Sialyl Lewis Antigens Research Articles

Overexpression of sialyl Lewisa carrying mucin-type glycoprotein in prostate cancer cell line contributes to aggressiveness and metastasis

Metastasis-promoting Lewis and sialyl Lewis antigens expressed on glycoproteins such as mucins are frequently displayed on the surface of prostate cancer cells and could thus be ideal candidates as measures of prostate cancer aggressiveness. The current study describes the altered expression of sialyl Lewisa (sLea) antigen attached to glycoproteins and key glycosyltransferases between normal prostate (RWPE-1) and cancerous cell lines (LNCaP and DU145). Our results suggest that the expression of sLea on different glycoproteins correlates with the aggressiveness of prostate cancer cells, as determined by flow cytometry and fluorescence microscopy. Blotting studies revealed that sLea-bearing glycoproteins, similar to mucins, are predominantly expressed in the more aggressive DU145 cells, followed by LNCaP cells. Immunohistochemistry technique showed a gradient of sLea expression, with low levels in low-grade prostate cancer (stage II/III) and increasing levels in high-grade cancer (stage IV), indicating its potential as a prognostic marker. Additionally, in qRT-PCR analysis significant upregulation of the glycosyltransferases GALNT5 and ST3GAL6 was observed, correlating with the increased sLea expression in LNCaP (3.2- and 14.5-fold) and DU145 (3.3- and 23.75-fold) cells. Our data indicates a correlation between sLea selectin ligand expression and prostate cancer aggressiveness. Furthermore, GALNT5 and ST3GAL6 could serve as benchmarks in PCa malignancy.

(Sialyl)Lewis Antigen Expression on Glycosphingolipids, N-, and O-Glycans in Colorectal Cancer Cell Lines is Linked to a Colon-Like Differentiation Program

Alterations in the glycomic profile are a hallmark of cancer, including colorectal cancer (CRC). While, the glycosylation of glycoproteins and glycolipids has been widely studied for CRC cell lines and tissues, a comprehensive overview of CRC glycomics is still lacking due to the usage of different samples and analytical methods. In this study, we compared glycosylation features of N-, O-glycans, and glycosphingolipid glycans for a set of 22 CRC cell lines, all measured by porous graphitized carbon nano-liquid chromatography-tandem mass spectrometry. An overall, high abundance of (sialyl)Lewis antigens for colon-like cell lines was found, while undifferentiated cell lines showed high expression of H blood group antigens and α2-3/6 sialylation. Moreover, significant associations of glycosylation features were found between the three classes of glycans, such as (sialyl)Lewis and H blood group antigens. Integration of the datasets with transcriptomics data revealed positive correlations between (sialyl)Lewis antigens, the corresponding glycosyltransferase FUT3 and transcription factors CDX1, ETS, HNF1/4A, MECOM, and MYB. This indicates a possible role of these transcription factors in the upregulation of (sialyl)Lewis antigens, particularly on glycosphingolipid glycans, via FUT3/4 expression in colon-like cell lines. In conclusion, our study provides insights into the possible regulation of glycans in CRC and can serve as a guide for the development of diagnostic and therapeutic biomarkers.

Robust Glycoproteomics Platform Reveals a Tetra-Antennary Site-Specific Glycan Capping with Sialyl-Lewis Antigen for Early Detection of Gastric Cancer.

The lack of efficient biomarkers for the early detection of gastric cancer (GC) contributes to its high mortality rate, so it is crucial to discover novel diagnostic targets for GC. Recent studies have implicated the potential of site-specific glycans in cancer diagnosis, yet it is challenging to perform highly reproducible and sensitive glycoproteomics analysis on large cohorts of samples. Here, a highly robust N-glycoproteomics (HRN) platform comprising an automated enrichment method, a stable microflow LC-MS/MS system, and a sensitive glycopeptide-spectra-deciphering tool is developed for large-scale quantitative N-glycoproteome analysis. The HRN platform is applied to analyze serum N-glycoproteomes of 278 subjects from three cohorts to investigate glycosylation changes of GC. It identifies over 20000 unique site-specific glycans from discovery and validation cohorts, and determines four site-specific glycans as biomarker candidates. One candidate has branched tetra-antennary structure capping with sialyl-Lewis antigen, and it significantly outperforms serum CEA with AUC values > 0.89 compared against < 0.67 for diagnosing early-stage GC. The four-marker panel can provide improved diagnostic performances. Besides, discrimination powers of four candidates are also testified with a verification cohort using PRM strategy. This findings highlight the value of this strong tool in analyzing aberrant site-specific glycans for cancer detection.

