H. pylori-encoded CagA disrupts tight junctions and induces invasiveness of AGS gastric carcinoma cells via Cdx2-dependent targeting of Claudin-2.

Helicobacter pylori encoded CagA is presently the only known virulence factor that is injected into gastric epithelial cells where it destroys apical junctional complexes and induces dedifferentiation of gastric epithelial cells, leading to H. pylori-related gastric carcinogensis. However, little is known about the molecular mechanisms by which CagA mediates these changes. Caudal-related homeobox 2 (Cdx2) is an intestine-specific transcription factor highly expressed in multistage tissues of dysplasia and cancer. One specific target of Cdx2, Claudin-2, is involved in the regulation of tight junction (TJ) permeability. In this study, our findings showed that the activity of Cdx2 binding to Cdx binding sites of CdxA (GTTTATG) and CdxB (TTTTAGG) of probes corresponding to claudin-2 flanking region increased in AGS cells, infected with CagA positive wild-type strain of H. pylori, compared to CagA negative isogenic mutant-type strain. Moreover, Cdx2 upregulated claudin-2 expression at transcriptional level and translational level. In the meantime, we found that TJs of AGS cells, infected with CagA positive wild-type strain of H. pylori, compared to CagA negative isogenic mutant-type strain, were more severely destroyed, leading to wider cell gap, interference of contact, scattering and highly elevated migration of cells. Herein, this study is firstly demonstrated that H. pylori-encoded CagA disrupts TJs and induces invasiveness of AGS gastric carcinoma cells via Cdx2-dependent targeting of Claudin-2. This provides a new mechanism whereby CagA induced dedifferentiation of AGS cells, leading to malignant behavior of biology.

Domain organization of XAF1 and the identification and characterization of XIAP(RING) -binding domain of XAF1.

X-linked inhibitor of apoptosis protein (XIAP)-associated factor 1 (XAF1) has been implicated as a novel tumor suppressor, which was proposed to exert pro-apoptotic effect by antagonizing the anticaspase activity of XIAP. Here, we delineated the domain architecture of XAF1 by applying limited proteolysis and peptide mass fingerprinting analysis. Our results indicated that XAF1 has a distinct domain organization, with a highly compact N-terminal domain (XAF1(NTD) ) followed by a middle domain (XAF1(MD) ), a 42-residue unstructured linker and a C-terminal domain (XAF1(CTD) ). The search of XIAP binding region within XAF1 revealed that a modest affinity XIAP(RING) binding site (dissociation constant, K(d) , ∼18 µM) is located at the C-terminal portion of XAF1. This C-terminal region, embracing XAF1(CTD) and a flexible tail at C-terminus (residue Thr251-Ser301), is functionally identified as XIAP(RING) -binding domain of XAF1 (XAF1(RBD) ) in the present study. We have also mapped the interaction sites for XAF1(RBD) on XIAP(RING) by using NMR spectroscopy. By applying in vitro ubiquitination assay, we observed that XAF1(RBD) /XIAP interaction is essential for the ubiquitination of GST-XAF1(RBD) fusion protein. In addition, the C-terminal XAF1 fragment harboring XAF1(RBD) was found to be substantially ubiquitinated by XIAP(RING) . Base on these observations, we speculate a possible role of XAF1(RBD) in targeting XAF1 for XIAP-mediated ubiquitination.

Structural analysis of the UBA domain of X-linked inhibitor of apoptosis protein reveals different surfaces for ubiquitin-binding and self-association.

