Biomedical subjects

Takuji Suzuki

Publications and source records attributed to Takuji Suzuki.

At least 19 recordsLinked to original sources

PubMed2006

Comparative analysis by frontal affinity chromatography of oligosaccharide specificity of GlcNAc-binding lectins, Griffonia simplicifolia lectin-II (GSL-II) and Boletopsis leucomelas lectin (BLL).

Lectin-based structural glycomics requires a search for useful lectins and their biochemical characterization to profile complex features of glycans. In this paper, two GlcNAc-binding lectins are reported with their detailed oligosaccharide specificity. One is a classic plant lectin, Griffonia simplicifolia lectin-II (GSL-II), and the other is a novel fungal lectin, Boletopsis leucomelas lectin (BLL). Their sugar-binding specificity was analyzed by frontal affinity chromatography using 146 glycans (125 pyridylaminated and 21 p-nitrophenyl saccharides). As a result, it was found that both GSL-II and BLL showed significant affinity toward complex-type N-glycans, which are either partially or completely agalactosylated. However, their branch-specific features differed significantly: GSL-II strongly bound to agalacto-type, tri- or tetra-antennary N-glycans with its primary recognition of a GlcNAc residue transferred by GlcNAc-transferase IV, while BLL preferred N-glycans with fewer branches. In fact, the presence of a GlcNAc residue transferred by GlcNAc-transferase V abolishes the binding of BLL. Thus, GSL-II and BLL forms a pair of complementally probes to profile a series of agalacto-type N-glycans.

Carbohydrate Conformation↗

PubMed2006

Prospective phase II study of gefitinib for chemotherapy-naive patients with advanced non-small-cell lung cancer with epidermal growth factor receptor gene mutations.

PURPOSE: This study was undertaken to investigate the efficacy and the feasibility of gefitinib for chemotherapy-naïve patients with advanced non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations. PATIENTS AND METHODS: The EGFR gene status in various tumor samples obtained from chemotherapy-naïve advanced NSCLC patients was examined by DNA sequencing of EGFR exons 18 to 23. Patients harboring EGFR mutations received gefitinib (250 mg/d) alone. The response rate, progression-free survival (PFS), and toxicity profile were assessed prospectively. RESULTS: Between June 2004 and October 2005, 75 patients were examined for the EGFR status, and 25 patients (33%) harbored EGFR mutations. EGFR mutations were significantly frequent in females (P < .01) and never or light smokers (P < .001). Sixteen patients with EGFR mutations were enrolled onto the study. The overall response rate in these patients was 75% (95% CI, 54% to 96%), and the disease control rate was 88% (95% CI, 71% to 100%). The median PFS time of these patients was 9.7 months (95% CI, 7.4 to 9.9 months). No life-threatening toxicity was observed. CONCLUSION: Treatment with gefitinib alone for chemotherapy-naïve NSCLC patients with EGFR mutations could achieve a high efficacy with acceptable toxicity. To assess the proper timing of gefitinib in such patients, a subsequent randomized trial comparing gefitinib with standard chemotherapy is warranted.

Adult↗

PubMed2006

Dendritic cells modified to express fractalkine/CX3CL1 in the treatment of preexisting tumors.

Fractalkine (CX3CL1) is a unique membrane-bound CX3C chemokine that serves as a potent chemoattractant for lymphocytes. The hypothesis of this study is that dendritic cells (DC) genetically modified ex vivo to overexpress fractalkine would enhance the T cell-mediated cellular immune response with a consequent induction of anti-tumor immunity to suppress tumor growth. To prove this hypothesis, established tumors of different mouse cancer cells (B16-F10 melanoma, H-2b, and Colon-26 colon adenocarcinoma, H-2d) were treated with intratumoral injection of bone marrow-derived DC that had been modified in vitro with an RGD fiber-mutant adenovirus vector expressing mouse fractalkine (Ad-FKN). In both tumor models tested, treatment of tumor-bearing mice with Ad-FKN-transduced DC gave rise to a significant suppression of tumor growth along with survival advantages in the treated mice. Immunohistochemical analysis of tumors treated with direct injection of Ad-FKN-transduced DC demonstrated that the treatment prompted CD8+ T cells and CD4+ T cells to accumulate in the tumor milieu, leading to activation of immune-relevant processes. Consistent with the finding, the intratumoral administration of Ad-FKN-transduced DC evoked tumor-specific cytotoxic T lymphocytes, which ensued from in vivo priming of Th1 immune responses in the treated host. In addition, the anti-tumor effect provided by intratumoral injection of Ad-FKN-transduced DC was completely abrogated in CD4+ T cell-deficient mice as well as in CD8+ T cell-deficient mice. These results support the concept that genetic modification of DC with a recombinant fractalkine adenovirus vector may be a useful strategy for cancer immunotherapy protocols.

