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Sumio Kawata

Publications and source records attributed to Sumio Kawata.

At least 19 recordsLinked to original sources
PubMed2003

Histogenesis of hepatoid adenocarcinoma of the stomach: molecular evidence of identical origin with coexistent tubular adenocarcinoma.

Hepatoid adenocarcinoma of the stomach is a highly malignant neoplasm. Most gastric hepatoid adenocarcinomas coexist with tubular adenocarcinoma. However, the relationship between hepatoid adenocarcinoma and tubular adenocarcinoma is still unclear. In the present study, the characteristics of the coexistent tubular adenocarcinomas were determined by examining their profiles of mucin production. Subsequently, molecular pathological techniques were applied to determine the clonality of 15 mixed hepatoid and tubular adenocarcinomas of the stomach. Mucin analysis suggested that the coexistent tubular adenocarcinomas with hepatoid adenocarcinoma were of the intestinal type. The patterns of chromosome X inactivation were identical between the hepatoid adenocarcinoma component and tubular adenocarcinoma component in all of 3 informative female cases. Mutations in the p53 gene were found in 5 cases. The sequences were identical within both tumor components in all 5 cases. Microsatellite analysis indicated more than 3 common patterns of loss of heterozygosity in 8 cases. These observations strongly suggested that hepatoid adenocarcinomas were of identical origin to coexistent tubular adenocarcinomas.

Adenocarcinoma↗
PubMed2003

Differentiation of bone marrow cells into cells that express liver-specific genes in vitro: implication of the Notch signals in differentiation.

Bone marrow (BM) stem cells have been shown to differentiate into liver cells. It remains difficult to sort and culture BM stem cells, and the gene expression of liver-specific proteins in these cells has not been fully investigated. We used a negative selective magnetic cell separation system to obtain stem cell-enriched BM cells. The cells obtained were cultured with hepatocytes or with hepatocyte growth factor (HGF), and the differentiation of BM cells into cells expressing liver-specific genes, hepatocyte nuclear factor (HNF) 1alpha, cytokeratin (CK) 8, alpha-fetoprotein (AFP), and albumin was investigated by the reverse transcription-polymerase chain reaction. We also investigated the gene expressions of Notch receptor-1 (Notch-1) and its ligand Jagged-1 in BM cell differentiation. Sorted BM cells showed positive for Sca-1 (Ataxin-1) by immunofluorescence staining. Fluorescence activated cell sorter analysis showed that 32.6% of sorted BM cells had a high level of expression of the hematopoietic stem cell marker CD90 (Thy-1). When cultured with hepatocytes, these cells expressed the liver-specific genes HNF1alpha and CK8 on culture day 3, AFP and albumin on culture day 7. When cultured with HGF (20ng/ml), the cells expressed HNF1alpha on day 3 and CK8 on day 7. Gene expressions of Notch-1 and Jagged-1 were detected in cultured BM cells on day 3. These results suggest that the negative selective magnetic cell separation system is useful for the rapid preparation of stem cell-enriched BM cells, and that the Notch signaling pathway plays a role in BM cell differentiation into a hepatocyte lineage in vitro.

Animals↗
PubMed2003

Spontaneous elimination of serum hepatitis C virus (HCV) RNA in chronic HCV carriers: a population-based cohort study.

The natural course of hepatitis C virus (HCV) infection has not been fully elucidated. To investigate whether HCV is spontaneously eliminated in chronic carriers, a long-term population-based cohort study was conducted on 435 chronic HCV carriers. Individual characteristics, serum HCV RNA, and liver function tests were analyzed, and ultra sonography (US) was performed in all subjects. Subjects were followed up for 7.2 +/- 2.4 years (mean +/- SD). Serum HCV RNA was spontaneously eliminated in 16/435 (3.7%) individuals during this period; thus, the incidence of spontaneous elimination of serum HCV RNA was 0.5%/year/person. Multivariate analysis revealed that both a low value of ZTT and no US finding of chronic liver disease were associated with spontaneous viral elimination in HCV carriers. Three of these 16 individuals had chronic hepatitis, and 13 of them had normal ALT levels. When the neutralization of binding (NOB) assay that evaluates inhibition of the HCV envelope-2 protein binding to human cells was examined using sera from these 16 individuals, the NOB antibody was detected in only 3 cases with chronic hepatitis. These results suggest that serum HCV RNA is spontaneously eliminated in chronic HCV carriers in a population, and that the development of NOB antibody is associated with a natural resolution of chronic hepatitis in the minority of them.

Adult↗
PubMed2003

Angiotensin II stimulates the nuclear translocation of Smad2 and induces PAI-1 mRNA in rat hepatic stellate cells.

