Jun Murata

Publications (4)6.94 Total impact

• Article: Histone deacetylase induces accelerated maturation in Xenopus laevis oocytes.

  Jun Iwashita, Ayumi Kodama, Yuuri Konno, Tatsuya Abe, Jun Murata
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  ABSTRACT: In oocyte maturation in Xenopus laevis, nuclear material induces rapid maturation and is required for entry into meiosis II. Nuclear material contains a large number of RNAs and proteins, including histone deacetylase (HDAC); however, it is not known which materials induce accelerated maturation. The HDAC activity modifies transcription rate and is required for normal meiosis; however, its function in oocyte maturation is still unclear. We investigated the function of HDAC activity, which is localized in the nuclear material, in the regulation of the speed of oocyte maturation. Inhibition of HDAC activity with trichostatin A (TSA) induced hyperacetylation of histone H3 and prolonged oocyte maturation. In contrast, increase in HDAC activity with an injection of FLAG-tagged maternal histone deacetylase (HDACm-FLAG) mRNA induced deacetylation of histone H3 and reduced the duration of oocyte maturation. Cdc2 kinase, Cdc25C or mitogen-activated protein kinase (MAPK), which are key regulators of the meiosis, were activated coincidently with maturation progression. In oocytes, the mRNA level of Cdc25C, an activator of Cdc2, was increased by HDACm-FLAG mRNA-injection; in contrast, the mRNA level of Cdc2 inhibitor Wee1 was increased by TSA treatment. These results suggest that HDAC activity is involved in the control of maturation speed through the regulation of mRNA levels of cell cycle regulators. Thus, HDACm is a candidate for the nuclear material component that induces rapid maturation in Xenopus oocytes.
  Embryologia 01/2013; · 2.21 Impact Factor
• Article: Inhibition of E-cadherin dependent cell-cell contact promotes MUC5AC mucin production through the activation of epidermal growth factor receptors.

  Jun Iwashita, Kyohei Ose, Hiroki Ito, Jun Murata, Tatsuya Abe
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  ABSTRACT: Mucin production by epithelial cells is modulated by many soluble factors, including epidermal growth factor (EGF). E-Cadherin promotes EGF receptor (EGFR)-mediated MUC5AC mucin production in airway epithelial cells in dense cultures, suggesting the involvement of E-cadherin in activating EGFRs and mucin production. However, the role of E-cadherin in modulating mucin production is not completely understood. We examined its role in MUC5AC production in a human lung epithelial cell line, NCI-H292. Treatment of low density NCI-H292 cells with an anti-E-cadherin monoclonal antibody (SHE78-7) inhibited cell-cell contact in the dispersed colonies, but promoted MUC5AC production. Furthermore, treatment of the NCI-H292 cells with anti-E-cadherin antibody stimulated phosphorylation of extracellular signal-regulated kinase (ERK). The enhanced production of MUC5AC was inhibited with an EGFR inhibitor and with a MEK inhibitor, but not with a Src family kinase inhibitor. These results suggest that inhibition of E-cadherin activates EGFRs independently of Src and promotes MUC5AC production through the ERK signaling pathway in sparsely cultured NCI-H292 cells.
  Bioscience Biotechnology and Biochemistry 05/2011; 75(4):688-93. · 1.28 Impact Factor
• Source

  Available from: iiarjournals.org

  Article: The histone deacetylase inhibitor butyrate inhibits melanoma cell invasion of Matrigel.

  Akiko Kuwajima, Jun Iwashita, Jun Murata, Tatsuya Abe
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  ABSTRACT: Histone deacetylase (HDAC) inhibitors have anticancer effects. Their effects on expression of cell adhesion molecules might be related to their effects on tumor cell invasion. Murine B16-BL6 cells were treated with the HDAC inhibitors, butyrate or trichostatin A. Melanoma cell invasion of the artificial basement membrane, Matrigel, was examined by Transwell chamber assay. Butyrate as well as trichostatin A inhibited the cell growth mainly by arresting the cell cycle. The cell invasion of Matrigel was inhibited by butyrate and trichostatin A. The butyrate treatment increased the cell-cell aggregation, although neither E-cadherin nor N-cadherin mRNA were up-regulated. Both mRNA expression and protein levels of the immunoglobulin superfamily cell adhesion molecules, Mel-CAM and L1-CAM, were increased in the butyrate-treated cells. The HDAC inhibitor butyrate blocked the B16-BL6 melanoma cell invasion of Matrigel, although it increased the expression of Mel-CAM and L1-CAM which are important to the metastatic potential.
  Anticancer research 27(6B):4163-9. · 1.73 Impact Factor
• Source

  Available from: iiarjournals.org

  Article: The tyrosine kinase inhibitor AG490 inhibits growth of cancer cells and activates ERK in LS174T and HT-29 cells.

  Koichi Saito, Jun Iwashita, Jun Murata, Tatsuya Abe
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  ABSTRACT: The activity of tyrosine kinases, although strictly regulated in normal cells, is often disturbed in cancer cells. The inhibition of a tyrosine kinase could be a target for treating cancer. The colon cancer cell lines LS174T and HT-29 and the lung cancer cell line NCI-H292 were used. The cells were incubated with 100 microM of the tyrosine kinase inhibitor AG490 for 1-3 days and were examined for growth. Extracellular signal-regulated kinase (ERK) activation was detected by anti-phospho ERK antibodies. The cell cycle was analyzed by flow cytometry. AG490 inhibited the growth of LS174T, HT-29 and NCI-H292 cells without inducing apoptosis. Short-term treatment with AG490 activated ERK and p38 MAPK in the LS174T and HT-29 cells, but not in NCI-H292 cells. ERK activation, however, was unrelated to the growth inhibition in LS174T cells, because the inhibition persisted even after the prevention of ERK activation. AG490 inhibits the growth of some cancer cells and activates ERK in LS174T and HT-29 cells. ERK activation is unrelated to growth inhibition.
  Anticancer research 26(2A):1085-90. · 1.73 Impact Factor