BACKGROUND: Inhibitor of apoptosis proteins (IAPs) belong to a pivotal antiapoptotic protein family that plays a crucial role in tumorigenesis, cancer progression, chemoresistance and poor patient-survival. X-linked inhibitor of apoptosis protein (XIAP) is a prominent member of IAPs attracting intense research because it has been demonstrated to be a physiological inhibitor of caspases and apoptosis. Recently, an evolutionarily conserved ubiquitin-associated (UBA) domain was identified in XIAP and a number of RING domain-bearing IAPs. This has placed the IAPs in the group of ubiquitin binding proteins. Here, we explore the three-dimensional structure of the XIAP UBA domain (XIAP-UBA) and how it interacts with mono-ubiquitin and diubiquitin conjugates. PRINCIPAL FINDINGS: The solution structure of the XIAP-UBA domain was determined by NMR spectroscopy. XIAP-UBA adopts a typical UBA domain fold of three tightly packed α-helices but with an additional N-terminal 3(10) helix. The XIAP-UBA binds mono-ubiquitin as well as Lys48-linked and linear-linked diubiquitins at low-micromolar affinities. NMR analysis of the XIAP-UBA-ubiquitin interaction reveals that it involves the classical hydrophobic patches surrounding Ile44 of ubiquitin and the conserved MGF/LV motif surfaces on XIAP-UBA. Furthermore, dimerization of XIAP-UBA was observed. Mapping of the self-association surface of XIAP-UBA reveals that the dimerization interface is formed by residues in the N-terminal 3(10) helix, helix α1 and helix α2, separate from the ubiquitin-binding surface. CONCLUSION: Our results provide the first structural information of XIAP-UBA and map its interaction with mono-ubiquitin, Lys48-linked and linear-linked diubiquitins. The notion that XIAP-UBA uses different surfaces for ubiquitin-binding and self-association provides a plausible model to explain the reported selectivity of XIAP in binding polyubiquitin chains with different linkages.

Epidemiology of uninvestigated and functional dyspepsia in Asia: facts and fiction.

Dyspepsia is a syndrome consisting of epigastric pain, burning, fullness, discomfort, early satiety, nausea, vomiting and belching. Functional dyspepsia (FD) is diagnosed if upper gastrointestinal endoscopy does not show structural abnormality explaining these symptoms. 8%-30% and 8%-23% of Asian people suffer from of uninvestigated dyspepsia and FD, respectively. Most patients with uninvestigated dyspepsia are found to have FD. Patients with FD are usually young and there is no predilection to any gender. Overlap of FD with other functional bowel diseases such as irritable bowel syndrome and gastroesophageal reflux disease is common in Asia. Cultural difference in reporting of symptoms of dyspepsia is well-known. Moreover, dietary factors, socio-cultural and psychological issues, gastrointestinal infection including that caused by Helicobacter pylori, frequency of organic diseases such as peptic ulcer and gastric cancer responsible for dyspeptic symptoms in the study population may also influence epidemiology of dyspepsia. There is considerable heterogeneity in the above issues among different Asian countries. More studies on epidemiology of FD are needed in Asia.

Backbone and side-chain 1H, 13C and 15N assignments of the ubiquitin-associated domain of human X-linked inhibitor of apoptosis protein.

X-linked inhibitor of apoptosis protein (XIAP), a leading member of the family of inhibitor of apoptosis (IAP) proteins, is considered as the most potent and versatile inhibitor of caspases and apoptosis. It has been reported that XIAP is frequently overexpressed in cancer and its expression level is implicated in contributing to tumorigenesis, disease progression, chemoresistance and poor patient-survival. Therefore, XIAP is one of the leading targets in drug development for cancer therapy. Recently, based on bioinformatics study, a previously unrecognized but evolutionarily conserved ubiquitin-associated (UBA) domain in IAPs was identified. The UBA domain is found to be essential for the oncogenic potential of IAP, to maintain endothelial cell survival and to protect cells from TNF-alpha-induced apoptosis. Moreover, the UBA domain is required for XIAP to activate NF-kappaB. In the present study, we report the near complete resonance assignments of the UBA domain-containing region of human XIAP protein. Secondary structure prediction based on chemical shift index (CSI) analysis reveals that the protein is predominately alpha-helical, which is consistent with the structures of known UBA proteins.

Restoration of XAF1 expression induces apoptosis and inhibits tumor growth in gastric cancer.

XAF1 (XIAP-associated factor 1) is a novel XIAP binding protein that can antagonize XIAP and sensitize cells to other cell death triggers. Our previous results have shown that aberrant hypermethylation of the CpG sites in XAF1 promoter is strongly associated with lower expression of XAF1 in gastric cancers. In our study, we investigated the effect of restoration of XAF1 expression on growth of gastric cancers. We found that the restoration of XAF1 expression suppressed anchorage-dependent and -independent growth and increased sensitivity to TRAIL and drug-induced apoptosis. Stable cell clones expressing XAF1 exhibited delayed tumor initiation in nude mice. Restoration of XAF1 expression mediated by adenovirus vector greatly increased apoptosis in gastric cancer cell lines in a time- and dose-dependent manner and sensitized cancer cells to TRAIL and drugs-induced apoptosis. Adeno-XAF1 transduction induced cell cycle G2/M arrest and upregulated the expression of p21 and downregulated the expression of cyclin B1 and cdc2. Notably, adeno-XAF1 treatment significantly inhibited tumor growth, strongly enhanced the antitumor activity of TRAIL in a gastric cancer xenograft model in vivo, and significantly prolonged the survival time of animals bearing tumor xenografts. Complete eradication of established tumors was achieved on combined treatment with adeno-XAF1 and TRAIL. Our results document that the restoration of XAF1 inhibits gastric tumorigenesis and tumor growth and that XAF1 is a promising candidate for cancer gene therapy.

