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Biomedical subjects

Fumio Imazeki

Publications and source records attributed to Fumio Imazeki.

At least 37 records · Page 2Linked to original sources
PubMed2005

Methylation status of p14ARF, p15INK4b, and p16INK4a genes in human hepatocellular carcinoma.

BACKGROUND: The INK4 locus consisting of three genes involved in the regulation of cell cycle, p16INK4a, p15INK4b, and p14ARF is often disrupted in human neoplasms. METHODS: We analyzed the promoter methylation of each gene by methylation-specific PCR in hepatocellular carcinoma (HCC). RESULTS: The methylation of p16INK4a, p15INK4b, and p14ARF was found to occur in 27 (69.2%), seven (17.9%), and none out of 39 HCC tumors, respectively. Regarding corresponding nontumorous liver tissues, the promoter regions of p16INK4a, p15INK4b, and p14ARF were methylated in three (17.6%), three (17.6%), and none out of 17 samples, respectively. Analysis of mRNA expression revealed that loss of p16INK4a expression was frequently observed in HCC. In contrast, transcripts of p14ARF and p15INK4b were detected in 16 (88.9%) and 16 (88.9%) of 18 tumors, respectively. CONCLUSIONS: The frequent loss of transcription of p16INK4a with promoter methylation not only in the advanced but also in the early stages of HCC suggests that the epigenetic alteration of p16INK4a promoter is likely to be involved in hepatocarcinogenesis. Together with the result of RT-PCR analysis, the role of aberrant methylation of p14ARF or p15INK4a promoter in hepatocarcinogenesis is thought to be limited.

Adult↗
PubMed2005

Evaluation of clinical usefulness of second-generation HCV core antigen assay: comparison with COBAS AMPLICOR HCV MONITOR assay version 2.0.

BACKGROUND: Hepatitis C virus (HCV) is an important etiologic agent for chronic liver diseases. METHODS: The aim of this study was to evaluate the clinical usefulness of second-generation HCV core antigen assay by comparing the results of the assay with those of the COBAS AMPLICOR HCV MONITOR version 2.0 (COBAS v2.0). RESULTS: HCV core antigen was detectable by this assay in 142/149 (95.3%) of serotype 1 (3821+/-322 fmol/l; mean+/-SD), in 56/58 (96.6%) of serotype 2 (2589+/-449 fmol/l), and in 6/6 (100%) of serotypes 1+2 (1240+/-548 fmol/l). The HCV core antigen levels measured by this assay correlated well with the HCV RNA levels by COBAS v2.0 (r=0.848, P<0.0001). In relation to the outcome of interferon monotherapy, the pretreatment HCV core antigen levels of sustained and non-sustained virological responders were 659+/-189 and 4904+/-376 fmol/l in serotype 1, 1993+/-740 and 3145+/-519 fmol/l in serotype 2. The cutoff values with the best accuracy for HCV core Ag levels to discriminate between sustained and non-sustained virological response were 699 fmol/l for serotype 1 and 292 fmol/l for serotype 2, respectively, by receiver operating characteristic curve analysis. CONCLUSION: This new assay was considered to be useful in evaluating the HCV levels in patients with chronic hepatitis C.

Adolescent↗
PubMed2005

Fas polymorphisms influence susceptibility to autoimmune hepatitis.

