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Biomedical subjects

M Ohtsuki

Publications and source records attributed to M Ohtsuki.

At least 19 recordsLinked to original sources
PubMed2006

Histone deacetylase inhibitor FK228 suppresses the Ras-MAP kinase signaling pathway by upregulating Rap1 and induces apoptosis in malignant melanoma.

Histone deacetylase (HDAC) inhibitors are expected to be effective for refractory cancer because their mechanism of action differs from that of conventional antineoplastic agents. In this study, we examined the effect of the HDAC inhibitor FK228 on malignant melanoma, as well as its molecular mechanisms. FK228 was highly effective against melanoma compared with other commonly used drugs. By comparing the gene expression profiles of melanoma cells and normal melanocytes, we defined a subset of genes specifically upregulated in melanoma cells by FK228, which included Rap1, a small GTP-binding protein of the Ras family. The expression of Rap1 mRNA and protein increased in FK228-treated melanoma cells in both a dose- and a time-dependent manner. A decrease in the phosphorylation of c-Raf, MEK1/2, and ERK1/2 was accompanied by an increase in Rap1 expression in both FK228-treated and Rap1-overexpressing cells. Inhibition of Rap1 upregulation by small interfering RNA (siRNA) abrogated the induction of apoptosis and suppression of ERK1/2 phosphorylation in FK228-treated melanoma cells. These results indicate that the cytotoxic effects of FK228 are mediated via the upregulation of Rap1. Furthermore, we found that Rap1 was overexpressed and formed a complex with B-Raf in melanoma cell lines with a V599E mutation of B-Raf. The siRNA-mediated abrogation of Rap1 overexpression increased the viability of these cells, suggesting that Rap1 is also an endogenous regulator of Ras-MAP kinase signaling in melanomas.

Animals↗
PubMed2003

Complete remission of metastatic clear cell sarcoma with DAV chemotherapy.

We report the first case of metastatic clear cell sarcoma with dramatic response to DAV treatment (DTIC + ACNU + VCR). Clear cell sarcoma of tendons and aponeuroses, or malignant melanoma of soft parts, is a rare tumour that occurs predominantly in the extremities of young adults. It tends to recur locally or metastasize and the prognosis is poor. Although the importance of surgery has been established, the role of adjuvant chemotherapy has yet to be determined. DAV should be considered as a first-line palliative treatment in disseminated disease as well as adjuvant therapy after surgery of primary clear cell sarcoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Constitutive activation of Wnt/beta-catenin signaling pathway in migration-active melanoma cells: role of LEF-1 in melanoma with increased metastatic potential.

A constitutive complex of beta-catenin and LEF-1 has been detected in melanoma cell lines expressing either mutant beta-catenin or mutant APC (Rubinfeld et al., Science, 275, 1790-1792, 1997). However, it has been recently reported that beta-catenin mutations are rare in primary malignant melanoma, but its nuclear and/or cytoplasmic localization, a potential indicator of Wnt/beta-catenin pathway activation, is frequently observed in melanoma (Rimm et al., Am. J. Pathol., 154, 325-329, 1999). In human malignant melanoma, the appearance of the tumorigenic phase represents a capacity for metastasis and is the significant phenotypic step in disease progression. Cell motility in invasive melanoma is thought to play a crucial role in metastatic behavior. In this work, we sought to determine which transcription factor of the LEF/TCF family was preferentially involved in human melanoma from different stages of tumor progression. We show that LEF-1 mRNA expression is predominant in highly migrating cells from metastatic melanomas. These actively migrating melanoma cells showed nuclear and cytoplasmic accumulation of beta-catenin and active transcription from a reporter plasmid of the LEF/TCF binding site. These results may provide a new insight into the role of the Wnt/beta-catenin signaling pathway in the tumor progression of malignant melanoma.

Cell Movement↗
PubMed2001

Therapeutic effect of novel anti-human Fas antibody HFE7a on graft-versus-host disease model.

