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Shingo Tsuji

Publications and source records attributed to Shingo Tsuji.

At least 19 recordsLinked to original sources
PubMed2006

An integrated map of p53-binding sites and histone modification in the human ENCODE regions.

TP53 (tumor protein p53; p53) regulates its target genes under various cellular stresses. By combining chromatin immunoprecipitation with oligonucleotide microarrays, we have mapped binding sites of p53 (p53-BS) in the genome of HCT116 human colon carcinoma cells, along with those of acetylated H3, acetylated H4, and methylated H3-K4. We analyzed a 30-Mb portion of the human genome selected as a representative model by the ENCODE Consortium. In the region, we found 37 p53-BS, of which the p53-binding motif was present in 32 (86%). Acetylated histone H3 and H4 were detected at 14 (38%) and 33 (89%) of the p53-BS, respectively. A significant portion (58%) of H4 acetylation in the p53-BS was not accompanied by H3 acetylation. Acetyl H3 were preferentially located at the 5' and 3' ends of genes, whereas acetyl H4 were distributed widely across the genome. These results provide novel insights into how p53 binding coordinates with histone modification in human.

Acetylation↗
PubMed2006

Helicobacter pylori eradication to prevent gastric cancer: underlying molecular and cellular mechanisms.

Numerous cellular and molecular events have been described in development of gastric cancer. In this article, we overviewed roles of Helicobacter pylori (H pylori) infection on some of the important events in gastric carcinogenesis and discussed whether these cellular and molecular events are reversible after cure of the infection. There are several bacterial components affecting gastric epithelial kinetics and promotion of gastric carcinogenesis. The bacterium also increases risks of genetic instability and mutations due to NO and other reactive oxygen species. Epigenetic silencing of tumor suppressor genes such as RUNX3 may alter the frequency of phenotype change of gastric glands to those with intestinal metaplasia. Host factors such as increased expression of growth factors, cytokines and COX-2 have been also reported in non-cancerous tissue in H pylori-positive subjects. It is noteworthy that most of the above phenomena are reversed after the cure of the infection. However, some of them including overexpression of COX-2 continue to exist and may increase risks for carcinogenesis in metaplastic or dysplastic mucosa even after successful H pylori eradication. Thus, H pylori eradication may not completely abolish the risk for gastric carcinogenesis. Efficiency of the cure of the infection in suppressing gastric cancer depends on the timing and the target population, and warrant further investigation.

Animals↗
PubMed2006

Influences of Helicobacter pylori on cyclooxygenase-2 expression and prostaglandinE2 synthesis in rat gastric epithelial cells in vitro.

BACKGROUND AND AIM: It is known that cyclooxygenase (COX)-2 is over expressed in gastrointestinal neoplasia and Helicobacter pylori (H. pylori) infection is causally linked to gastric cancer. The present study aimed to elucidate the effects of H. pylori on COX-2 expression and prostaglandinE(2) (PGE(2)) production in a gastric epithelial cell line derived from normal rat gastric mucosa (RGM1). METHOD: H. pylori water extracts were prepared from a supernatant of the H. pylori suspension in distilled water. RGM1 cells were cultured with H. pylori water extracts at the final concentration of 2.5, 5, 10 microg/mL for 24 h. For the time sequence study, RGM1 cells were cultured with 10 microg/mL H. pylori water extracts for 0, 6, 12, 24 and 48 h. COX-1 and COX-2 expression in the RGM1 cells was analyzed by western blotting. The levels of PGE(2) in the cultured media were measured by enzyme immunoassay. RESULTS: H. pylori did not affect COX-1 expression; whereas COX-2 expression increased by six-fold at 24 h after incubation of RGM1 cells with 10 microg/mL H. pylori water extracts. The increase in COX-2 expression was evident after 12 h of incubation; reached a peak at 24 h and declined at 48 h. H. pylori dose dependently increased COX-2 expression and PGE(2) synthesis in RGM1 cells. CONCLUSION: H. pylori induces COX-2 expression and increases PGE(2) synthesis in RGM1 cells in vitro. These results indicate that H. pylori-associated gastric carcinogenesis may depend on COX-2 expression.

Animals↗
PubMed2006

Oral glucose tolerance test predicts prognosis of patients with liver cirrhosis.

