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Naoto Watanabe

Publications and source records attributed to Naoto Watanabe.

At least 19 recordsLinked to original sources
PubMed2007

Intraperitoneal radioimmunotherapy to treat the early phase of peritoneal dissemination of human colon cancer cells in a murine model.

BACKGROUND AND AIM: In patients with a high risk of peritoneal dissemination of colon cancer, a treatment adjuvant to surgical resection would improve their prognosis. We aimed to determine whether radioimmunotherapy employing radiolabelled monoclonal antibody would work in this situation. METHODS: A murine model of peritoneal dissemination was established in female Balb/c nu/nu mice by intraperitoneal injection of LS180 human colon cancer cells. Radioimmunotherapy with 7.4 MBq of a murine IgG1, anti-colorectal A7 monoclonal antibody, radiolabelled with (131)I by the chloramine-T method was conducted intraperitoneally on days 0, 3, 7 and 14 after cell inoculation, respectively. RESULTS: Radioimmunotherapy at any timing improved survival of mice as compared with those of non-treated mice and mice treated with a daily dose of 30 mg x kg(-1) of 5-fluorouracil for 4 consecutive days. The best improvement was obtained when radioimmunotherapy was conducted on day 0. CONCLUSION: These results indicate that intraperitoneal radioimmunotherapy may effectively kill colon cancer cells disseminated in the peritoneal cavity before formation of tumours and, therefore, may work as an adjuvant treatment to prevent peritoneal metastasis of colon cancer.

Animals↗
PubMed2006

C-terminal fragment of presenilin is the molecular target of a dipeptidic gamma-secretase-specific inhibitor DAPT (N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester).

Gamma-secretase is a multimeric membrane protein complex composed of presenilin (PS), nicastrin, Aph-1 and, Pen-2 that is responsible for the intramembrane proteolysis of various type I transmembrane proteins, including amyloid beta-precursor protein and Notch. The direct labeling of PS polypeptides by transition-state analogue gamma-secretase inhibitors suggested that PS represents the catalytic center of gamma-secretase. Here we show that one of the major gamma-secretase inhibitors of dipeptidic type, N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT), targets the C-terminal fragment of PS, especially the transmembrane domain 7 or more C-terminal region, by designing and synthesizing DAP-BpB (N-[N-(3,5-difluorophenacetyl)-l-alanyl]-(S)-phenylglycine-4-(4-(8-biotinamido)octylamino)benzoyl)benzyl)methylamide), a photoactivable DAPT derivative. We also found that DAP-BpB selectively binds to the high molecular weight gamma-secretase complex in an activity-dependent manner. Photolabeling of PS by DAP-BpB is completely blocked by DAPT or its structural relatives (e.g. Compound E) as well as by arylsulfonamides. In contrast, transition-state analogue inhibitor L-685,458 or alpha-helical peptidic inhibitor attenuated the photolabeling of PS1 only at higher concentrations. These data illustrate the DAPT binding site as a novel functional domain within the PS C-terminal fragment that is distinct from the catalytic site or the substrate binding site.

Amyloid Precursor Protein Secretases↗
PubMed2006

99mTc-sestamibi to monitor treatment with antisense oligodeoxynucleotide complementary to MRP mRNA in human breast cancer cells.

OBJECTIVE: Technetium-99m sestamibi (MIBI) has been utilized to evaluate multi-drug resistance (MDR) phenomenon of malignant tumors and to predict chemotherapeutic effects on them. The current investigation examined the possibility of monitoring changes with respect to mRNA expression of multi-drug resistance associated protein (MRP) following antisense oligodeoxynucleotide (AS-ODN) treatment involving 99mTc-MIBI. METHODS: The human breast cancer MCF-7 cell line and its MDR-induced MCF-7/VP cell line were employed. Cell suspensions of the two cell lines at 1 x 10(4) cells/ml were inoculated in 24-well plates (0.2 ml/well) and incubated for one day. Antisense (AS) 20-mer phosphorothioate ODN complementary to the coding region of MRP mRNA and its sense (S) ODN were administered at final concentrations up to 25 microM, followed by a 5-day incubation. 99mTc-MIBI solution was added to each well and incubated for 30 min. Cellular 99mTc-MIBI uptake was corrected for protein concentration. MRP mRNA expression levels were analyzed via the reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Cellular uptake of 99mTc-MIBI in MCF-7/VP cells was only 15% of that of MCF-7 cells. Following AS-ODN treatment at 25 microM for five days, 99mTc-MIBI uptake in MCF-7/VP cells increased 2.4-fold in comparison with non-treated control cells. 99mTc-MIBI uptake in MCF-7 cells was unaffected by AS-ODN administration. Sense ODN did not alter uptake in either cell line. RT-PCR confirmed reduction of MRP mRNA in MCF-7/VP cells following AS-ODN treatment. CONCLUSION: Effects of AS-ODN administration on MRP function can be monitored via assessment of cellular uptake of 99mTc-MIBI.

