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Akio Mizuno

Publications and source records attributed to Akio Mizuno.

18 recordsLinked to original sources
PubMed2007

Clinicopathologic significance of EpCAM expression in squamous cell carcinoma of the tongue and its possibility as a potential target for tongue cancer gene therapy.

Epithelial adhesion molecule (EpCAM) is a transmembrane glycoprotein involved in intercellular adhesion. In particular, EpCAM appears to be overexpressed by the majority of human epithelial carcinomas, including colorectal, breast, head and neck, and hepatic carcinomas. We therefore hypothesized that EpCAM would be a good molecular target for cancer gene therapy. EpCAM protein expression in 48 primary tongue cancers and 10 normal oral mucosa was evaluated using anti-EpCAM immunohistochemistry, and correlation was examined with the clinicopathologic factors. In four human tongue cancer cell lines (SAS, HSC-2, OSC19 and OSC20), we investigated EpCAM expression by reverse transcription-polymerase chain reaction (RT-PCR). The invasive potential of cancer cells was evaluated using Matrigel invasion assay. Moreover, the effect of EpCAM inhibition was analyzed using RNA interference (RNAi). EpCAM overexpression was detected in 30 of 48 tongue cancers (62.5%), and was significantly higher in primary squamous cell carcinoma (SCC) of the tongue than in normal oral mucosa. The expression of EpCAM was significantly associated with tumor size, regional lymph node metastasis, histological differentiation and invasion pattern. Cancer cell lines with higher EpCAM expression had more invasive potential. Moreover, RNAi-mediated EpCAM reduction decreased the invasion potential and proliferation activity. These results indicated that the overexpression of EpCAM was correlated with a more aggressive phenotype of tongue cancer. Moreover, we suggested that EpCAM could be a molecular target, and that RNAi targeting EpCAM could be useful for tongue cancer gene therapy.

Aged↗
PubMed2006

Orotate phosphoribosyl transferase mRNA expression in oral squamous cell carcinoma and its relationship with the dihydropyrimidine dehydrogenase expression and the clinical effect of 5-fluorouracil.

In this study, we investigated whether orotate phosphoribosyl transferase (OPRT) correlates with the clinicopathological features and effect of 5-fluorouracil (5-FU) in human oral carcinoma. We examined the expression of OPRT mRNA by in situ hybridization in surgical specimens of oral squamous cell carcinoma. The expression of OPRT mRNA in oral carcinoma was observed in all specimens and such expression was higher than that seen in normal control tissue specimens. There was no correlation between the expression of OPRT mRNA and clinical factors, but the expression of OPRT mRNA was significantly associated with histological differentiation. The expression of OPRT mRNA showed correlation with effect of 5-FU for oral carcinoma in either in vivo or in vitro. These results suggest that the OPRT expressions may therefore be a prognostic factor of 5-FU efficacy in patients with oral squamous cell carcinoma.

Adult↗
PubMed2006

Pepstatin A, an aspartic proteinase inhibitor, suppresses RANKL-induced osteoclast differentiation.

Pepstatin A is well known to be an inhibitor of aspartic proteinases such as pepsin, cathepsins D and E. Except for its role as a proteinase inhibitor, however, the pharmacological action of pepstatin A upon cells remain unclear. In this study, we found that pepstatin A suppressed receptor activator of NF-kappaB ligand (RANKL)-induced osteoclast differentiation. Pepstatin A suppressed the formation of multinuclear osteoclasts dose-dependently. This inhibition of the formation only affected osteoclast cells, i.e., not osteoblast-like cells. Furthermore, pepstatin A also suppressed differentiation from pre-osteoclast cells to mononuclear osteoclast cells dose-dependently. This inhibition seems to be independent of the activities of proteinases such as cathepsin D, because the formation of osteoclasts was not suppressed with the concentration that inhibited the activity of cathepsin D. Cell signaling analysis indicated that the phosphorylation of ERK was inhibited in pepstatin A-treated cells, while the phosphorylation of IkappaB and Akt showed almost no change. Furthermore, pepstatin A decreased the expression of nuclear factor of activated T cells c1 (NFATc1). These results suggest that pepstatin A suppresses the differentiation of osteoclasts through the blockade of ERK signaling and the inhibition of NFATc1 expression.

