Histopathological and molecular classification of colorectal cancer and corresponding peritoneal metastases.

BACKGROUND: Patients with colorectal peritoneal carcinomatosis have a very poor prognosis. The recently developed consensus molecular subtype (CMS) classification of primary colorectal cancer categorizes tumours into four robust subtypes, which could guide subtype-targeted therapy. CMS4, also known as the mesenchymal subtype, has the greatest propensity to form distant metastases. CMS4 status and histopathological features of colorectal peritoneal carcinomatosis were investigated in this study. METHODS: Fresh-frozen tissue samples from primary colorectal cancer and paired peritoneal metastases from patients who underwent cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy were collected. Histopathological features were analysed, and a reverse transcriptase-quantitative PCR test was used to assess CMS4 status of all collected lesions. RESULTS: Colorectal peritoneal carcinomatosis was associated with adverse histopathological characteristics, including a high percentage of stroma in both primary tumours and metastases, and poor differentiation grade and high-grade tumour budding in primary tumours. Furthermore, CMS4 was significantly enriched in primary tumours with peritoneal metastases, compared with unselected stage I-IV tumours (60 per cent (12 of 20) versus 23 per cent; P = 0.002). The majority of peritoneal metastases (75 per cent, 21 of 28) were also classified as CMS4. Considerable intrapatient subtype heterogeneity was observed. Notably, 15 of 16 patients with paired tumours had at least one CMS4-positive tumour location. CONCLUSION: Significant enrichment for CMS4 was observed in colorectal peritoneal carcinomatosis. Surgical relevance Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) improves survival of selected patients with colorectal peritoneal carcinomatosis, but recurrence is common. Histopathological and molecular analysis of colorectal peritoneal carcinomatosis could provide clues for development of novel therapies. In this study, colorectal peritoneal carcinomatosis was found to be enriched for tumours with high stromal content and CMS4-positive status. To further improve prognosis for patients with colorectal peritoneal carcinomatosis, therapies that target tumour-stroma interaction could be added to CRS-HIPEC.

Donor-Specific Antibodies Are Produced Locally in Ectopic Lymphoid Structures in Cardiac Allografts.

Cardiac allograft vasculopathy (CAV) is a transplant pathology, limiting graft survival after heart transplantation. CAV arteries are surrounded by ectopic lymphoid structures (ELS) containing B cells and plasma cells. The aim of this study was to characterize the antigenic targets of antibodies produced in ELS. Coronary arteries and surrounding epicardial tissue from 56 transplant recipients were collected during autopsy. Immunofluorescence was used to identify antibody-producing plasma cells. Immunoglobulin levels in tissue lysates were measured by enzyme-linked immunosorbent assay and analyzed for donor-specific HLA antibodies by Luminex assay. Cytokine and receptor expression levels were quantified using quantitative polymerase chain reaction. Plasma cells in ELS were polyclonal and produced IgG and/or IgM antibodies. In epicardial tissue, IgG (p < 0.05) and IgM levels were higher in transplant patients with larger ELS than smaller ELS. In 4 of 21 (19%) patients with ELS, donor-specific HLA type II antibodies were detected locally. Cytokine and receptor expression (CXCR3, interferon γ and TGF-ß) was higher in large ELS in the epicardial tissue than in other vessel wall layers, suggesting active recruitment and proliferation of T and B lymphocytes. ELS exhibited active plasma cells producing locally manufactured antibodies that, in some cases, were directed against the donor HLA, potentially mediating rejection with major consequences for the graft.

T cells in cardiac allograft vasculopathy are skewed to memory Th-1 cells in the presence of a distinct Th-2 population.