It has recently been reported that angiotensin II (ANGII) stimulates gene expression of transforming growth factor-beta1 (TGF-beta1) and is involved in hepatic fibrosis. This effect is thought to be caused through ANGII type 1 receptor (ATR1). However, a role of ANGII at the postreceptor levels of TGF-beta1 signaling has not been identified. To clarify the role of ANGII on hepatic fibrosis, we investigated the effect of ANGII on rat hepatic stellate cells (HSCs). HSCs were isolated from male Sprague-Dawley rats. TGF-beta1 and matrix protein gene expression in HSCs was assessed by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) using SYBR Green I. The nuclear translocation of Smad2 in HSCs after 20 min ANGII stimulation was analyzed by Western blotting. ANGII was found to induce TGF-beta1 and matrix protein gene expression in HSCs. The nuclear translocation of Smad2 in HSCs was also induced by ANGII stimulation. These effects of ANGII were almost completely blocked by the ATR1 antagonist, CS-866. ANGII induces TGF-beta1 and matrix protein mRNA, and stimulates rapid nuclear translocation of Smad2 in rat HSCs through ATR1, which indicates that the ATR1 blockade represents a novel approach for the possible prevention of hepatic fibrosis.

Journal Article↗
PubMed2003

Liver regeneration in heparin-binding EGF-like growth factor transgenic mice after partial hepatectomy.

BACKGROUND & AIMS: Heparin-binding epidermal growth factor-like growth factor (HB-EGF), a member of the EGF family, is synthesized in the form of a membrane-anchored precursor (proHB-EGF), which subsequently is processed proteolytically to mature HB-EGF. This study describes the effects of HB-EGF on liver regeneration after 70% partial hepatectomy in proHB-EGF transgenic mice with liver-specific expression. METHODS & RESULTS: No significant differences in liver/body weight ratios and in bromodeoxyuridine (BrdU)-labeling index (the ratios of BrdU-positive hepatocyte nuclei) were found between adult transgenic and wild-type mice. However, in regenerating liver after partial hepatectomy, transgenic mice had higher liver/body weight ratios than wild-type mice and at 120 hours reached a level equal to that before partial hepatectomy. The BrdU-labeling index was about 5 times higher in the livers of transgenic mice compared with the wild type (51.5% vs. 10.2%, respectively; P < 0.01) at 48 hours after partial hepatectomy. Activation of microtubule-associated protein kinase after partial hepatectomy was higher and earlier in the transgenic mice as compared with the wild-type mice. Soluble HB-EGF was increased in the liver (at 8 min) after partial hepatectomy, indicating that the shedding of proHB-EGF occurred after partial hepatectomy. CONCLUSIONS: The transgenic expression of HB-EGF accelerates the proliferation of hepatocytes after partial hepatectomy, suggesting that HB-EGF functions as a hepatotrophic factor in vivo.

Animals↗
PubMed2003

Identification of hepatitis C virus (HCV) subtype 1b strains that are highly, or only weakly, associated with hepatocellular carcinoma on the basis of the secondary structure of an amino-terminal portion of the HCV NS3 protein.

The NS3 protein of hepatitis C virus subtype 1b (HCV-1b) isolates obtained from 89 patients with hepatocellular carcinoma (HCC) and 78 patients without HCC were analyzed. On the basis of the secondary structure of the amino-terminal 120 residues of NS3, HCV-1b isolates were classified into group A, group B, and an indeterminate group, each of which was further divided into a number of subgroups, such as A1-1, A1-2, A2-1, A2-2, B1-1, B1-2, B2-1, B2-2, C-1, C-2, and C-3. HCV-1b isolates of subgroup B1-1 were found in 53 (59.6%) of 89 patients with HCC and 19 (24.4%) of 78 patients without HCC, with the difference between the two patient groups being statistically significant (P < 0.00001). Although the number of isolates was small, subgroup B2-1 was also highly associated with HCC, with all five isolates in that subgroup being found in patients with HCC (P < 0.05). On the other hand, HCV-1b isolates of subgroup A1-1 were associated only weakly with HCC; they were found in 6 (6.7%) of 89 patients with HCC and in 25 (32.1%) of 78 patients without HCC, with the difference between the two patient groups being statistically significant (P < 0.0001). The other subgroups, such as A1-2, A2-1, B1-2, C-1, C-2, and C-3, were moderately associated with HCC; their distribution patterns among patients with HCC did not differ significantly from those among patients without HCC. Taken together, our results suggest that HCV-1b isolates of subgroups B1-1 and B2-1 are highly associated with HCC and that this secondary structure analysis may be useful for predicting the relative risk of developing HCC.

