Search PubMed⌕ Search

Biomedical subjects

Michiie Sakamoto

Publications and source records attributed to Michiie Sakamoto.

At least 73 records · Page 4Linked to original sources
PubMed2003

Primary carcinoid tumor in a polycystic kidney.

A case of a primary carcinoid tumor within a polycystic kidney is reported. A 51-year-old woman with autosomal dominant polycystic kidney disease (ADPKD) underwent a bilateral nephrectomy because of an infection in her polycystic kidneys. A tumor (1.5 cm in diameter) was incidentally found close to the hilum of the left kidney. Histologically, the tumor exhibited a predominantly trabecular pattern of cuboidal or columnar cells. Grimelius staining showed numerous silver-stained neurosecretory granules in most of the tumor cells; the tumor cells were also positive for chromogranin, synaptophysin, prostatic acid phosphatase (PAP) and neuron-specific enolase (NSE). The tumor was diagnosed as a primary carcinoid tumor of the kidney. Primary renal carcinoid is a very rare neoplasm, and this is the first report of such a lesion arising in a polycystic kidney.

Biomarkers, Tumor↗
PubMed2003

Expression profiling in multistage hepatocarcinogenesis: identification of HSP70 as a molecular marker of early hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) associated with chronic liver disease evolves from precancerous lesions and early HCC to a progressed form. Nodule-in-nodule-type HCC (progressed HCC within early HCC) represents the transition from early to progressed HCC and, therefore, is useful in molecular genetic analysis of HCC progression during multistage carcinogenesis. We compared expression profiles among 7 early components and 7 progressed components of nodule-in-nodule-type HCCs and their corresponding noncancerous liver tissues with oligonucleotide array. Of the approximately 12,600 genes that were analyzed, a set of 95 genes provided a molecular signature that distinguished between early HCC components and their noncancerous liver tissues, and a set of 92 genes distinguished between progressed and early HCC components. Of these genes, the most abundantly up-regulated gene in early HCC components (P <.001) was heat-shock protein 70 (HSP70). Real-time quantitative reverse transcription polymerase chain reaction (RT-PCR) confirmed this finding. Further immunohistochemical examination of HSP70 revealed its significant overexpression in early HCC compared with precancerous lesions (P <.001) and in progressed HCC compared with early HCC (P <.001). In conclusion, molecular signatures were clearly different in noncancerous liver tissue as compared with the early and progressed components of nodule-in-nodule-type HCC. Moreover, HSP70 could be a sensitive marker for the differential diagnosis of early HCC from precancerous lesion or noncancerous liver, a difficult distinction for pathologists due to very well differentiated histology with little atypia in early HCC.

Algorithms↗
PubMed2003

Overexpression of orphan G-protein-coupled receptor, Gpr49, in human hepatocellular carcinomas with beta-catenin mutations.

To identify the genes responsible for carcinogenesis and progression of hepatocellular carcinoma (HCC), we screened differentially expressed genes in several human HCC cell lines. Among these genes, Gpr49 was up-regulated in PLC/PRF/5 and HepG2. Gpr49 is a member of the glycoprotein hormone receptor subfamily, which includes the thyroid-stimulating hormone receptor (TSHR). However, Gpr49 remains to be an orphan G-protein-coupled receptor. By real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR) analysis, overexpression (>3-fold increase compared with the corresponding noncancerous liver tissue) of Gpr49 mRNA was observed in 18 of 38 (47%) HCCs compared with corresponding noncancerous livers. Clinicopathologically, overexpression of Gpr49 was frequently observed in HCC with mutation in beta-catenin exon 3 (14 of 16 cases, 87.5%). Moreover, introduction of mutant beta-catenin into mouse hepatocytes in culture caused up-regulation of the Gpr49 mouse homologue. Therefore, Gpr49 is likely to be a target gene activated by Wnt-signaling in HCC. In conclusion, although much is still unknown, Gpr49 may be critically involved in the development of HCCs with beta-catenin mutations and has the potential to be a new therapeutic target in the treatment of HCC.

Adult↗
PubMed2003

EBP50, a beta-catenin-associating protein, enhances Wnt signaling and is over-expressed in hepatocellular carcinoma.