The story of the Sda antigen and of its cognate enzyme B4GALNT2: What is new?

The structure Siaα2,3(GalNAcβ1,4)Gal- is the epitope of the Sda antigen, which is expressed on the erythrocytes and secretions of the vast majority of Caucasians, carried by N- and O-linked chains of glycoproteins, as well as by glycolipids. Sda is very similar, but not identical, to ganglioside GM2 [Siaα2,3(GalNAcβ1,4)Galβ1,4Glc-Cer]. The Sda synthase β1,4N-acetylgalactosaminyl transferase 2 (B4GALNT2) exists in a short and a long form, diverging in the aminoterminal domain. The latter has a very long cytoplasmic tail and displays a Golgi- as well as a post-Golgi localization. The biosynthesis of Sda is mutually exclusive with that of the cancer-associated sialyl Lewis antigens, whose structure is Siaα2,3Galβ1,3/4(Fucα1,4/3)GlcNAc-. B4GALNT2 is down-regulated in colon cancer but patients with higher expression survive longer. In experimental systems, B4GALNT2 inhibits colon cancer progression,not only through inhibition of sialyl Lewis antigen biosynthesis. By contrast, in breast cancer B4GALNT2 is associated with malignancy. In colon cancer, the B4GALNT2 gene is regulated by multiple mechanisms, which include miRNA and transcription factor expression, as well as CpG methylation. In addition, Sda/B4GALNT2 regulates the susceptibility to infectious agents, the protection from muscle dystrophy, the activity of immune system in pregnancy and the immune rejection in xenotransplantation.

Glycosylation Changes in Prostate Cancer Progression.

Prostate Cancer (PCa) is the most commonly diagnosed malignancy and second leading cause of cancer-related mortality in men. With the use of next generation sequencing and proteomic platforms, new biomarkers are constantly being developed to both improve diagnostic sensitivity and specificity and help stratify patients into different risk groups for optimal management. In recent years, it has become well accepted that altered glycosylation is a hallmark of cancer progression and that the glycan structures resulting from these mechanisms show tremendous promise as both diagnostic and prognostic biomarkers. In PCa, a wide range of structural alterations to glycans have been reported such as variations in sialylation and fucosylation, changes in branching, altered levels of Lewis and sialyl Lewis antigens, as well as the emergence of high mannose “cryptic” structures, which may be immunogenic and therapeutically relevant. Furthermore, aberrant expression of galectins, glycolipids, and proteoglycans have also been reported and associated with PCa cell survival and metastasis. In this review, we discuss the findings from various studies that have explored altered N- and O-linked glycosylation in PCa tissue and body fluids. We further discuss changes in O-GlcNAcylation as well as altered expression of galectins and glycoconjugates and their effects on PCa progression. Finally, we emphasize the clinical utility and potential impact of exploiting glycans as both biomarkers and therapeutic targets to improve our ability to diagnose clinically relevant tumors as well as expand treatment options for patients with advanced disease.

Helicobacter pylori BabA-SabA Key Roles in the Adherence Phase: The Synergic Mechanism for Successful Colonization and Disease Development.