Breast Neoplasms↗
PubMed2006

Expression and localization of TRPV1 in human nasal mucosa.

Capsaicin is the pungent principle in chili peppers and previous studies reported that topical application of capsaicin to patients with allergic and non-allergic rhinitis produced significant and long-lasting relief of symptoms. The capsaicin receptor (TRPV1, VR1) is a nociceptive transducer and the existence of TRPV1 in non-neuronal cells as well as neuronal cells has been reported. In order to clarify the role of TRPV1 on the upper airway, we examined the localization and the expression of TRPV1 in human nasal mucosa. Surgically obtained human nasal specimens were processed for immunohistochemistry with commercial anti-TRPV1 antibody. We also performed immunofluorescence with anti-TRPV1 antibody and anti-neurofilament antibody or anti-CD31 antibody. Epithelial cells and vascular endothelial cells were cultured from nasal turbinates, respectively. For RT-PCR analysis, total RNA was isolated, and then RT-PCR was performed. Immunohistochemical studies revealed that TRPV1 positive cells were found on epithelial cells, vascular endothelial cells, submucosal glands and nerves in human nasal mucosa. By RT-PCR analysis, the mRNA expression of TRPV1 was confirmed in human nasal mucosa. These results suggest that capsaicin can directly influence the epithelial secretory and various functions via TRPV1 as well as the activation of the sensory neurons.

Adolescent↗
PubMed2005

Prefrontal abnormalities in patients with simple schizophrenia: structural and functional brain-imaging studies in five cases.

Simple schizophrenia is an uncommon disorder with unknown pathophysiology, and its position in the current diagnostic system is ambiguous. Brain-imaging studies may help to elucidate its pathophysiology. Five patients fulfilling both ICD-10 criteria for simple schizophrenia and DSM-IV criteria for simple deteriorative disorder underwent computed tomography, magnetic resonance imaging, and single photon emission computed tomography. These scans were assessed individually by visual inspection as well as automatically by comparison with scans in normal controls or other schizophrenia subtype patients using voxel-based image analyses. Three of the five simple schizophrenia patients had findings of atrophy and reduced cerebral perfusion in the frontal areas. Voxel-based analyses also showed prefrontal grey matter deficits and hypoperfusion in simple schizophrenia patients compared with the controls. Although this study is limited by the small number of patients with simple schizophrenia, the results suggest that simple schizophrenia, or at least this subpopulation, may have rather homogeneous morphological and functional deficits in the prefrontal cortex. It is also suggested that simple schizophrenia may occupy an extreme position of the schizophrenic continuum where the prefrontal deficits and negative symptoms are most purely manifested.

Adult↗
PubMed2005

Pen-2 is incorporated into the gamma-secretase complex through binding to transmembrane domain 4 of presenilin 1.

gamma-Secretase is a multimeric membrane protein complex comprised of presenilin (PS), nicastrin (Nct), Aph-1, and Pen-2. It is a member of an atypical class of aspartic proteases that hydrolyzes peptide bonds within the membrane. During the biosynthetic process of the gamma-secretase complex, Nct and Aph-1 form a heterodimeric intermediate complex and bind to the C-terminal region of PS, serving as a stabilizing scaffold for the complex. Pen-2 is then recruited into this trimeric complex and triggers endoproteolysis of PS, conferring gamma-secretase activity. Although the Pen-2 accumulation depends on PS, the binding partner of Pen-2 within the gamma-secretase complex remains unknown. We reconstituted PS1 in Psen1/Psen2 deficient cells by expressing a series of PS1 mutants in which one of the N-terminal six transmembrane domains (TMDs) was swapped with those of CD4 (a type I transmembrane protein) or CLAC-P (a type II transmembrane protein). We report that the proximal two-thirds of TMD4 of PS1, including the conserved Trp-Asn-Phe sequence, are required for its interaction with Pen-2. Using a chimeric CD4 molecule harboring PS1 TMD4, we further demonstrate that the PS1 TMD4 bears a direct binding motif to Pen-2. Pen-2 may contribute to the activation of the gamma-secretase complex by directly binding to the TMD4 of PS1.

