ELAM-1 mediates cell adhesion by recognition of a carbohydrate ligand, sialyl-Lex

Multi-enzyme one-pot strategy for the synthesis of sialyl Lewis X-containing PSGL-1 glycopeptide

An enzymatic one-pot three-step glycosylation strategy was developed for the synthesis of sLex moiety of truncated PSGL-1 glycopeptide with and without sulfation. The method provided an efficient way to afford complex glycopeptides in a semi-preparative scale without further complicated and time-consuming purification process in each glycosylation step.

Airway epithelial wound repair: role of carbohydrate sialyl Lewisx

Epithelial repair is a complex cellular and molecular process, the details of which are still not clearly understood. Plasma membrane glycoconjugates can modulate cell function by altering the function of protein and lipids. Sialyl Lewisx (sLex), a fucose-containing tetrasaccharide, decorates membrane-bound and secreted proteins and mediates cell-cell interaction. In the present study we investigated the role of sLex in airway epithelial repair. Using immunohistochemistry, we showed an increased expression of sLex in areas of damaged bronchial epithelium compared with intact regions. Confluent monolayers of airway epithelial cells were mechanically wounded and allowed to close. Wounded monolayers were photographed for wound closure kinetics, fixed for immunocytochemical studies, or subjected to RNA extraction. Examining the expression of different alpha1,3-fucosyltransferases (FucT), enzymes that mediate the final step in the synthesis of sLex, we found that FucT-IV was the common gene expressed in all cell lines and primary airway epithelial cells. We demonstrated an increased expression of sLex over time after mechanical injury. Blocking of sLex with an inhibitory antibody completely prevented epithelial repair. Our data suggest an essential functional role for sLex in epithelial repair. Further studies are necessary to explore the exact mechanism for sLex in mediating cell-cell interaction in bronchial epithelial cells to facilitate epithelial migration and repair.

High serum concentrations of Sialyl Lewisx predict multilevel N2 disease in non-small-cell lung cancer

BACKGROUND

The purpose of this study was to analyze the clinical significance of serum Sialyl Lewisx (SLX) concentrations as a predictor of N2 disease in patients with non-small-cell lung cancer.

METHODS

The study included 272 patients with non-small-cell lung cancer who underwent pulmonary resection in our institution between January 1998 and December 2003. Of 272 patients, the serum concentrations of SLX were measured by using a commercially available radioimmunoassay kit.

RESULTS

The 5-year survival rates of patients with concentrations of SLX > 38 U/mL and those with lower concentrations were 32% and 69%, respectively (P < .0001). The median serum concentration of SLX in patients with multilevel N2 or N3, single-level N2, and N0/1 disease were 44, 30, and 27 U/mL, respectively. The concentrations of serum SLX in patients with multilevel N2 disease were significantly higher than those in patients with single-level N2 or those with N0/1 disease (Mann-Whitney U-test; P < .0001). Although the sensitivity of SLX for identifying patients with non-small-cell lung cancer was only 24% in all patients, the sensitivity of SLX increased as the N-factor increased; the sensitivity of N0/1 disease was 15%, that of single-level N2 disease was 22%, and that of multilevel N2 or N3 disease was 71%.

CONCLUSIONS

High serum concentrations of SLX predicted multilevel N2 disease and the associated poor outcome. Although the sensitivity of serum SLX is not acceptable for use as a screening tumor marker, we suggest that the serum concentration of SLX is useful as a staging marker to determine the strategy of treatment.

Nanoparticles for the optical imaging of tumor E-selectin

We designed a fluorescent peptide-magnetic nanoparticle conjugate that images E-selectin expression in mouse xenograft models of Lewis lung carcinoma (LLC) by fluorescence reflectance imaging. It was synthesized by attaching the E-selectin-binding peptide (ESBP; CDSDSDITWDQLWDLMK) to a CLIO(Cy5.5) nanoparticle to yield ESBP-CLIO(Cy5.5). Internalization by activated human umbilical vein endothelial cells (HUVECs) was rapid and mediated by E-selectin, indicated by the lack of uptake of nanoparticles bearing similar numbers of a scrambled peptide (Scram). To demonstrate the specificity of E-selectin targeting to ESBP-CLIO(Cy5.5) in vivo, we coinjected ESBP-CLIO(Cy5.5) and Scram-CLIO(Cy3.5) and demonstrated a high Cy5.5/Cy3.5 fluorescence ratio using the LLC. Histology showed that ESBP-CLIO was associated with tumor cells as well as endothelial cells, but fluorescence-activated cell sorter analysis showed a far less expression of E-selectin on LLC than on HUVECs. Using immunohistochemistry, we demonstrated E-selectin expression in both endothelial cells and cancer cells in human prostate cancer specimens. We conclude that ESBP-CLIO(Cy5.5) is a useful probe for imaging E-selectin associated with the LLC tumor, and that E-selectin is expressed not only on endothelial cells but also on LLC cells and human prostate cancer specimens.

Expression of Lea in gastric cancer cell lines depends on FUT3 expression regulated by promoter methylation

Aberrant expression of Lewis antigens has been demonstrated in gastric lesions, namely gastritis, intestinal metaplasia (IM) and gastric carcinoma (GC), and can be partly due to overexpression of the Lewis (FUT3) enzyme. Our aim was to evaluate the role of promoter methylation in FUT3 and Le(a) expression in gastric carcinoma cell lines. MKN45 cell line showed low amounts of Le(a), in the absence of FUT3; GP220 expressed high levels of Le(a) and FUT3. After 5aza-2'deoxycytidine MKN45 showed increased levels of FUT3 and Le(a), by immunohistochemistry and Real-Time PCR, whereas GP220 showed an increase in FUT3 without increase of Le(a). Enzyme activity assays confirmed an increase in alpha-1,4 fucosyltransferase activity in both cell lines by 5aza-2'deoxycytidine. Luciferase reporter gene assays, using methylated and unmethylated deletion constructs of FUT3 promoter, showed that FUT3 expression is regulated by methylation. Summing up, we showed that FUT3 overexpression in gastric cells depends upon promoter hypomethylation and that FUT3 is responsible for overexpression of Le(a) in gastric cells, in vitro. FUT3, Lea, Methylation.

Coexpression of beta1,6-N-acetylglucosaminyltransferase V glycoprotein substrates defines aggressive breast cancers with poor outcome

Beta1,6-n-acetylglucosaminyltransferase-V (GnT-V) catalyzes the addition of complex oligosaccharide side chains to glycoproteins, regulating the expression and function of several proteins involved in tumor metastasis. We analyzed the expression of five cell-surface glycoprotein substrates of GnT-V, matriptase, beta1-integrin, epidermal growth factor receptor, lamp-1, and N-cadherin, on a tissue microarray cohort of 670 breast carcinomas with 30-year follow-up. Phaseolus vulgaris leukocytic phytohemagglutinin (LPHA), a lectin specific for beta1,6-branched oligosaccharides, was used to assay GnT-V activity. Our results show a high degree of correlation of the LPHA staining with matriptase, lamp-1, and N-cadherin expressions, but not with epidermal growth factor receptor or beta1-integrin expressions. In addition, many of the GnT-V substrate proteins exhibited strong coassociations. Elevated levels of GnT-V substrates were correlated with various markers of tumor progression, including positive node status, large tumor size, estrogen receptor negativity, HER2/neu overexpression, and high nuclear grade. Furthermore, LPHA and matriptase showed significant association with disease-related survival. Unsupervised hierarchical clustering of the GnT-V substrate protein expression and LPHA revealed two distinct clusters: one with higher expression of all markers and poor patient outcome and one with lower expression and good outcome. These clusters showed independent prognostic value for disease-related survival when compared with traditional markers of tumor progression. Our results indicate that GnT-V substrate proteins represent a unique subset of coexpressed tumor markers associated with aggressive disease.

