Koji Miyamoto

Yamaguchi University, Yamaguchi-shi, Yamaguchi-ken, Japan

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Publications (7)30.69 Total impact

  • Article: Molecular dissection of a medicinal herb with anti-tumor activity by oligonucleotide microarray.
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    ABSTRACT: It is difficult to understand precisely the physiological actions of herbs because they contain a complex array of constituent molecules. In the present study we used DNA microarray data for 12600 genes to examine the anti-proliferative activity of the herb Coptidis rhizoma and eight constituent molecules against eight human pancreatic cancer cell lines. We identified 27 genes showing strong correlation with the 50% inhibitory dose (ID50) of C. rhizoma after 72-h exposure. Hierarchical cluster analysis with correlation coefficients between expression levels of these 27 C. rhizoma-related genes and the ID50 of each constituent molecule classified these test molecules into two clusters, one consisting of C. rhizoma and berberine and the other consisting of the remaining seven molecules. Our results suggest that one molecule, berberine, can account for the majority of the anti-proliferative activity of C. rhizoma and that DNA microarray analyses can be used to improve our understanding of the actions of an intact herb.
    Life Sciences 08/2005; 77(9):991-1002. · 2.53 Impact Factor
  • Article: Baicalein, a component of Scutellaria radix from Huang-Lian-Jie-Du-Tang (HLJDT), leads to suppression of proliferation and induction of apoptosis in human myeloma cells.
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    ABSTRACT: In the search for a more effective adjuvant therapy to treat multiple myeloma (MM), we investigated the effects of the traditional Chinese herbal medicines Huang-Lian-Jie-Du-Tang (HLJDT), Gui-Zhi-Fu-Ling-Wan (GZFLW), and Huang-Lian-Tang (HLT) on the proliferation and apoptosis of myeloma cells. HLJDT inhibited the proliferation of myeloma cell lines and the survival of primary myeloma cells, especially MPC-1- immature myeloma cells, and induced apoptosis in myeloma cell lines via a mitochondria-mediated pathway by reducing mitochondrial membrane potential and activating caspase-9 and caspase-3. Further experiments confirmed that Scutellaria radix was responsible for the suppressive effect of HLJDT on myeloma cell proliferation, and the baicalein in Scutellaria radix showed strong growth inhibition and induction of apoptosis in comparison with baicalin or wogonin. Baicalein as well as baicalin suppressed the survival in vitro of MPC-1- immature myeloma cells rather than MPC-1+ myeloma cells from myeloma patients. Baicalein inhibited the phosphorylation of IkB-alpha, which was followed by decreased expression of the IL-6 and XIAP genes and activation of caspase-9 and caspase-3. Therefore, HLJDT and Scutellaria radix have an antiproliferative effect on myeloma cells, especially MPC-1- immature myeloma cells, and baicalein may be responsible for the suppressive effect of Scutellaria radix by blocking IkB-alpha degradation.
    Blood 05/2005; 105(8):3312-8. · 9.90 Impact Factor
  • Article: A subpopulation of bone marrow cells depleted by a novel antibody, anti-Liv8, is useful for cell therapy to repair damaged liver.
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    ABSTRACT: We previously reported a new in vivo model named as "GFP/CCl(4) model" for monitoring the transdifferentiation of green fluorescent protein (GFP) positive bone marrow cell (BMC) into albumin-positive hepatocyte under the specific "niche" made by CCl(4) induced persistent liver damage, but the subpopulation which BMCs transdifferentiate into hepatocytes remains unknown. Here we developed a new monoclonal antibody, anti-Liv8, using mouse E 11.5 fetal liver as an antigen. Anti-Liv8 recognized both hematopoietic progenitor cells in fetal liver at E 11.5 and CD45-positive hematopoietic cells in adult bone marrow. We separated Liv8-positive and Liv8-negative cells and then transplanted these cells into a continuous liver damaged model. At 4 weeks after BMC transplantation, more efficient repopulation and transdifferentiation of BMC into hepatocytes were seen with Liv8-negative cells. These findings suggest that the subpopulation of Liv8-negative cells includes useful cells to perform cell therapy on repair damaged liver.
    Biochemical and Biophysical Research Communications 02/2004; 313(4):1110-8. · 2.48 Impact Factor
  • Article: An in vivo model for monitoring trans-differentiation of bone marrow cells into functional hepatocytes.
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    ABSTRACT: The plasticity of bone marrow cells (BMCs) remains controversial. The present study found that persistent injury induces efficient trans-differentiation of BMCs into functional hepatocytes. Mice with liver cirrhosis induced by carbon tetrachloride were injected with 1 x 10(5) non-treated green fluorescent protein (GFP)-positive BMCs via the tail vein. In these mice, transplanted GFP-positive BMCs efficiently migrated into the peri-portal area of liver lobules after one day, repopulating 25% of the recipient liver by 4 weeks. In contrast, no GFP-positive BMCs were detected following transplantation into control mice with undamaged livers. BMCs trans-differentiated into functional mature hepatocytes via immature hepatoblasts. Serum albumin levels were significantly elevated to compensate for chronic liver failure in BMC transplantation. These results reveal that recipient conditions and microenvironments represent key factors for successful cell therapy using BMCs.