Adenoviridae↗

PubMed2006

Carbohydrate specificity of lectins from Boletopsis leucomelas and Aralia cordate.

The carbohydrate specificity of three novel lectins, Boletopsis leucomelas lectin (BLL), Aralia cordate lectin (ACL), and Wasabia japonica lectin (WJL), was examined by frontal affinity chromatography using a panel of fluorescently labeled 47 oligosaccharides. The results indicate that BLL recognizes an agalacto structure of the biantennary chain and its bisecting structure. ACL showed strong affinity for triantennary oligosaccharides, but no affinity for tetraantennary structure. WJL showed no appreciable affinity for any of the 47 glycans examined. These lectins with a unique affinity specificity might be useful for examining alterations in the glycan structures of the glycoconjugates in association with development and various diseases.

Aralia↗

PubMed2006

1,25-Dihydroxyvitamin D3 suppresses exportin expression in human promyelocytic leukemia HL-60 cells.

The active form of vitamin D3, 1alpha,25-dihydroxyvitamin D3 (DVD), is a potent inducer of cell differentiation and inhibits proliferation of cells such as human promyelocytic leukemia HL-60 cells. In the present study, we examined the effects of DVD on the expression of exportin-1 and exportin-t, which play essential roles in the transport of mRNA and tRNA, respectively. The results of reverse transcription-polymerase chain reaction and quantitative real-time polymerase chain reaction indicated that DVD down-regulated the gene expression of these exportins. Western blotting revealed the decreased production of these proteins in DVD-treated cells. Thus, the present findings of decreased expression of exportin-1 and exportin-t induced by DVD can be correlated to inhibition of the proliferation of HL-60 cells.

Cell Proliferation↗

PubMed2006

DNA microarray analysis of changes in gene expression induced by 1,25-dihydroxyvitamin D3 in human promyelocytic leukemia HL-60 cells.

Using a DNA microarray, we analyzed about 16,600 genes for changes in expression associated with the differentiation of human promyelocytic leukemia HL-60 cells induced by 1alpha,25-dihydroxyvitamin D3 (DVD). Many of the up-regulated genes could be correlated to differentiation-associated changes toward a monocyte/macrophage lineage, and many down-regulated genes could be correlated to repressed cell growth. The present study revealed the down-regulated gene expression of importins and exportins 1, 5, 7, and exportin-tRNA. Thus, the present results confirmed our previous findings of down-regulation of exportin 1 and exportin-tRNA by DVD. Gene expression of exportin 6 is suggested to be regulated differently from that of exportins 1, 5, 7, and exportin-tRNA. The down-regulation of nuclear transport factors may be deeply associated with the differentiation of HL-60 cells induced by DVD.

Calcitriol↗

PubMed2006

[A case of pulmonary Langerhans cell histiocytosis discovered by CT mass screening and followed by bronchoalveolar lavage].

A 42-year-old woman who had a cigarette index of 420 had many cavitary lesions predominantly in the upper areas of both lungs. The lesions were detected on a health examination using CT. Analysis with bronchofiberscopy showed increased CD1a positive cells in bronchoalveolar fluid (BALF). Histological examination by video-associated lung biopsy demonstrated that both S-100 and vimentin-positive cells were present in the peribronchial fibrotic lesions. From these data, this disease was diagnosed as pulmonary Langerhans cell histiocytosis (PLCH). Three months after the cessation of smoking, the cavity lesions disappeared. As the image findings improved, CD1a positive cells in BALF decreased (4.9% --> 1.8%) and the CD4/CD8 ratio in BALF increased (1.66 --> 6.16). So far, there is no report describing the time course of both CD1a positive cells and CD4/CD8 ratio in BALF after cessation of smoking in PLCH. These findings attract our interest on the PLCH.

Adult↗

PubMed2005

Vaccination of dendritic cells loaded with interleukin-12-secreting cancer cells augments in vivo antitumor immunity: characteristics of syngeneic and allogeneic antigen-presenting cell cancer hybrid cells.