Roles of mucin-type O-glycans synthesized by core2beta1,6-N-acetylglucosaminyltransferase

Core 2 branched O-linked oligosaccharides (O-glycans) represent the first example of onco-developmental antigens in mucin-type O-glycans. Core 2 branched O-glycans are expressed in immature T lymphocytes (cortical thymocytes), disappear on mature T lymphocytes (medullary thymocytes) and T lymphocytes in the peripheral blood, and appear again in activated T lymphocytes, leukemic cells, and other cancer cells. Core 2 branched O-linked oligosaccharides are synthesized by Core2beta1,6-N-acetylglucosaminyltransferase (Core2GlcNAcT). The first cloned Core2GlcNAcT-1 has been inactivated in mice through homologous recombination, and mutants show significantly reduced leukocyte rolling on E-, P-, and L-selectin-coated plates. Moreover, mutant mice exhibit an impaired peritoneal inflammatory response associated with reduced neutrophil infusion. By contrast, lymphocyte homing to secondary lymphoid organs is only marginally compromised. These results combined indicate that Core2GlcNAcT-1 plays a major role in leukocyte trafficking and distinguish leukocyte trafficking to inflamed sites from lymphocyte homing to secondary lymphoid organs.

Metabolic Labeling of Glycans with Azido Sugars for Visualization and Glycoproteomics

The staggering complexity of glycans renders their analysis extraordinarily difficult, particularly in living systems. A recently developed technology, termed metabolic oligosaccharide engineering, enables glycan labeling with probes for visualization in cells and living animals, and enrichment of specific glycoconjugate types for proteomic analysis. This technology involves metabolic labeling of glycans with a specifically reactive, abiotic functional group, the azide. Azido sugars are fed to cells and integrated by the glycan biosynthetic machinery into various glycoconjugates. The azido sugars are then covalently tagged, either ex vivo or in vivo, using one of two azide-specific chemistries: the Staudinger ligation, or the strain-promoted [3+2] cycloaddition. These reactions can be used to tag glycans with imaging probes or epitope tags, thus enabling the visualization or enrichment of glycoconjugates. Applications to noninvasive imaging and glycoproteomic analyses are discussed.

Apoptosis of human carcinoma cells in the presence of inhibitors of glycosphingolipid biosynthesis: I. Treatment of Colo-205 and SKBR3 cells with isomers of PDMP and PPMP

Apoptosis, or programmed cell death, plays an important role in many physiological and diseased conditions. Induction of apoptosis in cancer cells by anti-cancer drugs and biosynthetic inhibitors of cells surface glycolipids in the human colon carcinoma cells (Colo-205) are of interest in recent years. In our present studies, we have employed different stereoisomers of PPMP and PDMP (inhibit GlcT-glycosyltransferase (GlcT-GLT)) to initiate apoptosis in Colo-205 cells grown in culture in the presence of (3)H-TdR and (3)H/or (14)C-L-Serine. Our analysis showed that the above reagents (between 1 to 20 microM) initiated apoptosis with induction of Caspase-3 activities and phenotypic morphological changes in a dose-dependent manner. We have observed an increase of radioactive ceramide formation in the presence of a low concentration (1-4 microM) of these reagents in these cell lines. However, high concentrations (4-20 microM) inhibited incorporation of radioactive serine in the higher glycolipids. Colo-205 cells were treated with L-threo-PPMP (0-20 microM) and activities of different GSL: GLTs were estimated in total Golgi-pellets. The cells contained high activity of GalT-4 (UDP-Gal: LcOse3Cer beta 1-4galactosyltransferase), whereas negligible activity of GalT-3 (UDP-Gal: GM2 beta 1-3galactosyltransferase) or GM2-synthase activity of the ganglioside pathway was detected. Previously, GLTs involved in the biosynthetic pathway of SA-Le(x) formation had been detected in these colon carcinoma (or Colo-205) cells (Basu M et al. Glycobiology 1, 527-35 (1991)). However, during progression of apoptosis in Colo-205 cells with increasing concentrations of L-PPMP, the GalT-4 activity was decreased significantly. These changes in the specific activity of GalT-4 in the total Golgi-membranes could be the resultant of decreased gene expression of the enzyme.

Overexpression of LAMP3/TSC403/DC-LAMP promotes metastasis in uterine cervical cancer

LAMP3 (DC-LAMP, TSC403, CD208) was originally isolated as a gene specifically expressed in lung tissues. LAMP3 is located on a chromosome 3q segment that is frequently amplified in some human cancers, including uterine cervical cancer. Because two other members of the LAMP family of lysosomal membrane glycoproteins, LAMP1 and LAMP2, were previously implicated in potentially modulating the interaction of vascular endothelial and cancer cells, we hypothesized that LAMP3 might also play an important part in metastasis. To clarify the metastatic potential of LAMP3 in cervical cancers, we transfected a LAMP3 expression vector into a human uterine cervical cancer cell line, TCS. In an in vitro invasion assay, the migration of LAMP3-overexpressing TCS cells was significantly higher than in control TCS cells. In an in vivo metastasis assay, distant metastasis was detected in 9 of 11 LAMP3-overexpressing TCS cell-injected mice and in only 1 of 11 control mice. Histologic study showed that LAMP3-overexpressing cells readily invaded into the lymph-vascular space. In clinical samples, quantitative real-time reverse transcription-PCR (RT-PCR) analyses showed that LAMP3 mRNA was significantly up-regulated in 47 of 47 (100%) cervical cancers and in 2 of 15 (13%) cervical intraepithelial neoplasias, compared with a low level of LAMP3 mRNA expressed in normal uterine cervixes. Interestingly, high LAMP3 expression was significantly correlated with the overall survival of patients with stage I/II cervical cancers. These findings indicate that LAMP3 overexpression is associated with an enhanced metastatic potential and may be a prognostic factor for cervical cancer.

L-selectin: adhesion, signalling and its importance in pathologic posttraumatic endotoxemia and non-septic inflammation

The leucocyte expressed surface-bound L-selectin belongs to the selectin family of adhesion molecules. It exhibits adhesive as well as signalling functions. Mainly, it is of importance in lymphocyte homing and in the extravasation of leucocytes into the surrounding tissue during inflammation. Acting in the initial step of the cell adhesion cascade, L-selectin is responsible for the rolling of leucocytes on endothelial layers. Therefore, L-selectin is thought to be an adequate target for pharmacological interventions. Beneath the discussion of the molecules' general features like molecule structure and its regulation, the review focuses firstly on L-selectin in the context of posttraumatic inflammatory disorders, and secondly on the importance of L-selectin specific signalling events.