Independent risk factors and predictive score for the development of hepatocellular carcinoma in chronic hepatitis B.

BACKGROUND/AIMS: To determine whether gender, age, hepatitis B virus genotype, core promoter and precore mutations, HBeAg/ anti-HBe status, HBV DNA, ALT levels and cirrhosis on presentation were independent risk factors and derive a novel risk score for the development of HCC. METHODS: CHB patients (820) were followed up (mean duration 76.8 months) for the occurrence of HCC. RESULTS: The 5- and 10-year prevalence of HCC were 4.4% and 6.3%, respectively. Cox regression analysis showed that male gender (p = 0.025, RR 2.98), increasing age (p < 0.001, RR 1.07), higher HBV DNA levels (p = 0.02, RR 1.28), core promoter mutations (p = 0.007, RR 3.66), and presence of cirrhosis (p < 0.001, RR 7.31) were independent risks for the development of HCC. A risk score was derived and validated with sensitivity > 84% and specificity > 76% to predict the 5- and 10- year risks for the development of HCC. The AUC for the 5- and 10-year prediction were 0.88 and 0.89, respectively. CONCLUSIONS: The risk score, based on age, gender, HBV DNA levels, core promoter mutations and cirrhosis, can estimate the chance of development of HCC in 5 and 10 years after presentation. It can be used to identify high-risk CHB patients for treatment and screening of HCC.

Management and outcome of peptic ulcers or erosions in patients receiving a combination of aspirin plus clopidogrel.

BACKGROUND: This multicenter retrospective study investigated the management and outcome of patients with peptic ulcer/erosion-related aspirin and clopidogrel (A + C) cotherapy. METHODS: From January 2002 to September 2006, patients with endoscopically proven peptic ulcers/erosions after receiving A + C cotherapy were analyzed. RESULTS: This group consisted of 106 patients (age, 69.3 +/- 11.7 years). Ulcers/erosions developed in 27 patients during hospitalization for cardiac events and in 79 patients after hospital discharge. Of 27 patients hospitalized for acute cardiac events, gastrointestinal (GI) bleeding and dyspepsia occurred in 24 and three, respectively. The most common lesion was gastric ulcer. Of 79 discharged patients, GI bleeding and dyspepsia occurred in 64 and 15, respectively. The most common bleeding and dyspeptic lesions were gastric ulcer and gastritis, respectively. Overall, 17 patients underwent endoscopic hemostasis all successfully. A + C cotherapy was continued in 57 patients for a median (interquartile range) of 3.0 (6.2) months. Most were coprescribed a proton pump inhibitor (PPI) (53, 93%). No recurrent GI bleeding was observed. CONCLUSIONS: After A + C cotherapy, gastric ulcer or gastritis were the most common endoscopic lesions. The combination of a PPI and endoscopic treatment for ulcer bleeding was highly successful. After patient stabilization, continuation of A + C cotherapy with a PPI appears to be safe.

Interaction of cigarette smoking with cyclooxygenase-2 on ulcerative colitis-associated neoplasia in mice.

The interactions of cigarette smoking with COX-2 on colitis and colitis-associated adenoma formation were studied. Mice were induced with colitis and exposed to cigarette smoke (CS) and/or SC236 (a COX-2 inhibitor). Results indicated that CS did not alter acute colonic inflammation. Addition of SC236 abolished the induction of proliferation and oxidative damage by colitis. Chronic SC236 treatment abolished the promoting effect of CS on colonic adenoma formation, via suppression of COX-2- and VEGF-mediated proliferation and angiogenesis, and reversed bcl-2-mediated inhibition of apoptosis by CS. To conclude, COX-2 inhibitor could be an implication on cancer prevention in smokers with chronic colitis.