Amino Acid Sequence↗
PubMed2002

Phosphorylation of Akt/PKB is required for suppression of cancer cell apoptosis and tumor progression in human colorectal carcinoma.

BACKGROUND: Akt/protein kinase B (PKB), which is included in phosphatidyl inositol-3-OH kinase (PI3K) signaling, controls many intracellular processes, such as the suppression of apoptosis and the promotion of the cell cycle. Therefore, the authors investigated phosphorylated Akt (Ser473) in colorectal carcinomas to reveal the role of PI3K signaling during the development of colorectal carcinoma. METHODS: Expression of phosphorylated Akt (Ser473) in two colon carcinoma cell lines (DLD-1 and Colo205) and 65 human colorectal carcinomas was analyzed using western blotting and immunohistochemistry, respectively. Growth inhibition and induction of apoptosis caused by LY294002, a specific inhibitor of PI3K, were also examined in these cell lines. In tumor samples, the level of cell proliferation activity (Ki-67) and number of apoptotic bodies (single stranded DNA) were determined by counting positive cells. RESULTS: LY294002 significantly affected the proliferation and apoptosis of Colo205 cells, suggesting an association with the low phosphorylation level of Akt protein. Immunohistochemic analysis showed that 46% of the tumors had a high level of expression of phosphorylated Akt with a close association with Ki-67 proliferative activity (P < 0.001) and the number of apoptotic bodies (P < 0.001). Akt phosphorylation was also correlated with some clinicopathologic parameters of the malignancies, including depth of invasion, infiltration to venous vessels, lymph node metastasis, and clinicopathologic stage. CONCLUSIONS: The phosphorylated Akt level can monitor cell growth and resistance to apoptosis, indicating that activation of Akt plays an important role during the progression of colorectal carcinomas by helping promote cell growth and rescue cells from apoptosis. These findings also suggest the possibility of using LY294002 for treatment of colorectal carcinoma.

Adult↗
PubMed2002

Expression of the Musashi1 gene encoding the RNA-binding protein in human hepatoma cell lines.

Musashi1, a neural RNA-binding protein, plays an important role in regulating cell differentiation in precursor cells. Recently, expression of Musashi1 has been detected in human tumor tissues such as gliomas and melanomas, suggesting its involvement in oncogenic development. To determine any association between Musashi1 and the development of liver cancer, we investigated its gene expression in seven human hepatoma cell lines: HuH6, HuH7, Hep3B, SK-Hep1, HepG2, HLE, and HLF. Musashi1 mRNA expression was analyzed using the reverse-transcription polymerase chain reaction (PCR), and the PCR products were sequenced using a subcloning procedure. Musashi1 protein expression was analyzed in HuH7 and HepG2 cells by Western blot and immunofluorescence staining. Musashi1 mRNA was detected in the HuH6, HuH7, and Hep3B hepatoma cell lines, but not in the others. Sequencing of the PCR-amplified Musashi1 cDNA in these three cell lines showed the expected sequence of the human Musashi1 gene. Musashi1 protein expression was confirmed in HuH7 cells, which were positive for Musashi1 mRNA expression, but not in HepG2 cells. These results suggest that Musashi1 expression may be an important factor in the development of several types of carcinoma such as human hepatoma, and may be a useful molecular marker for tumor detection.

Animals↗
PubMed2002

Frequent impairment of the spindle assembly checkpoint in hepatocellular carcinoma.

BACKGROUND: Chromosomal instability (CI) leading to aneuploidy is one form of genetic instability, a characteristic feature of various types of cancers. Recent work has suggested that CI can be induced by a spindle assembly checkpoint defect. The aim of the current study was to determine the frequency of a defect of the checkpoint in hepatocellular carcinoma (HCC) and to establish whether alterations of genes encoding the checkpoint were associated with CI in HCC. METHODS: Aneuploidy and the function of the spindle assembly checkpoint were examined using DNA flow cytometry and morphologic analysis with microtubule disrupting drugs. To explore the molecular basis, the authors examined the expression and alterations of the mitotic checkpoint gene, BUB1, using Northern hybridization and direct sequencing in 8 HCC cell lines and 50 HCC specimens. Furthermore, the authors examined the alterations of other mitotic checkpoint genes, BUBR1, BUB3, MAD2B, and CDC20, using direct sequencing in HCC cell lines with aneuploidy. RESULTS: An impaired spindle assembly checkpoint was found in five (62.5%) of the eight aneuploid cell lines. Transcriptional expressions of the BUB1 gene appeared in all cell lines. While some polymorphic base changes were noted in BUB1, BUBR1, and CDC20, no mutations responsible for impairment of the mitotic checkpoint were found in either the HCC cell lines or HCC specimens, which suggests that these genes did not seem to be involved in tumor development in HCC. CONCLUSIONS: The loss of spindle assembly checkpoint occurred with a high frequency in HCC with CI. However, other mechanisms might also contribute to CI in HCC.

