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Biomedical subjects

T Otsuki

Publications and source records attributed to T Otsuki.

At least 37 records · Page 2Linked to original sources
PubMed2001

Hypoxia reduces hormone responsiveness of human breast cancer cells.

Resistance to hormonal therapy frequently occurs following successful treatment in breast cancer. The mechanism responsible for this acquired resistance is still unknown. It has been suggested that a hypoxic tumor microenvironment promotes malignant progression of cancer, i.e., hypoxia may promote estrogen-independent growth (a more malignant phenotype) of breast cancer. To clarify this hypothesis, the effects of hypoxia on the growth responses to hormonal agents and the expression levels of estrogen receptor (ER)-alpha and progesterone receptor (PgR) were investigated in two human breast cancer cell lines, ML-20 and KPL-1. The expression level of ER-alpha was significantly decreased by hypoxia (1% O(2)) in a time-dependent manner in both cell lines. Hypoxia also significantly reduced the growth-promoting effect of estradiol (E2) and the growth-inhibitory effects of an antiestrogen, ICI 182 780, and a progestin, medroxyprogesterone acetate, in both cell lines. In addition, hypoxia markedly suppressed the induction of PgR mRNA and protein by E2 in both cell lines. To clarify further the effect of hypoxia on ER-alpha expression, the expression levels of hypoxia-inducible factor-1 alpha (HIF-1 alpha), a marker of hypoxia and ER-alpha were immunohistochemically examined in 36 breast cancer specimens. ER-alpha expression (both its proportion and intensity) was significantly lower in nuclear HIF-1 alpha-positive tumors than in negative tumors. These findings indicate that hypoxia down-regulates ER-alpha expression as well as ER-alpha function in breast cancer cells. These processes may lead to an acquired resistance to hormonal therapy in breast cancer.

Breast Neoplasms↗
PubMed2001

A radicicol derivative, KF58333, inhibits expression of hypoxia-inducible factor-1alpha and vascular endothelial growth factor, angiogenesis and growth of human breast cancer xenografts.

A novel oxime derivative of radicicol, KF58333, binds to the heat shock protein 90 (Hsp90) and destabilizes its associated signaling molecules. These effects play a critical role in the growth inhibition of tumor cells. To further investigate the effects of this agent, it was administered to two human breast cancer cell lines, KPL-1 and KPL-4, both in vitro and in vivo. KF58333 dose-dependently inhibited the growth and vascular endothelial growth factor (VEGF) secretion, concomitantly with a decrease in VEGF mRNA expression, in each cell line. This agent also suppressed the increase of VEGF secretion and expression induced by hypoxia (1% O(2)). Intravenous injections of this agent into nude mice bearing either KPL-1 or KPL-4 xenografts significantly inhibited the tumor growth associated with a decrease in the Ki67 labeling index and microvascular area and an increase in apoptosis and the necrotic area. These findings indicate that the antitumor activity of this radicicol derivative may be partly mediated by decreasing VEGF secretion from tumor cells and inhibiting tumor angiogenesis. To explore the action mechanisms of the anti-angiogenic effect, the expression level of hypoxia-inducible factor (HIF)-1alpha was investigated. KF58333 provided a significant decrease in the HIF-1alpha protein expression under both normoxic and hypoxic conditions. In contrast, the mRNA expression of HIF-1alpha was not decreased by this agent. It is suggested that the post-transcriptional down-regulation of HIF-1alpha expression by this agent may result in a decrease of VEGF expression and tumor angiogenesis.

Animals↗
PubMed2001

Post-transplant malignant lymphoma with monoclonal immunoglobulin gene rearrangement and polyclonal Epstein-Barr virus episomes.

This report describes the case of an 8 year old boy who developed ileocecal B cell lymphoma after liver transplantation. The patient underwent orthotopic liver transplantation for biliary atresia and had been given immunosuppressive drugs--cyclosporin A and tacrolimus hydrate. Six years after the liver transplantation, the patient had a sudden onset of fever and abdominal pain. Necropsy revealed an ileocecal mass that was a B cell lymphoma. Epstein-Barr virus (EBV) encoded RNA 1 was demonstrated in lymphoma cells and hyperplastic follicular germinal centre cells in various tissues. Although monoclonal immunoglobulin gene rearrangement was detected in the liver, EBV episomes were of polyclonal origin and lytic forms of EBV were also demonstrated by Southern blotting. Immunohistochemically, lymphoma cells were positive for p53 but negative for latent membrane protein 1 and EBV nuclear antigen 2. These findings suggested that this B cell lymphoma might have occurred sporadically, regardless of EBV infection.