A proteomic approach for the identification of bismuth-binding proteins in Helicobacter pylori.

Helicobacter pylori is a major human pathogen that can cause peptic ulcers and chronic gastritis. Bismuth-based triple or quadruple therapies are commonly recommended for the treatment of H. pylori infections. However, the molecular mechanisms underlying treatment with bismuth are currently not fully understood. We have conducted a detailed comparative proteomic analysis of H. pylori cells both before and after treatment with colloidal bismuth subcitrate (CBS). Eight proteins were found to be significantly upregulated or downregulated in the presence of CBS (20 microg mL(-1)). Bismuth-induced oxidative stress was confirmed by detecting higher levels of lipid hydroperoxide (approximately 1.8 times) and hemin (approximately 3.4 times), in whole cell extracts of bismuth-treated H. pylori cells, compared with those from untreated cells. The presence of bismuth also led to an approximately eightfold decrease in cellular protease activities. Using immobilized-bismuth affinity chromatography, we isolated and subsequently identified seven bismuth-binding proteins from H. pylori cell extracts. The intracellular levels of four of these proteins (HspA, HspB, NapA and TsaA) were influenced by the addition of CBS, which strongly suggests that they interact directly with bismuth. The other bismuth-interacting proteins identified were two enzymes (fumarase and the urease subunit UreB), and a translational factor (Ef-Tu). Our data suggest that the inhibition of proteases, modulation of cellular oxidative stress and interference with nickel homeostasis may be key processes underlying the molecular mechanism of bismuth's actions against H. pylori.

Intestinal tuberculosis mimicking fistulizing Crohn's disease.

A patient is reported with intestinal tuberculosis that mimicked fistulizing Crohn's disease endoscopically. He had complete resolution of symptoms after a full course of antituberculosis therapy. Gastroenterologists and general physicians should aware of the possibility of intestinal tuberculosis in areas with a high prevalence of tuberculosis infection.

Long-term lamivudine therapy reduces the risk of long-term complications of chronic hepatitis B infection even in patients without advanced disease.

BACKGROUND: Long-term effects of lamivudine treatment on chronic hepatitis B patients without advanced disease remain unknown. Our aim was to investigate the effects of long-term lamivudine treatment and lamivudine-resistant virus (YMDD) on the development of cirrhosis and hepatocellular carcinoma (HCC) in asymptomatic patients without advanced disease. METHODS: One hundred and forty-two hepatitis B e antigen (HBeAg)-positive patients (median age: 33.9 years) on long-term lamivudine (median treatment duration: 89.9 months) and 124 HBeAg-positive controls (median age: 33.4 years) were prospectively followed up. Patients were monitored for the development of cirrhosis and HCC, liver biochemistry, hepatitis B virus (HBV) DNA levels, HBeAg seroconversion and hepatitis flares. YMDD mutations (YMDD-MT) were determined annually. RESULTS: Lamivudine-treated patients had a significantly lower cumulative rate of development of cirrhosis and/or HCC compared with controls (P = 0.005). YMDD-MT occurred in 76.3% of patients after 8 years of lamivudine treatment. When compared with controls and patients with YMDD-MT, patients without YMDD-MT had the greatest reduction of HBV DNA and bilirubin levels, slowest decline of albumin level, highest rate of HBeAg seroconversion and lowest risk of hepatitis flare. Patients with YMDD-MT still had a lower risk for developing cirrhosis and/or HCC (P = 0.024) and a greater HBV DNA reduction (P = 0.001) in comparison with controls. Patients with YMDD-MT and controls had a similar chance of hepatitis flares and hepatic decompensation. CONCLUSIONS: Long-term lamivudine treatment was associated with a reduced chance of developing cirrhosis and HCC in patients without advanced disease. Although YMDD-MT reduced the benefits from lamivudine therapy, the outcome of these patients was still better than untreated patients.

Esomeprazole with aspirin versus clopidogrel for prevention of recurrent gastrointestinal ulcer complications.

