Biomedical subjects

Hideki Nagase

Publications and source records attributed to Hideki Nagase.

7 recordsLinked to original sources

PubMed2006

Additive antitumor effect of concurrent treatment of 4-hydroxy tamoxifen with 5-fluorouracil but not with doxorubicin in estrogen receptor-positive breast cancer cells.

PURPOSE: The sequential addition of tamoxifen (TAM) to chemotherapy seems superior to its concurrent addition in patients with breast cancer. This study was conducted to clarify the hypothesis that there are differential interactions among TAM and chemotherapeutic agents. METHODS: Estrogen receptor (ER)-alpha-positive or -negative breast cancer cells were treated with 4-hydroxy TAM (4OHT), 5-fluorouracil (FU) and/or doxorubicin (Dox). Changes in the expression levels of genes related to sensitivity and resistance to TAM, 5-FU or Dox were tested. RESULTS: Concurrent treatment of 4OHT with 5-FU but not with Dox additively inhibited the growth of ER-alpha-positive cells. 5-FU did not change the expression levels of any tested genes related to either sensitivity or resistance to TAM. Although Dox did not change the expression levels of any genes related to the sensitivity to TAM, Dox significantly increased the expression levels of some genes related to TAM resistance, Eph A-2, ER-beta, Fos and vascular endothelial growth factor. 4OHT significantly decreased thymidilate synthase (TS) activity. CONCLUSIONS: Although the antitumor effect of concurrent 4OHT and 5-FU was additive, that of concurrent 4OHT and Dox was less than additive in ER-alpha-positive cells. The increased expression of genes related to TAM resistance by Dox might be responsible for the interaction. Decreased TS activity by 4OHT might increase the antitumor activity of 5-FU. These findings may provide a preclinical rationale for concurrent use with 5-FU and TAM.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2006

Gene expression analysis using human cancer xenografts to identify novel predictive marker genes for the efficacy of 5-fluorouracil-based drugs.

The development of a diagnostic method for predicting the therapeutic efficacy or toxicity of anticancer drugs is a critical issue. We carried out a gene expression analysis to identify genes whose expression profiles were correlated with the sensitivity of 30 human tumor xenografts to 5-fluorouracil (5-FU)-based drugs (tegafur + uracil [UFT], tegafur + gimeracil + oteracil [S-1], 5'-deoxy-5-fluorouridine [5'-DFUR], and N4-pentyloxycarbonyl-5'-deoxy-5-fluorocytidine [capecitabine]), as well as three other drugs (cisplatin [CDDP], irinotecan hydrochloride [CPT-11], and paclitaxel) that have different modes of action. In the present study, we focused especially on the fluoropyrimidines. The efficacy of all anticancer drugs was assayed using human tumor xenografts in nude mice. The mRNA expression profile of each of these xenografts was analyzed using a Human Focus array. Correlation analysis between the gene expression profiles and the chemosensitivities of seven drugs identified 39 genes whose expression levels were correlated significantly with multidrug sensitivity, and we suggest that the angiogenic pathway plays a pivotal role in resistance to fluoropyrimidines. Furthermore, many genes showing specific correlations with each drug were also identified. Among the candidate genes associated with 5-FU resistance, the dihydropyrimidine dehydrogenase mRNA expression profiles of the tumors showed a significant negative correlation with chemosensitivity to all of the 5-FU based drugs except for S-1. Therefore, the administration of S-1 might be an effective strategy for the treatment of high dihydropyrimidine dehydrogenase-expressing tumors. The results of the present study may enhance the prediction of tumor response to anticancer drugs and contribute to the development of tailor-made chemotherapy.

Animals↗

PubMed2006

hRFI overexpressed in HCT116 cells modulates Bcl-2 family proteins when treated with 5-fluorouracil.