Biliary Atresia↗
PubMed2001

Expression and in vitro modification of parathyroid hormone-related protein (PTHrP) and PTH/PTHrP-receptor in human myeloma cells.

To elucidate the role of PTHrP in myeloma, we examined the expression levels of PTHrP and its receptor in human myeloma cell lines and clinical specimens from 13 myeloma cases. In vitro modification of PTHrP expression and production induced by TGF-beta and PMA in PTHrP expressing myeloma cell lines was also investigated. PTHrP expression was detected in six out of seven myeloma cell lines with an inverse correlation with the expression of its receptor, and in 10 out of 13 clinical specimens in varying degrees. The PTHrP expression and secretion into culture medium were enhanced by supplemental TGF-beta and PMA. PMA also seemed to affect PTHrP upregulation via TGF-beta activation. The fundamental role of PTHrP in bone lesions and hypercalcemia in myeloma may be important to consider even during the initial phase of the disease and particularly in the progression of bone complications with hypercalcemia.

Aged↗
PubMed2001

Establishment of CD7+ human myeloma sister cell lines, KMS-21-PE and KMS-21-BM, carrying t(11;14) and t(8;14).

Two new human myeloma cell lines were established from pleural effusion and bone marrow malignant cells derived from a single patient, who manifested hyperammonemia associated with multiple myeloma, and these were characterized. Both lines possess t(11;14)(q13;q32) and t(8;14)(q24;q32) reciprocal translocations and overexpress cyclin D1, but not c-myc. Human myeloma lines including these new lines produced and secreted excess ammonia into culture medium more than non-myelomatous hematological cell lines. In addition, these two lines were revealed to have high surface CD7 expression correlated with relatively high mRNA expression by MP-RT-PCR. Among 8 human myeloma lines, half of them revealed significant surface expression of CD7 and a positive correlation between expression levels of protein and message. CD7 message was also detected in surface negative lines. Consequently, there may be posttranslational regulation of the CD7 molecule, whose cellular biological role in expressing cells has not been elucidated.

Adult↗
PubMed2001

[Application and improvement of aflatoxin analysis in foods using a multifunctional column and HPLC].

In an earlier report, we developed a rapid, sensitive and clean method consisting of non-chloroform extraction, clean-up on a commercial multifunctional cartridge column and HPLC with fluorescence detection for the analyses of aflatoxins. In this report, we applied this method to analyze aflatoxins in nuts, giant corn, cereals, spice and black teas. The method was effective for macadamia nuts, walnuts, hazelnuts, brazil nuts, giant corn, rice, wheat and buckwheat, and the recoveries of aflatoxins B1, B2, G1 and G2 spiked in them at the level of 10 ng/g were 85-106%. However, in the chromatograms of spices and black tea, many background peaks were observed. Therefore, we added a purification step with an affinity column to the clean-up of these samples with the multifunctional cartridge column. After the additional purification, most of the background peaks were gone. The recoveries of aflatoxins B1, B2 and G1 spiked at the level of 10 ng/g were 71-112% except for the case of B2 in white pepper (48%). The recoveries of G2 were 49-95%.

Aflatoxins↗
PubMed2000

Detection of alternatively spliced variant messages of Fas gene and mutational screening of Fas and Fas ligand coding regions in peripheral blood mononuclear cells derived from silicosis patients.

Silicosis is clinically characterized not only by respiratory disorders but by immunological abnormalities such as the appearance of autoantibodies and complications of autoimmune diseases. Dysregulation of apoptosis, particularly in the Fas/Fas ligand (FasL) pathway, has been considered to play a role in the pathogenesis of autoimmune diseases. It has been found that serum soluble Fas (sFas) levels are elevated in silicosis patients (SIL) and the sFas message is dominantly expressed in peripheral blood mononuclear cells (PBMC) derived from these individuals. In the present study, one tried to detect alternatively spliced variant messages including typical sFas message and found four that were highly and frequently expressed, and which possess a signal peptide domain, but not transmembrane and signal transducing domains, in PBMC derived from SIL. Functional mutations were not detected in Fas and FasL genes in silicosis PBMC. Still, alternative spliced variants of the Fas gene including typical sFas message appear to play an important role in the immunological dysregulation in SIL.

Aged↗
PubMed2000

Concurrent activation of a novel putative transforming gene, myeov, and cyclin D1 in a subset of multiple myeloma cell lines with t(11;14)(q13;q32).

