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Biomedical subjects

F Takaku

Publications and source records attributed to F Takaku.

At least 19 recordsLinked to original sources
PubMed2001

Tyrosine phosphorylation of proteins in primary human myeloid leukemic cells stimulated by macrophage colony-stimulating factor: analysis by disease type and comparison with normal human hematopoietic cells.

We investigated tyrosine phosphorylation of proteins in primary human leukemic cells stimulated by macrophage colony-stimulating factor (M-CSF) in 60 patients with acute myeloid leukemia (AML) and 5 patients with chronic myelomonocytic leukemia and compared the findings for leukemic cells with those of normal human monocytes and bone marrow immature hematopoietic cells. M-CSF induced tyrosine phosphorylation of p140-200, p110, p60, p44, and p42 frequently, and that of p95 and p55 less frequently, in primary myeloid leukemic cells, whereas M-CSF-induced phosphorylation of proteins was not detected in the normal human hematopoietic cells tested. Of these phosphoproteins, p140-200 was phosphorylated in all patients who responded to M-CSF and was considered to be almost identical to Fms, a product of the c-fms proto-oncogene. M-CSF-induced tyrosine phosphorylation was observed frequently (89%) in AML of French-American-British class M4 and infrequently in all other subtypes of AML, including M5. In chronic myelomonocytic leukemia, M-CSF-induced protein phosphorylation was prominent in blast crisis but was not detected in the chronic phase. Both bone marrow immature cells and mature monocytes showed low responsiveness to M-CSF. These findings for responsiveness to M-CSF were correlated with the amount of Fms in each type of cell. We also identified tyrosine phosphorylation of Vav, Shc, and extracellular signal-regulated kinase by M-CSF in some cases. These findings clarified an M-CSF-specific pattern of protein tyrosine phosphorylation and the responsiveness to M-CSF of primary human myeloid cells. Particularly, enhanced phosphorylation responses to M-CSF and increased amounts of Fms protein were observed in restricted human hematopoietic cells with a premature myelomonocytic character.

Acute Disease↗
PubMed2001

CREB antisense oligonucleotides induce non-apoptotic cell death in proliferating leukemia cells, but not normal hematopoietic cells, by a bizarre non-antisense mechanism.

We report that antisense phosphorothioate oligodeoxyribonucleotides (PS-ODNs) against cyclic AMP response element-binding protein (CREB) induce the death of human leukemia cell lines including HL-60, Kasumi-1 and K562, OCI-AML1a and also primary leukemia cells isolated from patients with acute myelocytic leukemia and chronic myelocytic leukemia in blastic crisis. In contrast, normal human bone marrow CD34+ cells and normal peripheral blood lymphocytes were resistant to the antisense-mediated cell death. We found that antisense-treated HL-60 cells had prominent nuclear fragmentations but lacked apoptotic features including internucleosomal DNA cleavage and TUNEL positivity. Cell cycle analysis demonstrated a remarkable reduction in G1 phase population along with a mild accumulation of S phase and good preservation of G2/M phase, indicating cells died at G2/M without cycling into G1 phase. None of the sense-sequenced PS-ODNs induced cell death. Further, neither the expression nor the message of CREB protein was reduced by antisense treatment, indicating that cell death was mediated by a non-antisense mechanism. On the other hand, no consensus oligonucleotide sequence for cell death induction was detected. Rather, we found a good correlation between the melting temperatures and the anti-proliferative activities of the oligonucleotides. Thus, CREB antisense PS-ODNs selectively induce a non-apoptotic cell death in leukemic cells by an unknown hybridization-dependent mechanism.

Antigens, CD34↗
PubMed2001

[Overview on the millennium genome project].

Millennium genome project had started 2000 April as a national research project. In this project, analysis of single nucleotide polymorphism of human genome and application of its information on prevention, diagnosis and treatment of major diseases, and on drug development, regenerative medicine, and analysis of rice genome are included. This project is scheduled to complete by 2004. Since large amount of research money and research power is going to be poured to this project, fruitful results are a national expectation.

Forecasting↗
PubMed2000

Improved gene transfer to neuroblastoma cells by a monoclonal antibody targeting RET, a receptor tyrosine kinase.