Characterization of EBV-transformed B-cells established from an individual homozygously mutated (G329A) in the FUT7 alpha1,3-fucosyltransferase gene

The alpha1,3-fucosyltransferase VII (Fuc-TVII) is involved in the biosynthesis of E- and P-selectin ligands such as sialyl Lewis x (SLe(x)) on human leukocytes. Recently, individuals were characterized carrying a missense mutation (G329A; Arg110-Gln) in the FUT7 gene encoding this enzyme. The mutated FUT7 construct produced a Fuc-TVII enzyme with impaired activity compared with the wildtype enzyme. Polymorphonuclear granulocytes from an individual carrying this mutation homozygously also showed a reduced expression of SLe(x). In the present study, we have established Epstein-Barr virus-transformed B-cell lines from this individual (SIGN) and from an individual not carrying the mutation (IWO). The cell lines were confirmed to be of B-cell origin by flow cytometry analysis. IWO cells interacted with E-selectin in an in vitro flow chamber analysis whereas SIGN cell did not. However, when SIGN cell was transiently transfected with wildtype FUT7 cDNA, interaction with E-selectin could be restored. Cell surface expression of the SLe(x)-related epitopes recognized by antibodies CSLEX-1, KM-93 and HECA-452 was elevated on IWO cells compared with that on SIGN cells, consistent with a role of these antigens in E-selectin recognition. These cell lines will be useful in further characterization of E-selectin ligands and encourage further studies on the consequences of the FUT7-G329A mutation in vivo.

Altered glycosylation of proteins produced by malignant cells, and application for the diagnosis and immunotherapy of tumours

Most secretory and membrane-bound proteins produced by mammalian cells contain covalently linked sugar chains. Alterations of the sugar chain structures of glycoproteins have been found to occur in various tumours. Because the sugar chains of glycoproteins are essential for the maintenance of the ordered social behaviour of differentiated cells in multicellular organisms, alterations to the sugar chains are the molecular basis of abnormal social behaviours in tumour cells, such as invasion into the surrounding tissues and metastasis. In this review, the structure and enzymatic basis of typical alterations of the N-linked sugar chains, which are found in various tumours, are introduced. These data are useful for devising diagnostic methods and immunotherapies for the clinical treatment of tumours. Three beta-N-acetylglucosaminyltransferases, GnT-III, -IV and -V, play roles in the structural alteration of the complex-type sugar chains in various tumours. In addition, transcriptional changes in various glycosyltransferases, together with the transporters of sugar nucleotides and sulfate, which are responsible for the formation of the outer chain moieties of complex-type sugar chains, are the keys to inducing the alterations.

Cyclopedic protein expression analysis of cultured canine mammary gland adenocarcinoma cells from six tumours

We characterised cultured canine mammary gland adenocarcinoma cells by exhaustive step protein expression analysis to identify factors associated with tumour progression or metastasis of canine mammary gland tumour. Cultured adenocarcinoma cells derived from a total of 3 primary and 3 metastatic lesions from 3 dogs (CHMp/m, CIPp/m and CNMp/m, where CHM, CIP, and CNM indicate the 3 animals) were used in this study. The expression of 24 proteins reported to be related to tumourigenesis or malignancy of human breast cancers were examined by Western blot analysis using 24 antibodies. The expression of sialyl Lewis X [sLe(x)] was only observed in CHMm cells, which were derived from pleural effusion. This expression was further confirmed by immunohistochemistry. The levels of some factors, such as 14-3-3sigma, cyclinD1 and Rb, differed among cells or between the primary and metastatic cells in the pair. Though the difference in their expression was not consistent within the cells from primary and metastatic origin, this characterisation should provide useful information for further molecular analysis of these cultured cells. Since some of the factors, such as sLe(x), 14-3-3sigma, cyclinD1 and Rb, showed different levels of expression in the pair, these cultured cells might be meaningful tools for clarification of distant metastasis in canine mammary gland tumours.

Beta1,6-branched oligosaccharides are increased in lymph node metastases and predict poor outcome in breast carcinoma

PURPOSE

This study was designed to provide a comprehensive assessment on the role of beta1,6-branched oligosaccharides in the metastasis and outcome of breast carcinoma. Generation of these structures on N-glycans is initiated by beta1,6-N-acetylglucosaminyltransferase V and used by both myeloid cells and cancer cells in systemic migration.

EXPERIMENTAL DESIGN

Tissue microarrays of >700 tumors (>400 patients; 30-year follow-up data) were stained through lectin histochemistry with leukocytic phytohemagglutinin (LPHA), a selective marker for beta1,6-branched oligosaccharides. Node-negative and node-positive primary tumors and patient-matched lymph node metastases were scored by blinded observers.

RESULTS

Metastases stained at significantly greater intensities than did the patient-matched primary tumors (P < 0.0001), demonstrating for the first time that the abundance of beta1,6-branched oligosaccharides was directly associated with breast carcinoma nodal metastasis. Multivariate analyses revealed that beta1,6-branched oligosaccharides in primary tumors were a predictor of poor outcome, most notably in node-negative tumors, where an LPHA staining score of 3+ gave a risk factor of 3.3, independent of tumor size, nuclear grade, or patient age (P = 0.007).

CONCLUSIONS

The data firmly establish a role for beta1,6-N-acetylglucosaminyltransferase V activity and beta1,6-branched oligosaccharides in breast carcinoma metastasis, and reemphasize the involvement, although poorly understood, of aberrant glycosylation in tumor progression.

Modification of oligosaccharides by reactive oxygen species decreases sialyl lewis x-mediated cell adhesion

Modification of cell surface oligosaccharides by reactive oxygen species (ROS) and the biological effect of such modifications on cell adhesion were investigated. Treatment of HL60, a human promyelocyte leukemia cell line, with ROS, generated by a combination of hypoxanthine and xanthine oxidase (HX/XO), decreased the sialic acid content on the cell surface, as indicated by a flow cytometric analysis involving sialic acid-specific lectins, and a concomitant increase of free sialic acid was observed in the supernatant. A cell adhesion assay showed that the HX/XO treatment of HL60 cells decreases their capability of binding to human umbilical vein endothelial cells (HUVEC), probably because of an impairment of the interaction involving E-selectin, whereas the decrease in the binding was canceled by the addition of superoxide dismutase (SOD) and catalase. In fact, cell surface sialyl lewis x (sLe x), but not lewis x (Le x), was decreased by HX/XO treatment. Thus, it is more likely that the impaired interaction is based on diminished levels of the selectin ligand. Cleavage of sialic acid by ROS was further verified by the degradation of 4MU-Neu5Ac by HX/XO in the presence of hydrogen peroxide and iron ion. These results indicate that glycosidic linkage of sialic acid is a potential target for superoxide and other related ROS. It is well known that ROS cause cellular damages such as lipid peroxidation and protein oxidation, but, as suggested by the findings reported in the literature, ROS may also regulate cell adhesion via the structural alteration of sialylated oligosaccharides on the cell surface.