BACKGROUND AND AIMS: Genetic factors associated with autoimmune hepatitis (AIH) and primary biliary cirrhosis (PBC), immune-mediated chronic inflammatory liver diseases of unknown etiology, remain to be elucidated. Polymorphisms of the gene encoding Fas have been linked to a variety of autoimmune diseases. We hypothesized that Fas gene polymorphisms might be genetic markers for AIH and PBC. METHODS: To determine the frequency and significance of Fas polymorphisms in patients with AIH and PBC, 74 Japanese AIH patients, 98 Japanese PBC patients, and 132 ethnically matched control subjects were investigated by the use of the Taqman assay. RESULTS: We found significant differences between AIH patients and controls in allele frequencies of Fas-670 (p=0.009), Fas IVS (intervening sequence) 2nt176 (p=0.018), Fas IVS3nt46 (p=0.031), and Fas IVS5nt82 (p=0.013) polymorphisms. Haplotype analysis revealed that one of the haplotypes, GATGC, was associated with increased AIH prevalence. On the other hand, we found no statistically significant differences between PBC patients and controls in allele frequencies of the Fas polymorphisms genotyped in this study. CONCLUSIONS: These results indicate a genetic link of Fas polymorphisms to the development of AIH. Further studies are needed to determine the genetic factors contributing to the development of AIH.

Adolescent↗
PubMed2005

5-aza-2'-deoxycytidine sensitizes hepatoma and pancreatic cancer cell lines.

Hepatocellular carcinoma (HCC) and pancreatic cancer are at the forefront of chemotherapy-resistant tumors with poor prognosis. Even with innovative treatment regimens, response rates remain low and the duration of response is short. We examined whether the suppression of DNA methylation was capable of enhancing the sensitivity of hepatoma and pancreatic cancer cell lines to 5-fluorouracil (5-FU). 5-aza-2'-deoxycytidine (5-aza-dC) at 2 microM, a specific DNA methylation inhibitor, did not induce cell death in Huh-7 with or without HCV, HLE, HepG2 and MIA PaCa-2 cells. However, a combination of 5-aza-dC with 5-FU showed a reduction in cell viability and induction of apoptosis in these cell lines to a greater degree than with 5-FU only. These findings underline the fact that DNA methylation plays a key role in conferring chemoresistance to hepatoma and pancreatic cancer, and the combination of DNA methylation inhibitor with chemotherapy could be a novel and highly effective tool for future targeted therapy of chemoresistant tumors.

Antimetabolites, Antineoplastic↗
PubMed2004

Hypermethylation of NAD(P)H: quinone oxidoreductase 1 (NQO1) gene in human hepatocellular carcinoma.

BACKGROUND/AIMS: NAD(P)H: quinone oxydoreductase 1 (NQO1) and glutathione S-transferase P1 (GSTP1) belong to phase II xenobiotic-metabolizing enzymes. GSTP1 inactivation via CpG island hypermethylation in hepatocellular carcinoma (HCC) was previously reported, but the involvement of NQO1 in HCC is not well known. In this study, we assessed the transcription and status of methylation of NQO1 gene in human hepatoma cells and primary human HCC tissues. METHODS: NQO1 transcription and DNA hypermethylation in hepatoma cells with or without 5-aza-deoxycytidine (5-Aza-CdR) treatment were investigated by reverse-transcription PCR (RT-PCR), sodium bisulfite sequencing and methylation-specific PCR (MSP). The methylation status of NQO1 and GSTP1, and NQO1 mRNA in 44 HCC cases was also analyzed by MSP and real-time PCR, respectively. RESULTS: NQO1 transcription was down-regulated and the CpG island DNA was hypermethylated in Hep3B and HuH6 cells. After treatment with 5-Aza-CdR, NQO1 transcription was restored and CpG island DNA was demethylated in these cells. MSP analysis revealed that NQO1 hypermethylation occurred in 50.0% of HCC. All of the tumors that exhibited lesser amounts of NQO1 mRNA than corresponding non-tumorous tissues showed NQO1 hypermethylation. CONCLUSIONS: NQO1 transcription might be inappropriately suppressed by promoter hypermethylation in a subset of HCC, as well as GSTP1 gene.

Acetylation↗
PubMed2004

Gene expression profiles in liver regeneration with oval cell induction.