BACKGROUND AND AIMS: The role of clopidogrel in patients at risk for gastrointestinal complications is uncertain, although it has been recommended for patients who have gastrointestinal intolerance to aspirin. We tested the hypothesis that clopidogrel is as effective as esomeprazole and aspirin in preventing recurrences of ulcer complications. METHODS: This was a prospective, double-blind, randomized, controlled study of 170 patients who developed ulcer bleeding after the use of low-dose aspirin between November 2002 and January 2005. After healing of ulcers and eradication of Helicobacter pylori, if present, patients were assigned randomly to treatment with esomeprazole 20 mg/day and aspirin 100 mg/day (n = 86) or clopidogrel 75 mg/day (n = 84) for 52 weeks. The primary end point was recurrent ulcer complications. RESULTS: During a median follow-up period of 52 weeks, no patient in the esomeprazole group, as compared with 9 patients in the clopidogrel group, developed recurrent ulcer complications. The cumulative incidences of recurrent ulcer complications were 0% in patients receiving esomeprazole and aspirin and 13.6% in patients receiving clopidogrel (absolute difference, 13.6%; 95% confidence interval for the difference, 6.3-20.9; log-rank test, P = .0019). CONCLUSIONS: The combination of esomeprazole and aspirin is superior to clopidogrel in preventing ulcer complications in patients who have a past history of aspirin-related peptic ulcer bleeding.

Association of CTLA-4 gene microsatellite polymorphism with ulcerative colitis in Chinese patients.

Ulcerative colitis (UC) is characterized by chronic intestinal inflammation as a result of an exaggerated T cell response. Cytotoxic T lymphocyte associated antigen-4 (CTLA-4), expressed mainly in activated T cells, inhibits T cell activation and proliferation by combining B7 through competing CD28 and maintains immune homeostasis. Polymorphisms of the CTLA-4 gene are known to be associated with several autoimmune diseases. The aim of this study was to investigate the association between the CTLA-4 gene microsatellite polymorphism and UC in Chinese patients. Unrelated 100 Chinese patients with UC and 140 healthy controls were studied. The (AT) repeats in the 3' untranslated region of exon 4 of the CTLA-4 gene were amplified by allele-specific polymerase chain reaction (PCR). The amplified products were electrophoresed on a 12% polyacrylamide gel, followed by silver staining. Twenty alleles were found in Chinese patients and healthy controls. The 122-bp allele was increased in UC compared with healthy controls (9.5% vs 0.7%, P = 0.0001/Pc = 0.002, OR = 14.591, 95%CI 3.357-63.420). The frequency of the longer alleles (>or=118 bp) of UC was higher than that in healthy controls (26% vs 4%, P = 0.0001/Pc = 0.0002, OR = 7.644, 95%CI 3.950-14.792), but was not associated with location and severity of the disease. Furthermore, the longer alleles were not associated with haplotypes of C-318T/A+49G of the CTLA-4 gene in Chinese patients with UC. The longer alleles of the CTLA-4 gene microsatellite polymorphism were strongly associated with UC in Chinese patients.

Inhibition of Akt/PKB by a COX-2 inhibitor induces apoptosis in gastric cancer cells.

BACKGROUND/AIM: Inhibition of cyclooxygenase-2 has been proposed to be a potential mechanism for the chemoprevention of gastrointestinal tumors by nonsteroidal anti-inflammatory drugs. This study investigates the mechanisms by which the cyclooxygenase-2 inhibitor SC236 induces apoptosis of gastric cancer cell lines and its downstream signaling pathway. METHODS: Two gastric cancer cell lines, AGS and MKN28, were treated with SC236 and assessed for cell growth and apoptosis. The involvement of mitogen-activated protein kinase and Akt kinase/protein kinase B (Akt/PKB) pathways and their downstream signalings were studied in the AGS cell line. RESULTS: SC236 treatment induced apoptosis in gastric cancer cells and caused activation of p38 and stress-activated protein kinase/jun kinase, but down-regulated Akt/PKB. The specific p38 inhibitor SB203580 and the dominant-negative stress-activated protein kinase/jun kinase both failed, while the constitutively active form of Akt/PKB was able to block SC236-induced apoptosis. SC236-induced apoptosis was coupled with release of cytochrome c and activation of caspases. CONCLUSION: One of the pathways involved in SC-236-induced apoptosis in gastric cancer cells is through downregulation of Akt and then release of cytochrome c.

Effects of cyclooxygenase-1 and -2 gene disruption on Helicobacter pylori-induced gastric inflammation.