P- and E-Selectin Blockade Can Control Bacterial Translocation and Modulate Systemic Inflammatory Response

Bacterial translocation is an important phenomenon in clinical medicine and leads to an increase in patient morbidity and mortality by multiple organ failure. The selectin family plays an important role in the pathogenesis of inflammation, causing an increase in leukocyte-endothelium interactions and inducing a greater leukocyte's migration. This study considered the effect of a sulfo derivative of Sialyl-Lewis(X), GM 1998-016, that will block the P- and E-selectins interaction with a ligand, the Sialyl-Lewis(X), valuing the modulation of the systemic inflammatory response and the induced translocation. Seventy-five Wistar male rats were injected intraperitoneally with Zymosan A and treated with different doses of GM 1998-016 according to study groups. Measurements of values of qualitative and quantitative microbiology, neutrophil infiltration (myeloperoxidase), oxygen free radicals (superoxide anion, superoxide dismutase, catalase, and gluthatione peroxidase), and cytokines (tumor necrosis factor-alpha and interleukin-1beta) were taken at different times after Zymosan administration. A significant decrease of bacterial translocation, both local (MLN) and systemic (p < .05), was observed, with a decrease in the neutrophil infiltration (p < .001), the oxygen free radicals production (p < .01) and the studied cytokines (p < .01). In conclusion, GM 1998-016 showed a protective effect in an in vivo experimental model of bacterial translocation, downregulating the inflammatory response and the leukocyte-endothelium interactions.

Clostridium botulinum type A progenitor toxin binds to Intestine-407 cells via N-acetyllactosamine moiety

Botulism is a highly fatal disease caused by the botulinum progenitor toxin. In this study, the role of oligosaccharides for the binding of botulinum type A progenitor toxin (type A PTX) to human intestinal cells was investigated. The binding of type A PTX to Intestine-407 cells was inhibited by the addition of N-acetyllactosamine, lactose, and galactose. Treatment of Intestine-407 cells with neuraminidase led to a significant increase in the binding of type A PTX, while further digestion of cell surface oligosaccharides by beta-galactosidase and beta-N-acetylhexosaminidase decreased the binding. These results indicate that the N-acetyllactosamine moiety is responsible for the binding of type A PTX. These findings were further confirmed by a binding assay using synthesized oligosaccharides. Interestingly, sialylation or fucosylation of oligosaccharides inhibited the binding of type A PTX. These data suggest that the type A PTX binds to intestinal cells via cell surface N-acetyllactosamine moiety.

Changes in the glycolipid composition and characteristic activation of GM3 synthase in the thymus of mouse after administration of dexamethasone

Glycolipids in the thymus of mice after administration of dexamethasone were compared with those in control mice. In parallel with a decrease in the tissue weight due to the disappearance of immature thymocytes in the cortex, the amounts of GlcCer, Gg4Cer and GM1 decreased from 18 h after intraperitoneal administration of dexamethasone, but those of Gb4Cer and Forssman glycolipid did not change, indicating the differential distribution of ganglio- and globo-series glycolipids in the thymus, GlcCer, Gg4Cer and GM1 being on dexamethasone-sensitive cortical thymocytes, and Gb4Cer and Forssman glycolipid on dexamethasone-resistant cells including thymic stromal cells, respectively. At the same time, a characteristic increase in GM3, whose amount per thymus and concentration per mg of thymus were increased 4-fold and 13-fold compared to those in the control mice, respectively, was observed at the onset of the decrease in tissue weight and was due to the increased activity of LacCer sialyltransferase with the enhanced expression of its gene and the concomitant decrease in cytosolic sialidase activity. One can suggest that endogenous accumulation of GM3 is involved in the dexamethasone-induced apoptosis of cortical thymocytes. On radiolabeling of the thymus with CMP-[14C]-NeuAc, the incorporation of radioactivity into GM3 was preferentially observed in the thymuses of dexamethasone-administered mice, but not in those of control mice, suggesting the possible involvement of plasma membrane-associated sialytransferase in GM3 synthesis in the thymuses of dexamethasone-administered mice.

Expression of sialyl Lewisa relates to poor prognosis in cholangiocarcinoma

AIM: High levels of serum sialyl Lewis^a (sLe^a) are frequently found in cholangiocarcinoma (CCA) patients and have been suggested to be a serum marker for CCA. However, the significance of this antigen in CCA is unknown. In this study, the clinical significance of sLe^a expression in CCA tissues and the possible role of sLe^a in vascular invasion in vitro were elucidated.

METHODS: Expression of sLe^a in tumor tissues of 77 patients with mass-forming CCA and 33 with periductal infiltrating CCA was determined using immunohistochemistry. The in vitro assays on adhesion and transmigration of CCA cells to human umbilical vein endothelial cells were compared between CCA cell lines with and without sLe^a expression.

RESULTS: sLe^a was aberrantly expressed in 60% of CCA tumor tissues. A significant relationship was found between the frequency of sLe^a expression and the mass-forming type CCA (P = 0.041), well differentiated histological grading (P = 0.029), and vascular invasion (P = 0.030). Patients with positive sLe^a expression had a significantly poorer prognosis (21.28 wk, 95% CI = 16.75-25.81 wk) than those negative for sLe^a (37.30 wk, 95% CI = 27.03-47.57 wk) (P<0.001). Multivariate analysis with adjustment for all covariates showed that patients positive for sLe^a possessed a 2.3-fold higher risk of death than patients negative for sLe^a (P<0.001). The role of sLe^a in vascular invasion was demonstrated using in vitro adhesion and transmigration assays. KKU-M213, a human CCA cell-line with a high expression of sLe^a, adhered and transmigrated to IL-1β-activated endothelial cells of the human umbilical vein more than KKU-100, the line without sLe^a expression (P<0.001). These processes were significantly diminished when the antibodies specific to either sLe^a or E-selectin were added to the assays (P<0.001).

CONCLUSION: This study demonstrates the clinical significance of sLe^a expression in vascular invasion, and an unfavorable outcome in CCA. The role of sLe^a in vascular invasion which may lead to poor prognosis is supported by the in vitro adhesion and transmigration studies.

Specific detection of Lewis x-carbohydrates in biological samples using liquid chromatography/multiple-stage tandem mass spectrometry

The Lewis x structure [Lex, Galbeta1-4(Fucalpha1-3)GlcNAc] motif is one of the tumor antigens and plays an important role in oncogenesis, development, cellular differentiation and adhesion. The detection of Lex-carbohydrates and their structural analysis are necessary to clarify the role of Lex in several biological events. Mass spectrometry has been preferably used for the structural analysis of carbohydrates. Especially, collision-induced dissociation (CID) tandem mass spectrometry (MS/MS), which causes a glycosidic bond cleavage, is used for carbohydrate sequencing. However, Lex cannot be identified by MS/MS due to the existence of the positional isomers, such as Lewis a [Galbeta1-3(alpha1-4Fuc)GlcNAc]. In the present study, we demonstrate the specific detection of Lex-carbohydrates in a biological sample by using multiple-stage MS/MS (MSn). Using pyridylaminated oligosaccharides bearing Lex, we found that the Lex-motif yields a cross-ring fragment by the cleavage of a bond between C-3 and C-4 of GlcNAc in Gal(Fuc)GlcNAc. The Lex-specific cross-ring fragment ion at m/z 259 was effectively detected by sequential scans, consisting of a full MS1 scan, data-dependent CID MS2 scan, MS3 of [Gal(Fuc)GlcNAc+Na]+ at m/z 534, and MS4 of [GalGlcNAc+Na]+ at m/z 388. The sequential scan was applied to N-linked oligosaccharide profiling using a LC/ESI-MSn system equipped with a graphitized carbon column. We successfully detected the Lex-motif and elucidated the structures of several Lex and Lewis y [(Fucalpha1-2)Galbeta1-4(Fucalpha1-3)GlcNAc] oligosaccharides in the murine kidney used as a model tissue. Our method is expected to be a powerful tool for the specific detection of the Lex-motif, and structural elucidation of Lex-carbohydrates in biological samples.