In order to evaluate anti-human Fas antibody, we have established a new graft-versus-host disease (GVHD) model wherein splenocytes of human Fas transgenic mice (hFas-TgM) were transferred to immune-deficient SCID mice. In this model, although host SCID cells are not activated by or responsive to graft hFas-TgM cells, graft hFas-TgM cells are activated by and responsive to host SCID cells and thus cause GVHD symptoms. SCID mice that received hFas-TgM splenocytes had increased human Fas-positive lymphocytes in lymph nodes, decreased in body weight, and developed skin diseases, including rash and alopecia. Administration of novel anti-human Fas antibody HFE7A, which did not induce liver toxicity after administration to mice, decreased the level of the human Fas-positive lymphocytes, blocked the decrease of body weight, and suppressed development of skin diseases in this model. These results indicate that induction of apoptosis to activated graft cells with nontoxic anti-Fas antibody could reduce GVHD symptoms.

Acute Disease↗
PubMed2001

Expression profiling of cancer-related genes in human keratinocytes following non-lethal ultraviolet B irradiation.

Ultraviolet B irradiation initiates and promotes skin cancers, photo-aging, and immune suppression. In order to elucidate the effect of these processes at the level of gene expression, we used cDNA microarray technology to examine the effect of ultraviolet B irradiation on 588 cancer-related genes in human keratinocytes at 1, 6, and 24 h post-irradiation with a mildly cytotoxic dose of ultraviolet B (170 mJ/cm(2)). The viability of the irradiated keratinocytes was 75% at 24 h post-irradiation. Various cytokeratins and transcription factors were up-regulated within 1 h post-irradiation. After 6 h, expression of a variety of genes related to growth regulation (e.g. p21(WAF1), notch 4, and smoothened), apoptosis (e.g. caspase 10, hTRIP, and CRAF1), DNA repair (ERCC1, XRCC1), cytokines (e.g. IL-6, IL-13, TGF-beta, and endothelin 2), and cell adhesion (e.g. RhoE, and RhoGDI) were altered in human keratinocytes. These data suggest the changes in a cascade of gene expression in human keratinocytes occurring within 24 h after UVB exposure. Although the roles of these cellular genes after UVB-irradiation remain to be elucidated, microarray analysis may provide a new view of gene expression in epidermal keratinocytes following UVB exposure.

Apoptosis↗
PubMed2001

Gene gun-mediated oral mucosal transfer of interleukin 12 cDNA coupled with an irradiated melanoma vaccine in a hamster model: successful treatment of oral melanoma and distant skin lesion.

Malignant melanoma involving the oral cavity has a highly metastatic potential. Curative surgery is required to resect extensive oral tissues and often results in dysfunction as well as a severe cosmetic deformity in patients with the disease. An alternative technology for the local and sustained delivery of cytokines for cancer immunotherapy has been shown to induce tumor regression, suppression of metastasis, and development of systemic antitumor immunity. However, local immunization of the oral cavity has not previously been studied. In this study, we examined the efficacy of particle-mediated oral gene transfer on luciferase and green fluorescent protein production. The results showed that these proteins were more significantly expressed in oral mucosa than the skin, stomach, liver, and muscle. Using an established oral melanoma model in hamsters, particle-mediated oral gene gun therapy with interleukin (IL) 12 cDNA was then conducted. The results indicated that direct bombardment of mouse IL-12 cDNA suppressed tumor formation and improved the survival rate. The skin tumor model created by inoculation of melanoma cells was also significantly inhibited by the oral bombardment of IL-12 cDNA coupled with an irradiated melanoma vaccine administrated to the oral mucosa, compared to treatment with a percutaneous vaccine. IL-12 gene gun therapy, combined with an oral mucosal vaccine, induced interferon-gamma mRNA expression in the host spleen for a long time. These results suggest that immunization of oral mucosa may induce systemic antitumor immunity more efficiently than immunization of the skin and that oral mucosa may be one of the most suitable tissues for cancer gene therapy by means of particle-mediated gene transfer.

Animals↗
PubMed2001

Angioimmunoblastic lymphadenopathy-type peripheral T-cell lymphoma with cutaneous infiltration: report of a case and its gene expression profile.

