Tsukasa Suzuki

Nihon University, Edo, Tokyo, Japan

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Publications (7)23.53 Total impact

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    ABSTRACT: Recurrence after liver resection for hepatocellular carcinoma (HCC) is a major clinical problem, and prognostic markers for recurrence are urgently required. For 390 HCC cases, segmented linear regression analysis with two segments was performed, and the interval for the early and late recurrence groups was partitioned at the crosspoint (676 days). We investigated whether gene expression in non-tumorous tissues of remnant liver from 39 hepatitis C virus-positive HCC cases may be associated with early recurrence of this disease. By microarray analysis, 21 genes were identified as candidate recurrence-associated genes. Further gene expression analysis was performed, and the localization and expression of the gene products of these candidate genes were immunohistochemically evaluated. Low expression of the GBP1 gene and high expression of the TSC22D3 gene were significantly (both P=0.04) associated with the risk of early recurrence. Through backward step-wise multivariate logistic regression analysis for the 21 candidate genes, high expression of GBP1 reduced [odds ratio (OR)=0.20; 95% confidence interval (CI) 0.06-0.73, P=0.02] and high expression of TSC22D3 increased the risk of early recurrence (OR=19.6; 95% CI 1.14-337.2; P=0.04). Immunohistochemical analysis revealed that hepatocytes showed strong membranous expression for GBP1 in the late recurrence group, but weak membranous expression for GBP1 in the early recurrence group. TSC22D3 was frequently expressed in lymphocytes and in a few hepatocytes in tissues of the early recurrence group. Our observations suggest that the combination of the high expression of the TSC22D3 gene and low expression of the GBP1 gene in the non-tumorous tissue of the remnant liver is significantly associated with early recurrence after surgical resection of HCC.
    No preview · Article · May 2011 · Experimental and therapeutic medicine
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    ABSTRACT: Matrix metalloproteinase (MMP)-9, the 92-kDa type IV collagenase, contributes to tumor invasion and metastases, and strategies to down-regulate its expression could ultimately be of clinical utility. A pyrrole-imidazole (PI) polyamide that targets the activator protein-1 (AP-1)-binding site of the MMP-9 promoter was designed and synthesized as a gene-silencing agent for tumor metastases. The synthesized product showed selective DNA binding ability. The MMP-9 PI polyamide significantly inhibited MMP-9's mRNA expression, protein level, and enzymatic activity in human breast adenocarcinoma cells (MDA-MB-231). Furthermore, the MMP-9 PI polyamide inhibited migration and invasion by in vitro wound-healing and matrigel-invasion assay. The FITC-labeled PI polyamide was localized in nuclei in 45 min of incubation with an MDA-MB-231 cell and remained in the nuclei for up to 96 h after incubation in vitro. It was also quickly localized in the mouse cellular nuclei of many tissues, including liver, kidney, and spleen, after intravenous injection without using any drug-delivery system. Moreover, the polyamide treatment significantly decreased metastasis in a mouse model of liver metastasis. Our results suggest that this PI polyamide, which targets the MMP-9 gene promoter, can be a novel MMP-9 down-regulating molecule for antimetastasis.
    Full-text · Article · Mar 2010 · Cancer Science
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    ABSTRACT: We have designed and synthesized new types of pyrrole (P)-imidazole (I) polyamide conjugates 1 and 2 possessing a suberoylanilide hydroxamic acid (SAHA) moiety that is a strong inhibitor of histone deacetylase (HDAC). SAHA conjugate 2 was designed to target the promoter region of the p16 tumor suppressor gene. The DNA binding affinity of SAHA conjugate 2 to its target sequence was examined using surface plasmon resonance. HDAC inhibition activity of conjugates 1 and 2 was evaluated using a colorimetric assay. The results demonstrated that even though it possesses the relatively large SAHA moiety, conjugate 2 has high DNA sequence-specific binding properties and moderate HDAC inhibitory activity in vitro. SAHA conjugate 2 was found to cause morphological changes in HeLa cells and to induce selective Histone H3 lysine 9 acetylation.
    Full-text · Article · Dec 2009 · Tetrahedron Letters
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    ABSTRACT: cancer, EGFR, growth inhibition, HER2, HER2 transcription factor binding site, pyrrole–imidazole polyamide, transcription regulation