Characterization of a Computerized Assay for Rapid and Easy Determination of Leukocyte Adhesion to Endothelial Cells

We report on a facile and rapid computerized in-vitro assay for the quantification of leukocyte adhesion to endothelial cells under static conditions using bovine polymorphonuclear neutrophils (PMN) or human leukaemic Mono Mac 6 cells (MM6) and bovine aorta endothelial cells (BAEC). Images of leukocytes adherent to BAEC monolayers grown in microtiter plates were obtained by a digital camera attached to a conventional microscope and transferred to the public domain NIH ImageJ program for analysis. Using individually adapted program routines adherent leukocytes are easily discriminated and reproducibly quantified. The results obtained with our assay correspond to previous findings and demonstrate the suitability of the described procedure, which can easily be adapted to further standards as proven by the use of two different leukocyte species. This assay lends itself to the screening of pharmacological substances with different mechanism of action that might act on either leukocytes or endothelial cells.

Co-localization of beta1,6-branched oligosaccharides and coarse melanin in macrophage-melanoma fusion hybrids and human melanoma cells in vitro

Fusion hybrids between normal macrophages and Cloudman S91 melanoma cells were shown earlier to have increased metastatic potential, along with high expression of beta1,6-N-acetylglucosaminyltransferase V and beta1,6-branched oligosaccharides. Curiously, hybrids, but not parental melanoma cells, also produced 'coarse melanin'- autophagic vesicles with multiple melanosomes. As beta1,6-branched oligosaccharides were known to be associated with metastasis, and coarse melanin had been described in invasive human melanomas, we looked for potential relationships between the two. Using lectin- and immunohistochemistry, we analyzed cell lines producing coarse melanin for beta1,6-branched oligosaccharides: gp100/pmel-17 (a melanosomal structural component) and CD63 (a late endosome/lysosome component associated with melanoma and certain other human cancers). Cell lines used in this study were (i) hybrid 94-H48, a highly metastatic, macrophage-melanoma experimental fusion hybrid; (ii) 6(neo) mouse melanoma cells, the weakly metastatic, parental fusion partner; and (iii) SKmel-23, a human melanoma cell line derived from a metastasis. Coarse melanin granules were prominent both in hybrids and in SKmel-23 cells, and co-localized with stains for beta1,6-branched oligosaccharides, gp100/pmel 17, and CD63. This is the first report of this phenotype being expressed in vitro, although co-expression of beta1,6-branched oligosaccharides and coarse melanin was recently shown to be a common and pervasive characteristic in archival specimens of human melanomas, and was most prominent in metastases. The results suggest that pathways of melanogenesis in melanoma may differ significantly from those in normal melanocytes. In vitro expression of this phenotype provides new biological systems for more detailed analyses of its genesis and regulation at the molecular genetic level.

LEC12 and LEC29 Gain-of-Function Chinese Hamster Ovary Mutants Reveal Mechanisms for Regulating VIM-2 Antigen Synthesis and E-selectin Binding

LEC12 and LEC29 are two gain-of-function Chinese hamster ovary glycosylation mutants that express the Fut9 gene encoding alpha(1,3)fucosyltransferase IX (alpha(1,3) Fuc-TIX). Both mutants express the Lewis X (Le(X)) determinant Galbeta(1,4)[Fucalpha(1,3)]GlcNAc, and LEC12, but not LEC29 cells, also express the VIM-2 antigen SAalpha(2,3)-Galbeta(1,4)GlcNAcbeta(1,3)Galbeta(1,4)[Fucalpha(1,3)]GlcNAc. Here we show that LEC29 cells transfected with a Fut9 cDNA express VIM-2, and thus LEC29 cells synthesize appropriate acceptors to generate the VIM-2 epitope. Semiquantitative reverse transcription-PCR showed that LEC12 has 10- to 20-fold less Fut9 gene transcripts than LEC29. However, Western analysis revealed that LEC12 has approximately 20 times more Fut9 protein than LEC29. The latter finding was consistent with our previous observation that LEC12 has approximately 40 times more in vitro alpha(1,3)Fuc-T activity than LEC29. The basis for the difference in Fut9 protein levels was found to lie in sequence differences in the 5'-untranslated regions (5'-UTR) of LEC12 and LEC29 Fut9 gene transcripts. Whereas reporter assays with the respective 5'-UTR regions linked to luciferase did not indicate a reduced translation efficiency caused by the LEC29 5'-UTR, transfected full-length LEC29 Fut9 cDNA or in vitro-synthesized full-length LEC29 Fut9 RNA gave less Fut9 protein than similar constructs with a LEC12 5'-UTR. This difference appears to be largely responsible for the reduced alpha(1,3)Fuc-TIX activity and lack of VIM-2 expression of LEC29 cells. This could be of physiological relevance, because LEC29 and parent Chinese hamster ovary cells transiently expressing a Fut9 cDNA were able to bind mouse E-selectin, although they did not express sialyl-Le(X).

L-selectin shows time and gender dependency in association with MODS

BACKGROUND

Recent investigations have demonstrated gender related immunologic alterations after trauma. These complications arise due to polymorphonuclear granulocytes (PMN) interacting with endothelium via L-selectin. Therefore, the purpose of this study was to investigate gender related differences in the expression of L-selectin in relation to posttraumatic multiple organ dysfunction syndrome (MODS).

METHODS

Multiply injured patients were prospectively entered in the study. MODS was determined using the Denver score. The concentration of L-selectin on the surface of PMN was determined using flow cytometry during a 14 days' period.

RESULTS

48 patients were included in the study. The kinetics of L-selectin were different comparing male and female patients. Male patients with MODS initially showed a rapid decrease of surface L-selectin from 80 to 20 ng/ml. A return to admission levels was related to MODS. Male patients without MODS displayed elevated L-selectin levels up to 140 ng/ml. Female patients, however, all showed an initial rapid decrease of L-selectin to 20 ng/ml. Women who developed posttraumatic MODS had significantly increased levels up to 110 ng/ml before development of MODS developed.

CONCLUSIONS

We feel that a gender related dimorphism in the initial L-selectin expression following trauma exists and is associated with MODS. These findings indicate new therapeutic means for the treatment of MODS. Therapies should be timely and gender dependently coordinated.

Correlation between serum E-selectin levels and panoramic nailfold capillaroscopy in systemic sclerosis

E-selectin is expressed by the activated endothelium and its plasma levels are increased in patients with systemic sclerosis. Eighteen patients fulfilling the American Rheumatism Association criteria for systemic sclerosis, 15 females and 3 males, 42-70 years old, 9 with diffuse and 9 with limited forms, were sequentially recruited for this study. Serum E-selectin levels were determined by commercially available ELISA and their association with nailfold capillaroscopic abnormalities was investigated. Nailfold capillaries were analyzed by 16X magnification wide-field capillaroscopy. Two parameters on capillaroscopy were used to correlate to serum E-selectin: deletion and ectasia. Data were analyzed statistically by the Student t-test and Spearman correlation. Two-tailed P values below 0.05 were considered significant. E-selectin range was 38 to 200 ng/ml (80 +/- 39.94). There was a correlation between serum E-selectin levels and the deletion capillaroscopic score (r = 0.50, P < 0.035). This correlation was even stronger within the first 48 months of diagnosis (r = 0.63, P < 0.048). On the other hand, no association was observed between selectin and ectasia. Patients with diffuse disease presented higher serum E-selectin levels than patients with limited disease, although the difference was not statistically significant (96.44 +/- 48.04 vs 63.56 +/- 21.77 ng/dl; P = 0.08). The present study is the first showing a correlation between soluble serum E-selectin levels and alterations in capillaroscopy. The stronger correlation of deletion score in capillaroscopy in early disease suggests that serum E-selectin levels might be a useful biochemical marker of disease activity in systemic sclerosis.