Adult↗
PubMed2002

Combined intraarterial 5-fluorouracil and subcutaneous interferon-alpha therapy for advanced hepatocellular carcinoma with tumor thrombi in the major portal branches.

BACKGROUND: The prognosis of hepatocellular carcinoma (HCC) invading into the major branches of the portal vein (Vp3) is extremely poor. METHODS: Eleven consecutive patients with HCC and Vp3 were treated with 2-6 cycles of a "basic" combination therapy consisting of continuous arterial infusion of 5-fluorouracil (450-500 mg/day, for the initial 2 weeks) and subcutaneous injection of interferon-alpha (5 million international units, 3 times/week, 4 weeks). In the first 3 patients, methotrexate (90 mg/day 1 of every week), cisplatin (10 mg/day), and leucovorin (30 mg/days 2 and 3 of every week) also were administered for the initial 2 weeks ("full" regimen). RESULTS: In 8 (73%) of 11 patients, an objective response (complete response [CR] or partial response [PR]) was observed with marked regression of tumor and decrease in tumor markers. The use of the full regimen was associated with objective response in all patients; instead, they developed thrombocytopenia or leukopenia. In the subsequent 8 patients with basic regimen, 5 patients showed CR (2 cases) or PR (3 cases; objective response rate, 63%), and leukopenia was observed only in 1 patient. CONCLUSIONS: Simple combination therapy with subcutaneous interferon-alpha and intraarterial 5-fluorouracil therefore is a promising treatment modality for intractable HCC with Vp3.

Adult↗
PubMed2002

Clinical significance of a highly sensitive enzyme immunoassay of hepatitis B surface antigen using a novel electron spin resonance technique.

We developed a highly sensitive enzyme immunoassay (EIA), the p-AP/HHTIO method, that detects serum hepatitis B surface antigen (HBsAg) by measuring stabilized nitroxide radicals using a novel electron spin resonance technique [Matsuo et al. (1998) Free Radic Biol Med 25:929-935]. To demonstrate the clinical significance of this method and to reveal occult hepatitis B virus (HBV) infection in patients, we used the method to analyze serum samples of 30 patients with acute or fulminant hepatitis who were negative for HBsAg by standard EIA, and those of seven chronic HBV carriers who became negative for HBsAg during a follow-up period by standard EIA. We also examined serum HBV DNA by amplification of the HBV S gene, using the polymerase chain reaction (PCR) technique. The p-AP/HHTIO method showed that 9 of 20 (45%) patients with acute hepatitis and 2 of 10 (20%) with fulminant hepatitis were positive for HBsAg; PCR detected HBV DNA in these HBsAg-positive patients. Antibody against hepatitis B core antigen was detected in one patient with fulminant hepatitis. The p-AP/HHTIO method demonstrated prolonged seropositivity of HBsAg even after standard EIA showed a loss of HBsAg in all seven HBV carriers. Our p-AP/HHTIO method is useful for screening and diagnosing HBV infection in patients with liver diseases who are negative for conventional HBV-related serological markers.

Acetaminophen↗
PubMed2002

Activation of signal transducer and activator transcription 3 and expression of suppressor of cytokine signal 1 during liver regeneration in rats.

BACKGROUND/AIMS: Recent work has shown that the signal transducer and activator of transcription (STAT) 3 activation is important for the initiation of the proliferative response following partial hepatectomy (PH). However, the issue of where STAT3 is activated and how it is regulated is unclear. The aims of this study were to identify STAT3-activated cells and to clarify the expression of suppressor of cytokine signal (SOCS), a negative feedback molecule of STAT3, after PH. METHODS: STAT3-activated cells and SOCS1-positive cells were identified by immunohistochemistry after a two-thirds PH in rats. SOCS mRNA was examined by Northern analysis. RESULTS: STAT3 was activated in hepatocytes from those localized in the periportal zones of hepatic lobules after PH. STAT3 activation was also detected in Kupffer cells and sinusoidal endothelial cells prior to its detection in hepatocytes. After STAT3 activation, SOCS1 protein in response to PH was detected immunohistochemically in regenerating liver. SOCS1 and SOCS3 mRNA were induced in regenerating liver after PH. CONCLUSIONS: STAT3 signaling can occur in Kupffer cells and sinusoidal endothelial cells prior to in hepatocytes from those localized in the periportal zones. SOCS1 as well as SOCS3 may regulate STAT3 signaling negatively after PH.