Cardiac allograft vasculopathy (CAV) in heart transplantation (HTx) patients remains the major complication for long-term survival, due to concentric neointima hyperplasia induced by infiltrating mononuclear cells (MNC). Previously, we showed that activated memory T-helper-1 (Th-1) cells are the major component of infiltrating MNC in coronary arteries with CAV. In this study, a more detailed characterization of the MNC in human coronary arteries with CAV (n = 5) was performed and compared to coronary arteries without CAV (n = 5), by investigating MNC markers (CD1a, DRC-1, CD3, CD20, CD27, CD28, CD56, CD68, CD69, FOXP3 and HLA-DR), cytokines (IL-1A, 2, 4, 10, 12B, IFN-gamma, and TGF-beta1), and chemokine receptors (CCR3, CCR4, CCR5, CCR7, CCR8, CXCR3 and CX3CR1) by immunohistochemical double-labeling and quantitative PCR on mRNA isolated from laser microdissected layers of coronary arteries. T cells in the neointima and adventitia of CAV were skewed toward an activated memory Th-1 phenotype, but in the presence of a distinct Th-2 population. FOXP3 positive T cells were not detected and production of most cytokines was low or absent, except for IFN-gamma, and TGF-beta. This typical composition of T-helper cells and especially production of IFN-gamma and TGF-beta may play an important role in the proliferative CAV reaction.

Sulfated N-linked carbohydrate chains in porcine thyroglobulin.

N-linked carbohydrate chains of porcine thyroglobulin were released by the hydrazinolysis procedure. The resulting mixture of oligosaccharide-alditols was fractionated by high-voltage paper electrophoresis, the acidic fractions were further separated by high-performance liquid chromatography on Lichrosorb-NH2, and analyzed by 500-MHz 1H-NMR spectroscopy and, partially, by permethylation analysis. Of the acidic oligosaccharide-alditols, the following sulfated carbohydrate chains could be identified: NeuAc alpha 2----6Gal beta 1----4GlcNAc beta 1----2Man alpha 1----3[(SO3Na----3)Gal beta 1----4GlcNAc beta1----2-Mana alpha 1----6]Man beta 1----4GlcNAc beta 1----4[Fuc alpha 1----6]GlcNAc-ol and NeuAc alpha 2----6Gal beta 1----4(SO3Na----)0-1 GlcNAc beta 1----2-Man alpha 1----3[NeuAc alpha 2----6Gal beta 1----4(SO3Na----6)1-0GlcNAc beta 1----2Man alpha 1----6]Man beta 1----4GlcNAc beta 1----4[Fuc alpha 1----6]GlcNAc- ol. The sulfated structural elements for porcine thyroglobulin form novel details of N-linked carbohydrate chains. They contribute to the fine structure of these oligosaccharides and are another type of expression of microheterogeneity.

Conversion of GalNAc beta(1-4)GlcNAc beta-OMe into GalNAc beta (1-4)-[Fuc alpha(1-3)]GlcNAc beta-OMe using human milk alpha 3/4-fucosyltransferase. Synthesis of a novel terminal element in glycoprotein glycans.

Incubation of GalNAc beta(1-4)GlcNAc beta-OMe with GDP-Fuc in the presence of human milk alpha 3/4-fucosyltransferase resulted in the formation of GalNAc beta(1-4)[Fuc alpha(1-3)]GlcNAc beta-OMe. Under conditions that led to complete alpha 3-fucosylation of Gal beta(1-4)GlcNAc beta-OEt, GalNAc beta(1-4)GlcNAc beta-OMe was fucosylated for more than 85%. For the identification of the isolated fucosylated products one- and two-dimensional 1H-NMR spectroscopy was applied. In vacuo molecular dynamics simulations of Gal beta(1-4)[Fuc alpha(1-3)]GlcNAc beta-OEt and GalNAc beta(1-4)[Fuc alpha(1-3)]GlcNAc beta-OMe using the CHARMm based force field CHEAT, demonstrated only small differences between the conformations of these compounds. This illustrates the minor conformational influence of the substituent at C-2', i.e. a hydroxyl function versus a N-acetyl group.

Oxygenated metabolites of anandamide and 2-arachidonoylglycerol: conformational analysis and interaction with cannabinoid receptors, membrane transporter, and fatty acid amide hydrolase.