Through the application of the NIH/3T3 tumorigenicity assay to DNA from a gastric carcinoma, we have identified a novel transforming gene, designated myeov (myeloma overexpressed gene in a subset of t[11;14]-positive multiple myelomas). Sequence analyses did not reveal any homology with sequences present in the GenBank, except the deduced protein structure predicts a transmembrane localization. Myeov was mapped to chromosome 11q13 and localized by DNA fiber fluorescence in situ hybridization (FISH) 360-kilobase (kb) centromeric of cyclin D1. In 3 of 7 multiple myeloma (MM) cell lines with a t(11;14)(q13;q32) and cyclin-D1 overexpression, Northern blot analysis revealed overexpression of myeov as well. In all 7 cell lines, the translocation breakpoint was mapped within the 360-kb region between myeov and cyclin D1. DNA fiber FISH with a contig of probes covering the constant region of the immunoglobulin heavy chain (IgH) revealed that exclusively in the 3 myeov-overexpressing cell lines (KMS-12, KMS-21, and XG-5), either the 5' E(mu) enhancer or the most telomeric 3' Ealpha enhancer was juxtaposed to myeov. Although cyclin D1 overexpression represents a characteristic feature of all MM cell lines with t(11;14), our results demonstrate aberrant expression of a second putative oncogene in a subset of these cases, due to juxtaposition to IgH enhancers. The clinical relevance of this dual activation remains to be elucidated. (Blood. 2000;95:2691-2698)

Amino Acid Sequence↗
PubMed2000

Estrogen receptors in human myeloma cells.

It has recently been reported that the human myeloma cell line U266 proceeds to undergo apoptosis after cultivation with the antiestrogen tamoxifen, thus raising the possibility that antiestrogens may be candidates for use in myeloma therapy. To obtain basic information on the effects of antiestrogens on myeloma cells, we investigated the mRNA expression levels of estrogen receptor (ER)-alpha, ER-beta, and coactivators and corepressors in nine human myeloma cell lines and compared them with those of seven human breast cancer cell lines including four ER-positive and three ER-negative lines. The alterations in cell growth and mRNA expression of the target genes of ER or those of cytokines in the myeloma lines by estradiol or antiestrogens (tamoxifen and toremifene) were also investigated. In addition, effects on membrane Fas expression, appearance of apoptosis, and cell cycle perturbation were analyzed. It was revealed that ER-beta and corepressors were dominantly expressed in myeloma cells, and antiestrogens induced growth inhibition through apoptosis mediated by a Fas-related pathway and G1 arrest of the cell cycle in myeloma cell lines.

Antineoplastic Agents, Hormonal↗
PubMed2000

Interphase detection of t(4;14)(p16.3;q32.3) by in situ hybridization and FGFR3 overexpression in plasma cell malignancies.

The immunoglobulin (Ig) genes are frequently involved in chromosomal rearrangements with a wide variety of partner loci in multiple myeloma (MM). However, several partner chromosomes have not been detected by conventional cytogenetic methods; for example, 4p16.3 (FGFR3), 6p25.3 (IRF4), and 16q23 (c-maf). To clarify the incidence of t(4;14)(p16.3;q32.3) in primary tumors of MM and to evaluate possible correlations with specific manifestations of the disease, G-banding, double-color fluorescence in situ hybridization (DC-FISH), and/or reverse-transcriptase polymerase chain reaction (RT-PCR) were performed on 40 patients with MM-two with plasmacytoma (PCM) and three with plasma cell leukemia (PCL). All patients were studied by DC-FISH; 40 were studied by G-banding and 36 were studied by RT-PCR. The FISH probes consisted of a cosmid pC385.12 containing the FGFR3 gene, a YAC Y6 containing VH, and a phage Iggamma1-10 containing the gamma1 constant region (Cgamma). We identified eight patients with either FGFR3/Cgamma fusion or FGFR3 overexpression: six patients with both FGFR3/Cgamma fusion and FGFR3 overexpression, one patient with FGFR3/Cgamma, and one with FGFR3 overexpression. FGFR3/Cgamma fusion was demonstrated at a frequency of 19% to 38% on interphase nuclei in seven of the 45 patients. Lytic bone lesions were found to be associated with FGFR3 overexpression. Interphase FISH with FGFR3 and Cgamma probes combined with RT-PCR proved to be an effective tool for detection of this fully cryptic translocation, thus facilitating the characterization of clinical features of MM patients with t(4;14).

Adult↗
PubMed2000

Over-expression of the decoy receptor 3 (DcR3) gene in peripheral blood mononuclear cells (PBMC) derived from silicosis patients.