Helicobacter pylori is a pathogenic microorganism that successfully inhabits the human stomach, colonizing it by producing several virulence factors responsible for preventing host self-defense mechanisms. The adherence mechanism to gastric mucosal tissue is one of the most important processes for effective colonization in the stomach. The blood group antigen-binding adhesion (BabA) and sialic acid-binding adherence (SabA) are two H. pylori outer membrane proteins able to interact with antigens in the gastroduodenal tract. H. pylori possesses several mechanisms to control the regulation of both BabA and SabA in either the transcriptional or translational level. BabA is believed to be the most important protein in the early infection phase due to its ability to interact with various Lewis antigens, whereas SabA interaction with sialylated Lewis antigens may prove important for the adherence process in the inflamed gastric mucosal tissue in the ongoing-infection phase. The adherence mechanisms of BabA and SabA allow H. pylori to anchor in the gastric mucosa and begin the colonization process.

Microfibril associated protein 4 (MFAP4) is a carrier of the tumor associated carbohydrate sialyl-Lewis x (sLex) in pancreatic adenocarcinoma

Late diagnosis of pancreatic ductal adenocarcinoma (PDA) is one of the reasons of its low 5-year survival rate and it is due to its unspecific symptoms during the first stages of the disease and the lack of reliable serological markers. Since PDA shows an altered glycan expression, here we have focused on finding novel potential biomarkers, namely glycoproteins that express the tumor associated carbohydrate structure sialyl-Lewis x (sLex), which is described in PDA. Through a glycoproteomic approach, we have analyzed target proteins containing sLex from PDA tissues by 2DE and immunodetection techniques, and have identified by mass spectrometry the protein MFAP4 as a carrier of sLex in PDA. MFAP4 showed a higher expression in PDA tissues compared with pancreatic control tissues. In addition, the colocalization of sLex over MFAP4 was found only in PDA and not in control pancreatic tissues. The analysis of MFAP4 expression in PDA cell lines and their secretome, in combination with immunohistochemistry of pancreatic tissues, revealed that MFAP4 was not produced by PDA cells, but it was found in the pancreatic extracellular matrix. The specificity of MFAP4 glycoform containing sLex in PDA tissues shows its relevance as a potential PDA biomarker. SignificanceDespite advances in the field of cancer research, pancreatic ductal adenocarcinoma (PDA) lacks of a specific and sensitive biomarker for its early detection, when curative resection is still possible before metastases arise. Thus, efforts to discover new PDA biomarkers represent the first line in the fight against the increase of its incidence reported in recent years. Glycan alterations on glycoconjugates, such as glycoproteins have emerged as a rich source for the identification of novel cancer markers. In the present work, we aimed to shed light on novel biomarkers based on altered glycosylation in PDA, in particular those glycoproteins of PDA tissues carrying the tumor carbohydrate antigen sialyl-Lewis x (sLex). Through a glycoproteomic approach, we have shown that the glycoprotein MFAP4 carries sLex in PDA tissues and not in control pancreatic tissues. MFAP4 is found in the extracellular matrix in PDA and although its role in cancer progression is unclear, its sLex glycoform could be a potential biomarker in pancreatic ductal adenocarcinoma.

Knockdown of α2,3-Sialyltransferases Impairs Pancreatic Cancer Cell Migration, Invasion and E-selectin-Dependent Adhesion.

Aberrant sialylation is frequently found in pancreatic ductal adenocarcinoma (PDA). α2,3-Sialyltransferases (α2,3-STs) ST3GAL3 and ST3GAL4 are overexpressed in PDA tissues and are responsible for increased biosynthesis of sialyl-Lewis (sLe) antigens, which play an important role in metastasis. This study addresses the effect of α2,3-STs knockdown on the migratory and invasive phenotype of PDA cells, and on E-selectin-dependent adhesion. Characterization of the cell sialome, the α2,3-STs and fucosyltransferases involved in the biosynthesis of sLe antigens, using a panel of human PDA cells showed differences in the levels of sialylated determinants and α2,3-STs expression, reflecting their phenotypic heterogeneity. Knockdown of ST3GAL3 and ST3GAL4 in BxPC-3 and Capan-1 cells, which expressed moderate to high levels of sLe antigens and α2,3-STs, led to a significant reduction in sLex and in most cases in sLea, with slight increases in the α2,6-sialic acid content. Moreover, ST3GAL3 and ST3GAL4 downregulation resulted in a significant decrease in cell migration and invasion. Binding and rolling to E-selectin, which represent key steps in metastasis, were also markedly impaired in the α2,3-STs knockdown cells. Our results indicate that inhibition of ST3GAL3 and ST3GAL4 may be a novel strategy to block PDA metastasis, which is one of the reasons for its dismal prognosis.