    Full-text · Article · Jul 2009 · The Journal of Antibiotics
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    ABSTRACT: Pyrrole-imidazole polyamide (PIP) is a nuclease-resistant novel compound that inhibits gene expression through binding to the minor groove of DNA. Human aurora kinase-A (AURKA) and -B (AURKB) are important regulators in mitosis during the cell cycle. In this study, two specific PIPs (PIP-A and PIP-B) targeting AURKA and AURKB promoter regions were designed and synthesized, and their biological effects were investigated by several in vitro assays. PIP-A and PIP-B significantly inhibited the promoter activities, mRNA expression, and protein levels of AURKA and AURKB, respectively, in a concentration-dependent manner. Moreover, 1:1 combination treatment with both PIPs demonstrated prominent antiproliferative synergy (CI value [ED(50)] = 0.256) to HeLa cells as a result of inducing apoptosis-mediated severe catastrophe of cell-cycle progression. The novel synthesized PIP-A and PIP-B are potent and specific gene-silencing agents for AURKA and AURKB.
    Full-text · Article · Sep 2008 · Chemistry & Biology
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    ABSTRACT: Previously, we designed an internally controlled quantitative nested real-time (QNRT) PCR assay for Mycobacterium tuberculosis DNA in order to rapidly diagnose tuberculous meningitis. This technique combined the high sensitivity of nested PCR with the accurate quantification of real-time PCR. In this study, we attempted to improve the original QNRT-PCR assay and newly developed the wide-range QNRT-PCR (WR-QNRT-PCR) assay, which is more accurate and has a wider detection range. For use as an internal-control “calibrator” to measure the copy number of M. tuberculosis DNA, an original new-mutation plasmid (NM-plasmid) was developed. It had artificial random nucleotides in five regions annealing specific primers and probes. The NM-plasmid demonstrated statistically uniform amplifications (F = 1.086, P = 0.774) against a range (1 to 105) of copy numbers of mimic M. tuberculosis DNA and was regarded as appropriate for use as a new internal control in the WR-QNRT-PSR assay. In addition, by the optimization of assay conditions in WR-QNRT-PCR, two-step amplification of target DNA was completely consistent with the standard curve of this assay. Due to the development of the NM-plasmid as the new internal control, significantly improved quantitative accuracy and a wider detection range were realized with the WR-QNRT-PCR assay. In the next study, we will try to use this novel assay method with actual clinical samples and examine its clinical usefulness.
    Full-text · Article · Jun 2008 · Journal of clinical microbiology
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    ABSTRACT: Although the “gold standard” for diagnosis of tuberculous meningitis (TBM) is bacterial isolation of Mycobacterium tuberculosis, there are still several complex issues. Recently, we developed an internally controlled novel wide-range quantitative nested real-time PCR (WR-QNRT-PCR) assay for M. tuberculosis DNA in order to rapidly diagnose TBM. For use as an internal control calibrator to measure the copy number of M. tuberculosis DNA, an original new-mutation plasmid (NM-plasmid) was developed. Due to the development of the NM-plasmid, the WR-QNRT-PCR assay demonstrated statistically significant accuracy over a wide detection range (1 to 105 copies). In clinical applications, the WR-QNRT-PCR assay revealed sufficiently high sensitivity (95.8%) and specificity (100%) for 24 clinically suspected TBM patients. In conditional logistic regression analysis, a copy number of M. tuberculosis DNA (per 1 ml of cerebrospinal fluid) of >8,000 was an independent risk factor for poor prognosis for TBM (i.e., death) (odds ratio, 16.142; 95% confidence interval, 1.191 to 218.79; P value, 0.0365). In addition, the copy numbers demonstrated by analysis of variance statistically significant alterations (P < 0.01) during the clinical treatment course for 10 suspected TBM patients. In simple regression analysis, the significant correlation (R2 = 0.597; P < 0.0001) was demonstrated between copy number and clinical stage of TBM. We consider the WR-QNRT-PCR assay to be a useful and advanced assay technique for assessing the clinical treatment course of TBM.
    Full-text · Article · May 2008 · Journal of clinical microbiology

Publication Stats

113 Citations
23.53 Total Impact Points


  • 2008-2011
    • Nihon University
      • Advanced Research Institute for the Sciences and Humanities
      Edo, Tokyo, Japan