OBJECTIVE: The aim of this study was to evaluate whether oral glucose tolerance test (OGTT) was useful in evaluating the prognosis of patients with liver cirrhosis. METHODS: Fifty-six patients with liver cirrhosis were enrolled in a prospective cohort study. In all cases, glucose tolerance was diagnosed by a 75-g OGTT according to World Health Organization (WHO) criteria. The relationship of clinical variables to the cirrhosis-related prognosis was investigated using univariate and multivariate regression models. RESULTS: Diabetes mellitus (DM) was diagnosed in 21 subjects (38%), impaired glucose tolerance (IGT) in 13 subjects (23%), and normal glucose tolerance (NGT) in 22 subjects (39%) using OGTT. The cumulative survival rates of patients with liver cirrhosis and NGT were 94.7% at 5 yr; liver cirrhosis and IGT, 68.8% at 5 yr; liver cirrhosis and DM, 56.6% at 5 yr. The survival rates of patients with liver cirrhosis and DM significantly differed from those with NGT. Univariate analysis demonstrated that serum albumin, total bilirubin, prothrombin activity, Child-Pugh scores, and glucose intolerance were highly significant prognostic factors. Multiple regression analysis yielded albumin and DM as the most powerful independent negative predictors of survival. CONCLUSIONS: OGTT appears to be useful for evaluating the prognosis of cirrhotic patients.

Aged↗
PubMed2005

Endothelin-1, an ulcer inducer, promotes gastric ulcer healing via mobilizing gastric myofibroblasts and stimulates production of stroma-derived factors.

Endothelin (ET)-1 is a potent inducer of peptic ulcers. The roles of ET-1 in ulcer healing, however, have remained unclear, and these were investigated in mice. Gastric ulcers were induced in mice by serosal application of acetic acid. Three days later, mice were given a neutralizing ET-1 antibody or nonimmunized serum. The ulcer size, amount of fibrosis and myofibroblasts, and localization of ET-1 and ET(A/B) receptors were analyzed. To elucidate the mechanisms underlying the effects of ET-1, we examined the proliferation, migration, and release of growth and angiogenic factors in gastric myofibroblasts with or without ET-1. The expression of prepro-ET-1 (an ET-1 precursor) and ET-converting enzyme-1 was examined in gastric myofibroblasts using RT-PCR. Immunoneutralization of ET-1 delayed gastric ulcer healing. The areas of fibrosis and myofibroblasts were smaller in the anti-ET-1 antibody group than in the control. ET-1 was expressed in the gastric epithelium, myofibroblasts, and other cell types. ET(A) receptors, but not ET(B) receptors, were present in myofibroblasts. ET-1 increased proliferation and migration of gastric myofibroblasts. ET-1 stimulated the release of hepatocyte growth factor, VEGF, PGE(2), and IL-6 from gastric myofibroblasts. mRNA for prepro-ET-1 and ET-converting enzyme-1 was also expressed. ET-1 promotes the accumulation of gastric myofibroblasts and collagen fibrils at gastric ulcers. ET-1 also stimulates migration and proliferation of gastric myofibroblasts and enhances the release of growth factors, angiogenic factors, and PGE(2). Thus ET-1 has important roles not only in ulcer formation but also in ulcer healing via mobilizing myofibroblasts and inducing production of stroma-derived factors.

Angiogenesis Inducing Agents↗
PubMed2005

(2E,6Z,10E)-7-hydroxymethyl-3,11,15-trimethyl-2,6,10,14-hexadecatetraen-1-ol (Plaunotol) increases cyclooxygenase-2 expression via nuclear factor kappaB and cyclic AMP response element in rat gastric epithelial cells.

Plaunotol, [(2E,6Z,10E)-7-hydroxymethyl-3,11,15-trimethyl-2,6,10,14-hexadecatetraen-1-ol], a gastroprotective agent, increases the prostaglandin production in the gastric mucosa and accelerates ulcer healing. The precise mechanisms underlying the gastroprotective actions by plaunotol are not known. On the other hand, cyclooxygenase (COX)-2 is a key enzyme in PGE(2) production and its induction is thought to have an important role in ulcer healing. We investigated the mechanism of plaunotol-mediated COX-2 induction in rat gastric epithelial (RGM1) cells. We used a PGE(2) enzyme-linked immunoassay kit and Western blot analysis to measure PGE(2) production and COX-2 induction with plaunotol treatment in serum-starved RGM1 cells. In addition, gel-shift assay, Western blot analysis and a reporter assay were performed to observe which Cox-2 promoter was involved in plaunotol-induced Cox-2 expression. The findings indicated that plaunotol treatment dose-dependently increased COX-2 expression and PGE(2) production. The nuclear factor kappaB (NF-kappaB) and cyclic AMP response element (CRE) sites of the COX-2 gene promoter were critical to plaunotol-mediated COX-2 expression. In conclusion, plaunotol induced COX-2 expression and increased PGE(2) production in serum-starved RGM1 cells via activation of the NF-kappaB and CRE sites of Cox-2 gene promoters.

Animals↗
PubMed2005

Allelic dosage analysis with genotyping microarrays.

Genomic alternations, including dosage and allelic imbalance, constitute a major basis of neoplastic and other genetic disorders. Using oligonucleotide genotyping microarrays, here we report the development and usage of an algorithm, called genome imbalance map (GIM) algorithm, for allelic as well as total gene dosage analysis. Using the GIM algorithm, global genome imbalance status at over 100,000 loci was simultaneously analyzed with unprecedented accuracy and allelic discrimination.