Amino Acid Sequence↗
PubMed2005

Exercise training enhances tumor necrosis factor-alpha-induced expressions of anti-apoptotic genes without alterations in caspase-3 activity in rat epididymal adipocytes.

The effect of exercise training on tumor necrosis factor-alpha (TNF-alpha) signaling was investigated in rat epididymal adipocytes. Incubation of isolated adipocytes with TNF-alpha (20 ng/ml) for 5 h enhanced the expression of the inhibitor apoptosis protein 2 (IAP2) gene without any enhancement of caspase-3 activity in both the sedentary control (C) and exercise-trained (TR) groups. However, the ability of TNF-alpha to enhance IAP2 gene expression was significantly greater in TR than in C rats. The basal expression of the IkappaB kinase beta (IKK beta) gene and that of the BCL-x(L) gene were also higher in TR than in C rats. Mn-superoxidedismutase contents in adipocytes were higher in TR than in C rats. Moreover, no apoptotic nucleuses of adipocytes in response to acute exercise were observed in either group at least up to 5 h after exercise. Exercise training also enhanced the inhibitory effect of TNF-alpha on the gene expression of the fatty acid synthase (FAS), a lipogenic enzyme, suggesting that fatty acid synthesis may be reduced. Thus, exercise training enhanced TNF-alpha signaling directed toward the expressions of survival signals and the suppression of FAS gene expression.

Adipocytes↗
PubMed2005

Locoreginal radioimmunotherapy with 186Re-labeled monoclonal antibody in treating small peritoneal carcinomatosis of colon cancer in mice in comparison with 131I-counterpart.

The efficacy of locoregional radioimmunotherapy (RIT) in treating peritoneal tumors of colon cancer of <2 mm in diameter was examined at maximum tolerated doses, focusing the comparison between 186Re and 131I labeled to an anti-colorectal cancer IgG1. Estimated radiation doses to tumors were considerably higher with 186Re-RIT than with 131I-RIT. The advantage of 186Re-RIT decreased with decreasing tumor size, but 186Re-RIT delivered 1.6-times higher radiation to tumors of 1 mm. Consequently, 186Re-RIT attained better survival of mice than 131I-RIT or chemotherapy with 5-fluorouracil did. Therefore, locoregional 186Re-RIT may be an option in an adjuvant setting of colon cancer with high risk of peritoneal dissemination.

Animals↗
PubMed2005

Immunohistochemical localization of vanilloid receptor subtype 1 (TRPV1) in the guinea pig respiratory system.

Transient receptor potential vanilloid-1 (TRPV1) containing nerves are implicated in cough and bronchoconstriction although the significance of their documentation on non-neuronal cells is unclear. We have investigated the anatomical distribution and location of TRPV1 in an animal species often utilized in models of cough and airway inflammation. The distribution and localization of TRPV1 immunoreactivity in the lung was studied using confocal microscopy. Double labelling were carried out using the panaxonal marker, protein gene product 9.5 (PGP) and the neuropeptide substance P. TRPV1 was localized to fine axons within the epithelium of the trachea, however this represented only a fraction of the total axonal innervation of the epithelium. TRPV1 immunoreactive axons were also found in and around subepithelial regions of the airways, including smooth muscle and blood vessels and within the lower airways, found in the vicinity of bronchi and bronchioles, and in and around alveolar tissue. TRPV1 in the epithelium of the trachea was co-localized with substance P containing axons, although TRPV1 immunoreactive neuropeptide negative axons were also discernible. We found evidence for TRPV1 localization to axons throughout the respiratory tract. The distribution was heterogeneous and represented a fraction of the total neuronal innervation of the airways. No TRPV1 was found localized to airway epithelial cells. TRPV1 was often co-localized with the sensory neuropeptide substance P but there was evidence of TRPV1 positive neurones that did not express substance P. This suggests a role for TRPV1 in the airway that is independent of sensory neuropeptides.