The challenge of determining the impact of FUT3 tumor-associated polymorphism rs2306969 (-6951 C> T) in invasive breast cancer cells.

FUT3 gene is responsible for encode an homonymous α1,3/4-fucosyltransferase involved in the synthesis of sialyl-Lewis antigens. FUT3-fucosylated glycoconjugates play key roles in pathways involved in tumor biology and metastasis, such as cellular ligation to E-selectins, TGF-β-induced epithelial-mesenchymal transition, NK cell-mediated tumor cytotoxicity and apoptosis. Tumor-associated FUT3 promoter polymorphism rs2306969 (-6951 C> T, position related to the gene's translation start site) has been linked to breast, ovarian and intestinal gastric cancer. Although non-coding polymorphisms accounts for the majority of variations founded in breast cancer, their functional roles are still poorly understood. This study aimed to investigate the impact of different alleles for this variation in FUT3 expression of invasive breast tumors. A luciferase reporter assay was performed using two breast tumor cell lines to evaluate respectively the impact of FUT3 rs2306969 (-6951 CC) and (-6951 TT) on protein expression. Gene and protein expressions were also measured in twenty-nine fresh biopsies of invasive breast tumors. Rs2306969 did not significantly influence FUT3 expression in both used systems. However, this study is defiant since the biological role of this polymorphism in breast cancer and other tumor types could be linked to cis/trans modulation of other genes, respond to different environmental stimuli or impact gene expression only in association with other variations. Rs2306969 did not modulate FUT3 expression in breast tumors under non-stimulated conditions. Nevertheless, our study contributes to the notably challenging task that is to understand how non-coding polymorphisms can drive the overall risk in cancer development.

ST3Gal III modulates breast cancer cell adhesion and invasion by altering the expression of invasion-related molecules.

Changes in the carbohydrate structure on the surface of tumor cells is an important feature of cancer metastasis. The specific role of sialic acids in the glycoconjugate terminal has not yet been clearly elucidated in these processes. Previously, we reported that α2,3-sialic acid residues in breast cancer are associated with metastatic potential. The α2,3-sialyltransferase ST3GalIII, which adds α2,3-sialic acids to glycoproteins, is overexpressed in various tumors, and enzyme activity is correlated withtumormetastasis, yet its mechanistic role has not been fully evaluated. In the present study, we aimed to investigate the influence of ST3GalIII on key steps in the process of breast cancer metastasis. ST3GalIII-overexpressing and ST3GalIII-silenced breast cancer MDA-MB-231 cell lines were generated. They showed an increase or decrease in the tumor-associated antigen sialyl-LewisX(SLeX). The E-selectin binding capacity of the transfectants was proportional to cell surface SLeX levels. Cell migration and invasion were positively correlated with ST3GalIII levels. Moreover, ST3GalIII expression modulated the protein expression of invasion-related molecules, including β1integrin, matrix metalloproteinase(MMP)-2, MMP-9 and cyclooxygenase-2, which may account for the mechanism involved in the effects of ST3GalIII on breast cancer invasiveness. In conclusion, our findings in these novel models of ST3GalIII expression revealed a critical requirement for ST3GalIII in several steps of breast cancer metastasis. ST3GalIII modulates breast cancer cell adhesion and invasion by altering the expression of invasion-related molecules. This study provides novel insights into the mechanisms underlying metastasis and suggests a new target for the effective drug treatment of breast cancer metastasis.