Animals↗
PubMed2005

Rh(I)-catalyzed cyclization of 1-arylprop-2-yn-1-ol derivatives utilizing rhodium 1,4-migration.

A highly useful method for the construction of cyclopentanone derivatives fused with aromatic ring based on hydrorhodation-1,4-rhodium migration sequence is achieved. Treatment of 1-aryl-prop-2-yn-1-ols, which are easily accessible via an addition of acetylides to the corresponding aryl aldehydes, with a catalytic amount of [Rh(cod)2]2(BF4) and P(p-tolyl)3 in the presence of a base gives cyclopentanone derivatives in moderate to good yield.

Journal Article↗
PubMed2005

Ameloblastoma.

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Aged↗
PubMed2005

Identification of the pentapeptide constituting a dominant epitope common to all eukaryotic heat shock protein 90 molecular chaperones.

We previously reported that, in human heat shock protein (Hsp) 90 (hHsp90), there are 4 highly immunogenic sites, designated sites Ia, Ib, Ic, and II. This study was performed to further characterize their epitopes and to identify the epitope that is potentially common to all members of the Hsp90 family. Panning of a bacterial library carrying randomized dodecapeptides revealed that Glu251-Ser-X-Asp254 constituted site Ia and Pro295-Ile-Trp-Thr-Arg299, site Ic. Site II (Asp701-Pro717) was composed of several epitopes. When 19 anti-hHsp90 monoclonal antibodies (mAbs) were subjected to immunoblotting against recombinant forms of 7 Hsp90-family members, 2 mAbs (K41110 and K41116C) that recognized site Ic bound to yeast Hsp90 with affinity identical to that for hHsp90, and 1 mAb (K3729) that recognized Glu222-Ala23, of hHsp90beta could bind to human 94-kDa glucose-regulated protein (Grp94), an endoplasmic reticulum paralog of Hsp90. Among the 5 amino acids constituting site Ic, Trp297 and Pro295 were essential for recognition by all anti-site-Ic mAbs, and Arg299 was important for most of them. The necessity of Ile296, Thr298, and Arg299, which are replaced by Leu, Met/Leu, and Lys, respectively, in some eukaryotic Hsp90, was dependent on the mAbs, and K41110 and K41116C could react with Hsp90s carrying these substitutions. From these data taken together, we propose that the pentapeptide Pro295-Ile-Trp-Thr-Arg299 of hHsp90 functions as an immunodominant epitope common to all eukaryotic Hsp90.

Amino Acid Sequence↗
PubMed2004

Silencing of the p53R2 gene by RNA interference inhibits growth and enhances 5-fluorouracil sensitivity of oral cancer cells.

The p53R2 gene encodes the ribonucleotide reductase (RR) small subunit 2 homologue, and is induced by several stress signals activating p53, such as DNA-damaging agents. The p53R2 gene product causes an increase in the deoxynucleotide triphosphate (dNTP) pool in the nucleus, which facilitates DNA repair and synthesis. We hypothesized that p53R2 would be a good molecular target for cancer gene therapy. In this study, three human oral cancer cell lines (SAS, HSC-4 and Ca9-22), a human breast cancer cell line MCF-7, and a normal human fibroblast cell line NHDF were tested. We silenced the expression of p53R2 with the highly specific post-transcriptional suppression of RNA interference (RNAi). We investigated p53R2 expression with the reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. The sensitivity to anticancer agents was evaluated by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The expression of p53R2 showed no association with the mutational status of p53. The cancer cell lines with higher p53R2 expression were more resistant to 5-FU. RNAi-mediated p53R2 reduction selectivity inhibited growth and enhanced chemosensitivity in cancer cell lines but not in normal fibroblasts. These results suggest that basal transcription of p53R2 could be associated with the sensitivity to anticancer agents. Moreover, we assessed the possibility that p53R2 would be a good molecular target, and report that RNAi targeting of p53R2 could be useful for oral cancer gene therapy.