Algorithms↗
PubMed2005

Juvenile hepatocellular carcinoma with congestive liver cirrhosis.

A case of juvenile hepatocellular carcinoma (HCC) with congestive liver cirrhosis is reported. The patient was a 21-year-old woman. She had been diagnosed as having transposition of the great arteries, type 2, in 1978. She underwent the Mustard operation, but suffered from chronic heart failure. In 1995, she experienced abdominal pain and underwent examination. The laboratory data were normal, except for elevated total bilirubin (5.2 mg/dl). Blood examinations were performed at frequent intervals, and the total bilirubin level fluctuated between 0.9 and 8.1 mg/dl over the next 4 years, but the transaminase level remained normal. In 1999, she experienced abdominal pain again and was admitted to our hospital. Computed tomography showed four space-occupying lesions in the liver; 45 mm, 20 mm, 12 mm, and 10 mm in size. She was diagnosed as having HCC, and transcatheter arterial chemoembolization and percutaneous ethanol injection therapy were performed. Histology of the cancerous and the noncancerous liver tissue revealed HCC, moderately differentiated type, in cirrhotic liver with congestion. This patient had no background factors of liver disease, except for liver congestion, associated with the chronic heart failure. Because most patients with cardiac cirrhosis die of cardiac disease, only a small number of these patients develop liver failure. However, the incidence of HCC in patients with congestive liver disease is likely to increase in the future, as survival time is prolonged with the advances in treatment for chronic heart failure. Therefore, patients with congestive liver disease should be followed, taking into account the possibility of HCC.

Adult↗
PubMed2005

Efficiency of bone marrow-derived cells in regeneration of the stomach after induction of ethanol-induced ulcers in rats.

BACKGROUND: Bone marrow contains hematopoietic stem cells, nonhematopoietic mesenchymal stem cells, and several precursor cells for osteoblasts, chondrocytes, adipocytes, myocytes, hepatocytes, and even neural cells. Research findings indicate that multipotent stem cells in the adult body may be used to recover the lost functions of damaged tissues. This study examined the involvement of bone marrow-derived cells in the regeneration of the stomach after experimental gastric ulcers were produced in rats. METHODS: We transplanted the bone marrow of transgenic rats that expressed green fluorescence protein (GFP) throughout the body. Twenty-one days after the bone marrow transplantation (BMT), gastric ulceration was induced, using absolute ethanol. Control animals received saline. After various observation periods, rats harboring GFP-positive bone marrow-derived cells were killed, and the tissues were removed and processed to prepare paraffin-embedded sections. Cells expressing GFP were identified by conventional immunohistochemistry, using anti-GFP antibody. To identify whether cells expressing GFP were epithelial cells or interstitial cells such as fibroblasts, serial sections were examined with anti-cytokeratin antibody or anti-vimentin antibody, respectively. Furthermore, to confirm that cells expressing GFP were epithelial cells or interstitial cells, we used double-staining analysis with anti-GFP antibody or anti-cytokeratin antibody, respectively. RESULTS: GFP-positive, bone marrow-derived cells were found in the cytokeratin-positive gastrointestinal epithelium, as well as among vimentin-positive interstitial cells. Interestingly, the proportions of GFP-positive, cytokeratin-positive epithelial cells and vimentin-positive interstitial cells were significantly greater in the ethanol-treated damaged stomachs than in the saline-treated controls. CONCLUSIONS: The present study clearly demonstrates that bone marrow-derived cells are involved in the regeneration of the stomach after ethanol-induced ulcers in rats.

Animals↗
PubMed2005

Gastro-protective agent rebamipide induces cyclooxygenease-2 (COX-2) in gastric epithelial cells.

Cyclooxyngease-2 (COX-2) is a key enzyme in prostaglandin (PG) synthesis, and COX-2 induction plays an important role in the healing of gastric ulceration. Rebamipide is a gastro-protective agent and attenuates the activity of neutrophils. A number of reports have shown that rebamipide treatment increases PG production in the gastric mucosa {in vivo}. Although its clinical significance in ulcer healing has been demonstrated, {in vitro} evidence remains to be accumulated. Non-transformed rat gastric mucosal cells (RGM1 cells) were stimulated with rebamipide. RT-PCR and Western blot analysis revealed time and dose-dependent transcriptional and translational stimulation of COX-2. PGE(2) was also produced dose-dependently. However, marked COX-2 induction by rebamipide was transient and lasted less than 24 hr. COX-1 expression was unaltered by rebamipide. Reporter assay results confirmed the stimulation of Cox-2 promoter activity by rebamipide. In conclusion, this study provides {in vitro} evidence that rebamipide transcriptionally induces COX-2 and supports the rationale for its clinical use.