Wnt signaling mediated by beta-catenin plays crucial roles in the development of hepatocellular carcinoma and other cancers such as colorectal cancer. beta-Catenin associates with T-cell factor (TCF) transcription factors and functions as a transcriptional activator in the nucleus. By protein interaction screening, we identified EBP50, a cytoplasmic protein with 2 PDZ domains, as a beta-catenin-associating molecule. EBP50 interacted with beta-catenin through its carboxyl-PDZ domain in vitro and in vivo. Northern blot and RT-PCR analysis revealed an increase of EBP50 messenger RNA (mRNA) in hepatocellular carcinoma (HCC) cell lines and surgical specimens of human HCC. Over-expression of EBP50 protein with focal nuclear localization was detected in human HCC. In human HCC and colorectal cancer cell lines, EBP50 enhanced beta-catenin/TCF-dependent transcription in a dose-dependent manner. In an HCC cell line, over-expression of the carboxyl PDZ domain resulted in a decrease of endogenous beta-catenin/TCF transactivation. EBP50 promoted beta-catenin-mediated transactivation only in cells in which beta-catenin was already stabilized, suggesting that EBP50 may work with stabilized beta-catenin for transcriptional regulation. In conclusion, the EBP50/beta-catenin complex promotes Wnt signaling, and over-expression of EBP50 may work cooperatively with beta-catenin in the development of liver cancer.

Carcinoma, Hepatocellular↗
PubMed2003

Combined hepatocellular and cholangiocarcinoma: a clinicopathologic study of 26 resected cases.

BACKGROUND: Combined hepatocellular and cholangiocarcinoma (cHCC-CC) is an uncommon subtype of primary liver cancer, the clinicopathological features of which have rarely been reported in detail. The aim of this study was to clarify the characteristics of cHCC-CC in comparison with hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC). METHODS: The clinicopathological features of 26 cHCC-CC patients, who were surgically treated, were reviewed by comparing them with the features of patients suffering from ordinary hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC). RESULTS: The cHCC-CC patients showed greater similarity with HCC patients than with CC patients with regard to male/female ratio, status of hepatitis viral infection, serum alpha-fetoprotein (AFP) level, and non-tumor liver histology. The disease stage of the cHCC-CC patients was more advanced than that of either the HCC or CC patients. The cHCC-CC tumors were significantly more invasive to the portal vein than the HCC tumors and were comparable to the CC tumors. The overall 3-, 5-, and 10-year survival rates and the median survival times (95% confidence interval) were 34.6%, 23.1%, 11.5% and 1.8 (0.7-3.0) years for cHCC-CC patients, 86.7%, 66.2%, 46.8% and 4.6 (4.3-5.0) years for HCC patients, and 68.5%, 32.3%, 23.9% and 1.9 (1.1-2.7) years for CC patients, respectively. Survival of patients with cHCC-CC was significantly poorer than that of HCC or CC patients. Among the 26 patients, six survived for >5 years. CONCLUSIONS: In most cases, cHCC-CC seems to be a variant of ordinary HCC with cholangiocellular features, rather than a true intermediate disease entity between HCC and CC. The surgical approach is recommended for selected patients with cHCC-CC.

Adolescent↗
PubMed2003

Prediction of invasive activities in hepatocellular carcinomas with special reference to alpha-fetoprotein and des-gamma-carboxyprothrombin.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the world's major malignancies, especially in Asian countries. To improve the prognosis of HCC, it is essential to predict its invasive behavior in both intra- and extra-hepatic modalities. For this purpose, we examined the predictive values of two tumor markers, alpha-fetoprotein (AFP) and des-gamma-carboxyprothrombin (DCP). METHODS: 194 HCC cases at the National Cancer Center Hospital were selected from the Pathology Records. Detailed information regarding the existence of extra-hepatic venous invasion (EHVI) at the portal vein and intra-hepatic multiple malignant tumors (IHMTs) were collected and combined with the preoperative AFP and DCP testing results. Furthermore, information about the viral infection status such as HBs antigen positive or HCV antibody positive or no viral hepatitis was obtained. The information was analyzed by the ROC (Receiver Operating Characteristic Curve) method. RESULTS: and CONCLUSIONS: In both the EHVI group and the IHMT group, all the combinations except the HCV-positive group of IHMT revealed a tendency for DCP to offer better diagnostic accuracies, although this was statistically significant only in the HBs-positive group of IHMT. This result indicates either (1). that in a strict sense, DCP is not necessarily better than AFP at predicting the invasive characteristics or (2). that DCP is better than AFP at reflecting the invasive characteristics of HCC although not statistically significant. In either situation, from a long-term viewpoint, it is advisable to find a new marker or to re-evaluate the existing markers in order to predict the invasive characteristics more accurately.