Cell Line, Tumor↗
PubMed2004

Intracellularly labeled pyramidal neurons in the cortical areas projecting to the spinal cord. I. Electrophysiological properties of pyramidal neurons.

To study cortical motor control, we examined electrical characteristics of pyramidal neurons in the present report, and intra- or juxta-columnar connections of the pyramidal neurons to corticospinal neurons in the accompanying report. Pyramidal neurons were intracellularly recorded and stained in slices of rat motorsensory cortices (areas FL, HL and M1) where many corticospinal neurons were labeled retrogradely. They were morphologically classified into classical, star and other modified pyramidal neurons, and electrophysiologically into regular-spiking (RS), intrinsic bursting (IB) and irregular-spiking (IS) neurons on the basis of spiking pattern in response to 500 ms depolarizing current pulses. RS responses were further divided into RS with slow adaptation (RS-SA) and RS with fast adaptation (RS-FA). The electrical properties were associated with the laminar location of the neurons; RS-SA responses were observed frequently in layer II/III and less frequently in layers IV-VI, and IB and IS responses were exclusively found in layers V and VI, respectively. Interestingly, all layer IV neurons in area FL/HL were RS-FA star-pyramidal neurons, whereas layer IV neurons in area M1 were RS-SA classical pyramidal neurons. Although weak stimulation of areas FL/HL and M1 is known to elicit movement, these results suggest different information processings between the two areas.

Action Potentials↗
PubMed2004

Intracellularly labeled pyramidal neurons in the cortical areas projecting to the spinal cord. II. Intra- and juxta-columnar projection of pyramidal neurons to corticospinal neurons.

Intra- or juxta-columnar connections of pyramidal neurons to corticospinal neurons in rat motorsensory cortices were examined with brain slices by combining intracellular staining with Golgi-like retrograde labeling of corticospinal neurons. Of 108 intracellularly labeled pyramidal neurons, 27 neurons were selected for morphological analysis by successful staining of their axonal arborizations and sufficient retrograde labeling of corticospinal neurons. Many varicosities of local axon collaterals of each pyramidal neuron were closely apposed to the dendrites of corticospinal neurons, suggesting the convergent projections of layer II-VI pyramidal neurons to corticospinal neurons. Particularly, the varicosities of a layer IV star-pyramidal neuron made two- to three-fold more appositions to the dendrites of corticospinal neurons than those of a pyramidal neuron in the other layers. Fifteen appositions were examined electron-microscopically and 60% of them made asymmetric axospinous synapses. The present results together with those of the preceding report suggest that thalamic inputs are conveyed to corticospinal neurons preferentially via layer IV star-pyramidal neurons with phasic response properties, and thereby might contribute to the initiation or switching of movement. In contrast, inputs with tonic response properties from the other layers seem to be integrated in corticospinal neurons, and might be useful in maintaining the activity of corticospinal neurons.

Action Potentials↗
PubMed2004

A comprehensive study on the immunological reactivity of the Hsp90 molecular chaperone.