Alanine↗
PubMed2004

Concanavalin a injection activates intrahepatic innate immune cells to provoke an antitumor effect in murine liver.

Concanavalin A (ConA), directly injected into mice, induces T cell-mediated liver injury. However, it remains unclear whether ConA injection can activate innate immune cells, including natural killer (NK) cells and natural killer T (NKT) cells, both of which exist abundantly in the liver. Here we report that ConA injection stimulated interferon (IFN)-gamma production from liver NKT cells as early as 2 hours after injection and augmented YAC-1 cytotoxicity of liver NK cells. ConA-induced NK cell activation required other types of immune cells and critically depended on IFN-gamma. Because a nonhepatotoxic low dose of ConA was capable of fully activating both NKT cells and NK cells, we next addressed the possibility of ConA injection displaying an antitumor effect in the liver without liver injury. A nonhepatotoxic low-dose ConA injection augmented the cytotoxicity of liver NK cells against Colon-26 colon cancer cells and suppressed hepatic metastasis of Colon-26 cells in a NK cell- and IFN-gamma-dependent manner. In conclusion, a nonhepatotoxic low dose of ConA might serve as an immunomodulator that can preferentially activate the innate immune cells to induce an antitumor effect against metastatic liver tumor.

Animals↗
PubMed2004

The significance of interferon and ribavirin combination therapy followed by interferon monotherapy for patients with chronic hepatitis C in Japan.

One hundred seventy-one patients with chronic hepatitis C were included in this study (genotype1 and high viral loads (1H), [Formula: see text]; non-1H, [Formula: see text]; N.D., [Formula: see text] ). The combination therapy of interferon and ribavirin for 24 weeks with an additional 24 weeks of interferon monotherapy (48-week treatment) was undergone by 42 1H patients and 5 non-1H patients. The combination therapy of interferon and ribavirin was administered for 24 weeks in 67 1H patients and 22 non-1H patients. Among the 1H patients, the HCV relapse rate was significantly higher in those receiving 24-week combination treatment than in those receiving 48-week treatment (78% versus 42%, [Formula: see text] ). Among the non-1H patients, no significant difference was found between them. Sustained virological response (SVR) rates were observed to decrease as the timing of HCV RNA disappearance was delayed. In spite of the small rate (16%), SVR was obtained from the patients who became negative for HCV RNA by week 24 (beyond week 12) only in those receiving 48-week treatment. In 1H patients, 24-week combination treatment followed by interferon monotherapy for 24 weeks was concluded to be the treatment offering the most hope among those that the medical insurance can be applied in Japan.

Journal Article↗
PubMed2004

Promoter hypermethylation silences cyclooxygenase-2 (Cox-2) and regulates growth of human hepatocellular carcinoma cells.

Cyclooxygenase-2 (COX-2) upregulation is recognized to confer advantage in progression in a wide variety of cancers, with colorectal cancer most intensively investigated. Epidemiologically, chemopreventive effects of COX-2 inhibitors have been proven on numerous cancers, but not on hepatocellular carcinoma (HCC). Although the antiapoptotic feature of COX-2 generally supports cancer cell growth, previous reports have shown that COX-2 expression, upregulated in early HCC, is downregulated in advanced HCC. Therefore, COX-2 downregulation may be somehow advantageous and specific for HCC development. However, its mechanism remains unclear. Since promoter hypermethylation often silences the gene expression, we hypothesized that the epigenetic mechanism might regulate COX-2 expression in HCC. We examined the methylation status of the Cox-2 promoter in six human HCC cell lines (Hep3B, HepG2, SK-Hep1, HuH7, PLC, and FLC-7 cells) using methylation-specific PCR. The promoter was remarkably hypermethylated in Hep3B and FLC-7 cells and moderately in HepG2 and SK-Hep1 cells, but not in HuH7 and PLC cells. In Hep3B cells, coincubation with 5-aza-2'-deoxycytidine, a demethylator, demethylated the promoter and upregulated COX-2 expression as well as prostaglandin E2 production dose dependently. On the other hand, no such effects were observed in HuH7 cells. Additionally, the methylator suppressed growth of Hep3B cells dose dependently, accompanied by cyclin D1 downregulation, and the growth suppression was abrogated by potent COX-2 inhibition with a COX-2 selective inhibitor celecoxib, but these responses were not found in HuH7 cells. These results indicated that cell growth was largely retarded by Cox-2 upregulation via promoter demethylation, rather than the potentially reactivated genes concurrently demethylated by 5-aza-2'-deoxycytidine. In conclusion, promoter hypermethylation transcriptionally silences Cox-2 in HCC cells. Epigenetic alteration of Cox-2, at least in part, modulates the growth of HCC cells.

Azacitidine↗