Exogenous overexpression of hRFI, originally isolated in our laboratory, inhibits not only death receptor-mediated apoptosis but also the mitochondrial apoptosis induced by several chemotherapeutic agents including 5-fluorouracil (5-FU). Recently, it has become clear that hRFI targets and degradates caspase-8 and -10 in death receptor-mediated apoptosis by E3 ubiquitin activity in a ring finger domain homologous to that of X-chromosome-linked inhibitor of apoptosis protein (XIAP). However, the cellular mechanism of the inhibition of mitochondrial apoptosis by hRFI has not been fully elucidated. We prepared HCT116 overexpressing hRFI (HCT116/hRFI) cells and comprehensively analyzed the expression changes of 51 apoptosis-related genes with or without 5-FU treatment between HCT116/hRFI and mock cells using microfluidic low-density arrays. As a result, we identified four genes (Bcl-2, Bcl-XL, cIAP2, and CFLAR) whose expression was four or more times higher in HCT116/ hRFI cells than in HCT116/LacZ cells, and found that Bcl-2 and the ratio of Bcl-2/Bax or Bcl-2/Bak were upregulated when HCT116/hRFI cells were treated with 5-FU. Furthermore, we also validated the up-regulation of Bcl-2 and Bcl-XL in HCT116/hRFI cells treated with 5-FU by Western blot analysis. Such evidence suggests that the modulation of Bcl-2 family proteins seen in 5-FU treatment plays an important role in the anti-apoptotic function of HCT116/hRFI cells.

Antimetabolites, Antineoplastic↗

PubMed2003

Prolonged bleeding time induced by anticoagulant glycosaminoglycans in dogs is associated with the inhibition of thrombin-induced platelet aggregation.

INTRODUCTION: The clinical use of unfractionated heparin (UFH) is complicated by hemorrhage. This has led to a search for safer alternatives, one of which, the recently identified depolymerized holothurian glycosaminoglycan (DHG), causes less bleeding and exhibits a better antithrombotic-hemorrhagic ratio in rats and dogs than UFH and low-molecular-weight heparin (LMWH). In contrast to UFH and LMWH, which exert their anticoagulant effects by inhibiting thrombin in the presence of antithrombin III (AT), DHG exerts its anticoagulant effect by inhibiting the intrinsic factor Xase complex and thrombin in the presence of heparin cofactor II (HCII). MATERIALS AND METHODS: The hemorrhagic effect of DHG was compared with those of UFH and LMWH in healthy dogs, and the mechanism responsible for prolonging bleeding time was examined both in dogs and with human platelets. RESULTS: DHG prolonged template-bleeding time in dogs less than UFH and LMWH do. Although the maximum noneffective concentrations of each glycosaminoglycan (GAG) that prolong the bleeding time are almost the same as the concentrations that inhibit thrombin-induced platelet aggregation, they are not related to those that inhibit ADP-induced platelet aggregation. Results of experiments on gel-filtered platelets from humans indicate that the inhibition of thrombin-induced platelet aggregation caused by UFH and LMWH in the presence of AT is more prominent than that caused by DHG with HCII. CONCLUSIONS: These results suggest that the prolongation of bleeding time caused by GAGs are associated with the inhibition of thrombin-induced platelet aggregation, and DHG may cause less bleeding than UFH and LMWH because of its different thrombin inhibition mechanism in platelet-rich plasma (PRP).

Animals↗

PubMed2003

Depolymerized holothurian glycosaminoglycan (DHG), a novel alternative anticoagulant for hemodialysis, is safe and effective in a dog renal failure model.