This study was aimed at finding structural requirements for the interaction of the acyl chain of endocannabinoids with cannabinoid receptors, membrane transporter protein, and fatty acid amide hydrolase (FAAH). To this end, the flexibility of the acyl chain was restricted by introduction of an 1-hydroxy-2Z,4E-pentadiene system in anandamide (N-arachidonoylethanolamine, AEA) and 2-arachidonoylglycerol (2-AG) at various positions using different lipoxygenases. This brought about selectivity and attenuated the binding potency of AEA and 2-AG. Although the displacement constants were modest, 15(S)-hydroxy-eicosa-5Z,8Z,11Z,13E-tetraenoyl-N-(2-hydroxyethyl)amine was found to bind selectively to the CB(1) receptor, whereas its 1-arachidonoyl-sn-glycerol analogue and 13(S)-hydroxy-octadeca-9Z,11E-dienoyl-N-(2-hydroxyethyl)amine could selectively bind to the CB(2) receptor. 11(S)-Hydroxy-eicosa-5Z,8Z,12E,14Z-tetraenoyl-N-(2-hydroxyethyl)amine did not bind to either receptor, whereas 12(S)-hydroxy-eicosa-5Z,8Z,10E,14Z-tetraenoyl-N-(2-hydroxyethyl)amine did bind to both CB receptors with an affinity similar to that of AEA. All oxygenated anandamide derivatives were good inhibitors of FAAH (low micromolar K(i)) but were ineffective on the AEA transporter. 2-AG rapidly isomerizes into 1(3)-arachidonoyl-sn-glycerol. Both 1- and 3-arachidonoyl-sn-glycerol did not bind to either CB receptor and did not interfere with AEA transport. Thus, after it is isomerized, 2-AG is inactivated, thereby decreasing effective concentrations of 2-AG. Analysis of (1)H NMR spectra revealed that chloroform did not induce notably different conformations in the acyl chain of 15(S)-hydroxy-eicosa-5Z,8Z,11Z,13E-tetraenoic acid as compared with water. Molecular dynamics (MD) simulations of AEA and its analogues in the presence of explicit water molecules revealed that a tightly folded conformation of the acyl chain is not the only requirement for CB(1) binding. Structural details of the C(2)-C(15) loop, such as an sp(2) carbon at position 11, are necessary for receptor binding. The MD simulations may suggest that the average orientations of the pentyl tail of AEA and 12(S)-hydroxy-eicosa-5Z,8Z,10E,14Z-tetraenoyl-N-(2-hydroxyethyl)amine are different from that of the low-affinity, inactive ligands.

Additional fucosyl residues on membrane glycoproteins but not a secreted glycoprotein from cystic fibrosis fibroblasts.

Glycopeptides derived from peripheral membrane glycoproteins of skin fibroblasts of seven patients with cystic fibrosis (CF) had an increase in fucosyl residues when compared with those of seven age, race and sex matched controls (Pediatr Res 1985;19:368-374). To further define these results, the membrane glycopeptides which bound to immobilized lentil lectin and thereby enriched in fucosyl residues linked alpha 1----6 to N-acetylglucosamine attached to asparagine, were Pronase digested, partially purified and examined by 500-MHz 1H-NMR spectroscopy. The CF derived glycopeptides had two different features when compared to those from Controls (1) an increased number of fucosyl residues linked alpha 1----6 to the N-acetylglucosamine attached to asparagine and (2) fucosyl residues linked alpha 1----3 to a branch N-acetylglucosamine. The glycopeptides from both sources were of the di and triantennary type containing sialic acid linked alpha 2----3 and alpha 2----6 to galactose in an approximate molar ratio of 3:2 and 2:1, from CF and Control, respectively. Glycopeptides derived from a glycoprotein, fibronectin, secreted from CF fibroblasts were also examined by 1H-NMR spectroscopy and showed no evidence of fucosyl residues linked alpha 1----3 to branch N-acetylglucosamine and a lesser percentage of core fucose than found in the peripheral membrane glycopeptides. These results define further the altered fucosylation of the CF peripheral membrane glycoproteins.

A 1H NMR database computer program for the analysis of the primary structure of complex carbohydrates.

A 1H NMR database computer program has been developed to determine the primary structure of complex carbohydrates. The database contains carbohydrate structures, their corresponding 1H NMR data, and literature references. From an input list of chemical shift values, the program generates an output list of partially or completely matching carbohydrate structures. In order to facilitate the recognition of the matching part of the selected carbohydrate structures, these structures are displayed with the matching structural elements highlighted. This new 1H NMR database, together with the search program described, now provides a fast access to the published 1H NMR data of complex carbohydrates and furnishes easy links to carbohydrate structures. The performance of the program is demonstrated by the analysis of five carbohydrate fractions prepared from a pool of horse serum glycoproteins.