Periodontitis is a chronic infectious disease, Porphyromonas gingivalis being the most implicated pathogen. In the present study, we investigated the role of P. gingivalis HtpG (PgHtpG), a bacterial ortholog of mammalian Hsp90, in the growth of P. gingivalis and also assessed the immunological cross-reactivity of the members of the Hsp90 family. Antiserum against rat liver Hsp90 potently reacted with yeast Hsp90, called Hsc82, and also weakly with human Hsp90 (hHsp90) and human mitochondrial paralog Trap1, but did not react with PgHtpG, Escherichia coli HtpG, or human endoplasmic reticulum paralog Grp94. Moreover, among 19 monoclonal antibodies raised against hHsp90, nine cross-reacted with yeast Hsc82, and one with human Grp94, but none bound to PgHtpG or E. coli HtpG. Among them, three mAbs that strongly reacted with yeast Hsc82 recognized Asn(291)-Ile(304), a conserved region of the family protein. The polyclonal antibody raised against a peptide, Met(315)-Glu(328), of human Grp94, which corresponded to the conserved region of hHsp90, cross-reacted with hHsp90, but not with other Hsp90-family members. Thus, although mammalian Hsp90 shares some immunological reactivity with yeast Hsc82, human Grp94, and human Trap1, it is considerably distinct from its bacterial ortholog, HtpG. Disruption of the P. gingivalis htpG gene neither affected bacterial survival nor altered the sensitivity of P. gingivalis to various forms of stress.

Animals↗
PubMed2003

Expression of p53R2, newly p53 target in oral normal epithelium, epithelial dysplasia and squamous cell carcinoma.

Recently, the p53R2 gene has been isolated and shown to play a crucial role in DNA repair after DNA damage. The p53R2 gene encodes the p53 inducible ribonucleotide reductase small subunit 2 homologue, which is part of the p53 pathway. However, the function of p53R2 in human cancer is still unclear. We investigated p53R2 mRNA expression in human oral normal epithelium, epithelial dysplasias and squamous cell carcinomas (SCCs). Surgical or biopsy-proven specimens of 10 normal epithelium, 48 epithelial dysplasias and 63 SCCs were collected in our department. Then, p53R2 was identified by in situ hybridization to visualize and localize the expression of specific mRNAs. The authors examined the p53 gene mutation by polymerase chain reaction-single strand conformation polymorphism analysis. p53, mdm2, p21(WAF1/CIP1) and Ki-67 expression was detected by immunohistochemistry. p53R2 expression was detected in none of ten normal epithelium (0%), ten of 48 dysplasias (20.8%) and 33 of 63 SCCs (52.4%). In oral SCC, the expression of p53R2 was significantly associated with tumor size, lymph node metastasis and histological differentiation (P=0.014, 0.046 and 0.022, respectively). p53R2 expression was significantly associated with p53 abnormality in epithelial dysplasia and SCC (P=0.034 and 0.009, respectively). Of 63 patients, 37 received preoperative radiochemotherapy. p53R2 mRNA expression was significantly associated with the pathologic response to radiochemotherapy (P=0.031). This study suggested that p53R2 expression could be associated with oral carcinogenesis. The presence of p53R2 mRNA expression would be a predictive factor for tumor development, tumor cell differentiation and the sensitivity to radiochemotherapy in oral SCC.

Cell Cycle Proteins↗
PubMed2003

A hydrophobic segment within the C-terminal domain is essential for both client-binding and dimer formation of the HSP90-family molecular chaperone.

The alpha isoform of human 90-kDa heat shock protein (HSP90alpha) is composed of three domains: the N-terminal (residues 1-400); middle (residues 401-615) and C-terminal (residues 621-732). The middle domain is simultaneously associated with the N- and C-terminal domains, and the interaction with the latter mediates the dimeric configuration of HSP90. Besides one in the N-terminal domain, an additional client-binding site exists in the C-terminal domain of HSP90. The aim of the present study is to elucidate the regions within the C-terminal domain responsible for the bindings to the middle domain and to a client protein, and to define the relationship between the two functions. A bacterial two-hybrid system revealed that residues 650-697 of HSP90alpha were essential for the binding to the middle domain. An almost identical region (residues 657-720) was required for the suppression of heat-induced aggregation of citrate synthase, a model client protein. Replacement of either Leu665-Leu666 or Leu671-Leu672 to Ser-Ser within the hydrophobic segment (residues 662-678) of the C-terminal domain caused the loss of bindings to both the middle domain and the client protein. The interaction between the middle and C-terminal domains was also found in human 94-kDa glucose-regulated protein. Moreover, Escherichia coli HtpG, a bacterial HSP90 homologue, formed heterodimeric complexes with HSP90alpha and the 94-kDa glucose-regulated protein through their middle-C-terminal domains. Taken together, it is concluded that the identical region including the hydrophobic segment of the C-terminal domain is essential for both the client binding and dimer formation of the HSP90-family molecular chaperone and that the dimeric configuration appears to be similar in the HSP90-family proteins.