Angioimmunoblastic T-cell lymphoma is a type of peripheral T-cell lymphoma that is clinically characterized by high fever and generalized lymphadenopathy with or without cutaneous involvement. A 55-year-old Japanese man presented with red papular lesions on the trunk and limbs, oedema, and generalized lymphadenopathy. Histological findings in the lymph nodes showed destructive germinal centres, proliferation of arborizing postcapillary venules, and atypical medium-sized lymphocytes. The cutaneous lesions also contained atypical lymphocytes. Immunohistochemical studies indicated that the neoplastic cells were mature CD4+ T lymphocytes. Southern blot analysis detected a clonal expansion of T-cell receptor beta. Based on these findings, a diagnosis of angioimmunoblastic T-cell lymphoma with cutaneous infiltration was made. Despite systemic chemotherapy, the disease exhibited a high level of activity and continued on a fatal course. An analysis of gene expression profiling using complementary DNA microarrays revealed significant expression of some chemokines and cytokines, e.g. secondary lymphoid tissue chemokine, macrophage inflammatory protein (MIP)-1beta, MIP-3alpha, MIP-3beta, B-lymphocyte chemokine, interleukin-16 and tumour necrosis factor-beta, and an apoptosis-inhibitory protein (FLICE inhibitory protein) in the affected lymph nodes. Profiling of gene expression patterns for a variety of genes in additional cases may be helpful in determining which factors predict the biological and clinical behaviour of angioimmunoblastic T-cell lymphoma or other aggressive malignant lymphomas.

Cytokines↗
PubMed2001

Gene expression profile in a case of primary cutaneous CD30-negative large T-cell lymphoma with a blastic phenotype.

A 65-year-old Japanese woman presented with disseminated erythematous patches, plaques, and nodules on the trunk and limbs. Histological examination showed diffuse and dense infiltrates located in the dermis and subcutis, composed of large pleomorphic T lymphocytes. Immunohistochemically, neoplastic cells were positive for blastic T-cell markers, but negative for CD30 (Ki-1) antigen. Based on the clinicopathological findings, a diagnosis of primary cutaneous large T-cell lymphoma was made. Despite systemic chemotherapy, the patient died 7 months after diagnosis. Gene expression profiling using complementary DNA microarrays indicated significantly increased expression of an apoptosis-inhibitory protein and certain cyokines and cytokine receptors (e.g. MCP-1, MCP-2, IP-10, and IL-2R gamma) in the tumour-indurated skin. Comprehensive gene expression patterning in additional cases may provide useful information regarding the biological and clinical behaviour of aggressive cutaneous lymphomas such as CD30-negative large T-cell lymphoma.

Aged↗
PubMed2001

Preclinical evaluation of an immunotherapeutic peptide comprising 7 T-cell determinants of Cry j 1 and Cry j 2, the major Japanese cedar pollen allergens.

BACKGROUND: Peptide immunotherapy is a new approach to treating allergic diseases, but a therapeutic peptide for Japanese cedar pollinosis has not yet been developed. OBJECTIVE: The aim of this study is to prepare and preclinically evaluate a hybrid peptide comprising 7 T-cell determinants of Cry j 1 and Cry j 2, the major Japanese cedar pollen allergens. METHODS: The recombinant hybrid peptide was prepared after immunodominance of 7 T-cell determinants was confirmed by means of PBMC proliferation assay in 113 volunteers with pollinosis. The hybrid peptide was compared with a mixture of the 7 T-cell determinants in a dose-dependent PBMC proliferation assay in 6 volunteers with pollinosis. PBMC proliferation and binding activity of serum IgE antibody against the hybrid peptide, Cry j 1, and Cry j 2 were investigated in 48 volunteers with pollinosis. RESULTS: The hybrid peptide induced T-cell proliferation with an average 100-fold lower concentration than a mixture of the 7 peptides. PBMCs from 44 (92%) of 48 volunteers proliferated against the hybrid peptide, with significant correlation (r = 0.87) in T-cell proliferation against Cry j 1 and Cry j 2. No serum IgE antibodies specific to Cry j 1 or Cry j 2 bound to the hybrid peptide. CONCLUSION: A hybrid peptide comprising 7 T-cell determinants has the potential for inducing T-cell proliferative responses that is superior to the potential of a mixture of the T-cell determinants and comparable with that of Cry j 1 and Cry j 2. The hybrid peptide will be of use in specific immunotherapy against Japanese cedar pollinosis.