Cancer immunotherapy by fusion of antigen-presenting cells and tumor cells has been shown to induce potent antitumor immunity. In this study, we characterized syngeneic and allogeneic, murine macrophage/dendritic cell (DC)-cancer fusion cells for the antitumor effects. The results showed the superiority of allogeneic cells as fusion partners in both types of antigen-presenting cells in an in vivo immunotherapy model. A potent induction of tumor-specific CTLs was observed in these immunized conditions. In addition, the immunization with DC-cancer fusion cells was better than that with macrophage-cancer fusion cells. Both syngeneic and allogeneic DC-cancer fusion cells induced higher levels of IFN-gamma production than macrophage-cancer fusion cells. Interestingly, allogeneic DC-cancer fusion cells were superior in that they efficiently induced Th1-type cytokines but not the Th2-type cytokines interleukin (IL)-10 and IL-4, whereas syngeneic DC-cancer fusion cells were powerful inducers of both Th1 and Th2 cytokines. These results suggest that allogeneic DCs are suitable as fusion cells in cancer immunotherapy. To further enhance the antitumor immunity in the clinical setting, we prepared DCs fused with IL-12 gene-transferred cancer cells and thus generated IL-12-secreting DC-cancer fusion cells. Immunization with these gene-modified DC-cancer fusion cells was able to elicit a markedly enhanced antitumor effect in the in vivo therapeutic model. This novel IL-12-producing fusion cell vaccine might be one promising intervention for future cancer immunotherapy.

Animals↗

PubMed2005

Antitumor immune response by CX3CL1 fractalkine gene transfer depends on both NK and T cells.

The CX3C chemokine fractalkine (CX3CL1) exists as both a membrane-bound form promoting firm cell-cell adhesion and a soluble form chemoattracting leukocytes expressing its receptor CX3CR1. When adenoviral vector expressing mouse fractalkine (AdFKN) was transduced to the tumor cells, fractalkine was expressed as both membrane-bound form on the tumor cells and soluble form in the supernatant in vitro. Intratumoral injection of AdFKN (1 x 10(9)PFU/tumor) into C26 and B16F10 tumors resulted in marked reduction of tumor growth compared to control (C26: 86.5%, p<0.001; B16F10: 85.5%, p<0.001). Histological examination of tumor tissues revealed abundant infiltration of NK cells, dendritic cells, and CD8(+) T lymphocytes 3 and/or 6 days after treatment with AdFKN. Splenocytes from mice treated by AdFKN developed tumor-specific cytotoxic T cells, and thereby protected from rechallenging with parental tumor cells. Antitumor effects by AdFKN were completely abrogated in both NK cell-depleted mice and CD8(-/-) mice, and partially blocked in CD4(-/-) mice. These data indicated that fractalkine mediates antitumor effects by both NK cell-dependent and T cell-dependent mechanisms. This study suggests that fractalkine can be a suitable candidate for immunogene therapy of cancer because fractalkine induces both innate and adaptive immunity.

Animals↗

PubMed2005

1,25-Dihydroxyvitamin D3 suppresses gene expression of eukaryotic translation initiation factor 2 in human promyelocytic leukemia HL-60 cells.

The physiologically active metabolite of vitamin D(3), 1alpha,25-dihydroxyvitamin D(3) (DVD), is a potent inducer of cell differentiation in human myeloid leukemia cells. In the present study, we examined changes in gene expression during DVD-induced cell differentiation of promyelocytic HL-60 cells employing a DNA microarray technique. The results identified 7 up-regulated and 9 down-regulated genes with a change greater than 1.5-fold after the DVD-treatment for both 2 and 6 days. Seven of these genes were further examined by reverse transcription-polymerase chain reaction (RT-PCR). The results showed that findings obtained from the DNA microarray analysis and RT-PCR are generally comparable with each other. Gene expression of the subunits of eukaryotic translation initiation factor 2 was then examined by methods including RT-PCR and real-time PCR. The results indicated the suppression of these genes, suggesting a linkage to differentiation-associated growth inhibition of these cells.

Calcitriol↗

PubMed2005

Stimulation of IL-8 production by Aralia cordate lectin in human colon carcinoma Caco-2 cells.

Some lectins are known to stimulate interleukin-8 (IL-8) productions in human colon carcinoma Caco-2 cells. Since IL-8 may cause deleterious effects, we examined this stimulatory activity of Aralia cordate lectin (ACL) and Wasabia japonica lectin (WJL), both of which we isolated recently. The results indicate that ACL exhibited strong stimulatory activity for IL-8 protein production, while WJL showed marginal activity. The activity of ACL was associated with high enhancement of IL-8 gene expression. The effect of ACL was abolished almost completely in the presence of brefeldin A, indicating that internalization into cells is necessary for ACL to exert activity. The findings suggest that ingestion of a large amount of raw vegetable Aralia cordate might cause unfavorable effects on the colon.

Aralia↗

PubMed2005

Effects of tea constituents on cell cycle progression of human leukemia U937 cells.