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

The discoveries of sialylated, fucosylated lacto-, and neolacto-type carbohydrate structures were accomplished with the aid of analytical methods and monoclonal antibodies such as the immunostaining of thin layer chromatograms. Based on the use of such antibodies, these structures, notably sialyl Le(a) and sialyl Le(x), were demonstrated to be highly expressed in many malignant cancers. A diagnostic assay using one of these antibodies (CA19-9) is now established as one of the more commonly used assays for pancreatic and gastrointestinal cancers worldwide. Upon further study, several laboratories have demonstrated that the level of expression of these carbohydrate tumor markers is also positively correlated with patient survival and is a prognostic indicator of metastatic disease. Concurrent with this finding, both sialyl Le(a) and sialyl Le(x) were shown to bind to a family of carbohydrate-binding proteins involved in the extravasation of cells from the bloodstream, called the selectins. Thus, sialyl Le(a) and sialyl Le(x) expressed on cell surfaces play functional roles in medical conditions that require extravasation of cells from the bloodstream which include a wide range of inflammatory diseases and cancer metastasis. Many studies have confirmed the function of sialyl Le(a) and sialyl Le(x) in animal models of these diseases and the inhibition of binding of sialyl Le(a) and sialyl Le(x) to the selectins is a validated drug target in the pharmaceutical industry. Thus, a new class of drugs, arising from the field of glycobiology, is based on the rational design of small molecule drugs that mimic the structures sialyl Le(a) and sialyl Le(x) and can potently inhibit their functional binding to the selectins.

Glycolipid-mediated cell-cell recognition in inflammation and nerve regeneration

Cell surface complex carbohydrates have emerged as key recognition molecules, mediating physiological interactions between cells. Typically, glycans on one cell surface are engaged by complementary carbohydrate binding proteins (lectins) on an apposing cell, initiating appropriate cellular responses. Although many cell surface lectins have been identified in vertebrates, only a few of their endogenous carbohydrate ligands have been established. Each major class of cell surface glycans-glycoproteins, glycolipids, and proteoglycans-has been implicated as physiologically relevant lectin ligands. The current minireview focuses on findings that implicate glycosphingolipids as especially important molecules in cell-cell recognition in two different systems: the recognition of human leukocytes by E-selectin on the vascular endothelium during inflammation and the recognition of nerve cell axons by myelin-associated glycoprotein in myelin-axon stabilization and the regulation of axon regeneration.

Human milk oligosaccharides reduce platelet-neutrophil complex formation leading to a decrease in neutrophil beta 2 integrin expression

Human milk is thought by many authorities to be preferable to formula as a source of nutrients for infants. Some of the benefits may stem from its high concentration of unbound oligosaccharides (5-10 g/L). These sugars have structural similarities to selectin ligands, known to mediate important cell-cell interactions in the immune system. Platelet-neutrophil complexes (PNC) exist in healthy individuals but have been implicated in disease states. Formation of these complexes requires selectins and as such, could be influenced by human milk oligosaccharides (HMO). Here, we investigate this possibility by examining the effect of HMO on the formation of PNC and activation of associated neutrophils. We collected blood from 10 healthy volunteers, activated platelets with adenosine 5'-diphosphate, and added HMO, oligosaccharide standards, or phosphate-buffered saline as a control. We determined the influence of HMO on PNC formation and adjacent neutrophil activation with fluorescein-activated cell sorter analysis after labeling with antibodies for the platelet marker CD42a and the neutrophil activation marker CD11b. Within physiologically achievable concentrations (6.25-125 microg/mL), an acidic HMO fraction reduced PNC formation up to 20%, which was similar to the effect seen with high concentrations of sialyl-Lewis x. Associated neutrophils showed a dose-dependent decrease in beta 2 integrin expression, up to 30%, at high but physiological concentrations. The neutral HMO fraction had no effect. These results support the hypothesis that acidic HMO serve as anti-inflammatory components of human milk and thus, contribute to the lower incidence of inflammatory diseases such as necrotizing enterocolitis in breast-fed versus formula-fed infants.

Proteomic analysis of pulmonary edema fluid and plasma in patients with acute lung injury

Proteomics is the large-scale analysis of protein profiles. This approach has not yet been reported in the study of acute lung injury (ALI). This study details protein profiles in plasma and pulmonary edema fluid (EF) from 16 ALI patients and plasma and bronchoalveolar lavage fluid (BALF) from 12 normal subjects. More than 300 distinct protein spots were evident in the EF and BALF of both normal subjects and ALI patients. Of these, 158 were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. In the plasma and EF protein profile of ALI patients, there were multiple qualitative changes. For instance, in all normal subjects, but in only one of the ALI patients, seven distinct surfactant protein A isoforms were evident. Nearly all ALI patients also had protein spots that indicate truncation or other posttranslational modifications. Several of these novel changes could serve as new biomarkers of lung injury.

Aggregates of endothelial microparticles and platelets circulate in peripheral blood. Variations during stable coronary disease and acute myocardial infarction

INTRODUCTION

Activated endothelial cells on the surface of atherosclerotic plaques can shed membrane microparticles (MPs) with procoagulant potential. We have investigated whether circulating endothelial MPs could bind platelets, form aggregates, and be involved in thrombus formation during acute myocardial infarction (AMI).

PATIENTS/METHODS AND RESULTS

We first assessed the in vitro formation of aggregates comprising endothelial MPs and platelets by incubating supernatants of activated endothelial cells in culture with freshly isolated platelets. Endothelial MP-platelets (EMP-P) aggregates were characterized by flow cytometry using antibodies to specific markers of endothelial cells and of platelets. Identical EMP-P aggregates were detected in vivo in the peripheral blood of healthy individuals, of patients with stable coronary disease (SCD), and of patients with AMI. The levels of EMP-P aggregates were significantly higher in patients with SCD than in controls (16.7+/-1.8/microl versus 7.1+/-0.3/microl, P<0.0002). In contrast, the levels of EMP-P aggregates in the first hours of AMI were significantly lower than in controls and in SCD, both before primary angioplasty (2.5+/-0.7/microl) and 2 h after reperfusion (1.7+/-0.3 microl) (P<0.0001 versus healthy controls and versus SCD). However, 48 h after the onset of AMI, the levels of EMP-P aggregates (14.7+/-1.8/microl) had returned to values close to those observed in SCD.

CONCLUSIONS

Endothelial MPs can bind to platelets and form aggregates. The enumeration of those aggregates in peripheral blood shows significant differences between the various groups of patients tested. This new test can help in the evaluation of the level of endothelial cell activation and the damages created by chronic atherosclerosis.