Animals↗
PubMed2005

Anti-angiogenic therapy and chemotherapy affect 99mTc sestamibi and 99mTc-HL91 accumulation differently in tumour xenografts.

BACKGROUND: Favourable effects of cytotoxic chemotherapy for tumours are characterized by the reduced accumulation of radiotracers such as 99mTc sestamibi (MIBI). Anti-angiogenic therapy is primarily cytostatic; consequently, its influence on tracer accumulation may differ from that of cytotoxic treatments. METHODS: Anti-angiogenic therapy employing 2-methoxyestradiol was administered in mice bearing subcutaneous xenografts of LS180 colon cancer cells. The effects of chemotherapy with 5-fluorouracil were examined as a cytotoxic counterpart. Treatments were conducted for 4 days from day 8. Distribution of 99mTc-MIBI and Tc-HL91, a hypoxic marker, was observed on days 8 and 12. Oxygen tension (PO2) in tumours was measured by a microelectrode. Cellular uptake of tracers was examined in vitro in normoxic and hypoxic conditions. RESULTS: 99mTc-MIBI accumulation decreased with increasing tumour weight when no treatment was conducted. Tumour growth was suppressed by anti-angiogenic therapy and chemotherapy. 99mTc-MIBI accumulation in tumours decreased after chemotherapy as compared to pre-therapeutic values, whereas accumulation of 99mTc-HL91 increased. In contrast, accumulation of tracers did not significantly change after anti-angiogenic therapy as compared to that observed pre-therapeutically. Tumour PO2 decreased with increasing tumour volume when no treatment was conducted. Chemotherapy reduced PO2 in tumours. PO2 in tumours treated with anti-angiogenic therapy was as high as that observed before treatment. 2-Methoxyestradiol or 5-fluorouracil did not significantly affect tracer accumulation in cells under both normoxic and hypoxic conditions in vitro. CONCLUSION: These findings indicate that scintigraphic assessment of therapeutic efficacy of anti-angiogenic therapy should be performed from a perspective distinct from that of cytotoxic treatment.

2-Methoxyestradiol↗
PubMed2005

Distinct patterns of gene expression in hepatocellular carcinomas and adjacent non-cancerous, cirrhotic liver tissues in rats fed a choline-deficient, L-amino acid-defined diet.

Gene expression profiles of HCC and surrounding non-cancerous tissues in rats fed a CDAA diet for 70 weeks, as well as normal liver tissues, were explored using an oligonucleotide microarray for 3757 genes. A total of 146 genes were identified as differentially expressed; the affected functions including metabolism, apoptosis, cell cycling, RNA splicing, Wnt signaling, reactive oxygen species-induced stress, and fibro/cirrhogenesis. The genes were found to fit into four distinct expression patterns after classification by hierarchical and k-means clustering procedures. Notably, genes within the same functional category tended to be found within the same cluster, thus gene functions appeared to be related to their expression patterns. For example, genes encoding receptors (Fisher's exact test, P < 0.01) and cytokines (Fisher's exact test, P < 0.05) were both enriched in a cluster characterized by low expression in HCC compared to their surrounding tissues. While some of the receptors in this cluster had cell-proliferative potential, others are known to be growth-suppressive. It was noted, however, that four of the 10 receptor genes encode G-protein-coupled receptors, for which growth-suppressive potential has been reported. The seven growth factors in the same cluster included two fibroblast growth factors. The current findings suggest the possibility that genes differentially expressed in this multistep carcinogenic model may be classified into relatively few clusters according to their expression patterns, and that these clusters may be associated with gene functional categories.

Amino Acids↗
PubMed2004

Improved survival of mice bearing liver metastases of colon cancer cells treated with a combination of radioimmunotherapy and antiangiogenic therapy.