Biomarkers↗
PubMed2003

Expression of liver-intestine cadherin and its possible interaction with galectin-3 in ductal adenocarcinoma of the pancreas.

Liver-intestine (LI) cadherin represents a novel type of cadherin within the cadherin superfamily, and is distinguished from other cadherins by specific structural and functional features. Among normal tissues, LI-cadherin is known to be expressed in the intestinal mucosa, while its expression in cancerous tissue has not been investigated to date, except in gastric carcinoma. In the present study we investigated LI-cadherin expression immunohistochemically using our newly established monoclonal antibody in a large set (n = 102) of tumor specimens from patients with ductal adenocarcinoma of the pancreas, and correlated the findings with the patients' survival. LI-cadherin expression was seen focally in normal pancreatic ducts. In carcinoma, well-differentiated carcinoma cases strongly expressed LI-cadherin, whereas less differentiated areas and poorly differentiated carcinoma cases expressed less or were negative. Kaplan-Meier analysis for all patients demonstrated that high LI-cadherin expression (>25% of cells stained positive) correlated with good survival (P < 0.001). Cox regression analyses demonstrated that LI-cadherin expression was one of the strongest predictors of outcome, independent of all other variables, and low LI-cadherin expression correlated with tumor de-differentiation and advanced stage. Furthermore, galectin-3 was identified as being coimmunoprecipitated with LI-cadherin and this interaction was inhibited by lactose in a dose-dependent manner, but not by sucrose. Because galectin-3 has been observed to show a similar expression pattern to LI-cadherin in ductal adenocarcinoma of the pancreas, expression of LI-cadherin and this interaction could have some role in ductal adenocarcinoma of the pancreas.

Aged↗
PubMed2003

[Methodologies for isolation, expansion and differentiation of somatic stem cells(tissue stem cells)].

Recent studies have shown that pluriponten stem cells are also found in adult tissue. These adult stem cells has a great advantage over other stem cells sources, human embryos or human fetal tissue, that trouble many people on ethical grounds. While the adult stem cells have great potential for use in the cell therapy, we must pass numerous technical hurdles to reach a goal. Here we describe a subset of problems encountered in isolation and expansion of somatic stem cells for clinical application. As it is necessary to obtain the enough number of cells to supply the defect tissue and organ, we required purification and ex vivo expansion of stem cells, overcoming senescence. We also refer to the argument about plasticity of adult stem cells.

Adult↗
PubMed2002

Satellite lesions in patients with small hepatocellular carcinoma with reference to clinicopathologic features.

BACKGROUND: It is not rare to find satellite lesions in patients with small hepatocellular carcinoma (HCC). The purpose of this study was to elucidate the factors associated with satellite lesions in these patients. METHODS: We investigated the prevalence of satellite lesions, the relationship of clinicopathologic factors to satellite lesions, and the distance from the main tumor to the satellite lesion in 149 patients. Patients, who had a solitary HCC of 3.0 cm or less in diameter but no satellite lesions on preoperative imaging procedures, underwent potentially curative resection. The main tumors were macroscopically classified into four groups: early HCC, a vaguely nodular type showing preservation of the preexisting liver structure; single nodular type; single nodular type with extranodular growth; and confluent multinodular type. RESULTS: Of 149 resected specimens, 28 (19%) showed satellite lesions. Of the clinicopathologic factors investigated, the macroscopic type and tumor differentiation were significantly associated with the prevalence of satellite lesions. Both the single nodular type with extranodular growth and the confluent multinodular type showed satellite lesions more frequently than the early HCC and the single nodular type. A significantly higher prevalence of satellite lesions was observed in poorly differentiated HCC than in well and moderately differentiated HCC. The satellite lesions were located 0.5 cm or less from the main tumor in 8 (33%) specimens, 0.6-1.0 cm in 12 (50%), and 1.1-2.0 cm in 4 (17%). No identifiable factors were significantly related to the distance from the main tumor to the satellite lesion. However, all satellite lesions located more than 1.0 cm from the main tumor coexisted with poorly differentiated HCC, which were the single nodular type with extranodular growth or the confluent multinodular type. CONCLUSION: In the single nodular type with extranodular growth, confluent multinodular type, and poorly differentiated HCC, extensive treatment achieving a large safety margin and/or frequent posttreatment follow-up examinations may be needed because of the high prevalence of satellite lesions.