Hypoxia induces adhesion molecules on cancer cells: A missing link between Warburg effect and induction of selectin-ligand carbohydrates

Cancer cells undergo distinct metabolic changes to cope with their hypoxic environment. These changes are achieved at least partly by the action of transcriptional factors called hypoxia-inducible factors (HIFs). We investigated gene expression in cultured human colon cancer cells induced by hypoxic conditions with special reference to cell-adhesion molecules and carbohydrate determinants having cell-adhesive activity by using DNA-microarray and RT-PCR techniques. Hypoxic culture of colon cancer cells induced a marked increase in expression of selectin ligands, the sialyl Lewis x and sialyl Lewis a determinants at the cell surface, which led to a definite increase in cancer cell adhesion to endothelial E-selectin. The transcription of genes for fucosyltransferase VII (FUT7), sialyltransferase ST3Gal-I (ST3O), and UDP-galactose transporter-1 (UGT1), which are all known to be involved in the synthesis of the carbohydrate ligands for E-selectin, was significantly induced in cancer cells by hypoxic culture. In addition, a remarkable induction was detected in the genes for syndecan-4 (SDC4) and alpha5-integrin (ITGA5), the cell-adhesion molecules involved in the enhanced adhesion of cancer cells to fibronectin. The transcriptional induction by hypoxia was reproduced in the luciferase-reporter assays for these genes, which were significantly suppressed by the co-transfection of a dominant-negative form of HIF. These results indicate that the metabolic shifts of cancer cells partly mediated by HIFs significantly enhance their adhesion to vascular endothelial cells, through both selectin- and integrin-mediated pathways, and suggest that this enhancement further facilitates hematogenous metastasis of cancers and tumor angiogenesis.

Carbohydrate-mediated cell adhesion in cancer metastasis and angiogenesis

Malignant transformation is associated with abnormal glycosylation, resulting in the synthesis and expression of altered carbohydrate determinants including sialyl Lewisa and sialyl Lewisx. The sialyl Lewisa and sialyl Lewisx determinants appear in the sera of patients with cancer, and are extensively utilized for serum diagnosis of cancers in Japan. Sialyl Lewisa and sialyl Lewisx are involved in selectin-mediated adhesion of cancer cells to vascular endothelium, and these determinants are thought to be closely associated with hematogenous metastasis of cancers. Recent progress in this area includes the following: 1. Substantial increases in solid clinical statistics that further confirm the contribution of these determinants in the progression of a wide variety of cancers; 2. Elucidation of the ligand specificity of the three family members of selectins and evaluation of the roles of these molecules in cancer cell adhesion; and 3. Advances in the study of the mechanism that leads to the enhanced expression of the sialyl Lewis(a/x) determinants in malignant cells. These recent results have confirmed that these determinants are not merely markers for cancers, but are functionally implicated in the malignant behavior of cancer cells. The results also suggested that the increase of these determinants in malignant cells is an inevitable consequence of the malignant transformation of cells. Considerable new knowledge has also been accumulated regarding the therapeutic implications for suppression of hematogenous metastasis targeting this cell adhesion system.

Th1 cell-mediated resistance to cutaneous infection with Leishmania major is independent of P- and E-selectins

Studies in several models of inflammation have underscored the importance of P- and E-selectins in the migration of T cells to inflamed tissues. However, the role of the endothelial selectins in infection-induced cutaneous inflammation and host-protective immunity has not been investigated. In this study, we demonstrate that CD4(+) T cells recruited to the cutaneous compartment during infection with Leishmania major express P- and E-selectin ligands. Furthermore, expression of P- and E-selectin ligands correlates with activated Leishmania-specific Th1 cells and is dependent upon IL-12. To investigate the functional role of the endothelial selectins during leishmaniasis, we infected mice either singly or doubly deficient in the expression of P- and E- selectins. Mice lacking both P- and E-selectins developed significantly less inflammation at the site of a primary and secondary infection, and exhibited an impaired delayed-type hypersensitivity response. Surprisingly, the absence of the endothelial selectins had no effect on the control of parasite replication or immunity to reinfection. Thus, these data demonstrate that although the endothelial selectins contribute to the inflammatory response, they are not required for protective immunity to L. major. Moreover, these data suggest that by blocking P- and E-selectins, the immune pathology associated with cutaneous leishmaniasis might be ameliorated without compromising immunity to infection.

Low expression of polypeptide GalNAc N-acetylgalactosaminyl transferase-3 in lung adenocarcinoma: impact on poor prognosis and early recurrence

Initial glycosylation of mucin-type O-linked protein is catalysed by one of the UDP-GalNAc: polypeptide N-acetyl-galactosaminyl transferase-3 (GalNAc-T3). O-glycosylation is important in the binding of cell adhesion molecules, cell differentiation, invasion, and metastasis in tumours. This study was designed to detect GalNAc-T3 expression in lung adenocarcinoma by using immunohistochemical staining, and to evaluate the relationship between the GalNAc-T3 expression level and prognosis and recurrence in completely resected lung adenocarcinoma patients. A low expression of GalNAc-T3 was detected in the cytoplasm of tumour cells in 79 of 148 patients (53.4%) with lung adenocarcinoma. The low expression of GalNAc-T3 was associated with poorly differentiated tumour (P<0.0001), poor pathologic stage (P<0.0001), lymph node metastasis (P<0.0001), and tumour recurrence (P=0.016). The lung carcinoma patients with low GalNAc-T3 expression had a poorer prognosis than those with high GalNAc-T3 expression, using both univariate and multivariate analyses (overall survival: P<0.0001 and P=0.011, respectively). In addition, multivariate analysis of the clinicopathological characteristics of stage I lung adenocarcinoma indicated that the low expression of GalNAc-T3 was a significant independent factor for predicting poor prognosis and early recurrence (P=0.006, rr=2.87 and P=0.019, rr=3.05, respectively). The low expression of GalNAc-T3 may be a useful marker for predicting poor prognosis and early recurrence in completely resected lung carcinoma patients, particularly patients with stage I diseases.

Formation of LacNAc mimetics employing novel donor substrates for enzymatic β1→4 galactosylation

In examining C-6 modified 4-nitrophenyl beta-D-galactopyranosides as donor structures the beta-galactosidase (Bacillus circulans) revealed an unexpectedly broad substrate specificity which allowed successful syntheses of various disaccharide components.

Carbohydrate-mediated adhesion of human colon carcinoma cells to human liver sections

Clinicopathological observations have revealed that the expression level of a carbohydrate antigen recognized by the monoclonal antibody (mAb) FH6 in colorectal carcinomas is higher at advanced stages than at early stages. The present study aimed to elucidate whether human colon carcinoma cell surface glycans recognized by mAb FH6 determine the ability of these cells to adhere to sections of human liver. Variant human colon carcinoma cell lines selected for high and low binding of mAb FH6 were compared with respect to their adhesive capacity. The cells expressing the higher level of FH6 binding also showed a greater ability to adhere to liver sections. This adhesion was not blocked by anti-E-selectin monoclonal antibodies, but pretreatment of the carcinoma cells with endo-beta-galactosidase significantly reduced both cell surface binding of mAb FH6 and the ability of the cells to adhere to liver sections. Our observations suggest that endo-beta-galactosidase-sensitive carbohydrate chains containing an epitope recognized by mAb FH6 play an important role in the adhesion of human colon carcinoma cells to human liver sections. Whether these interactions have any relationship to the mechanism(s) of liver metastasis remains to be elucidated.

