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Masato Takahashi

Publications and source records attributed to Masato Takahashi.

32 records · Page 2Linked to original sources
PubMed2004

[In vitro chemosensitivity test for hepatocellular carcinoma using collagen-gel droplet embedded cultures].

This study evaluated an in vitro assay for chemosensitivity test using a collagen-gel droplet-embedded culture drug sensitivity test (CD-DST) for hepatocellular carcinoma (HCC). In 25 patients with HCC, in vitro chemosensitivity to 5-fluorouracil (5-FU), epirubicin (EPI), and cisplatin (CDDP) was examined by CD-DST, and 5-FU, EPI, and paclitaxel (PTX) were examined in 38 patients with breast cancer. Successful rates of chemosensitive evaluation by CD-DST were 64% for HCC and 79% for breast cancers. Although chemosensitivities of breast cancer were 5-FU 23.1%, EPI 83.3%, and PTX 67.7%, only one HCC sample was sensitive to EPI. Growth rates of HCC for 7 days of culture were significantly lower than those of breast cancers (1.04 vs 3.61). The culture methods for HCC in CD-DST should be improved to estimate accurate results.

Antineoplastic Agents↗
PubMed2003

Microwave-mediated analysis for sugar, fatty acid, and sphingoid compositions of glycosphingolipids.

For chemical characterization of glycosphingolipids, it is necessary to determine the chemical compositions of three constituents, i.e., sugars, fatty acids, and sphingoids. A new rapid analytical method is described using a one-pot reaction in a household microwave oven, producing sugars, fatty acids, and especially sphingoids free of by-products, from a single aliquot of a biological sample. Glycosphingolipids were hydrolyzed by microwave exposure with 0.1 M NaOH/CH(3)OH for 2 min followed by 1 M HCl/CH(3)OH for 45 s. The alkaline methanolysis step produced intermediate lysoglycosphingolipids virtually free of by-products such as the O-methyl ethers usually seen. The fatty acid methyl esters were extracted with n-hexane, and other reaction products were dried, taken up in aqueous alkaline methanol, and shaken with chloroform. Sphingoids partitioned into the organic phase under these conditions, whereas the sugar portion that partitioned into the aqueous phase was re-N-acetylated and remethanolyzed for 30 s by microwave exposure. Analysis of the profiles of glycosphingolipid constituents obtained using the microwave oven method showed that they were quantitatively and qualitatively comparable to those obtained by time-consuming conventional methods, which require reaction for several hours. Analysis of the three constituents, including analysis by gas chromatography, may be obtained within 1 day using the method described here.

Acetylation↗
PubMed2003

Negative autoregulation of p73 and p53 by DeltaNp73 in regulating differentiation and survival of human neuroblastoma cells.

p73, mapped to 1p36.2-3, is a p53-related tumor suppressor but is also induced by the oncogene products such as E2F1, raising a question whether p73 is a tumor suppressor gene or oncogene. p73 has several splicing variants including DeltaNp73 which lacks the NH(2)-terminal transactivation domain. In developing neurons, DeltaNp73 is expressed abundantly and seems to inhibit the pro-apoptotic function of p53. However, the role of TAp73 and DeltaNp73 as well as their regulatory mechanism in cell growth and differentiation of neuroblastoma cells are poorly understood. We have found that TAp73 directly activates the transcription of endogenous DeltaNp73 by binding to the TAp73-specific target element located at position-76 to 57 within the DeltaNp73 promoter region. DeltaNp73 was physically associated with TAp73alpha, TAp73beta and p53, and inhibited their transactivation activities when used reporters of Mdm2, Bax or DeltaNp73 itself in SAOS-2 cells. Overexpression of DeltaNp73 in SH-SY5Y neuroblastoma cells promoted cell survival by competing with p53 and TAp73 itself. Thus, our results suggest that the negative feedback regulation of TAp73 by its target DeltaNp73 is a novel autoregulatory system for modulating cell survival and death, that is also functioning in neuroblastoma cells.

Cell Differentiation↗
PubMed2003

Function of p73, not of p53, is inhibited by the physical interaction with RACK1 and its inhibitory effect is counteracted by pRB.