Adult↗
PubMed2002

Target disruption of the mutant beta-catenin gene in colon cancer cell line HCT116: preservation of its malignant phenotype.

Most colorectal carcinomas harbor genetic alterations that result in stabilization of beta-catenin. A colorectal carcinoma cell line, HCT116, which has both mutated and wild-type beta-catenin genes, was engineered by homologous recombination to investigate the significance of beta-catenin gene mutation. As expected, the mutant allele-targeted clones showed decreased beta-catenin expression and downregulation of T-cell factor (TCF)/lymphoid enhancer factor (LEF)-dependent transcription. Morphologically, targeted clones were only minimally altered under usual culture conditions, but under low serum conditions, mutant allele-targeted clones still grew in plane, in contrast to parental cell line and wild allele-targeted clones, which formed spheroids. The mutant allele-targeted clones showed no significant changes in growth rate and anchorage-independent growth in vitro, and displayed rather increased growth in vivo. Although beta-catenin stabilization affects some biological characteristics including adhesive properties, it may not have growth-promoting effects at least in some colorectal carcinomas.

Animals↗
PubMed2002

Overexpression of a splice variant of DNA methyltransferase 3b, DNMT3b4, associated with DNA hypomethylation on pericentromeric satellite regions during human hepatocarcinogenesis.

DNA hypomethylation on pericentromeric satellite regions is an early and frequent event associated with heterochromatin instability during human hepatocarcinogenesis. A DNA methyltransferase, DNMT3b, is required for methylation on pericentromeric satellite regions during mouse development. To clarify the molecular mechanism underlying DNA hypomethylation on pericentromeric satellite regions during human hepatocarcinogenesis, we examined mutations of the DNMT3b gene and mRNA expression levels of splice variants of DNMT3b in noncancerous liver tissues showing chronic hepatitis and cirrhosis, which are considered to be precancerous conditions, and in hepatocellular carcinomas (HCCs). Mutation of the DNMT3b gene was not found in HCCs. Overexpression of DNMT3b4, a splice variant of DNMT3b lacking conserved methyltransferase motifs IX and X, significantly correlated with DNA hypomethylation on pericentromeric satellite regions in precancerous conditions and HCCs (P = 0.0001). In particular, the ratio of expression of DNMT3b4 to that of DNMT3b3, which is the major splice variant in normal liver tissues and retains conserved methyltransferase motifs I, IV, VI, IX, and X, showed significant correlation with DNA hypomethylation (P = 0.009). Transfection of human epithelial 293 cells with DNMT3b4 cDNA induced DNA demethylation on satellite 2 in pericentromeric heterochromatin DNA. These results suggest that overexpression of DNMT3b4, which may lack DNA methyltransferase activity and compete with DNMT3b3 for targeting to pericentromeric satellite regions, results in DNA hypomethylation on these regions, even in precancerous stages, and plays a critical role in human hepatocarcinogenesis by inducing chromosomal instability.

Alternative Splicing↗
PubMed2002

Motility enhancement by tumor-derived mutant E-cadherin is sensitive to treatment with epidermal growth factor receptor and phosphatidylinositol 3-kinase inhibitors.