Progress of Glycomics in Breast Cancer

Breast cancer remains a public-health issue on a global scale. Although mammographic screening and molecular-based classification have been applied to the clinical treatment effectively, breast cancer still has high incidence and mortality in women. Therefore, the discovery of novel biomarkers and molecular targets for early diagnosis and treatment is still essential. Glycosylation is the enzymatic addition of sugars, or oligosaccharides, to proteins and lipids. This increases the diversity of the proteome and lipidome to a level unmatched by any other post-translational modification due to the various aspects of the molecule that can be modified, including the glycosidic bond and glycan composition, structure, and length. Altered glycosylation, a predominant feature of tumor cells, plays an important role in the pathogenesis and progression of various malignancies. This review describes the variety of glycosylation processes, such as O -GlcNAcylation, sialyl-Lewis antigen, mucin type O -linked glycosylation, and b 1-6 GlcNAc-branched N -glycans with poly-LacNAc structure, involved in breast carcinogenesis, their effects in the regulation of metabolism, cell-cell adhesion of tumor cells, and preservation of tumor cell activity in the circulatory system, as well as promotion of angiogenesis of tumor tissue. Finally, the application referred to glycosylation, glycoproteins, glycan genes, enzymes, and anti-carbohydrate antibodies in the clinical management of patients with breast cancer is also discussed.

Novel aspects of sialoglycan recognition by the Siglec-like domains of streptococcal SRR glycoproteins.

Serine-rich repeat glycoproteins are adhesins expressed by commensal and pathogenic Gram-positive bacteria. A subset of these adhesins, expressed by oral streptococci, binds sialylated glycans decorating human salivary mucin MG2/MUC7, and platelet glycoprotein GPIb. Specific sialoglycan targets were previously identified for the ligand-binding regions (BRs) of GspB and Hsa, two serine-rich repeat glycoproteins expressed by Streptococcus gordonii While GspB selectively binds sialyl-T antigen, Hsa displays broader specificity. Here we examine the binding properties of four additional BRs from Streptococcus sanguinis or Streptococcus mitis and characterize the molecular determinants of ligand selectivity and affinity. Each BR has two domains that are essential for sialoglycan binding by GspB. One domain is structurally similar to the glycan-binding module of mammalian Siglecs (sialic acid-binding immunoglobulin-like lectins), including an arginine residue that is critical for glycan recognition, and that resides within a novel, conserved YTRY motif. Despite low sequence similarity to GspB, one of the BRs selectively binds sialyl-T antigen. Although the other three BRs are highly similar to Hsa, each displayed a unique ligand repertoire, including differential recognition of sialyl Lewis antigens and sulfated glycans. These differences in glycan selectivity were closely associated with differential binding to salivary and platelet glycoproteins. Specificity of sialoglycan adherence is likely an evolving trait that may influence the propensity of streptococci expressing Siglec-like adhesins to cause infective endocarditis.

Protein glycosylation in gastric and colorectal cancers: Toward cancer detection and targeted therapeutics

Glycosylation is the most frequent and structurally complex posttranslational modification in cell-surface and secreted proteins. Glycans are major orchestrators of biological processes, namely, by controlling protein folding and key biological functions such as cell adhesion, migration, signaling and immune recognition. Altered glycosylation is considered a hallmark of malignant transformations that decisively contributes to disease outcome. This review comprehensively summarizes the main findings related with gastrointestinal cancers and the decisive impact of aberrant glycosylation on tumor biology toward more aggressive phenotypes. Particular emphasis is given to alterations in O-glycosylation, namely, the overexpression of immature O-glycans, and the sialylated Lewis antigens sialyl-LeA and sialyl-LeX, frequently implicated in lymphohematogenous metastasis. We further discuss how recent contributions from glycoproteomics and glycoengineering fields have broadened our understanding of the human O-glycoproteome and its implications for cancer research. Finally, we address the tremendous potential of glycans in the context of targeted therapeutics (selective inhibition of glycosylation pathways, immunotherapy) and discuss the need to include glycomics/glycoproteomics in holistic panomics models toward true precision medicine settings.

Humoral response against sialyl-Le(a) glycosylated protein species in esophageal cancer: Insights for immunoproteomic studies.