Oligosaccharide composition of the neurotoxin-responsive sodium channel of mouse neuroblastoma and requirement of sialic acid for biological activity.

A glycoprotein, M(r) 200,000, which has the biological activity of the neurotoxin-responsive Na+ channel, was isolated from a clonal line of mouse neuroblastoma cells, N-18. The glycoprotein was purified to homogeneity in 18% yield by methods used to purify glycoproteins, which included metabolic labeling of the cells with L-[3H]fucose and binding of the radioactive glycoproteins to WGA- and lentil-Sepharose, and DEAE-cellulose. The glycoprotein has biological activity of neurotoxin-responsive ion flux when reconstituted into artificial phospholipid vesicles. This activity was shown to depend on the presence of sialic acid since treatment of the purified, reconstituted glycoprotein with Vibrio cholerae neuraminidase abolished the response to neurotoxins of 86Rb flux. The [3H]fucose-containing glycopeptides derived by Pronase digestion of the glycoprotein were characterized by affinity to immobilized lectins and contained di-, tri-, and tetra-antennary oligosaccharides in a ratio of 2:4:3. Most of the glycopeptides were sialylated as shown by binding characteristics to immobilized serotonin-Sepharose with and without neuraminidase. The structure of the diantennary oligosaccharides was elucidated by 500-MHz 1H NMR spectroscopy. The Con A-bound fraction contains alpha-NeuNAc-(2-->6)-bound group on the GlcNAc5' antenna and an alpha-NeuNAc-(2-->3)-bound groups on the GlcNAc5 antenna. An alpha-L-fucosyl group is (1-->6)-bound to the Asn core GlcNAc1 residue.

Primary structure of the low-molecular-weight carbohydrate chains of Helix pomatia alpha-hemocyanin. Xylose as a constituent of N-linked oligosaccharides in an animal glycoprotein.

alpha-Hemocyanin of Helix pomatia is a copper-containing glycoprotein which serves as an oxygen carrier in the hemolymph. Its carbohydrate moiety has as constituents fucose, xylose, 3-O-methylgalactose, mannose, galactose, N-acetylgalactosamine, and N-acetyl-glucosamine residues. Alkaline borhydride did not split off any carbohydrate material, suggesting the absence of O-glycosidic chains. The N-glycosidic carbohydrate chains of this glycoprotein were liberated by hydrazinolysis of a Pronase digest then fractionated as alditols on Bio-Gel P-4. The fractions containing the low-molecular-weight glycans were investigated by 500-MHz 1H NMR spectroscopy in conjunction with sugar and methylation analysis. The largest, and most abundant, compound was established to be: (Formula: see text). Another compound was characterized as the afuco analogue of this structure. H. pomatia alpha-hemocyanin is the first example of an animal glycoprotein having xylose as a constituent of N-glycosidic carbohydrate chains.

Structure, position, and biosynthesis of the high mannose and the complex oligosaccharide side chains of the bean storage protein phaseolin.