    Journal of Biochemistry 11/2003; 134(4):551-8. · 2.37 Impact Factor
  • Article: Identification of common or distinct genes related to antitumor activities of a medicinal herb and its major component by oligonucleotide microarray.
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    ABSTRACT: Although the physiological actions of many herbs are gradually being elucidated at the molecular level, it remains unclear how individual components of herbs contribute to their biological activities. In the present study, the antiproliferative activity of Coptidis rhizoma, a medicinal herb, and the major component berberine was investigated in 8 human pancreatic cancer cell lines. Gene expression patterns associated with sensitivities to each agent were analyzed with oligonucleotide arrays that comprised approximately 11,000 genes. We used a tetrazolium dye (MTT) assay to determine ID(50) values after the 8 cell lines were exposed to the 2 agents for 72 hr. The ID(50) value for berberine was correlated positively with that for C. rhizoma (r=0.725, p=0.0401). C. rhizoma killed tumor cells more effectively than purified berberine when normalized to the level of berberine present in the herb. From the oligonucleotide array data, we selected 20 and 13 genes with strong correlations (r(2)>0.81) to ID(50) values for berberine and C. rhizoma, respectively. Among these 33 genes, the levels of expression of 12 were correlated with the ID(50) values of both agents, suggesting that these genes are associated with tumor-killing activity of berberine in C. rhizoma. Expression of the remaining 21 genes was correlated with the ID(50) value of either purified berberine or C. rhizoma. Thus, we identified common and distinct genes responsible for anti-proliferative activities of purified berberine and C. rhizoma. This strategy may improve our understanding of the actions of herbs with antitumor activities.
    International Journal of Cancer 11/2003; 107(4):666-72. · 5.44 Impact Factor
  • Article: Anticachectic effects of the natural herb Coptidis rhizoma and berberine on mice bearing colon 26/clone 20 adenocarcinoma.
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    ABSTRACT: We previously showed that the natural herb Coptidis rhizoma has an anticachectic effect in nude mice bearing human esophageal cancer cells. We further investigated this phenomenon by examining the anticachectic effect of C. rhizoma in syngeneic mice bearing colon 26/clone 20 carcinoma cells, which cause IL-6-related cachexia after cell injection. We evaluated nutritional parameters such as serum glucose level and wasting of adipose tissue and muscle in tumor-bearing and non-tumor-bearing mice treated with C. rhizoma (CR) supplement or a normal diet. IL-6 levels in those mice were quantified by ELISA and real-time RT-PCR. CR supplementation significantly attenuated weight loss in tumor-bearing mice without changing food intake or tumor growth. Furthermore, these mice maintained good nutritional status. IL-6 mRNA levels in tumors and spleens and IL-6 protein levels in tumors and sera were significantly lower in tumor-bearing mice treated with CR supplement than in those treated with a normal diet. CR supplementation did not affect food intake, body weight, nutritional parameters and IL-6 levels in non-tumor-bearing mice. An in vitro study showed that C. rhizoma and its major component, berberine, inhibited IL-1-induced IL-6 mRNA expression in a dose-dependent manner in colon 26/clone 20 cells. Our results showed that C. rhizoma exerts an anticachectic effect on colon 26/clone 20-transplanted mice and that its effect is associated with tumor IL-6 production. We also suggest that its effect might be due to berberine.
    International Journal of Cancer 06/2002; 99(2):286-91. · 5.44 Impact Factor
  • Article: Hydrogen peroxide induced chemokine production in the glia-rich cultured cerebellar granule cells under acidosis.
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    ABSTRACT: We have documented the time-dependent production of chemotactic cytokine, i.e., IL-8, in the extracellular fluid of astrocyte-rich cultured rat cerebellar granule cells under acidified conditions. In this paper, the mechanism of this production was evaluated based on the production of hydrogen peroxide (H2O2). Significant and time-dependent increases of cytosolic H2O2 were detected under acidosis in astrocyte-rich cultured cell. Upon exposure to 10 microM H2O2, significant levels of IL-8 appeared in the extracellular fluid of astrocyte-rich cells, although an initial transient increase of IL-8 was also seen in the intracellular space. Concurrently, after H2O2 exposure cell injury and a delayed increase of cytosolic Ca2+ levels were detected in astrocyte-rich cells. However, in the absence of extracellular Ca2+, the cell injury and the increase of IL-8 production were significantly attenuated. A synergistic effect of cyclosporine A (an inhibitor of the Ca2+/calmodulin-regulated protein phosphatase) and trifluoperazine (an inhibitor of phospholipase A2) on the suppression of H2O2-induced IL-8 production was clearly evident. These results suggest that extracellular acidosis induced Ca2+-dependent H2O2 production, which in turn stimulated IL-8 expression. which is regulated by the cytosolic Ca2+ cascade. Thus, the production of IL-8 from glia cells may have a role in regulating in the process of cell injury.
    Life Sciences 02/2002; 70(7):821-31. · 2.53 Impact Factor