BACKGROUND: Cyclooxygenases (COXs) play important roles in inflammation and carcinogenesis. The present study aimed to determine the effects of COX-1 and COX-2 gene disruption on Helicobacter pylori-induced gastric inflammation. METHODS: Wild-type (WT), COX-1 and COX-2 heterozygous (COX-1+/- and COX-2+/-), and homozygous COX-deficient (COX-1-/- and COX-2-/-) mice were inoculated with H. pylori strain TN2 and killed after 24 weeks of infection. Uninfected WT and COX-deficient mice were used as controls. Levels of gastric mucosal inflammation, epithelial cell proliferation and apoptosis, and cytokine expression were determined. RESULTS: COX deficiency facilitated H. pylori-induced gastritis. In the presence of H. pylori infection, apoptosis was increased in both WT and COX-deficient mice, whereas cell proliferation was increased in WT and COX-1-deficient, but not in COX-2-deficient, mice. Tumor necrosis factor (TNF)-alpha and interleukin-10 mRNA expression was elevated in H. pylori-infected mice, but only TNF-alpha mRNA expression was further increased by COX deficiency. Prostaglandin E2 levels were increased in infected WT and COX-2-deficient mice but were at very low levels in infected COX-1-deficient mice. Leukotriene (LT) B4 and LTC4 levels were increased to a similar extent in infected WT and COX-deficient mice. CONCLUSIONS: COX deficiency enhances H. pylori-induced gastritis, probably via TNF-alpha expression. COX-2, but not COX-1, deficiency suppresses H. pylori-induced cell proliferation.

Inhibition of human telomerase reverse transcriptase by nonsteroidal antiinflammatory drugs in colon carcinoma.

BACKGROUND: Telomerase activation, which is observed in most human cancers, plays an important role in carcinogenesis. Human telomerase reverse transcriptase (hTERT) is a subunit of telomerase that is essential for telomerase activity. The aim of the study was to investigate whether nonsteroidal antiinflammatory drugs (NSAIDs) inhibit telomerase activity and hTERT. METHODS: Four colon carcinoma cell lines, HT-29, COLO205, CRL-2134, and SW1116, were used in the experiments. Polymerase chain reaction-based telomeric repeat amplification (TRAP) enzyme-linked immunosorbent assay (ELISA) was used to measure telomerase activity in the cells after treatment with aspirin, indomethacin, or SC-236 (a specific cyclooxygenase-2 [COX-2] inhibitor). Expression of hTERT mRNA and protein was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively. The dual luciferase reporter assay was performed to identify the potential cis-response elements to NSAIDs in the promoter region of hTERT. RESULTS: Aspirin, indomethacin, and SC-236 inhibited telomerase activity in HT-29, COLO205, and CRL-2134 cell lines, but not in the SW1116 cell line. NSAIDs inhibited hTERT mRNA and protein expression through suppression of hTERT transcriptional activity. The hTERT promoter fragment -145 to -330 basepairs (bp) upstream of the ATG starting site was sufficient to respond to the NSAID-induced inhibitory effect and the inhibition was COX-2-independent. CONCLUSION: NSAIDs inhibit telomerase activity at hTERT transcriptional, mRNA, and protein levels in colon carcinoma cells. The hTERT promoter fragment -145 to -330 bp may be the cis-response element to NSAIDs.

Induction of apoptosis and cell cycle arrest by a specific c-Jun NH2-terminal kinase (JNK) inhibitor, SP-600125, in gastrointestinal cancers.

The c-Jun NH(2)-terminal kinase (JNK) is activated in several tumor cell lines. The aim of this study was to determine the effects of SP-600125, a specific JNK inhibitor, on the viability, apoptosis, cell cycle distribution of gastrointestinal cancer cells, and the potential anti-tumor mechanisms. Three gastric cancer cell lines, AGS, BCG-823 and MKN-45, and three colorectal cancer cell lines, SW1116, COLO205 and HT-29, were used. Cells were treated with SP-600125, and cell viability, apoptosis and cell cycle distribution, caspase-3 activity, expression of JNK and apoptosis related proteins were detected. SP-600125 inhibited cell proliferation by 10-80% for the different cell lines, and increased apoptosis by 1.5-4.5 folds for COLO205, BCG-823, MKN-45, AGS cells. Caspase-8 and caspase-3 were involved in the induction of apoptosis. SP-600125 caused G2/M cell cycle arrest and elevation of cyclin B1 and p27(kip). The differential response in cells to SP-600125 was associated with the basal level of phosphorylated JNK2. It is concluded that SP-600125 inhibits proliferation, induces apoptosis and causes cell cycle arrest in gastrointestinal cancer cells, indicating that JNK inhibitors have an anti-tumor effect and are potential therapeutic agents for cancers.