We attempted to determine whether the combined regimen of radioimmunotherapy (RIT) and antiangiogenic therapy would favorably affect the survival of animals bearing liver metastases of colon cancer cells. Daily antiangiogenic therapy with 2-methoxyestradiol (2-ME), 75 mg/kg, was initiated at 3 days following intrasplenic cell inoculation of LS180 colon cancer cells. RIT with 7 MBq of (131)I-A7, an IgG1 anti-colorectal monoclonal antibody, or (131)I-HPMS-1, an irrelevant IgG1, was conducted at 7 days. Production of vascular endothelial growth factor (VEGF) by LS180 cells was assessed in vitro. All nontreated mice died by 31 days following cell inoculation ( n=5). Monotherapy comprising 2-ME treatment resulted in slightly better survival of mice ( n=8) ( P<0.05). (131)I-A7 RIT displayed a marked therapeutic effect ( n=8) ( P<0.001); however, all animals eventually died due to metastases by 99 days. The combined regimen of (131)I-A7 RIT and antiangiogenic therapy demonstrated a superior therapeutic effect in comparison to monotherapy consisting of either RIT or antiangiogenic therapy ( n=10) ( P<0.05); three mice survived the entire 160-day observation period. The combination of antiangiogenic therapy and (131)I-HPMS-1 RIT failed to provide an appreciable benefit ( n=5). Treatment with 2-ME decreased VEGF production by LS180 cells in a dose-dependent fashion. In conclusion, a combination regimen comprising RIT and antiangiogenic therapy initiated at the early stage of metastasis would be of great benefit in terms of improvement of the therapeutic efficacy with respect to liver metastases.

Angiogenesis Inhibitors↗
PubMed2004

FDG-PET imaging in duodenal cancer.

F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) imaging is a useful modality in the detection of various tumors, including colon cancer and gastric cancer. We evaluated a patient with duodenal cancer with multiple metastases including brain metastases using FDG-PET imaging. It revealed multiple tumor uptake in the brain, clavicular fossa, mediastinum, right adrenal gland and duodenum. These results suggest that FDG-PET imaging may be useful in detecting the primary and metastatic lesions of duodenal adenocarcinoma.

Adenocarcinoma↗
PubMed2004

A case of renal pelvic tumor visualized by 18F-FDG-PET imaging.

18F fluorodeoxyglucose positron emission tomography (18F-FDG PET) imaging is a useful modality in detecting various tumors, including renal cell carcinoma. We evaluated a patient with renal pelvic tumor (transitional cell carcinoma) with multiple metastases using 18F-FDG PET imaging and detected abnormal increased uptake of a right renal pelvic tumor extending to the renal cortex with liver metastasis and paraaortic lymph node metastases. These results suggest that 18F-FDG PET imaging may be useful in detecting primary and metastatic lesions of renal pelvic tumor (transitional cell carcinoma).

Aged↗
PubMed2004

Limitations of (99m)Tc tetrofosmin in assessing reversal effects of verapamil on the function of multi-drug resistance associated protein 1.

BACKGROUND: Previous reports have demonstrated the feasibility of scintigraphic assessment of the multi-drug resistance (MDR) of tumours caused by ATP binding cassette (ABC) transporters by using Tc cationic tracers such as Tc tetrofosmin (TF). Furthermore, the potential of these tracers for evaluating the effects of reversal agents for MDR has been documented. However, most reversal agents simultaneously affect cationic ion transporters related to tracer accumulation in tumours. METHODS: The uptake of Tc-TF was examined in the MCF7/WT cell line, a wild-type breast cancer cell line that does not exhibit MDR, and its subclonal etoposide resistant cell line MCF7/VP, which expresses high levels of MRP1, one of the multi-drug resistance associated proteins (MRPs), in the presence of increasing concentrations of verapamil, a classical MDR modulator. In the absence of verapamil, MCF7/VP cells showed significantly lower Tc-TF uptake than did MCF7/WT cells, indicating that Tc-TF is a substrate for MRP1. The presence of verapamil enhanced the uptake of Tc-TF in MCF7/VP cells. On the other hand, verapamil also increased tracer uptake in MCF7/WT cells, which was readily appreciated when the uptake values were corrected by viable cell numbers: an approximately 100% increase of Tc-TF uptake was observed in comparison with that in the absence of verapamil in viable MCF7/WT cells whereas a 100-200% increase occurred in viable MCF7/VP cells. In addition, verapamil prolonged the retention of radioactivity in both MCF7/WT cells and MCF7/VP cells. CONCLUSION: These results suggest that cellular functions other than MRP1 function, probably cationic ion transporters, are simultaneously and significantly involved in the verapamil induced changes of cellular uptake of Tc-TF. Tc-TF scintigraphy may overestimate the reversal effects of modulators on chemoresistance caused by MRP1 when the modulators simultaneously affect ion transporters.

ATP Binding Cassette Transporter, Subfamily B, Mem↗