Adult↗
PubMed2001

[Perspectives on tetrahydrobiopterin research].

Tetrahydrobiopterin ((6R)-L-erythro-tetrahydrobiopterin, BH4) is de novo synthesized from GTP. Enzymes involved in its synthesis are the rate limiting enzyme GTP cyclohydrolase I, 6-pyruvoyl tetrahydropterin synthase (PTPS) and sepiapterin reductase. Abnormalities in the metabolism of BH4 have been demonstrated in some diseases affecting the central nervous systems such as atypical phenylketonuria, hereditary progressive dystonia (Segawa's disease). Furthermore, BH4 has been shown to be involved in vascular protection. It is suggested that the dysfunction of endothelial BH4 leads to atherosclerosis. Recently we established BH4-deficient mice by disrupting the PTPS gene to investigate the effects of BH4 depletion on the animals and the involvement of BH4 in regulating biological functions including neural systems. Investigation utilizing this model animal can contribute to the development of new therapeutic strategies toward various diseases involving neurological and vascular systems. Pterin derivatives other than biopterin may also be involved in the regulation of a variety of biological functions. We found that ciliated protozoan Tetrahymena pyriformis synthesizes tetrahydromonapterin, isomer of BH4, and its levels alter according to the progress of the cell cycle. How pterin derivatives are related to the human physiology and diseases is an interesting subject of investigation.

Animals↗
PubMed2001

The first host record of trichinosis in a red fox, Vulpes vulpes japonica, from Aomori Prefecture, northern Honshu, Japan.

A case of wildlife trichinosis was found in a red fox (Vulpes vulpes japonica) captured at Rokkasho, Aomori Prefecture on November 27, 1998. Trichinella larvae were obtained from almost all of the muscle tissues except for the masseter. The highest number of larvae per gram of tissue was found in the muscles of the gluteal region and throat. The lowest number was found in the diaphragm and tongue. Trichina cysts within the muscle fibers had groups of fatty cells at the poles, and minimal tissue reaction was observed around the cyst. No calcification was found in the cyst. These morphological findings suggested that the considerable time had elapsed since the invasion. This is the first case of trichinosis in a red fox in Japan.

Animals↗
PubMed2001

[Adverse effects of beta-blocker eye drops on the ocular surface].

PURPOSE: We investigated the adverse effects of beta-blocker eye drops on tears and ocular surface epithelium. METHODS: We studied twenty-three eyes of twenty three glaucoma patients [10 males, 13 females: 53.8 +/- 12.2 (yrs; mean +/- standard deviation)] treated with beta-blocker eye drops for more than three months and thirty two control subjects (16 males, 16 females: 50.4 +/- 10.9). The parameters described below were compared between the groups: 1. the radius of tear meniscus curvature, 2. grades for tear lipid layer interference patterns, 3. non-invasive breakup time (N-BUT), 4. cotton thread value, 5. scores of fluorescein staining, 6. fluorescein breakup time (F-BUT), 7. scores of rose bengal staining, 8. and Schirmer I value. RESULTS: The glaucoma group showed a significant decrease in the radius of tear meniscus curvature (p = 0.0007), a significantly lower distribution in the grades for tear lipid layer interference patterns (p = 0.0270), a significant difference in the scores of fluorescein staining (p < 0.0001), a significant shortening in F-BUT (p = 0.0050), a significantly higher distribution in the scores of rose Bengal staining (p = 0.0010), and a significantly smaller value in Schirmer I value (p = 0.0042). However, there was no significant difference in N-BUT and cotton thread value. CONCLUSIONS: These results clearly demonstrate that the ocular surface in glaucoma patients treated with beta-blocker eye drops show dry-eye-like changes in terms of tears and ocular surface epithelium.

Adrenergic beta-Antagonists↗