The liver has the unique ability to regenerate even in adulthood. While mature hepatocytes can proliferate by themselves, stem cells also play a critical role in liver regeneration and oval cells are considered to be the progeny of activated hepatic stem cells. We herein investigated the gene expression profiles in the conditions inducing oval cells, using microarray analysis. Two approaches were used to induce oval cells. In the first, animals were treated with a combination of an N-2-acetylaminofluorene (AAF)-containing diet and partial hepatectomy (PHx). In the second, animals were supplied with chow containing a 1:1 mixture of choline-deficient and normal diets, as well as 0.075% ethionine in drinking water. Using in-house cDNA microarrays consisting of 2304 cDNA clones from the mouse liver, 69 and 89 genes, respectively, were found to be up-regulated in these two models. Six genes, i.e., those for insulin-like growth factor binding protein-1, CYP4a14, carnitine octanoyltransferase, osteopontin, and two expressed sequence tags (ESTs) were up-regulated in these models but not in ordinary model with PHx alone. They might be specifically activated in the induction of oval cells, and help to clarify the nature of stem cell stimulation that occurs during liver regeneration.

2-Acetylaminofluorene↗
PubMed2004

A case of severe acute hepatitis of unknown etiology treated with the Chinese herbal medicine Inchinko-to.

A prolonged severe hepatitis of unknown etiology was treated with Inchinko-to, a Chinese herbal medicine, and this case is herein described. Inchinko-to was given with ursodeoxycholic acid (UDCA) and glycyrrhizin. The improvement in the patient's liver function seemed to be accelerated after the treatment, especially after stopping the administration of kanamycin sulfate which might possibly inhibit the conversion of geniposide, one of the constituents of Inchinko-to, to an active ingredient through the suppression of the bacterial growth in intestinal flora, suggesting the usefulness of Inchinko-to for treatment of severe hepatitis.

Journal Article↗
PubMed2004

Identification of genes up-regulated by histone deacetylase inhibition with cDNA microarray and exploration of epigenetic alterations on hepatoma cells.

BACKGROUND/AIMS: Epigenetics is the key factor in the regulation of gene expression. We conducted cDNA microarray analysis to screen for genes induced by histone deacetylase (HDAC) inhibition and examined epigenetic alterations. METHODS: Microarray analysis was performed in six hepatoma cell lines and primary hepatocytes treated with trichostatin A (TSA). mRNA expression of several genes was examined by reverse transcription-polymerase chain reaction in TSA-treated cells and hepatoma samples. Acetylated histones and methylation status in 5'CpG islands was assessed by chromatin immunoprecipitation (ChIP) assay and bisulfite genomic sequencing, respectively. RESULTS: Fifty-seven genes showed greater than 2-fold change after TSA treatment in multiple cell lines. Among them, four genes including p21(WAF1) exhibited substantial induction (greater than 5-fold changes). Decreased mRNA levels of these genes in hepatoma tissues were observed in more than half of patients. ChIP assay, in general, demonstrated a good correlation between mRNA expression and histone acetylation, but only a limited correlation with the methylated DNA in the promoter region. CONCLUSIONS: We identified 57 up-regulated genes by TSA treatment in hepatoma cells and some of them appeared to be cancer-related genes in hepatomas. The alterations in acetylated histones are likely closely associated with gene expression.

Acetylation↗
PubMed2004

Fatal chronic active Epstein-Barr virus infection mimicking autoimmune hepatitis.

We report a 22-year-old female who presented with pyrexia, pancytopenia and liver dysfunction. The patient showed mild liver dysfunction with low-grade fever and mild hepatosplenomegaly 6 years previously, and autoimmune hepatitis (AIH) was diagnosed based on the examination of the laboratory data and liver biopsy. On admission, both markers of Epstein-Barr virus (EBV) and in-situ hybridisation from a liver biopsy specimen indicated chronic active EBV infection (CAEBV). The patient was administered an immunosuppressive agent and antiviral drug added to steroid therapy, but ultimately died from liver failure and virus-associated haemophagocytosis 10 months after the definite diagnosis. Retrospective examination of the serum at the diagnosis of AIH revealed extremely high titres of antibody to EBV, and EBV-DNA was also detectable by polymerase chain reaction. These results suggest the possibility that the patient may already have suffered from CAEBV at the initial diagnosis. We presume that hepatic involvement of CAEBV should be considered as differential diagnosis in cases showing liver dysfunction with clinical and biochemical features observed in AIH.