Esophageal cancers (ECs) show poor prognosis and decreased overall survival due to late diagnosis and ineffective therapeutics, urging the introduction of novel biomarkers to aid disease management. The levels of sialyl-Lewis(a) antigen (sLe(a) ) are frequently increased in digestive tumours, which has been explored in serological non-invasive prognostication (CA19-9 test); however, with low sensitivity and specificity. Autoantibodies against cancer antigens are considered the next generation biomarkers, as they are present in circulation long before tumour-associated proteins. Based on these observations we have mined the serum of EC patients (n = 7) for antibodies against sLe(a) -glycosylated protein species. All EC were positive for sLe(a) , irrespectively of their histological nature but only two patients showed elevated CA19-9. Moreover, IgG titers, with emphasis on IgG1, were elevated in EC patients in comparison to the control group. SLe(a) -glycoproteins were then extracted from tumours of patients with negative CA19-9, isolated by immunoprecipitation and blotted with patients IgG. Autoantibodies against sLe(a) -glycosylated proteins were detected in all cases. Different SLe(a) -glycoproteins were observed for tumours of distinct histological natures, which now require identification and validation in larger patient sets. This preliminary data suggests that antoantibodies against sLe(a) glycosylated proteins hold potential for non-invasive diagnosis in CA19-9 negative cases and sets the rational for future immunoproteomic studies envisaging highly specific EC biomarkers.

A Novel Function of CD82/KAI1 in Sialyl Lewis Antigen-Mediated Adhesion of Cancer Cells: Evidence for an Anti-Metastasis Effect by Down-Regulation of Sialyl Lewis Antigens.

We have recently elucidated a novel function for CD82 in E-cadherin-mediated homocellular adhesion; due to this function, it can inhibit cancer cell dissociation from the primary cancer nest and limit metastasis. However, the effect of CD82 on selectin ligand-mediated heterocellular adhesion has not yet been elucidated. In this study, we focused on the effects of the metastasis suppressor CD82/KAI1 on heterocellular adhesion of cancer cells to the endothelium of blood vessels in order to further elucidate the function of tetraspanins. The over-expression of CD82 in cancer cells led to the inhibition of experimentally induced lung metastases in mice and significantly inhibited the adhesion of these cells to human umbilical vein epithelial cells (HUVECs) in vitro. Pre-treatment of the cells with function-perturbing antibodies against sLea/x significantly inhibited the adhesion of CD82-negative cells to HUVECs. In addition, cells over-expressing CD82 exhibited reduced expression of sLea/x compared to CD82-negative wild-type cells. Significant down-regulation of ST3 β-galactoside α-2, 3-sialyltransferase 4 (ST3GAL4) was detected by cDNA microarray, real-time PCR, and western blotting analyses. Knockdown of ST3GAL4 on CD82-negative wild-type cells inhibited expression of sLex and reduced cell adhesion to HUVECs. We concluded that CD82 decreases sLea/x expression via the down-regulation of ST3GAL4 expression and thereby reduces the adhesion of cancer cells to blood vessels, which results in inhibition of metastasis.

Abstract 1123: Fucosylated TGF-ß receptors transduce a signal for epithelial-mesenchymal transition in colorectal cancer cells

Abstract Background: Transforming growth factor-ß (TGF-ß) is a major inducer of epithelial-mesenchymal transition (EMT) in different cell types. TGF-ß-mediated EMT is thought to contribute to tumor cell spread and metastasis. Sialyl Lewis antigens synthesized by fucosyltransferase (FUT) 3 and FUT6 are highly expressed in patients with metastatic colorectal cancer (CRC) and are utilized as tumor markers for cancer detection and evaluation of treatment efficacy. However, the role of FUT3 and FUT6 in augmenting the malignant potential of CRC induced by TGF-ß is unclear. Methods: CRC cell lines were transfected with siRNAs for FUT3/6 and were examined by cell proliferation, invasion, and migration assays. The expression and phosphorylation status of TGF-ß downstream molecules were analyzed by western blot. Fucosylation of TGF-ß receptor was examined by lectin blot analysis. Results: Inhibition of FUT3/6 expression by siRNAs suppressed the fucosylation of type I TGF-ß receptor and phosphorylation of the downstream molecules, thereby inhibiting the invasion and migration of CRC cells by EMT. Citation Format: Rishu Takimoto, Masahiro Hirakawa, Fumito Tamura, Makoto Yoshida, Michihiro Ono, Yasushi Sato, Takahiro Osuga, Junji Kato. Fucosylated TGF-ß receptors transduce a signal for epithelial-mesenchymal transition in colorectal cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1123. doi:10.1158/1538-7445.AM2014-1123

