Helicobacter pylori infects the stomachs of nearly a half the human population, yet most infected individuals remain asymptomatic, which suggests that there is a host defense against this bacterium. Because H. pylori is rarely found in deeper portions of the gastric mucosa, where O-glycans are expressed that have terminal alpha1,4-linked N-acetylglucosamine, we tested whether these O-glycans might affect H. pylori growth. Here, we report that these O-glycans have antimicrobial activity against H. pylori, inhibiting its biosynthesis of cholesteryl-alpha-D-glucopyranoside, a major cell wall component. Thus, the unique O-glycans in gastric mucin appeared to function as a natural antibiotic, protecting the host from H. pylori infection.

␣-Dystroglycan (␣-DG) represents a highly glycosylated cell surface molecule that is expressed in the epithelial cell-basement membrane (BM) interface and plays an essential role in epithelium development and tissue organization. The ␣-DG-mediated epithelial cell-BM interaction is often impaired in invasive carcinomas, yet roles and underlying mechanisms of such an impaired interaction in tumor progression remain unclear. We report here a suppressor function of laminin-binding glycans on ␣-DG in tumor progression. In aggressive prostate and breast carcinoma cell lines, lamininbinding glycans are dramatically decreased, although the amount of ␣-DG and ␤-dystroglycan is maintained. The decrease of lamininbinding glycans and consequent increased cell migration were associated with the decreased expression of ␤3-N-acetylglucosaminyltransferase-1 (␤3GnT1). Forced expression of ␤3GnT1 in aggressive cancer cells restored the laminin-binding glycans and decreased tumor formation. ␤3GnT1 was found to be required for laminin-binding glycan synthesis through formation of a complex with LARGE, thus regulating the function of LARGE. Interaction of the laminin-binding glycans with laminin and other adhesive molecules in BM attenuates tumor cell migratory potential by antagonizing ERK/AKT phosphorylation induced by the components in the ECM. These results identify a previously undescribed role of carbohydrate-dependent cell-BM interaction in tumor suppression and its control by ␤3GnT1 and LARGE.glycosylation ͉ cell adhesion ͉ basement membrane ͉ carcinoma I nteraction of epithelial cells with basement membrane (BM) is mediated by cell adhesion molecules, which operate at the interface of epithelial cell-ECM and regulate cell growth, motility, and differentiation by integrating signals from ECM or soluble factors (1-3). One of the most important epithelial cell-BM interactions is mediated by ␣-dystroglycan (␣-DG) on epithelial cells (4).␣-DG is a cell surface receptor for several major BM proteins, including laminin, perlecan, and agrin. A laminin G-like domain in all these glycoproteins binds to a unique glycan structure attached to ␣-DG, and this interaction has been shown to be critical in assembling BM (5, 6). This unique glycan structure is referred to as laminin-binding glycans hereafter. ␣-DG is not attached directly to the plasma membrane but is bound to it through attachment to the transmembrane protein ␤-dystroglycan (␤-DG), which binds to the cytoplasmic protein dystrophin, which, in turn, binds to the actin cytoskeleton and many adaptor molecules involved in cellular signaling (4,5).␣-DG is highly glycosylated and contains both N-linked glycans and mucin type O-glycans. The mucin type O-glycans are clustered in a mucin-like domain at the N-terminal of mature ␣-DG, which includes unique O-mannosyl glycans and sialic acid ␣233Gal␤134GlcNAc␤132Man␣13Ser/Thr (7). Defects in glycosylation of the O-mannosyl glycans have been shown to cause muscular dystrophy (8). So far, 7 glycosyltransferases or glycosyltransferase-like ...

Gastric gland mucin secreted from the lower portion of the gastric mucosa contains unique O-linked oligosaccharides (O-glycans) having terminal α1,4-linked N-acetylglucosamine residues (αGlcNAc). Previously, we identified human α1,4-N-acetylglucosaminyltransferase (α4GnT), which is responsible for the O-glycan biosynthesis and characterized αGlcNAc function in suppressing Helicobacter pylori in vitro. In the present study, we engineered A4gnt -/-mice to better understand its role in vivo. A4gnt -/-mice showed complete lack of αGlcNAc expression in gastric gland mucin. Surprisingly, all the mutant mice developed gastric adenocarcinoma through a hyperplasia-dysplasia-carcinoma sequence in the absence of H. pylori infection. Microarray and quantitative RT-PCR analysis revealed upregulation of genes encoding inflammatory chemokine ligands, proinflammatory cytokines, and growth factors, such as Ccl2, Il-11, and Hgf in the gastric mucosa of A4gnt -/-mice. Further supporting an important role for this O-glycan in cancer progression, we also observed significantly reduced αGlcNAc in human gastric adenocarcinoma and adenoma. Our results demonstrate that the absence of αGlcNAc triggers gastric tumorigenesis through inflammation-associated pathways in vivo. Thus, αGlcNAc-terminated gastric mucin plays dual roles in preventing gastric cancer by inhibiting H. pylori infection and also suppressing tumor-promoting inflammation.