Diffuse-type gastric and lobular breast cancers are characterized by frequent mutations in the cell adhesion molecule E-cadherin. Here we report that tumor-associated mutations of E-cadherin enhanced random cell movement of transfected MDA-MB-435S mammary carcinoma cells as compared to wild-type (wt) E-cadherin-expressing cells. The mutations included in frame deletions of exons 8 or 9 and a point mutation in exon 8 which all affect putative calcium-binding sites within the linker region of the second and third extracellular domain. Motility enhancement by mutant E-cadherin was investigated by time-lapse laser scanning microscopy. Increased cell motility stimulated by mutant E-cadherin was influenced by cell-matrix interactions. The motility-increasing activity of mutant E-cadherin was blocked by application of pharmacological inhibitors of epidermal growth factor receptor and phosphatidylinositol (PI) 3-kinase. Investigation of the activation status of PI 3-kinase and the downstream signaling molecules Akt/protein kinase B and MAP kinase p44/42 showed that these kinases are not more strongly activated in mutant E-cadherin-expressing cells than in wt E-cadherin-expressing cells. Instead, the basal level of PI 3-kinase is necessary for mutant E-cadherin-enhanced cell motility. Our data suggest a critical role of E-cadherin mutations for the fine tuning of tumor cell motility.

Breast Neoplasms↗
PubMed2002

Critical involvement of the phosphatidylinositol 3-kinase/Akt pathway in anchorage-independent growth and hematogeneous intrahepatic metastasis of liver cancer.

In the multistep process of metastasis, "anchorage-independent growth," where cancer cells need to survive without cell-substratum interaction, is supposed to be important. In this study, we found that anchorage-independent growth analyzed using the soft agar colony formation assay correlated with hematogeneous intrahepatic metastasis of liver cancer cell lines and also Akt activation status. Two highly metastatic liver cancer cell lines showed high Akt activity and formed many colonies in soft agar, whereas three nonmetastatic cell lines showed less Akt activity and formed fewer colonies. Inhibition of Akt activation in the highly metastatic cell line Li7 by transfection with kinase-dead Akt or the phosphatidylinositol 3-kinase inhibitor, LY294002, resulted in formation of fewer colonies in soft agar than was the case with control cells. Moreover, in orthotopic implantation model, this inhibition resulted in a reduced rate of hematogeneous intrahepatic metastasis. These findings indicated that anchorage-independent growth regulated by phosphatidylinositol 3-kinase/Akt pathway plays a critical role in metastasis, and that this could be a potential therapeutic target to combat metastasis.

Animals↗
PubMed2002

Mixed mucinous-type and non-mucinous-type adenocarcinoma of the lung: immunohistochemical examination and K- ras gene mutation.

Mucinous-type adenocarcinoma and non-mucinous-type adenocarcinoma are known to be the representative histological subtypes of bronchioloalveolar carcinoma. Mucinous-type adenocarcinoma is also known to carry abnormalities of the K- ras gene at high frequency. However, the mixed subtype of the both mucinous-type and non-mucinous-type adenocarcinoma (mixed-type) has not been analyzed in detail, although its existence has been reported in a few papers. In this study we carried out immunohistochemical and molecular biological analyses of 15 examples of the mixed-type, in comparison with 11 cases of mucinous-type and 21 cases of non-mucinous-type adenocarcinoma. Immunohistochemically, lysozyme - one of the specific markers of mucinous-type adenocarcinoma - was not stained in the mucinous component of the mixed-type. K- ras gene mutations were detected only in mucinous-type (73%) and non-mucinous-type (10%) adenocarcinomas and not in either the mucinous or non-mucinous component of the mixed-type (0%). Therefore, although mixed-type adenocarcinomas consist of tumor cells showing both mucinous and non-mucinous morphology, the mucinous component of this type differs from mucinous-type adenocarcinoma in terms of immunohistochemical features and K- ras gene alteration.

Adenocarcinoma, Mucinous↗
PubMed2002

Epidermal growth factor receptor gene amplification is correlated with laminin-5 gamma2 chain expression in oral squamous cell carcinoma cell lines.