Hepatitis B virus X protein specially regulates the sialyl lewis a synthesis among glycosylation events for metastasis.

BackgroundThe metastasis of hematogenous cancer cells is associated with abnormal glycosylation such as sialyl lewis antigens. Although the hepatitis B virus X protein (HBx) plays important role in liver disease, the precise function of HBx on aberrant glycosylation for metastasis remains unclear.MethodsThe human hepatocellular carcinoma tissues, HBx transgenic mice and HBx-transfected cells were used to check the correlation of expressions between HBx and Sialyl lewis antigen for cancer metastasis. To investigate whether expression levels of glycosyltransferases induced in HBx-transfected cells are specifically associated with sialyl lewis A (SLA) synthesis, which enhances metastasis by interaction of liver cancer cells with endothelial cells, ShRNA and siRNAs targeting specific glycosyltransferases were used.ResultsHBx expression in liver cancer region of HCC is associated with the specific synthesis of SLA. Furthermore, the SLA was specifically induced both in liver tissues from HBx-transgenic mice and in in vitro HBx-transfected cells. HBx increased transcription levels and activities of α2-3 sialyltransferases (ST3Gal III), α1-3/4 fucosyltransferases III and VII (FUT III and VII) genes, which were specific for SLA synthesis, allowing dramatic cell-cell adhesion for metastatic potential. Interestingly, HBx specifically induced expression of N-acetylglucosamine-β1-3 galactosyltransferase V (β1-3GalT 5) gene associated with the initial synthesis of sialyl lewis A, but not β1-4GalT I. The β1-3GalT 5 shRNA suppressed SLA expression by HBx, blocking the adhesion of HBx-transfected cells to the endothelial cells. Moreover, β1-3GalT 5 silencing suppressed lung metastasis of HBx-transfected cells in in vivo lung metastasis system.ConclusionHBx targets the specific glycosyltransferases for the SLA synthesis and this process regulates hematogenous cancer cell adhesion to endothelial cells for cancer metastasis.Electronic supplementary materialThe online version of this article (doi:10.1186/1476-4598-13-222) contains supplementary material, which is available to authorized users.

A randomized, placebo-controlled, double-blind phase II trial of peri-operative cimetidine in early colorectal cancer.

509 Background: A Cochrane meta-analysis of randomised trials using histamine-type 2 receptor antagonists with surgery for colorectal cancer (CRC) demonstrated a hazard ratio of 0.53 for mortality if patients used cimetidine. The benefit is likely to be specific to patients whose tumours express the antigens that allow circulating cells to bind to endothelial selectin (E-selectin), the expression of which is induced by inflammatory cytokines perioperatively and inhibited by cimetidine. This trial sought to evaluate several key issues critical to informing the conduct of a phase 3 trial. Methods: Patients with non-metastatic CRC planned for curative-intent surgery were randomised to receive cimetidine 800mg BID or placebo orally for 5 weeks, starting 2-7 days preoperatively. A subset of patients had serial blood sampling for inflammatory cytokines. In addition to DFS and OS, endpoints assessed include treatment compliance and toxicity, recruitment issues, post-operative stay and complications, and tumour characteristics including expression of sialyl Lewis antigens and COX-2. Results: 123 patients (36% female) have been recruited in 4 centres over 3.5 years; another 4 are required to complete the planned 120 treated patients. The primary tumour was rectal in 45% and pathological postoperative tumour stage was 0-I, II, III, and IV in 29%, 33%, 35%, and 2% respectively. About 50% of CRC patients were eligible and fewer than half of those were recruited. Patient compliance was excellent with 89% of patients taking their medication orally in the first 2 days postoperatively. Inflammatory cytokines were commonly elevated postoperatively for up to 2 weeks but normalised by 4 weeks. Immunostaining for tumour antigens is in progress and will be presented. DFS and OS data are immature. Conclusions: Oral administration of cimetidine for 5 weeks is well-tolerated and feasible over the perioperative period, and covers the duration of elevated inflammatory cytokines. Correlative immunostaining studies will be presented. Clinical trial information: 12609000769280.