Disseminated cancer cells in the blood and expression of sialylated antigen in gastric cancer

BACKGROUND

In gastric cancer, disseminated cancer cells (DCC) can be detected in peripheral blood using bio-molecular techniques. It is known that patients having DCC exhibit a high occurrence of postoperative relapse in gastrointestinal cancer. However, more than half of gastric cancer patients having positive DCC do not show cancer relapse. Sialylated Lewis antigens are considered to be crucial molecules in the metastasis of disseminated cancer. The current study investigated whether combination analysis of DCC and sialylated Lewis antigen are useful in estimating the recurrence risk of gastric cancer.

PATIENTS AND METHODS

Subjects were 106 consecutive gastric cancer patients who underwent curative gastrectomy. DCC in the peripheral blood were detected using the carcinoembryonic antigen (CEA)-mRNA by RT-PCR method. Sialylated Lewis antigen expression (sLeA and sLeX) of the primary tumor was assessed immunohistochemically.

RESULTS

Of 106 gastric cancer patients, 43 (40%) were positive for DCC. Immunohistochemically, 53 (50%) and 49 (46%) patients were positive for sLeA and sLeX, respectively. The presence of DCC did not correlate with sLeA and sLeX expression in gastric cancer. Postoperative tumors were present in 19 patients (7 hematogenous and 12 non-hematogenous), 12 of which were positive for DCC. Six sLeA-positive patients (26%) with DCC and 13 sLeX-positive patients (57%) with DCC suffered from postoperative recurrence of gastric cancer. The p value of CEA-mRNA and sLeX combination analysis was more significant (p<0.01) than that of CEA-mRNA alone (p=0.02).

CONCLUSION

Analyzing both DCC and sLeX expression in gastric cancer may enable more accurate prediction of postoperative recurrence.

The effect of apheresis on adhesion molecules

The adhesion molecules on the leukocytes and the endothelial cells mediate interaction between their cells. The plasma levels of soluble adhesion molecules increase in patients with ischemic heart disease, atherosclerotic aortic disease. Hypercholesterolemia is one of risk factors for atherosclerosis, and it is considered that the expression of adhesion molecules in endothelial cells is related to the development of atherosclerosis. Low-density lipoprotein (LDL) apheresis has been applied to patients with hypercholesterolemia. LDL apheresis may have an effect on adhesion molecules in patients with hypercholesterolemia.

GnT-V, macrophage and cancer metastasis: a common link

GnT-V generated, beta1,6-branched polylactosamines are a common feature shared by normal granulocytes, monocytes, and a variety of malignant cells. Furthermore, activation of GnT-V in oncogenic transformation induces invasiveness and metastatic potential in mice as well as in humans. In view of the common expression of lymphocytic/monocytic trait, motility, and GnT-V by metastatic cancer cells, macrophage fusion hybrids were generated in vitro with Cloudman S91 mouse melanoma cells to test whether the parental traits are co-expressed in hybrids and how those are related to altered phenotypes in relation to metastasis. In fact, the fusion hybrids are highly metastatic in vivo, motile in vitro, and express macrophage-associated traits of increased GnT-V activity, beta1,6 branching, and polylactosamine content. A Spontaneously formed lung melanoma metastases have been identified and characterized as host x tumor hybrid containing higher DNA content than parental cells and increased GnT-V activity. The results, taken together, could reflect prior fusion of tumor-associated macrophages with cells of the primary tumor, and therefore establish a possible common link between elevated expression of GnT-V and malignant transformation, a well-known report. Moreover, the fusion hybrids with metastatic potential ranging from high to low offer a genetically matched model system, for identification and characterization of differentially expressed genes in association with metastasis, since the fusion partners are derived from the same species of mouse (DBA/2J).

Purification, characterization, and molecular cloning of a novel keratan sulfate hydrolase, endo-beta-N-acetylglucosaminidase, from Bacillus circulans

Keratan sulfate (KS) is degraded by various enzymes including endo-beta-galactosidase, keratanase, and keratanase II, which are used for the structural analysis of KS. We purified a novel KS hydrolase, endo-beta-N-acetylglucosaminidase, from the cell pellet and conditioned medium of Bacillus circulans, by sequential chromatography using DE52 and phenyl-Sepharose columns with approximately 63- and 180-fold purity and 58 and 12.5% recovery, respectively. Like keratanase II of Bacillus sp. Ks36, the enzyme, designated Bc keratanase II, hydrolyzed KS between the 4GlcNAcbeta1-3Gal1 structure (endo-beta-N-acetylglucosaminidase), but not hyaluronan, heparan sulfate, heparin, and chondroitin sulfate C, demonstrating a strict specificity to KS. The enzyme digested shark cartilage KS to disaccharides and tetrasaccharides and bovine cornea KS to hexasaccharide, indicating that it prefers highly sulfated KS. Distinct from keratanase II of strain Ks36, the enzyme digested shark cartilage KS at an optimal temperature of 55 degrees C. Based on partial peptide sequencing of the enzyme, we molecularly cloned the gene, which encodes a protein with a predicted molecular mass of approximately 200 kDa. From the deduced protein sequence, Bc keratanase II contained a domain at the C terminus, homologous to the S-layer-like domain of pullulanase from Thermoanaerobacterium thermosulfurigenes and endoxylanase from Thermoanaerobacterium saccharolyticum, and a carbohydrate-binding domain, which may serve to specifically recognize KS chains. A full-length recombinant enzyme showed keratanase II activity. These results may prove useful for the structural analysis of KS toward achieving an understanding of its function.

Src and phosphatidylinositol 3-kinase mediate soluble E-selectin-induced angiogenesis

Angiogenesis plays an important role in a variety of pathophysiologic processes, including tumor growth and rheumatoid arthritis. We have previously shown that soluble E-selectin (sE-selectin) is an important angiogenic mediator. However, the mechanism by which sE-selectin mediates angiogenesis is still unknown. In this study, we show that sE-selectin is a potent mediator of human dermal microvascular endothelial cell (HMVEC) chemotaxis, which is predominantly mediated through the Src and the phosphatidylinositiol 3-kinase (PI3K) pathways. Further, sE-selectin induced a 2.2-fold increase in HMVEC tube formation in the Matrigel in vitro assay. HMVECs pretreated with the Src inhibitor (PP2) and the PI3K inhibitor (LY294002) or transfected with Src antisense oligonucleotides or Akt dominant-negative mutants significantly inhibited sE-selectin-mediated HMVEC tube formation. In contrast, HMVECs transfected with an extracellular signal-related kinase 1/2 (ERK1/2) mutant or pretreated with the mitogen-activated protein kinase (MAPK) inhibitor PD98059 failed to show sE-selectin-mediated HMVEC tube formation. Similarly, in the Matrigel-plug in vivo assay, sE-selectin induced a 2.2-fold increase in blood vessel formation, which was significantly inhibited by PP2 and LY294002 but not by PD98059. sE-selectin induced a marked increase in Src, ERK1/2, and PI3K phosphorylation. PI3K and ERK1/2 phosphorylation was significantly inhibited by PP2, thereby suggesting that both of these pathways may be activated via Src kinase. Even though the ERK1/2 pathway was activated by sE-selectin in HMVECs, it seems not to be essential for sE-selectin-mediated angiogenesis. Taken together, our data clearly show that sE-selectin-induced angiogenesis is predominantly mediated through the Src-PI3K pathway.