Phaseolin, the major storage protein of the common bean (Phaseolus vulgaris), is a glycoprotein which is synthesized during seed development and accumulates in protein storage vacuoles or protein bodies. The protein has three different N-linked oligosaccharide side chains: Man9(GlcNAc)2, Man7(GlcNAc)2, and Xyl-Man3(GlcNAc)2 (where Xyl represents xylose). The structures of these glycans were determined by 1H NMR spectroscopy. The Man9(GlcNAc)2 glycan has the typical structure found in plant and animal glycoproteins. The structures of the two other glycans are shown below. (Formula; see text) Phaseolin was separated by electrophoresis on denaturing gels into four size classes of polypeptides. The two abundant ones have two oligosaccharides each, whereas the less abundant ones have only one oligosaccharide each. Polypeptides with two glycans have Man7(GlcNAc)2 attached to Asn252 and Man9(GlcNAc)2 attached to Asn341. Polypeptides with only one glycan have Xyl-Man3(GlcNAc)2 attached to Asn252. Both these asparagine residues are in canonical glycosylation sites; the numbering starts with the N-terminal methionine of the signal peptide of phaseolin. The presence of the Man7(GlcNAc)2 and of Xyl-Man3(GlcNAc)2 at the same asparagine residue (position 252) of different polypeptides seems to be controlled by the glycosylation status of Asn341. When Asp341 is unoccupied, the glycan at Asn252 is complex. When Asn341 is occupied, the glycan at Asn252 is only modified to the extent that 2 mannosyl residues are removed. The processing of the glycans, after the removal of the glucose residues, involves enzymes in the Golgi apparatus as well as in the protein bodies. Formation of the Xyl-Man3(GlcNAc)2 glycan is a multistep process that involves the Golgi apparatus-mediated removal of 6 mannose residues and the addition of 2 N-acetylglucosamine residues and 1 xylose. The terminal N-acetylglucosamine residues are later removed in the protein bodies. The conversion of Man9(GlcNAc)2 to Man7(GlcNAc)2 is a late processing event which occurs in the protein bodies. Experiments in which [3H]glucosamine-labeled phaseolin obtained from the endoplasmic reticulum (i.e. precursor phaseolin) is incubated with jack bean alpha-mannosidase show that the high mannose glycan on Asn252, but not the one on Asn341, is susceptible to enzyme degradation. Incubation of [3H] glucosamine-labeled phaseolin obtained from the Golgi apparatus with jack bean beta-N-acetylglucosaminidase results in the removal of the terminal N-acetylglucosamine residues from the complex chain.(ABSTRACT TRUNCATED AT 400 WORDS)

Primary structure of the neutral carbohydrate chains of hemocyanin from Panulirus interruptus.

The N-glycosidic carbohydrate chains of Panulirus interruptus hemocyanin, consisting of only mannose and N-acetylglucosamine residues, were liberated by hydrazinolysis of a pronase digest of the purified glycoprotein. The carbohydrate chains were fractionated by high-voltage paper electrophoresis, yielding mainly neutral oligosaccharide-alditols. These were further separated by high-performance liquid chromatography and characterized by 500-MHz 1H-NMR spectroscopy as (formula; see text).

Modeling of the structure in aqueous solution of the exopolysaccharide produced by Lactobacillus helveticus 766.

A method is described for constructing a conformational model in water of a heteropolysaccharide built up from repeating units, and is applied to the exopolysaccharide produced by Lactobacillus helveticus 766. The molecular modeling method is based on energy minima, obtained from molecular mechanics calculations of each of the constituting disaccharide fragments of the repeating unit in vacuo, as starting points. Subsequently, adaptive umbrella sampling of the potential of mean force is applied to extract rotamer populations of glycosidic dihedral angles of oligosaccharide fragments in solution. From these analyses, the most probable conformations are constructed for the hexasaccharide-repeating unit of the polysaccharide. After exploring the conformational space of each of the individual structures by molecular dynamics simulations, the different repeating unit conformations are used as building blocks for the generation of oligo- and polysaccharide models, by using a polysaccharide building program. The created models of the exopolysaccharide produced by L. helveticus 766 exhibit a flexible twisted secondary structure and tend to adopt a random coil conformation as tertiary structure.

Primary structure determination of seven novel N-linked carbohydrate chains derived from hemocyanin of Lymnaea stagnalis. 3-O-methyl-D-galactose and N-acetyl-D-galactosamine as constituents of xylose-containing N-linked oligosaccharides in an animal glycoprotein.

Hemocyanin from the freshwater snail Lymnaea stagnalis is a high-molecular-mass copper-containing glyco-protein which functions as oxygen carrier in the hemolymph. To release the carbohydrate chains, the protein was digested by pronase followed by hydrazinolysis and reduction. The oligosaccharide-alditols were purified by gel permeation chromatography on Bio-Gel P-4, followed by HPLC on a Lichrosorb-NH2 column. Using 500-MHz 1H-NMR spectroscopy, in conjunction with sugar, methylation and deamination analysis, the following seven novel primary oligosaccharide structures could be unravelled. (Formula: see text).

Primary structure of the glycans of porcine pancreatic lipase.

The glycan primary structure of the main glycopeptide fraction obtained by pronase and carboxypeptidase A digestions of porcine pancreatic lipase has been investigated by 500-MHz 1H-NMR spectroscopy and methylation analysis. The results demonstrate that the glycopeptide fraction was a mixture containing the following structures: (formula; see text)

Primary structure of a low-molecular-mass N-linked oligosaccharide from hemocyanin of Lymnaea stagnalis. 3-O-methyl-D-mannose as a constituent of the xylose-containing core structure in an animal glycoprotein.

