glycosylation is estimated to be found in over 50% of human proteins. Aberrant protein glycosylation and alteration of glycans are closely related to many diseases. More than half of the cancer biomarkers are glycosylated-proteins, and specific glycoforms of glycosylated-proteins may serve as biomarkers for either the early detection of disease or the evaluation of therapeutic efficacy for treatment of diseases. Glycoproteomics, therefore, becomes an emerging field that can make unique contributions to the discovery of biomarkers of cancers. The recent advances in mass spectrometry (MS)-based glycoproteomics, which can analyze thousands of glycosylated-proteins in a single experiment, have shown great promise for this purpose. Herein, we described the MS-based strategies that are available for glycoproteomics, and discussed the sensitivity and high throughput in both qualitative and quantitative manners. The discovery of glycosylated-proteins as biomarkers in some representative diseases by employing glycoproteomics was also summarized.

Leczyme: a new candidate drug for cancer therapy

Sialic acid-binding lectin (SBL), isolated from oocytes of Rana catesbeiana, is leczyme and has both lectin and ribonuclease (RNase) activities. A remarkable antitumor effect of SBL has also been reported. SBL agglutinates various kinds of tumor cells but not normal cells. SBL agglutination activity is not affected by mono- or oligosaccharides. However, SBL-induced agglutination and antitumor effects are inhibited by sialomucin but not asialomucin. In addition, SBL has very little effect on sialidase-treated cells. SBL causes cancer-selective induction of apoptosis by multiple signaling pathways, which target RNA. Synergistic antitumor effects with other molecules, such as tumor necrosis factor-related apoptosis ligand (TRAIL) and interferon-γ (IFN-γ), have been reported. Thus, SBL may be a novel candidate molecule for anticancer drug development. Sialoglycoconjugates on the tumor cell surface may be associated with lectin activity and antitumor effects of SBL. We review the properties of SBL, particularly its lectin, RNase, and antitumor activities, and comprehensively examine the potential application of SBL for clinical purposes.

Cancer biomarker discovery for cholangiocarcinoma: the high-throughput approaches

Cholangiocarcinoma (CCA) is difficult to diagnose at an early stage and most tumors are detected at late stage where surgery or other therapy is ineffective. Many advanced techniques are applied to diagnose CCA; however, most are expensive and have varying degrees of accuracy. A less invasive and simpler procedure such as serum markers would be of substantial clinical benefit for diagnosis, monitoring, and predicting outcome for CCA patients. Recent advances in "Omics" technologies offer remarkable opportunities for establishment of biomarker-related to diseases. In this review, the potential biomarkers obtained from proteomics and glycomic studies are evaluated. Several protein markers were discovered from patient specimen, using two dimensional-differential gel electrophoresis couple with liquid chromatography tandem mass spectrometry (2D-DIGE/LC-MS-MS), matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS), surface enhanced laser desorption/ionization (SELDI)-TOF-MS and capillary electrophoresis (CE)-MS, etc. Newly reported CCA-associated glyco-biomarkers were identified using lectin-assisted, monoclonal antibody-assisted or specific-target strategies. The combination between carbohydrate binding-lectin and core protein-binding mAb significantly increased the values for detection of the glyco-biomarkers for CCA. Searching for specific and sensitive molecular markers to be used for population screening is worth being evaluated. This could lead to earlier diagnosis and improve outcome. Further investigation of those biomarker functions is also of value in order to better understand the tumor biology and use them as targets for future therapeutic agents.

Analysis of new biomarkers for cholangiocarcinoma

Cholangiocarcinoma is one of the most serious diseases in northeast Thailand, where its incidence is reported to be the highest in the world. We tried to develop a new method to detect cholangiocarcinoma in the early stages using serum proteins. We found that after fluorescent labeling of the sugar moiety of serum proteins, a new peak was identified, which might be a promising marker for cholangiocarcinoma.

Differential glycan analysis of an endogenous glycoprotein: toward clinical implementation--from sample pretreatment to data standardization

There are huge numbers of clinical specimens being stored that contain potential diagnostic marker molecules buried by the coexistence of high-abundance proteins. To utilize such valuable stocks efficiently, we must develop appropriate techniques to verify the molecules. Glycoproteins with disease-related glycosylation changes are a group of useful molecules that have long been recognized, but their application is not fully implemented. The technology for comparative analysis of such glycoproteins in biological specimens has tended to be left behind, which often leads to loss of useful information without it being recognized. In this chapter, we feature antibody-assisted lectin profiling employing antibody-overlay lectin microarray, the most suitable technology for comparative glycoanalysis of a trace amount of glycoproteins contained in biological specimens. We believe that sharing this detailed protocol will accelerate the glycoproteomics-based discovery of glyco-biomarkers that has attracted recent attention; simultaneously, it will increase the value of clinical specimens as a gold mine of information that has yet to be exploited.

Terminal N-acetylgalactosamine-specific leguminous lectin from Wisteria japonica as a probe for human lung squamous cell carcinoma

Millettia japonica was recently reclassified into the genus Wisteria japonica based on chloroplast and nuclear DNA sequences. Because the seed of Wisteria floribunda expresses leguminous lectins with unique N-acetylgalactosamine-binding specificity, we purified lectin from Wisteria japonica seeds using ion exchange and gel filtration chromatography. Glycan microarray analysis demonstrated that unlike Wisteria floribunda and Wisteria brachybotrys lectins, which bind to both terminal N-acetylgalactosamine and galactose residues, Wisteria japonica lectin (WJA) specifically bound to both α- and β-linked terminal N-acetylgalactosamine, but not galactose residues on oligosaccharides and glycoproteins. Further, frontal affinity chromatography using more than 100 2-aminopyridine-labeled and p-nitrophenyl-derivatized oligosaccharides demonstrated that the ligands with the highest affinity for Wisteria japonica lectin were GalNAcβ1-3GlcNAc and GalNAcβ1-4GlcNAc, with K_a values of 9.5 × 10⁴ and 1.4 × 10⁵ M^-1, respectively. In addition, when binding was assessed in a variety of cell lines, Wisteria japonica lectin bound specifically to EBC-1 and HEK293 cells while other Wisteria lectins bound equally to all of the cell lines tested. Wisteria japonica lectin binding to EBC-1 and HEK293 cells was dramatically decreased in the presence of N-acetylgalactosamine, but not galactose, mannose, or N-acetylglucosamine, and was completely abrogated by β-hexosaminidase-digestion of these cells. These results clearly demonstrate that Wisteria japonica lectin binds to terminal N-acetylgalactosamine but not galactose. In addition, histochemical analysis of human squamous cell carcinoma tissue sections demonstrated that Wisteria japonica lectin specifically bound to differentiated cancer tissues but not normal tissue. This novel binding characteristic of Wisteria japonica lectin has the potential to become a powerful tool for clinical applications.