Receptor-mediated gene transfer is an effective strategy among nonviral vector systems. It is, however, crucial to develop various types of monoclonal antibodies satisfying both the binding specificity for cell targeting and the capacity of endocytosis required for gene transfer. In the present study, we generated a novel monoclonal antibody (NBL-1) to RET, a receptor tyrosine kinase expressed in both neuroblastoma cells and cells present in substantia nigra, a responsive locus of Parkinson's disease. NBL-1, when added to the culture medium of the neuroblastoma cells, was incorporated by endocytosis in a wortmannin-sensitive manner. Using a biotinylated NBL-1 complexed with plasmid DNAs based on electrostatic interaction through avidin-conjugated polylysines, exogenous luciferase genes were expressed in neuroblastoma cells at a more than 10-fold higher level. The expression level of the gene based on NBL-1 was comparable to that obtained by a geneporter system, an improved nonviral gene transduction method. Furthermore, the NBL-1-based gene transfer mediated the formation of more than 20-fold higher numbers of drug-resistant colonies. In contrast, RET-negative cells, which included HeLa, HT1080, Caco-2, and Colo205 cells, did not show any increased expression of an exogenous gene by NBL-1. These data suggest that the RET molecules enable selective gene transduction, and that NBL-1 may possibly be applied to gene therapy for neuroblastomas and Parkinson's disease.

Antibodies, Monoclonal↗
PubMed2000

Bcl-2 down-regulation causes autophagy in a caspase-independent manner in human leukemic HL60 cells.

To understand the roles of bcl-2 for the survival of leukemic cells, we constructed human leukemic HL60 transformant lines in which full length bcl-2 antisense message was conditionally expressed by a tetracycline-regulatable expression system. Cell growth was completely inhibited after antisense message induction and massive cell death was induced. Electron microscopic examinations show that cells died by autophagy, but not by apoptosis. The morphology and the function of mitochondria remained intact: neither the reduction in mitochondrial membrane potential nor the nuclear translocation of AIF, a mitochondrial protein that translocates to nuclei in cases of apoptosis, was observed. Caspase inhibitors did not rescue bcl-2-antisense-mediated autophagy. Thus, bcl-2 is essential for leukemic cell survival and its down-regulation results in autophagy. Cell Death and Differentiation (2000) 7, 1263 - 1269.

Anti-Bacterial Agents↗
PubMed2000

[Clinical evaluation of rhG-CSF in patients with neutropenia induced by chemotherapy for multiple myeloma].

A randomized controlled study of patients with multiple myeloma was performed to evaluate the efficacy and safety of recombinant human granulocyte colony-stimulating factor (rhG-CSF:KW-2228) in treating neutropenia induced by chemotherapy, and its influence on the dose intensity of, and response rate to, chemotherapy. As a rule, 3 courses of chemotherapy at intervals of 4 weeks were administered both to the untreated and KW-2228-treated groups. Among 98 eligible patients evaluated for neutrophil recovery, a markedly reduced duration of neutropenia was observed during each course in the KW-2228 treated group. No significant difference distinguished the two groups in terms of incidence or duration of infection. However, febrile neutropenia appeared only in the untreated group. There was no significant difference in terms of response rate or dose intensity. However, only patients in the untreated group withdrew from the study due to protracted neutropenia. These results demonstrated that KW-2228 is effective and safe, and has a significant effect on the acceleration of neutrophil recovery in patients with neutropenia induced by chemotherapy for multiple myeloma, and is useful for the completion of chemotherapy regimens.

Adolescent↗
PubMed2000

[Evidence-based medicine: present status and problems in our country].

Present status and problems of evidence-based medicine (EBM) in our country are discussed in this paper based on the report from the committee on the EBM of the Ministry of Health and Welfare of our country. Before introducing the content of the report from the above-mentioned governmental committee, a short history of the development of EBM and necessity of introducing the EBM in our country are discussed. In this report, 3 factors necessary to conduct the EBM; 1) clinical practice guidelines which are going to be developed in our country, 2) a strategy to conduct EBM in our country, and 3) problems of EBM in clinical practice have been discussed with a proposal of strategies for the future development of EBM in our country.

Evidence-Based Medicine↗
PubMed2000

[Efficacy and safety of cefozopran (CZOP) monotherapy and combination therapy with CZOP and amikacin (AMK) for infections accompanying hematological diseases].

We evaluated efficacy and safety of monotherapy with CZOP (1-2 g x 2/day) and combination therapy with CZOP (1-2 g x 2/day) and AMK (200 mg x 2/day) for infections in patients with hematological diseases. Efficacy was evaluated in 71 patients of monotherapy group and 70 patients of combination therapy group. Underlying diseases were mostly leukemia and lymphoma. Infections included sepsis, suspected sepsis, pneumonia and so on. Efficacy in CZOP monotherapy was excellent in 21 patients (31.3%), good in 23 patients (34.3%), fair in 5 patients (7.5%) and the efficacy rate was 65.7%. On the other hand, in combination therapy, each was 14 patients (21.2%), 23 patients (34.8%), 12 patients (18.2%) and the efficacy rate was 56.1%. Side effects such as eruption were noted in 2 patients. Abnormal laboratory findings were noted in 9 patients. All side effects as well as abnormal laboratory findings were minimal. It was concluded that CZOP monotherapy was effective in the treatment of various infections accompanying hematological diseases.