Amino Acid Sequence↗
PubMed2002

Interaction between the N-terminal and middle regions is essential for the in vivo function of HSP90 molecular chaperone.

At the primary structure level, the 90-kDa heat shock protein (HSP90) is composed of three regions: the N-terminal (Met(1)-Arg(400)), middle (Glu(401)-Lys(615)), and C-terminal (Asp(621)-Asp(732)) regions. In the present study, we investigated potential subregion structures of these three regions and their roles. Limited proteolysis revealed that the N-terminal region could be split into two fragments carrying residues Met(1) to Lys(281) (or Lys(283)) and Glu(282) (or Tyr(284)) to Arg(400). The former is known to carry the ATP-binding domain. The fragments carrying the N-terminal two-thirds (Glu(401)-Lys(546)) and C-terminal one-third of the middle region were sufficient for the interactions with the N- and C-terminal regions, respectively. Yeast HSC82 that carried point mutations in the middle region causing deficient binding to the N-terminal region could not support the growth of HSP82-depleted cells at an elevated temperature. Taken together, our data show that the N-terminal and middle regions of the HSP90 family protein are structurally divided into two respective subregions. Moreover, the interaction between the N-terminal and middle regions is essential for the in vivo function of HSP90 in yeast.

Amino Acid Sequence↗
PubMed2002

Mucoepidermoid carcinoma arising in Warthin's tumor of the parotid gland.

Malignant transformation of Warthin's tumor is extremely rare, although it is the second most common benign tumor of the parotid gland. We describe our experience of mucoepidermoid carcinoma arising in Warthin's tumor of the parotid gland in a 64-year-old man. He had a swelling in the left parotid-masseteric region. The removed tumor was well encapsulated and histopathologically comprised Warthin's tumor and low-grade mucoepidermoid carcinoma. The mucoepidermoid carcinoma infiltrated lymphoid stroma of the Warthin's tumor, but capsular invasion is not found. Considering the clinical course and physical examination, the lesion was diagnosed as mucoepidermoid carcinoma arising in Warthin's tumor because its features filled the criteria of malignant transformation of Warthin's tumor. There has been no recurrence or distant metastasis for 19 months. Histological change from Warthin's tumor to mucoepidermoid carcinoma may be implicated in squamous or goblet cell metaplasia of epithelial cells. It is considered that the neoplastic cells of Warthin's tumor acquire malignant genotypes simultaneously with this dual differentiation.

Adenolymphoma↗
PubMed2002

Cathepsin expression in oral squamous cell carcinoma: relationship with clinicopathologic factors.