Helicobacter pylori infects over half the world's population and is a leading cause of peptic ulcer and gastric cancer. H. pylori infection results in chronic inflammation of the gastric mucosa, and progression of chronic inflammation leads to glandular atrophy and intestinal metaplasia. However, how this chronic inflammation is induced or maintained is not well known. Here, we show that chronic inflammation caused by H. pylori infection is highly correlated with de novo synthesis of peripheral lymph node addressin (PNAd) presented on high-endothelial venule (HEV)-like vessels. The number of HEV-like vessels dramatically increases as chronic inflammation progresses. We found that the PNAd is bound by L-selectin⅐IgM chimeric protein, and decorated by NCC-ST-439 antibody, which is suggested to recognize both nonsulfated and 6-sulfated sialyl Lewis X on core 2 branched O-glycans, and MECA-79 antibody, which reacts with 6-sulfo N-acetyllactosamine on extended core 1 O-glycans. These results indicate that PNAd on HEV-like vessels present in the gastric mucosa subsequent to H. pylori infection is similar to those on HEVs present in the secondary lymphoid organs, which are essential for lymphocyte circulation. Moreover, eradication of H. pylori is associated with the disappearance of HEV-like vessels in the gastric mucosa. By contrast, very few PNAd were found in the gastric mucosa of patients with chemical gastritis caused by nonsteroidal antiinflammatory drugs. These results strongly suggest that PNAd in HEV-like vessels plays a critical role in lymphocyte recruitment during chronic inflammation induced by H. pylori infection.inflammation ͉ peptic ulcers ͉ gastric carcinoma

Dolastatin 10 (1) is a potent antineoplastic pentapeptide. Novel dolastatin 10 analogs each modified at one of the constituent amino acid derivatives, were synthesized and their antitumor activity was evaluated against P388 leukemia in mice. The structural requirements for antitumor activity are discussed. Some of the analogs, 31c, 35c, 38b, and 50c showed excellent activity in vivo. Highly active 50c, which lacks the thiazole group of 1, was selected for further development as an antitumor agent.

T-cell recruitment via PNAd-expressing HEV-like vessels induced by expression of GlcNAc6ST-1 may play a role in UC pathogenesis.

Dolastatin 10, a pentapeptide isolated from the marine mollusk Dolabella auricularia, has antitumor activity. TZT‐1027, a dolastatin 10 derivative, is a newly synthesized antitumor compound. We evaluated its antitumor activity against a variety of transplantable tumors in mice. Intermittent injections of TZT‐1027 were more effective than single or repeated injections in rake with P388 leukemia and B16 melanoma. Consequently, TZT‐1027 shows schedule dependency. TZT‐1027 was effective against P388 leukemia not only when administered i.p., but also when given i.v. However, although TZT‐1027 given i.v. was active against murine solid tumors, TZT‐1027 administered i.p. was ineffective against all the tumors tested with the exception of colon 26 adenocarcinoma. The i.v. injection of TZT‐1027 at a dose of 2.0 mg/Ag remarkably inhibited the growth of three murine solid tumors; colon 26 adenocarcinoma, B16 melanoma and M5076 sarcoma, with T/C values of less than 6%. The antitumor activities of TZT‐1027 against these tumors were superior or comparable to those of the reference agents; dolastatin 10, cisplatin, vincristine, 5‐fluorouracil (5‐FU) and E7010. In experiments with drug‐resistant P388 leukemia, TZT‐1027 showed good activity against cisplatin‐resistant P388 and moderate activity against vincristine‐ and 5‐fluorouracil‐resistant P388, but no activity against adriamycin‐resistant P388. TZT‐1027 was also effective against human xenografts, that is, tumor regression was observed in mice bearing MX‐1 breast and LX‐1 lμng carcinomas. TZT‐1027 at 10 μM almost completely inhibited the assembly of porcine brain microtubules. Therefore, its mechanism of antitumor action seems to he, at least in part, ascrihable to the inhibition of microtubule assembly. Because of its good preclinical activity, TZT‐1027 has been entered into phase I clinical trials.

Background-A diffuse lymphocyte infiltrate is one of the characteristic features of ulcerative colitis (UC). Such lymphocyte recruitment requires lymphocyte rolling mediated by L-selectin ligand carbohydrates (6-sulfo sialyl Lewis X-capped O-glycans) and/or mucosal addressin cell adhesion molecule 1 (MAdCAM-1) expressed on high endothelial venule (HEV)-like vessels. The present study was undertaken to elucidate the role of MAdCAM-1 posttranslationally modified ("decorated") with L-selectin ligand carbohydrates in UC pathogenesis and consequent clinical outcomes.