Tea and tea constituents are known to induce apoptosis in a variety of cancerous cells, suggesting their beneficial effects as chemopreventive agents. Previous studies have shown that low molecular weight constituent catechins and high molecular weight fractions of tea have the apoptosis-inducing activity, but that their action mechanisms may be different. Since cell cycle arrest is known to be one of the underlying mechanisms of apoptosis, we examined the effects of these tea constituents on cell cycle progression of human leukemia U937 cells. The results showed that the high molecular weight fractions of green tea and black tea caused G2/M arrest associated with up-regulation of p21/Waf1, but that epigallocatechin gallate, a major component of green tea catechins, gave little effects of cell cycle progression and p21/Waf1 expression. Thus, the present results suggest the difference in the apoptosis-induction mechanism between the two types of tea constituents.

Anticarcinogenic Agents↗

PubMed2005

Green tea with a high catechin content suppresses inflammatory cytokine expression in the galactosamine-injured rat liver.

Galactosamine is known to induce hepatic injury in rats and the galactosamine-induced hepatitis is believed to be similar to viral hepatitis both morphologically and functionally. In the present study, we examined how drinking green tea affects the gene expression of inflammatory cytokines which may be up-regulated in galactosamine-induced hepatitis. As has been reported, galactosamine caused hepatic injury in rats as evidenced by an increase in serum transaminase activities and histological observations of the liver. The results of the reverse transcription and polymerase chain reaction indicated an increased gene expression of inflammatory cytokines, tumor necrosis factor-alpha and interleukin-1beta, in the injured liver and the enzyme linked immunoassay showed an increase in the serum levels of these cytokines. Oral administration of green tea rich in catechins (Healthya green tea) restored these biomarkers in the galacotsamine-treated rats to near the control levels. These results suggest that the drinking of green tea with a high catechin content may help to prevent and/or attenuate the development of a certain type of hepatitis.

Animals↗

PubMed2004

Adenovirus vector-mediated in vivo gene transfer of OX40 ligand to tumor cells enhances antitumor immunity of tumor-bearing hosts.

OX40 ligand (OX40L), the ligand for OX40 on activated CD4+ T cells, has adjuvant properties for establishing effective T-cell immunity, a potent effector arm of the immune system against cancer. The hypothesis of this study is that in vivo genetic engineering of tumor cells to express OX40L will stimulate tumor-specific T cells by the OX40L-OX40 engagement, leading to an induction of systemic antitumor immunity. To investigate this hypothesis, s.c. established tumors of three different mouse cancer cells (B16 melanoma, H-2b; Lewis lung carcinoma, H-2b; and Colon-26 colon adenocarcinoma, H-2d) were treated with intratumoral injection of a recombinant adenovirus vector expressing mouse OX40L (AdOX40L). In all tumor models tested, treatment of tumor-bearing mice with AdOX40L induced a significant suppression of tumor growth along with survival advantages in the treated mice. The in vivo AdOX40L modification of tumors evoked tumor-specific cytotoxic T lymphocytes in the treated host correlated with in vivo priming of T helper 1 immune responses in a tumor-specific manner. Consistent with the finding, the antitumor effect provided by intratumoral injection of AdOX40L was completely abrogated in a CD4+ T cell-deficient or CD8+ T cell-deficient condition. In addition, ex vivo AdOX40L-transduced B16 cells also elicited B16-specific cytotoxic T lymphocyte responses, and significantly suppressed the B16 tumor growth in the immunization-challenge experiment. All of these results support the concept that genetic modification of tumor cells with a recombinant OX40L adenovirus vector may be of benefit in cancer immunotherapy protocols.

Adenoviridae↗

PubMed2004

Dendritic cells pulsed with live and dead Legionella pneumophila elicit distinct immune responses.

Legionella pneumophila is the causative pathogen of Legionnaires' disease, which is characterized by severe pneumonia. In regard to the pathophysiology of Legionella infection, the role of inflammatory phagocytes such as macrophages has been well documented, but the involvement of dendritic cells (DCs) has not been clarified. In this study, we have investigated the immune responses that DCs generate in vitro and in vivo after contact with L. pneumophila. Heat- and formalin-killed L. pneumophila, but not live L. pneumophila, induced immature DCs to undergo similar phenotypic maturation, but the secreted proinflammatory cytokines showed different patterns. The mechanisms of the DC maturation by heat- or formalin-killed L. pneumophila depended, at least in part, on Toll-like receptor 4 signaling or on Legionella LPS, respectively. After transfer to naive mice, DCs pulsed with dead Legionella produced serum Ig isotype responses specific for Legionella, leading to protective immunity against an otherwise lethal respiratory challenge with L. pneumophila. The in vivo immune responses required the Ag presentation of DCs, especially that on MHC class II molecules, and the immunity yielded cross-protection between clinical and environmental strains of L. pneumophila. Although the DC maturation was impaired by live Legionella, macrophages were activated by live as well as dead L. pneumophila, as evidenced by the up-regulation of MHC class II. Finally, DCs, but not macrophages, exhibited a proliferative response to live L. pneumophila that was consistent with their cell cycle progression. These findings provide a better understanding of the role of DCs in adaptive immunity to Legionella infection.