Fucosylated TGF-β receptors transduces a signal for epithelial–mesenchymal transition in colorectal cancer cells

Background:Transforming growth factor-β (TGF-β) is a major inducer of epithelial–mesenchymal transition (EMT) in different cell types. TGF-β-mediated EMT is thought to contribute to tumour cell spread and metastasis. Sialyl Lewis antigens synthesised by fucosyltransferase (FUT) 3 and FUT6 are highly expressed in patients with metastatic colorectal cancer (CRC) and are utilised as tumour markers for cancer detection and evaluation of treatment efficacy. However, the role of FUT3 and FUT6 in augmenting the malignant potential of CRC induced by TGF-β is unclear.Methods:Colorectal cancer cell lines were transfected with siRNAs for FUT3/6 and were examined by cell proliferation, invasion and migration assays. The expression and phosphorylation status of TGF-β downstream molecules were analysed by western blot. Fucosylation of TGF-β receptor (TβR) was examined by lectin blot analysis.Results:Inhibition of FUT3/6 expression by siRNAs suppressed the fucosylation of type I TβR and phosphorylation of the downstream molecules, thereby inhibiting the invasion and migration of CRC cells by EMT.Conclusion:Fucosyltransferase 3/6 has an essential role in cancer cell adhesion to endothelial cells by upregulation of sialyl Lewis antigens and also by enhancement of cancer cell migration through TGF-β-mediated EMT.

Prognostic molecular markers in head and neck squamous cell carcinoma in a New Zealand population: matrix metalloproteinase‐2 and sialyl Lewis x antigen

The survival rate for head and neck squamous cell carcinoma (HNSCC) is among the lowest of the major cancers and has not substantially improved in the past two decades. Tumours with similar histological features may have widely differing clinical outcomes and thus identification of prognostic and predictive biomarkers may be valuable for determining appropriate clinical management strategies. The objective of this study was to establish the prognostic significance of six molecular markers in HNSCC in a New Zealand population: matrix metalloproteinases 2 and 9 (MMP-2, MMP-9), tissue inhibitor of matrix metalloproteinase-1, sialyl Lewis antigens a and x (sLe(a) , sLe(x) ) and alpha B-crystallin. Retrospective review of 145 sequential HNSCC patients from a tertiary centre with minimum 3 years surveillance. Sections from formalin-fixed paraffin-embedded tumour blocks were immunostained for the molecular markers and scored. Cox regression modelling was used to adjust for potential confounding variables impacting on cancer survival. Multivariate analysis for individual biomarkers, controlling for age, sex, tumour grade, N-stage, T-stage, tumour site, smoking history and alcohol use, revealed poorer survival with tumour expression of MMP-2 (hazard ratio = 1.98, 95% confidence interval: 1.11-3.52, P = 0.021) and sLe(x) (hazard ratio = 3.22, 95% confidence interval: 1.33-7.80, P = 0.010). A stepwise analysis showed that MMP-2 and sLe(x) were independently prognostic after covariate adjustment. MMP-2 and sLe(x) were negative prognostic markers for survival in these HNSCC patients. This offers opportunities for clinical trials to reduce the risk of nodal and distant metastases through blocking tumour cell adhesion to endothelium.