The newly identified p53-related gene, p73, encodes a nuclear transcription factor. Unlike p53, p73 has various isoforms with different NH(2)- and COOH-terminal tails. p73alpha with the longest COOH-terminal extension is most abundantly expressed in many tissues and cells among those splicing isoforms of p73 and the COOH-terminal region appears to have an autoregulatory function. To isolate and characterize the cellular protein(s) that interacts with the unique COOH-terminal region of p73alpha, we employed a yeast two-hybrid screen with a human fetal brain and 293 cell cDNA libraries. We identified the receptor for activated C kinase (RACK1) as a new member of p73alpha-binding proteins. The interaction was confirmed by coimmunoprecipitation experiments, whereas RACK1 did not interact with p53 or p73beta. Ectopic overexpression of RACK1 in SAOS-2 cells reduced the p73alpha-mediated transcription from the p53/p73-responsive promoters, and inhibited the p73alpha-dependent apoptosis. On the other hand, the p53-dependent transcriptional activation as well as apoptosis was unaffected in the presence of RACK1. Furthermore, we found that pRB physically bound to RACK1, and repressed the RACK1-dependent inhibition of p73alpha. Taken together, our observations suggest that pRB diminishes the RACK1-mediated inhibition of p73alpha activity through the interaction with RACK1.

Animals↗
PubMed2003

Metastatic breast cancer of HER2 scored 2+ by IHC and HER2 gene amplification assayed by FISH has a good response to single agent therapy with trastuzumab: a case report.

We report that single agent therapy with trastuzumab had a significant effect on metastatic breast cancer, which was confirmed to be HER2 positive by Herceptest showing 2+staining, and gene amplification positively detected by FISH analysis. A 48-year-old woman underwent extended radical mastectomy (T2N0M0 stage II). Three years after the operation supraclavicular lymph node metastasis was noted. Bone scintigraphy showed metastases to the left ribs 5 years after operation. She was treated with chemo-endocrine therapy, but nonetheless could not bear the back pain caused by the bone metastases. Another chemotherapy course could not be permitted because of leukopenia. Immunohistochemistry (IHC) analysis with Herceptest showed 2+staining for HER2 and FISH analysis showed gene amplification of HER2. We started single agent therapy with trastuzumab and she subsequently had remarkably improved back pain. Physical examination and ultrasonography showed disappearance of the previous palpable supraclaviclar lymph nodes. Serum tumor markers were also reduced after the first administration of trastuzumab. The patient is currently alive, with no further progression of the lymph node or bone metastases.

Antibodies, Monoclonal↗
PubMed2003

[Weekly paclitaxel administration in the adjuvant therapy of primary breast cancer].

PURPOSE: To investigate feasibility and toxicity of weekly paclitaxel administration in the adjuvant therapy of primary breast cancer. PATIENTS AND METHODS: Thirty-one patients with primary breast cancer received sustained weekly infusion of paclitaxel at a dose of 90 mg/body for 6 weeks followed by a 2-week interval. This weekly schedule was repeated twice. Leukocytes were checked immediately before every infusion and the dose was reduced to 80 mg/body when grade 1 neutropenia occurred. All patients were assessable for feasibility and toxicity. RESULTS: A total 349 weekly paclitaxel infusions were administrated to 31 patients (median, 12 infusions/patient). The median delivered dose-intensity was 88.0 mg/body/week (range 80 to 90). Therapy was well tolerated and completed in 27 patients. Four patients refused to continue the therapy because of nausea, fatigue, dizziness and weight gain. Grade 2 neutropenia occurred in 10 patients (32.3%), but grade 3 neutropenia did not occur. Grade 1 peripheral neuropathy occurred in 3 patients (9.7%). Grade 1 nausea occurred in 3 patients (9.7%). CONCLUSION: Weekly paclitaxel administration is well tolerated with a favorable toxicity profile in patients with primary breast cancer in the adjuvant setting. Weekly paclitaxel therapy can be performed safely in the outpatient setting.

Adult↗
PubMed2002

Inhaled Nitric Oxide as a Preoperative Test (INOP Test I): the INOP Test Study Group.