Significance of viral load, core promoter/precore mutations and specific sequences of polymerase gene in HBV-infected patients on 3-year lamivudine treatment.

BACKGROUND: Comprehensive study on viral factors predicting treatment responsiveness to lamivudine is lacking. AIMS: To define the significance of various viral factors and changes of viral population with lamivudine treatment. PATIENTS AND METHODS: Hepatitis B virus (HBV) DNA levels at baseline, week 24, 52 and year 3 were measured in 80 patients on continuous lamivudine therapy for 3 years. Genotypes, core promoter/precore mutations, YMDD mutations, polymorphic sequence of polymerase gene (rt91 I/L, rt256S/C) were determined at baseline, week 12, 24 and 52. YMDD mutations were also determined at year 3. RESULTS: High alanine aminotransferase levels and presence of core promoter/ precore mutations at baseline were associated with higher chance of achieving HBV DNA <1,000 copies/ml (good response) and higher rate of hepatitis Be antigen (HBeAg) seroconversion at week 52. Achieving HBV DNA levels <1,000 copies/mi at week 24 as well as baseline core promoter/precore mutations were associated with higher chance of achieving good response, higher rate of HBeAg seroconversion and lower rate of YMDD mutations at year 3. Lamivudine reversed core promoter mutations to wild type in 25% of patients. All 5 patients with rt256C had poor HBV DNA response, persistent HBeAg and YMDD mutations by year 3. There was no difference in treatment response between patients with genotype B and C. CONCLUSIONS: Achieving HBV DNA levels <1,000 copies/ml at 24 week is the best target for short- and long-term treatment efficacy. Core promoter and precore mutations were associated with better treatment outcome, and rt256C polymorphism in the polymerase gene with poor response.

Celecoxib compared with lansoprazole and naproxen to prevent gastrointestinal ulcer complications.

PURPOSE: Selective cyclooxygenase-2 (COX-2) inhibitors cause significantly fewer peptic ulcers than conventional nonselective nonsteroidal anti-inflammatory drugs (NSAIDs) in patients at low risk or high risk for peptic ulcers. On the other hand, proton pump inhibitor co-therapy has also been shown to be effective in preventing relapse of peptic ulcers in high-risk patients using nonselective NSAIDs. We compared the efficacy of a selective COX-2 inhibitor with that of proton pump inhibitor co-therapy in the reduction in the incidence of ulcer relapse in patients with a history of NSAID-related peptic ulcers. MATERIALS AND METHODS: For this study, we recruited 224 patients who developed ulcer complications after NSAID use. We excluded patients who required concomitant aspirin treatment and who had renal impairment. After healing of ulcers and eradication of Helicobacter pylori, patients were randomly assigned to treatment with celecoxib 200 mg daily (n = 120) or naproxen 750 mg daily and lansoprazole 30 mg daily (n = 122) for 24 weeks. The primary endpoint was recurrent ulcer complications. RESULTS: During a median follow-up of 24 weeks, 4 (3.7%, 95% confidence interval [CI] 0.0%-7.3%) patients in the celecoxib group, compared with 7 patients (6.3%, 95% CI 1.6%-11.1%) in the lansoprazole group, developed recurrent ulcer complications (absolute difference -2.6%; 95% CI for the difference -9.1%-3.7%). Celecoxib was statistically non-inferior to lansoprazole co-therapy in the prevention of recurrent ulcer complications. Concomitant illness (hazard ratio 4.72, 95% CI 1.24-18.18) and age 65 years or more (hazard ratio 18.52, 95% CI 2.26-142.86) were independent risk factors for ulcer recurrences. Significantly more patients receiving celecoxib (15.0%, 95% CI 9.7-22.5) developed dyspepsia than patients receiving lansoprazole (5.7%, 95% CI 2.8-11.4. P = .02). CONCLUSIONS: Celecoxib was as effective as lansoprazole co-therapy in the prevention of recurrences of ulcer complications in subjects with a history of NSAID-related complicated peptic ulcers. However, celecoxib, similar to lansoprazole co-therapy, was still associated with a significant proportion of ulcer complication recurrences. In addition, more patients receiving celecoxib developed dyspepsia than patients receiving lansoprazole and naproxen.