Both epidermal growth factor receptor (EGFR) gene amplification and laminin (Ln)-5 gamma2 chain overexpression have been reported to be poor prognostic factors in patients with squamous cell carcinoma (SCC) of the head and neck. Here we report our investigation of the relationship between EGFR gene amplification and Ln-5 gamma2 chain expression in seven SCC cell lines, since both epidermal growth factor (EGF) signaling and Ln-5 gamma2 have been reported to be involved in cell motility. The degree of correlation between EGFR gene amplification and Ln-5 gamma2 chain expression was evaluated by Southern and Western blot analyses. EGFR gene amplification was detected in all SCC cell lines at levels 5-50 times those in DNA from normal liver tissue. EGFR gene amplification increased with Ln-5 gamma2 chain protein expression in seven cell lines, showing close correlation between EGFR gene amplification and Ln-5 gamma2 chain protein expression. In order to show the causal relationship, we analyzed the effects of transforming growth factor-alpha (TGF-alpha), tyrosine kinase inhibitor of EGFR, and neutralizing antibody against EGFR, on the expression of Ln-5 gamma2 in these cell lines. In two cell lines in which EGFR gene amplification was low, expression of both protein and mRNA of the Ln-5 gamma2 chain increased in the presence of TGF-alpha, and Ln-5 gamma2 chain expression was inhibited by neutralizing antibody against EGFR. In all cell lines, Ln-5 gamma2 chain expression was inhibited by tyrosine kinase inhibitor which acts selectively on the EGFR signal transduction pathway under the stimulus of TGF-alpha. These results suggest that EGFR gene amplification and the EGFR signaling pathway can act as positive regulators on the induction of the Ln-5 gamma2 chain secreted by tumor cells.

Carcinoma, Squamous Cell↗
PubMed2002

Prognostic significance of laminin-5 gamma2 chain expression in colorectal carcinoma: immunohistochemical analysis of 103 cases.

PURPOSE: The laminin-5 gamma2 chain plays an important role in cell migration during tumor invasion and tissue remodeling. Although this chain has been reported to be expressed in tumor-stroma interface of colorectal carcinoma, prognostic significance of its expression has not been elucidated in these tumors, so we investigated the clinicopathologic significance of Laminin-5 gamma2 chain expression in colorectal carcinoma. METHODS: Laminin-5 gamma2 chain expression was investigated immunohistochemically in 103 colorectal carcinoma patients with Stage II, III, and IV disease. The patients were categorized into three groups according to the number of immunopositive tumor cells in the sections containing the maximum diameter of the tumor as follows: +, less than 20 tumor cells were positive; ++, 20 to 500 tumor cells were positive; +++, more than 500 tumor cells were positive. RESULTS: Laminin-5 gamma2 chain expression was observed in cytoplasm of tumor cells, especially those in the invasive front of the tumor penetration. Eighteen (17 percent) of tumors showed +, 60 (58 percent) showed ++, and 25 (24 percent) showed +++. The increased number of immunopositive tumor cells was significantly associated with synchronous liver metastasis (P = 0.048). The univariate (P = 0.036) and multivariate (P = 0.001) analysis of the patients' survival revealed that the prognosis became significantly poorer in patients with the increased number of immunopositive tumor cells. CONCLUSIONS: Increased laminin-5 gamma2 chain immunoreactivity, suggesting a high invasive potential of tumor cells, was a significant poor prognostic indicator for the patients with colorectal carcinoma.

Adenocarcinoma↗
PubMed2002

Craniopharyngiomas of adamantinomatous type harbor beta-catenin gene mutations.

Craniopharyngioma is a rare tumor occurring in the sellar region comprising 3% of all intracranial tumors. To elucidate the contribution of beta-catenin gene mutation to tumorigenesis, we examined genetic alterations and expression of beta-catenin in 10 cases of adamantinomatous and 6 cases of papillary craniopharyngiomas. Beta-catenin gene mutations were found in all of the adamantinomatous and none of the papillary craniopharyngiomas. Immunohistochemically, all cases of adamantinomatous craniopharyngioma showed cytoplasmic and nuclear expression of beta-catenin. In contrast, papillary craniopharyngiomas showed exclusively membranous expression. The results suggest that adamantinomatous- and papillary-type craniopharyngiomas are not only clinicopathologically, but also genetically, distinctive variants. Mutation of the beta-catenin gene therefore seems to play an important role in the tumorigenesis of adamantinomatous craniopharyngioma. Among the adamantinomatous-type tumors, beta-catenin-positive mesenchymal cells were observed in two cases. Microdissection-based mutational analysis revealed that these mesenchymal cells also harbor the same beta-catenin gene mutations as those of epithelial cells, suggesting their tumorous nature. Thus, at least a subset of adamantinomatous craniopharyngioma is considered to be biphasic.

Adult↗