BACKGROUND: This study was performed to determine whether a preoperative hemodynamic evaluation with oxygen and inhaled nitric oxide identifies patients with pulmonary hypertension who are appropriate candidates for corrective cardiac surgery or transplantation more accurately than an evaluation with oxygen alone. METHODS AND RESULTS: At 10 institutions, 124 patients with heart disease and severe pulmonary hypertension underwent cardiac catheterization to determine operability. The ratio of pulmonary and systemic vascular resistance (Rp:Rs) was determined at baseline while breathing approximately 21% to 30% oxygen, and in approximately 100% oxygen and approximately 100% oxygen with 10 to 80 parts per million nitric oxide to evaluate pulmonary vascular reactivity. Surgery was performed in 74 patients. Twelve patients died or developed right heart failure secondary to pulmonary hypertension following surgery. Rp:Rs<0.33 and a 20% decrease in Rp:Rs from baseline were chosen as 2 criteria for operability to determine, in retrospect, the efficacy of preoperative testing in patient selection. In comparison to an evaluation with oxygen alone, sensitivity (64% versus 97%) and accuracy (68% versus 90%) were increased by an evaluation with oxygen and nitric oxide when Rp:Rs<0.33 was used as the criterion for operability. Specificity was only 8% when a 20% decrease in Rp:Rs from baseline was used as the criterion for operability. CONCLUSION: By using a combination of oxygen and inhaled nitric oxide, a greater number of appropriate candidates for corrective cardiac surgery or transplantation can be identified during preoperative testing when a specific value of Rp:Rs is used as a criterion for operability.

Administration, Inhalation↗
PubMed2002

Identification of the p33(ING1)-regulated genes that include cyclin B1 and proto-oncogene DEK by using cDNA microarray in a mouse mammary epithelial cell line NMuMG.

The candidate tumor suppressor p33(ING1) plays an important role in inducinggrowth arrest at G(0)-G(1) phase of the cell cycle and/or promoting apoptosis in cancerous cells. p33(ING1) is reported to act as a transcriptional cofactor by associating with tumor suppressor p53, HAT, or histone deacetyltransferase, suggesting that p33(ING1) is involved in chromatin-mediated transcriptional regulation. However, the molecular mechanism of p33(ING1)-mediated transcriptional regulation is poorly understood. Here we analyzed expression profiles in mouse mammary epithelial cells (NMuMG) by using a cDNA microarray consisting of 2304 mouse cDNAs after inducing transformation with antisense inhibitor of growth 1 (ING1) in retrovirus vector. The subsequent confirmation of the altered expression levels of the selected genes by semiquantitative reverse transcription-PCR demonstrated that overexpression of the antisense ING1 stimulated expression of 14 genes, which included cyclin B1, 12-O-tetradecanoylphorbol-13-acetate-inducible sequence 11, proto-oncogene DEK, and osteopontin, whereas we have detected transcriptional repression of 5 genes, including TPT1. In addition, adenovirus-mediated overexpression of ING1 in NMuMG cells resulted in down-regulation of cyclin B1, 12-O-tetradecanoylphorbol-13-acetate-inducible sequence 11, DEK, and osteopontin, whereas the levels of TPT1 expression were increased. The further analysis using p53(-/-) SAOS2 cells showed that the p33(ING1)-induced cyclin B1 down-regulation was p53 dependent. Thus, our cDNA microarray analysis suggested that p33(ING1) targets the multiple genes, including proto-oncogene DEK and cyclin B1, at least some of which are regulated in a p53-dependent manner, in the cells undergoing cell growth or apoptosis.

Animals↗
PubMed2002

Physical interaction of p73 with c-Myc and MM1, a c-Myc-binding protein, and modulation of the p73 function.

p73 shares high sequence homology with the tumor suppressor p53. Like p53, ectopic overexpression of p73 induces cell cycle arrest and/or apoptosis, and these biological activities are linked to its sequence-specific transactivation function. The COOH-terminal region of p73 is unique and has a function to modulate DNA-binding ability and transactivation activity. To identify and characterize cellular proteins that interact with the COOH-terminal region of p73 alpha and regulate its activity, we employed a yeast-based two-hybrid screen with a human fetal brain cDNA library. We found MM1, a nuclear c-Myc-binding protein, was associated with p73 alpha in both yeast two-hybrid and in vitro pull-down assays. In mammalian cells, MM1 co-immunoprecipitated with p73 alpha, whereas p73 beta and tumor suppressor p53 did not interact with MM1. Overexpression of MM1 in p53-deficient osteosarcoma SAOS-2 cells enhanced the p73 alpha-dependent transcription from the p53/p73-responsive Bax and PG13 promoters, whereas p73 beta- and p53-mediated transcriptional activation was unaffected in the presence of MM1. MM1 also stimulated the p73 alpha-mediated growth suppression in SAOS-2 cells. More importantly, we found that c-Myc was physically associated with p73 alpha and significantly impaired the transcriptional activity of p73 alpha on Bax and p21(waf1) promoters. Expression of MM1 strongly reduced the c-Myc-mediated inhibitory activity on p73 alpha. These results suggest that MM1 may act as a molecular partner for p73 to prevent the c-Myc-mediated inhibitory effect on its activity.