Animals↗

PubMed2003

Increased susceptibility to LPS-induced endotoxin shock in secretory leukoprotease inhibitor (SLPI)-deficient mice.

Secretory leukoprotease inhibitor (SLPI) protects tissue against the destructive action of neutrophil elastase at the site of inflammation. Recent studies on new functions of SLPI have demonstrated that SLPI may play a larger role in innate immunity than merely as a protease inhibitor. To clarify the functions of SLPI in bacterial infections, we generated SLPI-deficient mice (SLPI(-/-) mice) and analyzed their response to experimental endotoxin shock induced by lipopolysaccharide (LPS). SLPI(-/-) mice showed a higher mortality from endotoxin shock than did wild type mice. This may be explained in part by our observation that SLPI(-/-) macro-phages show higher interleukin 6 and high-mobility group (HMG)-1 production and nuclear factor kappaB activities after LPS treatment than do SLPI(+/+) macrophages. SLPI also affects B cell function. SLPI(-/-) B cells show more proliferation and IgM production after LPS treatment than SLPI(+/+) B cells. Our results suggest that SLPI attenuates excessive inflammatory responses and thus assures balanced functioning of innate immunity.

Animals↗

PubMed2003

Gene expression profile in human leukocytes.

Leukocytes are classified as myelocytic or lymphocytic, and each class of leukocytes consists of several types of cells that have different phenotypes and different roles. To define the gene expression in these cells, we have performed serial analysis of gene expression (SAGE) using human leukocytes and have provided the gene database for these cells not only at the resting stage but also at the activated stage. A total of 709,990 tags from 17 libraries were analyzed for the manifestation of gene expression profiles in various types of human leukocytes. Types of leukocytes analyzed were as follows: peripheral blood monocytes, colony-stimulating factor-induced macrophages, monocyte-derived immature dendritic cells, mature/activated dendritic cells, granulocytes, natural killer (NK) cells, resting B cells, activated B cells, naive T cells, CCR4(-) memory T cells (resting T(H)1 cells), CCR4(+) memory T cells (resting T(H)2 cells), activated T(H)1 cells, and activated T(H)2 cells. Among 38,961 distinct tags that appeared more than once in the combined total libraries, 27,323 tags were found to represent unique genes in certain type(s) of leukocytes. Using probability (P) and hierarchical clustering analysis, we identified the genes selectively expressed in each type of leukocytes. Identification of the genes specifically expressed in different types of leukocytes provides not only a novel molecular signature to define different subsets of resting and activated cells but also contributes to further understanding of the biologic function of leukocytes in the host defense system.

Databases, Factual↗

PubMed2003

Lipopolysaccharide-inducible gene expression profile in human monocytes.

Monocytes/macrophages play a key role in host defense by phagocytosing invaded pathogens, presenting antigens to immune cells and producing numerous inflammatory mediators. Although the expression of many proteins and genes has been described to be up-regulated in activated human monocytes, a complete picture of the pathophysiological function of activated human monocytes has not yet been drawn. In this study the serial analysis of gene expression (SAGE) procedure was applied to lipopolysaccharide (LPS)-stimulated human monocytes. A total of 35,874 tags corresponding to more than 12,000 different transcripts was sequenced. In addition, the Long SAGE procedure was conducted in LPS-stimulated monocytes to increase the accuracy of corresponding gene identification. Comparison of the gene expression profile with that of resting monocytes revealed the whole LPS-inducible gene expression profile. The functional classifications of LPS-inducible genes (> or = 8-fold increase compared with resting monocytes) in monocytes showed that 25% of inducible genes were identified to encode cytokines and chemokines, followed by proteins related to metabolism (11%), cell surface antigens (9%), nuclear proteins (8%), proteases (6%), proteins related to extracellular transport (4%) and intracellular transducers (4%). Moreover, 14% of LPS-inducible genes still encode proteins with unknown function. This study represents the first global analysis of LPS-inducible genes in human monocytes and provides tremendous novel information for the function of LPS-activated monocytes and targets for diagnosing, monitoring and treating sepsis and various human infectious and inflammatory diseases.

Gene Expression Profiling↗