Dysregulation of apoptosis, particularly in the Fas/Fas ligand (FasL) pathway, is considered to be involved in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE). Recently, a soluble decoy receptor, termed decoy receptor 3 (DcR3), that binds FasL and inhibits FasL-induced apoptosis, has been identified. Silicosis is clinically characterized not only by respiratory disorders but by immunological abnormalities. We have found that serum soluble Fas (sFas) levels are elevated in silicosis patients and that sFas message is dominantly expressed in PBMC derived from these patients. This study examined DcR3 gene expression in PBMC derived from patients with silicosis, SLE, or progressive systemic sclerosis (PSS), and compared it with that in healthy volunteers (HV). The relative expression level of the DcR3 gene was examined in PBMC derived from 37 patients with silicosis without clinical symptoms of autoimmune disease, nine patients with SLE, 12 patients with PSS, and 28 HV using the semiquantitative multiplex-reverse transcriptase-polymerase chain reaction (MP-RT-PCR). The correlation between the relative expression level of the DcR3 gene and multiple clinical parameters for respiratory disorders and immunological abnormalities in individuals with silicosis was analysed. The DcR3 gene was significantly over-expressed in cases of silicosis or SLE when compared with HV. In addition, the DcR3 relative expression level was positively correlated with the serum sFas level in silicosis patients. It is unclear, however, whether over-expression of the DcR3 gene in silicosis is caused by chronic silica exposure, merely accompanies the alteration in Fas-related molecules, or precedes the clinical onset of autoimmune abnormalities. It will be necessary to study these patients further, establish an in vitro model of human T cells exposed recurrently to silica compounds, and resolve whether the increase in DcR3 mRNA expression is a cause or consequence of disease.

Adult↗
PubMed2000

Expression of vascular endothelial growth factor and its receptors correlates closely with formation of the plexiform lesion in human pulmonary hypertension.

The pulmonary vasculature exhibits various morphological changes in patients with pulmonary hypertension (PH). Among them, the plexiform lesion is one of the most characteristic vascular lesions, although nothing is known about the molecular mechanisms of its formation. In the present study, the expression of vascular endothelial growth factor (VEGF), an endothelial cell-specific angiogenic mitogen, and its receptors, fms-like tyrosine kinase (Flt-1) and kinase insert domain-containing receptor (KDR), in the lungs of five cases with PH, were examined. By in situ hybridization, VEGF expression was found in modified smooth muscle cells inside the plexiform lesions as well as in medial smooth muscle cells of the arteries adjacent to the lesions. The expression of Flt-1 mRNA was observed in endothelial cells of the arteries adjacent to the plexiform lesions, while KDR mRNA was expressed in the endothelial cells inside the plexiform lesions. VEGF was immunolocalized to the endothelial cells expressing its receptors as well as the modified smooth muscle cells producing VEGF. These results demonstrate that VEGF and its receptors are upregulated with a close correlation to the plexiform lesions, and suggest that VEGF expressed by smooth muscle cells may activate the endothelial cells to form the plexiform lesions.

Adolescent↗
PubMed2000

Anti-HER2 antibody enhances the growth inhibitory effect of anti-oestrogen on breast cancer cells expressing both oestrogen receptors and HER2.

Anti-oestrogen is effective for the treatment of oestrogen receptor (ER)-positive breast carcinomas, but most of these tumours become resistant to anti-oestrogen. It has been suggested that anti-oestrogen therapy may induce a HER2 signalling pathway in breast cancer cells and this may cause resistance to anti-oestrogen. Thus, it is conceivable that combined therapy with anti-oestrogen and anti-HER2 antibody might be more effective. In the present study, we investigated the effect of combined treatment with a humanized anti-HER2 monoclonal antibody, rhumAbHER2 (trastuzumab), and an anti-oestrogen, ICI 182,780, on the cell growth of three human breast cancer cell lines which respectively express different levels of ER and HER2. The combined treatment enhanced the growth inhibitory effect on ML-20 cells, which express a high level of ER and a moderate level of HER2, but showed no additive effect on either KPL-4 cells, which express no ER and a moderate level of HER2, or MDA-MB-231 cells, which express no ER and a low level of HER2. It is also suggested that both the antibody and anti-oestrogen induce a G1-S blockade and apoptosis. These findings indicate that combined treatment with anti-HER2 antibody and anti-oestrogen may be useful for the treatment of patients with breast cancer expressing both ER and HER2.

Antibodies, Monoclonal↗
PubMed2000

Surgical treatment of intractable epilepsy in children: indication for resective surgery.

Good surgical outcome can be expected for intractable epilepsy in children by resective surgery when a focal cortical abnormality is demonstrated by neuroimaging studies such as MRI, SPECT, and PET. Improvement in behavioral and cognitive development can be expected with seizure cessation after surgery. Early surgical intervention for intractable epilepsy in children is considered a safe and effective choice of treatment to avoid cognitive delay and learning disability.