Base Sequence↗
PubMed2002

Respiratory epithelial adenomatoid hamartoma in the nasal cavity.

We report a 65-year-old male with a hamartoma in the left nasal cavity. A mass was found in the left nasal cavity and was diagnosed as a benign tumor on the basis of preoperative findings. Left lateral rhinotomy was performed to completely remove it and the lesion was found to have arisen from the inferior turbinate. The pathological diagnosis was respiratory epithelial adenomatoid hamartoma. We discuss the pathological features of this disease.

Adenoma↗
PubMed2002

Autoinhibitory regulation of p73 by Delta Np73 to modulate cell survival and death through a p73-specific target element within the Delta Np73 promoter.

p73 is a p53-related tumor suppressor but is also induced by oncogene products such as E2F-1, raising a question as to whether p73 is a tumor suppressor gene or oncogene. Unlike p53, p73 has several variants, including Delta Np73, which lacks the NH(2)-terminal transactivation domain. Although, in developing neurons, Delta Np73 is expressed abundantly and seems to inhibit the proapoptotic function of p53, the role of p73 and Delta Np73 and their regulatory mechanism in cell growth and differentiation are poorly understood. Here we report that p73, but not p53, directly activates the transcription of endogenous Delta Np73 by binding to the p73-specific target element located at positions -76 to -57 within the Delta Np73 promoter region. The activation of Delta Np73 promoter by p63 was marginal. Delta Np73 was associated with p73 alpha, p73 beta, and p53, as demonstrated by immunoprecipitation assays, and inhibited their transactivation activities when we used reporters of Mdm2, Bax, or Delta Np73 itself in SAOS-2 cells. Furthermore, induction or overexpression of Delta Np73 promoted cell survival by competing with p53 and p73 itself. Thus, our results suggest that the negative feedback regulation of p73 by its target Delta Np73 is a novel autoregulatory system for modulating cell survival and death.

Animals↗
PubMed2002

Monitoring of side shift exercise using an electromagnetic three-dimensional measuring device.

In order to investigate the usefulness of an electromagnetic three-dimensional measuring device as a monitor for the side shift exercise, the evaluation by the well-trained physical therapist as to whether the exercise was properly performed or not was compared with the evaluation using data obtained by the device. The side shift exercises performed by twenty-four female patients with idiopathic scoliosis were classified as "good," "rotation," or "bend" by the well-trained physical therapist. By the use of the data obtained by the electromagnetic three-dimensional measuring device, whether the exercise was "rotation" or not could be predicted with 100% sensitivity and 100% specificity, and whether the exercise was "bend" or not could be predicted with 83% sensitivity and 100% specificity. These results suggested that the electromagnetic three-dimensional measuring device could be a useful monitor for the side shift exercise.

Adolescent↗
PubMedDate not supplied

Expression of ABC transporters in human hepatocyte carcinoma cells with cross-resistance to epirubicin and mitoxantrone.

BACKGROUND: In order to understand the cross-resistance between epirubicin (EPI) and mitoxantrone (MIT), EPI- and MIT-resistant cells were established and their cross-resistance was evaluated. MATERIALS AND METHODS: The degrees of growth inhibition of EPI-resistant HLE-EPI cells and MIT-resistant HLE-MIT cells by anticancer drugs were measured. The mRNA expressions of multidrug resistance protein 1 (MDR1)/ABCB1 and breast cancer resistance protein (BCRP)/ABCG2 were also measured by quantitative real-time RT-PCR. Moreover, intracellular accumulation of EPI was investigated. RESULTS: HLE-EPI cells were resistant to EPI, MIT and docetaxel. HLE-MIT cells were resistant to EPI, MIT and SN-38. HLE-EPI cells overexpressed MDR1 and HLE-MIT cells overexpressed BCRP. The intracellular accumulation of EPI was decreased in HLE-EPI and HLE-MIT cells. CONCLUSION: The results suggest that both MDR1 and BCRP can up-regulate the efflux of EPI causing resistance to EPI in HLE-EPI and HLE-MIT cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