Hemocyanin from the freshwater snail Lymnaea stagnalis is a high-molecular-mass copper-containing oxygen-transport protein, which occurs freely dissolved in the hemolymph. It is a glycoprotein containing fucose, xylose, 3-O-methylmannose, 3-O-methylgalactose, mannose, galactose, N-acetylgalactosamine and N-acetylglucosamine residues as sugar constituents. The N-glycosidic carbohydrate chains of this glycoprotein were released by hydrazinolysis of a pronase digest and subsequently fractionated as oligosaccharide-alditols on Bio-Gel P-4 followed by Lichrosorb-NH2. Investigation with 500-MHz 1H-NMR spectroscopy, in conjunction with sugar and methylation analysis revealed the lowest-molecular-mass glycan chain to have the structure: (Formula: see text).

Effects of the N-linked glycans on the 3D structure of the free alpha-subunit of human chorionic gonadotropin.

To gain insight into intramolecular carbohydrate-protein interactions at the molecular level, the solution structure of differently deglycosylated variants of the alpha-subunit of human chorionic gonadotropin have been studied by NMR spectroscopy. Significant differences in chemical shifts and NOE intensities were observed for amino acid residues close to the carbohydrate chain at Asn78 upon deglycosylation beyond Asn78-bound GlcNAc. As no straightforward strategy is available for the calculation of the NMR structure of intact glycoproteins, a suitable computational protocol had to be developed. To this end, the X-PLOR carbohydrate force field designed for structure refinement was extended and modified. Furthermore, a computational strategy was devised to facilitate successful protein folding in the presence of extended glycans during the simulation. The values for phi and psi dihedral angles of the glycosidic linkages of the oligosaccharide core fragments GlcNAc2(beta1-4)GlcNAc1 and Man3(beta1-4)GlcNAc2 are restricted to a limited range of the broad conformational energy minima accessible for free glycans. This demonstrates that the protein core affects the dynamic behavior of the glycan at Asn78 by steric hindrance. Reciprocally, the NMR structures indicate that the glycan at Asn78 affects the stability of the protein core. The backbone angular order parameters and displacement data of the generated conformers display especially for the beta-turn 20-23 a decreased structural order upon splitting off the glycan beyond the Asn78-bound GlcNAc. In particular, the Asn-bound GlcNAc shields the protein surface from the hydrophilic environment through interaction with predominantly hydrophobic amino acid residues located in both twisted beta-hairpins consisting of residues 10-28 and 59-84.

A novel open-chain nononic acid linked by an ether bond to glucose as a polysaccharide constituent.

A novel sugar constituent was isolated from the heteropolysaccharide excreted by Streptococcus thermophilus 8 S when grown in skimmed milk. The structure and absolute configuration were determined by means of chemical analysis, mass spectrometry, NMR spectroscopy, along with molecular dynamics simulations, and was shown to be 6-O-(3',9'-dideoxy-D-threo-D-altro-nononic acid-2'-yl)-D-glucopyranose.

Structural requirements of the fructan-lipid interaction.

Fructans are a group of fructose-based oligo- and polysaccharides. They are proposed to be involved in membrane protection of plants during dehydration. In accordance with this hypothesis, they show an interaction with hydrated lipid model systems. However, the structural requirements for this interaction are not known both with respect to the fructans as to the lipids. To get insight into this matter, the interaction of several inulins and levan with lipids was investigated using a monomolecular lipid system or the MC 540 probe in a bilayer system. MD was used to get conformational information concerning the polysaccharides. It was found that levan-type fructan interacted comparably with model membranes composed of glyco- or phospholipids but showed a preference for lipids with a small headgroup. Furthermore, it was found that there was an inulin chain-length-dependent interaction with lipids. The results also suggested that inulin-type fructan had a more profound interaction with the membrane than levan-type fructan. MD simulations indicated that the favorable conformation for levan is a helix, whereas inulin tends to form random coil structures. This suggests that flexibility is an important determinant for the fructan-lipid interaction.