Animals↗
PubMed2002

NF-kappaB activation in non-parenchymal liver cells after partial hepatectomy in rats: possible involvement in expression of heparin-binding epidermal growth factor-like growth factor.

BACKGROUND/AIMS: Nuclear factor (NF) B activation plays a critical role in the initiation of liver growth after partial hepatectomy (PH). However, the issue of where specifically NF-B is activated is unclear. We previously reported that heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a hepatotrophic factor. The aims of this study were to identify NF-B-activated cells and to clarify their involvement in HB-EGF expression after PH. METHODS: Using rats, a two-thirds PH was performed, after which NF-B-activated cells and HB-EGF-positive cells were identified by Southwestern histochemistry or immunohistochemistry. NF-B binding activity and HB-EGF gene expression were analyzed in rat hepatocytes and non-parenchymal cells (NPC) in primary culture. RESULTS: NF-B was activated in Kupffer cells and sinusoidal endothelial cells prior to activation in hepatocytes. HB-EGF immunoreactivity was detected after NF-B activation in the sinusoidal cells from those localized in the periportal zones of hepatic lobules. HB-EGF gene expression by tumor necrosis factor was accompanied by an increase in NF-B binding activity in NPC but not in hepatocytes in primary culture, which was abolished by pyrrolidine dithiocarbamate, an inhibitor of NF-B activation. CONCLUSIONS; NF-B was activated in NPC prior to activation in hepatocytes. NF-B activation may be involved in HB-EGF expression in NPC after PH.

Animals↗
PubMed2002

Hypermethylation of the TSLC1 gene promoter in primary gastric cancers and gastric cancer cell lines.

The TSLC1 (tumor suppressor in lung cancer-1) gene is a novel tumor suppressor gene on chromosomal region 11q23.2, and is frequently inactivated by concordant promoter hypermethylation and loss of heterozygosity (LOH) in non-small cell lung cancer (NSCLC). Because LOH on 11q has also been observed frequently in other human neoplasms including gastric cancer, we investigated the promoter methylation status of TSLC1 in 10 gastric cancer cell lines and 97 primary gastric cancers, as well as the corresponding non-cancerous gastric tissues, by bisulfite-SSCP analysis followed by direct sequencing. Allelic status of the TSLC1 gene was also investigated in these cell lines and primary gastric cancers. The TSLC1 promoter was methylated in two gastric cancer cell lines, KATO-III and ECC10, and in 15 out of 97 (16%) primary gastric cancers. It was not methylated in non-cancerous gastric tissues, suggesting that this hypermethylation is a cancer-specific alteration. KATO-III and ECC10 cells retained two alleles of TSLC1, both of which showed hypermethylation, associated with complete loss of gene expression. Most of the primary gastric cancers with promoter methylation also retained heterozygosity at the TSLC1 locus on 11q23.2. These data indicate that bi-allelic hypermethylation of the TSLC1 promoter and resulting gene silencing occur in a subset of primary gastric cancers.

Adult↗
PubMed2002

Effect of lipopolysaccharide on peptide transporter 1 expression in rat small intestine and its attenuation by dexamethasone.

BACKGROUND/AIM: The peptide transporter (PepT1) activity is upregulated or preserved under certain pathological conditions. The aim of this study was to investigate the PepT1 expression during lipopolysaccharide (LPS) treatment and the effect of dexamethasone on PepT1 expression. METHODS: Rats were injected daily for 3 days with (1) LPS; (2) LPS plus dexamethasone; (3) dexamethasone, and (4) saline only. Mucosal specimens were used for Northern blot and Western blot analyses. Tissues of small intestine were taken for histological studies. In addition, tumor necrosis factor alpha and interleukin 1 beta levels were determined 3 h after single injections of the above mediators. RESULTS: Northern blot analysis revealed that LPS treatment significantly decreased the expression of mRNA for PepT1 (32-62% of controls) at different time points. In the LPS + dexamethasone group, it was 66-95% of controls. The protein level of PepT1 in the jejunum was consistent with the mRNA expression level. Immunohistochemistry also showed a reduction of PepT1 immunoreactivity in the LPS group. LPS treatment resulted in increased tumor necrosis factor alpha and interleukin 1 beta levels, but dexamethasone treatment profoundly counteracted the cytokine production. CONCLUSIONS: This is the first report that LPS treatment reduces PepT1 expression in the rat small intestine. Short-term treatment with dexamethasone attenuated the effects of LPS by decreasing the cytokine levels.

Animals↗