OBJECTIVE: Proteases are involved in the invasion and metastasis of carcinoma cells. In vivo, oral carcinoma cells easily invade the bone tissue and metastasize to the submandibular and neck lymph nodes. Cathepsin expression has been shown in some neoplastic tissues and serves as a prognostic indicator. The purpose of this study was to investigate the relationship between clinicopathohistologic grades and cathepsin expressions in oral squamous cell carcinoma and to investigate which cathepsin provides prognostic information for patients with oral carcinoma. STUDY DESIGN: Immunohistochemical studies were performed on 78 carcinoma samples with monoclonal antibodies against cathepsins B, H, and L, and a polyclonal antibody against cathepsin D. Serial sections were stained by hematoxylin-eosin staining and classified by Anneroth's classification. Cathepsin B, H, L and D activities of blood serum were determined. Positive results indicative of the presence of cathepsin were investigated to determine any correlation between a particular cathepsin and histologic malignancy grades, tumor cell growth, serum cathepsin activities, and clinical factors. RESULTS: Cathepsins B, H, L, and D were positive in every case. Although the labeling indices for cathepsins B (CB-LI), H (CH-LI), and D (CD-LI) for the cancer cases showed significant differences from those of controls, cathepsin L (CL-LI) of cancer cases showed no difference from that of controls (P <.05). A close correlation was found between CD-LI and T categories of TNM classification (P <.05), and between CD-LI and PCNA-LI (P <.05). Furthermore, a close correlation was found between CD-LI and N categories in TNM classification (P <.05). Pathologically, a close correlation was found between CB-LI or CD-LI and the pattern and/or stage of invasion (P <.05). CONCLUSION: Cathepsin D and B expression were closely correlated with carcinoma invasion and progression. These proteases may be useful in determining the prognoses of patients with oral carcinoma.

Adult↗
PubMed2002

Thymidylate synthase and dihydropyrimidine dehydrogenase expression in oral squamous cell carcinoma: an immunohistochemical and clinicopathologic study.

OBJECTIVE: Thymidylate synthase (TS) is the target enzyme for 5-fluorouracil (5-FU), and dihydropyrimidine dehydrogenase (DPD) is the first enzyme that metabolizes 5-fluorouracil. Until now, only the enzyme activities of TS and DPD have been investigated; however, there are few reports about the immunohistochemistry of TS and DPD and none regarding oral carcinoma. The purpose of this article was to investigate the expression of TS and DPD in oral squamous cell carcinoma. STUDY DESIGN: In this study, 109 oral squamous cell carcinomas were investigated for the immunohistochemical expression of TS and DPD proteins. RESULTS: The expressions of TS in carcinoma cases was significantly higher than in controls (P <.05, t test). DPD was expressed both in carcinomas and in areas adjacent to the carcinomas. There was no correlation between the clinical factors and the TS labeling index or between the clinical factors and the DPD labeling index (DPD-LI). Pathologically, DPD-LI was significantly different in both the World Health Organization classification and Anneroth's classification. The TS labeling index was significantly correlated with the Ki-67 LI (P <.05, Pearson's correlation coefficient). Although TS showed no correlation between tegafur-uracil response and TS labeling index, there was a significant correlation between the tegafur-uracil response and DPD-LI. CONCLUSIONS: TS may reveal tumor cell proliferation, but DPD-LI may correlate with a response to anticancer drug treatment.

Adult↗
PubMed2002

p53, mdm2, and p21 expression in oral squamous cell carcinomas: relationship with clinicopathologic factors.

OBJECTIVE: The purpose of this study was to clarify the correlation of expression of cell cycle-associated gene proteins with clinicopathologic factors in oral squamous cell carcinoma (SCC). STUDY DESIGN: Formalin-fixed paraffin-embedded tissues from 69 oral SCC cases and 10 normal mucosa cases were stained by immunohistochemistry (IHC) for p53, mdm 2, and p21 proteins. RESULTS: We found p53, mdm 2, and p21 expression in 44 of 69 (63.8%), 25 of 69 (36.2%), and 37 of 69 (53.6%) oral SCCs, respectively. Ki-67-labeling index of combined p53(+)/mdm 2(+) expression cases was significantly higher than those that lacked combined expression (P =.004). Combined p53(+)/p21(+) expression showed a significant association with lymph node metastasis (P =.019). In survival analysis, combined p53(+)/p21(+) and p53(+)/mdm 2(+)/p21(+) expression was associated with poor clinical outcome (P =.018 and.012, respectively). CONCLUSION: Combined p53/mdm 2 expression was associated with tumor proliferation in oral SCC. Combined p53/p21 and p53/mdm 2/p21 expression may be a predictive factor in lymph node metastasis.

Aged↗