Adolescent↗
PubMed2000

[Hematology].

Explore the source record for details and available documents.

Forecasting↗
PubMed2000

Oxidative stress as a necessary factor in room temperature-induced apoptosis of HL-60 cells.

HL-60 cells undergo apoptosis when placed at room temperature (RT) [Shimura et al. (1997) FEBS Lett. 417, 379-384]. We report that superoxide anion radical, one of the reactive oxygen species (ROS), was produced after RT treatment. Affinity blot analysis with a biotinylated YVAD-CHO detected the generation of processed peptides with molecular masses of 15-25 kDa. Activation of such an ICE-like protease was completely abolished by N-acetylcysteine and exogenously expressed Bcl-2, known as antioxidants. We concluded that oxidative stress was a critical factor in the signal cascade of the apoptosis. Western blot analysis and experiments using tetrapeptide inhibitors suggested that caspases-1, -3, -4, -6, and -9 did not have an essential role in the apoptotic cascade. It is interesting that cyclosporin A (CsA) blocked RT-induced apoptosis with an inhibition of cytochrome c release from mitochondria. CsA, however, generated a significant amount of ROS with considerable reduction of mitochondrial membrane potential, implying that oxidative stress was one necessary factor for RT-induced apoptosis. It is also likely that mitochondrial membrane potential and the release of apoptotic factors from cytoplasm are differently regulated. Taken together with the reports that some Burkitt lymphoma cells showed apoptosis when exposed at low temperature followed by rewarming, and that hepatocytes or liver endothelial cells are susceptible to cold-induced apoptosis through the ROS function, we propose that studying the mechanism of RT-induced apoptosis of HL-60 cells may provide a therapeutic strategy for pathological conditions involving ROS, such as neurodegenerative diseases and ischemia.

Amino Acid Chloromethyl Ketones↗
PubMed2000

[Long-term follow up of chronic myelogenous leukemia patients treated with natural interferon alpha--multi-institutional cooperative study].

The effects on survival in patients with chronic myelogenous leukemia (CML) treated with natural interferon alpha (Sumiferon) were analyzed. The subjects were 131 patients with CML who underwent treatment with Sumiferon between August 1991 and December 1992. Sumiferon was administered more than 8 weeks, and patients were followed for 5 years. In the end, 101 patients were analyzed after 30 patients were dropped from the study because they had received bone marrow transplantation. Survivals from the start of Sumiferon administration were 63.4% at 3 years, 52.5% at 4 years, and 42.6% at 5 years, respectively. Survivals were compared between the 74 patients who received Sumiferon administration with 1 year of diagnosis, and the 27 patients who received Sumiferon administration after more than 1 year from diagnosis. The 50% survivals were 2,089 days and 868 days, respectively (p = 0.0011). It was concluded that early administration of interferon alpha results in a prolonged survival of CML patients.

Adult↗
PubMed1999

Aberrant expression of cAMP-response-element-binding protein ('CREB') induces apoptosis.

We have reported previously that cAMP-response-element-binding protein (CREB) was phosphorylated in a cell-cycle-dependent manner, showing that it was phosphorylated at early S-phase at casein kinase II target sites. To assess the possible involvement of CREB in cell cycle progression, CREB expression vector was transiently transfected into various cells. Unexpectedly we found that transfection with CREB expression vector resulted in an abundance of dead cells. Morphological examination revealed that these cells had undergone apoptosis. The coincidence of CREB overexpression and apoptosis induction at the individual cell level was confirmed by a immunohistochemical study. To confirm that overexpression of CREB was the cause of apoptosis, a dominant-negative mutant of CREB, KCREB, was co-expressed with the wild type. The co-existence of KCREB effectively rescued CREB-mediated apoptosis in a dose-dependent manner, verifying that apoptosis was truly a specific effect of overexpressed CREB and not an artifact of the transfection procedure. Deletion analysis indicates that neither the Q1 transactivation domain, which functions in transcription, nor the kinase-inducible domain, in which a cluster of various kinase targets exists, is necessary; however, the Q2 transactivation domain is required for the induction of apoptosis. A more precise study indicates that the four-residue stretch Glu-Glu-Ala-Ala at the most C-terminal region of the Q2 domain is especially important for the induction of apoptosis. Thus overexpressed CREB induces apoptosis by transmitting certain signals from the C-terminal portion of the Q2 domain. Possible roles of cell-cycle-regulated phosphorylation and also an elevation of the intracellular cAMP level in CREB-induced apoptosis are suggested.