Adult↗
PubMed2004

Cell growth inhibition and gene expression induced by the histone deacetylase inhibitor, trichostatin A, on human hepatoma cells.

OBJECTIVE: Histone deacetylase (HDAC) inhibitors have been reported to induce cell growth arrest, apoptosis and differentiation in tumor cells. The effect of the HDAC inhibitor, trichostatin A (TSA), on hepatoma cells, however, has not been well studied. In this study, we examined cell viability and gene expression profile in hepatoma cell lines treated with TSA. METHODS: To study cell growth inhibition and induction of apoptosis by TSA on human hepatoma cell lines including HuH7, Hep3B, HepG2, and PLC/PRF/5, cells were treated with TSA at various concentrations and analyzed by the 3-(4, 5-dimethyl-2-thiazolyl)-2H-tetrazolium bromide (MTT) and TUNEL assays, respectively. Changes in gene expression profile after exposure to TSA were assessed using a cDNA microarray consisting of 557 distinct cDNA of cancer-related genes. The levels of acetylated histones were examined by the chromatin immunoprecipitation (ChIP) assay using anti-acetylated histone H3 or H4 antibody. RESULTS: The MTT assay demonstrated that TSA showed cell growth inhibition not only in a concentration-dependent but also a time-dependent manner on all cell lines studied. The TUNEL assay also revealed the potential of TSA to induce apoptosis. The microarray analysis revealed that 8 genes including collagen type 1, alpha2 (COL1A2), insulin-like growth factor binding protein 2 (IGFBP2), integrin, alpha7 (ITGA7), basigin (BSG), quiescin Q6 (QSCN6), superoxide dismutase 3, extracellular (SOD3), nerve growth factor receptor (NGFR), and p53-induced protein (PIG11) exhibited substantial induction (ratio >2.0) after TSA treatment in multiple cell lines. ChIP assay, in general, showed a good correlation between the expression level of mRNA and levels of acetylated histones in these upregulated genes. CONCLUSIONS: This study showed cell growth inhibition and the gene expression profile in hepatoma cell lines exposed to TSA. The alteration in levels of acetylated histones was closely associated with expression of specific cancer-related genes in hepatoma cells.

Antineoplastic Agents↗
PubMed2004

High sustained virologic response rate after interferon monotherapy in Japanese hepatitis C patients with a low HCV RNA titer and/or HCV genotype 2. A prospective study.

OBJECTIVE: Hepatitis C virus (HCV) RNA titer and HCV genotype are considered to be major determinants of the outcome of interferon monotherapy. To clarify whether interferon monotherapy is really effective in patients with the appropriate viral parameters, we prospectively examined these parameters and treated the patients with interferon monotherapy. METHODS: Sixty-four patients with an HCV RNA titer <100 kIU/ml and/or HCV genotype 2 were enrolled in the study. Eighteen patients with an HCV RNA titer >100 kIU/ml and genotype 1 were also enrolled as controls. All patients were treated with 10 megaunits of interferon-alpha2b every day for 2 weeks and then 3 times a week for 24 weeks. RESULTS: Of the 64 patients with either HCV RNA <100 kIU/ml and/or genotype 2, seven dropped out from the study. Of the remaining 57 who completed the treatment, 48 (84%) showed a virologic sustained response. In contrast, only 4 of the 18 patients (22%) with HCV RNA >100 kIU/ml and genotype 1 were virologic sustained responders (p < 0.001). CONCLUSION: Our current study showed that the patients with HCV RNA <100 kIU/ml and/or HCV genotype 2 are good candidates for interferon monotherapy.

Antiviral Agents↗