BACKGROUND: Depolymerized holothurian glycosaminoglycan (DHG) is a new agent with anticoagulant properties quite different from those of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) in terms of antithrombin III-dependency, and exerts an antithrombotic effect with less bleeding than UFH and LMWH in vivo. In this study, the anticoagulant and hemorrhagic effects of DHG were investigated on hemodialysis in a dog model of renal failure and compared with those of UFH, LMWH, and nafamostat mesilate (FUT). METHODS: The dog renal failure model was prepared by 7/8 renal artery ligation. Effectiveness was based on completion of 3-hour hemodialysis, no marked clot deposition in the extracorporeal circuit, and permeability of blood urea nitrogen (BUN) and creatinine. Template bleeding was measured by determining the hemoglobin content of the blood from the wound. RESULTS: DHG induced no major bleeding or clot formation during 3-hour hemodialysis, in contrast to UFH and LMWH, each of which induced marked bleeding. These glycosaminoglycans (GAGs) were equally effective in decreasing plasma levels of BUN and creatinine. On the other hand, dogs treated with FUT failed to complete 3-hour hemodialysis. These anticoagulants prolonged activated partial thromboplastin time (APTT) to different extents and GAGs prolonged thrombin clotting time markedly but FUT did not. CONCLUSION: Our findings suggest that thrombin clotting time prolongation can contribute to prevention of clot formation in extracorporeal circuits, and the non-antithrombin III-dependent activities of DHG may be related to its low risk of hemorrhage for hemodialysis. DHG appears to be promising as an alternative anticoagulant with low risk of hemorrhage for hemodialysis.

Animals↗

PubMed2002

Species-specific differences in the glucocorticoid receptor transactivation function upon binding with betamethasone-esters.

Glucocorticoids (GCs) are the most effective drugs for anti-inflammatory diseases. A number of adverse side effects, however, limit chronic treatment with GCs. To improve their therapeutic usefulness, attempts have been made to dissociate the two main actions of the glucocorticoid receptor (GR), transactivation and transrepression, which are believed to be responsible for the side effects and anti-inflammatory effects, respectively. We report here species-specific differences in the transactivation response mediated by GR. Dexamethasone (DEX), betamethasone (BM), and their esterified-derivatives had full transrepression agonistic activity in a reporter assay using CV-1 cells transfected with either human or rat GR. These GCs also had full transactivation agonistic activity in CV-1 cells transfected with human GR. The esterified-BM, however, had only partial transactivation agonistic activity in cells transfected with rat GR, whereas BM and esterified-DEX had full transactivation agonistic activity. Moreover, in rat hepatoma H4-II-E cells, the esterified-BM failed to induce tyrosine aminotransferase, which is regulated by GR-mediated transactivation activity. There were no significant differences between the binding affinity of these GCs to human and rat GR. Consistent with the weak transactivation activity of esterified-BM mediated by rat GR, there were few side effects, evaluated by thymus involution and body weight loss, in an antigen-induced asthmatic model in rats. These results suggest that the potency of esterified-BM to induce transactivation activity is different between species and that this difference is not due to differences in receptor binding.

Animals↗

PubMed2002

Cell type-dependent divergence of transactivation by glucocorticoid receptor ligand.

The glucocorticoid receptor regulates gene expression mainly by two mechanisms; transactivation and trans-repression. A ligand with strong transrepression and weak transactivation activity is predicted to be a beneficial agent with potent anti-inflammatory activity and minor adverse effects. Recently, the profile of a synthetic steroid, RU24858, has been reported to fulfill this condition in vitro, but others have reported no dissociation between the anti-inflammatory activity and side effects in vivo. To gain further information on the profile of this compound, we evaluated its transactivation ability using a reporter gene analysis both in vitro and in vivo. In the in vitro analysis, RU24858 demonstrated only a weak transactivation activity in HeLa cells, when compared with prednisolone. In CV-1 cells, however, these two glucocorticoids exhibited equivalent transactivation activities. This behavior is independent of whether the reporter gene is regulated by mouse mammary tumor virus promoter or multiple copies of glucocorticoid response element. When the reporter plasmid was inoculated into mouse abdominal skin using a gene gun, followed by orally administration of glucocorticoids, RU24858 induced significantly higher reporter enzyme activity than prednisolone. These results suggest that the profile of RU24858 is divergent and its transactivation ability is comparable to prednisolone depending on the cell-type both in vitro and in vivo.

Animals↗