Age Factors↗
PubMed2000

Paradoxical hormone responses of KPL-1 breast cancer cells in vivo: a significant role of angiogenesis in tumor growth.

In our previous study, the growth of KPL-1 human breast cancer cells was found to be stimulated by an antiestrogen, ICI 182, 780, and inhibited by 17 beta-estradiol (E2) in vivo but not in vitro. To investigate the action mechanisms of these paradoxical responses, the effects of E2, ovariectomy (Ovex) and medroxyprogesterone acetate (MPA) on the growth, angiogenesis, apoptosis and expression of vascular endothelial growth factor (VEGF) were investigated. E2 stimulated the growth of KPL-1 cells but MPA inhibited it in vitro. In contrast, E2 propionate inhibited the growth of KPL-1 cells in female nude mice but Ovex and MPA stimulated it. E2 propionate suppressed angiogenesis and increased apoptosis in KPL-1 tumors, but Ovex and MPA promoted angiogenesis and decreased apoptosis. Both mRNA expression and secretion of VEGF were stimulated by MPA in KPL-1 cells, but in E2-dependent ML-20 cells they were both inhibited by MPA. E2 did not significantly influence VEGF expression in either cell line. These findings suggest that the abnormal modulation of VEGF expression by MPA and of the other angiogenic factor by E2 are responsible for the paradoxical growth responses of KPL-1 cells in vivo. To support this hypothesis, an antiangiogenic agent, TNP-470, was administered to mice bearing KPL-1 tumors. TNP-470 significantly inhibited the growth of KPL-1 tumors stimulated by MPA. Antiangiogenic agents may be effective for the treatment of hormone-refractory breast cancer.

Antibiotics, Antineoplastic↗
PubMed2000

All-trans-retinoic acid modulates expression levels of thyroglobulin and cytokines in a new human poorly differentiated papillary thyroid carcinoma cell line, KTC-1.

A new human thyroid carcinoma cell line, KTC-1, was established from the malignant pleural effusion of a recurrent thyroid carcinoma patient. Cytogenetic analysis revealed a normal karyotype, and no p53 mutation in exons 5-9 was detected. This cell line is tumorigenic in athymic nude mice. Histological findings by light and electron microscopy, such as the absence of follicular structures and the existence of intranuclear cytoplasmic inclusions and psammoma bodies, indicated transplanted tumors to be a poorly differentiated papillary thyroid carcinoma. A low expression level of thyroglobulin was detected by immunocytochemistry and RT-PCR. Messenger ribonucleic acid (mRNA) expression of thyroid transcription factor-1 and PAX-8 was also detected. No mRNA expression of TSH receptors, thyroid peroxidase, or Na+/I- symporter was detected. Interleukin-6 and leukemia inhibitory factor were secreted into the medium. These findings suggest this cell line to be functionally poorly differentiated. Moreover, all-trans-retinoic acid increased the mRNA expression of thyroglobulin and decreased both the mRNA expression and secretion of interleukin-6 and leukemia inhibitory factor while significantly stimulating growth. RT-PCR analysis of retinoic acid receptors (RARs) revealed that KTC-1 cells express a moderate level of RARalpha and -gamma, but a low level of RARbeta. This cell line may be useful for studying redifferentiation therapy for thyroid carcinoma.

Animals↗
PubMed2000

Semi-quantitative comparison of the differentiation markers and sodium iodide symporter messenger ribonucleic acids in papillary thyroid carcinomas using RT-PCR.

OBJECTIVE: To investigate the levels of expression of the sodium iodide symporter (NIS) and three differentiation markers (thyroglobulin (Tg), thyroid peroxidase (TPO) and thyrotrophin receptor (TSH-R)) in 35 patients with primary (n=31) or recurrent (n=4) papillary thyroid carcinoma, and to compare the findings with clinical data. METHODS: We performed a multiplex semi-quantitative RT-PCR to analyse the relative levels of expression of Tg, TPO and TSH-R mRNAs, and a separate semi-quantitative RT-PCR for NIS mRNA. RESULTS: Tg, TPO and TSH-R mRNAs were expressed in all the patients, whereas NIS mRNA was expressed in all but eight. Analysis of the expression of the differentiation markers in all patients showed a significant correlation among Tg, TPO and NIS. With regard to the relationship between the expression of each gene and the MACIS score, there was significant correlation only for the Tg gene (P<0.05). CONCLUSIONS: The levels of expression of NIS mRNA correlated significantly with those of Tg and TPO mRNAs, but not with those of TSH-R mRNA. The relationship with clinical stage and prognostic score, however, varied among these differentiation markers.

Adult↗