Amino Acid Sequence↗
PubMed1999

Inhibition of Vpr-induced cell cycle abnormality by quercetin: a novel strategy for searching compounds targeting Vpr.

Vpr, an accessory gene product of HIV-1 which induces cell cycle abnormality leading to the increased HIV replication, is supposed to be a possible target for anti-AIDS drugs. We recently established a cell line (MIT-23) in which Vpr-induced cell cycle perturbation could be manipulated by a tetracycline promoter. Here, we screened anti-Vpr activity in 27 kinds of herb drugs using MIT-23 cells. One of the extracts prepared from Houttuyniae herba showed an inhibitory activity. Quercetin (QCT), a compound of this crude drug, efficiently inhibited Vpr function without affecting its expression. Furthermore, data suggested that Vpr-induced transcription from HIV-LTR was considerably abrogated by QCT. These data indicate that QCT, a flavonoid previously reported to inhibit HIV replication, also targets Vpr, implicating that MIT-23 cell provides a novel strategy for screening compounds possessing anti-Vpr activity which would be in turn utilized for clarifying the mechanism of Vpr function.

Anti-HIV Agents↗
PubMed1999

Micronuclei formation with chromosome breaks and gene amplification caused by Vpr, an accessory gene of human immunodeficiency virus.

Vpr, an accessory gene of human immunodeficiency virus, induces cell cycle abnormality by accumulating cells at the G2-M phase. We reported recently that Vpr caused both micronuclei formation and aneuploidy. Here, we show that Vpr also induced chromosome breaks and gene amplification. Expression of Vpr induced more than 10-fold increase of colonies resistant to N-(phosphonacetyl)-L-aspartate, an inhibitor of pyrimidine de novo synthesis. Fluorescence in situ hybridization analysis detected that 4 of 10 N-(phosphonacetyl)-L-aspartate resistant clones studied had intrachromosomal amplification of carbamyl-phosphate synthetase/aspartate transcarbamoylase/dihydroorotase gene. Another single clone had dicentrics. Data suggested that the Vpr-induced chromosome breaks leading to gene amplification, followed by bridge-breakage-fusion cycle, were one of the possible mechanisms of Vpr-induced genomic instability.

Aneuploidy↗
PubMed1999

Cell-cycle-regulated phosphorylation of cAMP response element-binding protein: identification of novel phosphorylation sites.

We report that the cAMP response element binding protein (CREB) undergoes cell-cycle-regulated phosphorylation. In human amnion FL cells, CREB was expressed as two forms with different molecular masses, 45 and 45.5 kDa. Although asynchronous cells contained predominantly the 45 kDa forms, this form shifted to 45.5 kDa when the cells were synchronized with the early S-phase. Furthermore the expression of the 45.5 kDa band was increased when cells were treated with okadaic acid, confirming that the 45.5 kDa band was a phosphorylated form of the 45 kDa band. Mutation analysis indicated that neither Ser133, the target of cAMP-dependent protein kinase and calcium calmodulin kinase, nor Ser129, the target of glycogen synthetase kinase 3, was responsible for the expression of the 45.5 kDa band, but that Ser108, Ser111 and Ser114, located in a region matching the consensus sequence for the casein kinase II target, were required. A mutant in which Ser111 and Ser114 were each replaced by a glutamic residue, mimicking a phosphorylated state, had a higher activation potential in cAMP response element-mediated transcription. These results strongly suggest that the casein kinase II target region is involved in cell cycle-regulated phosphorylation of the CREB protein and also in transcriptional enhancement.

Amino Acid Sequence↗
PubMed1999

Signal transduction pathways in normal human monocytes stimulated by cytokines and mediators: comparative study with normal human neutrophils or transformed cells and the putative roles in functionality and cell biology.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL) -3 induced tyrosine phosphorylation of 92-kDa protein in normal human monocytes. We identified this 92-kDa protein as STAT5, but not as STATs1, 3, and 6 nor c-fes and vav protooncogene products, and demonstrated its translocation to the nucleus, enhancement of specific DNA binding capacity, and potentiation of trancriptional activity by GM-CSF. N-formyl-methionyl-leucyl-phenylalanine (FMLP) and phorbol myristate acetate (PMA) induced tyrosine phosphorylation of 42- and 44-kDa proteins, which were identified as extracellular signal-regulated kinase (ERK), in human monocytes. In marked contrast to neutrophils and MO7e cells, GM-CSF did not induce tyrosine phosphorylation and activation of ERK in monocytes. Among upstream signaling molecules of ERK, Shc was constitutively associated with Grb2 and was not tyrosine-phosphorylated by GM-CSF and FMLP, and Sos1 and c-Raf-1 were not phosphorylated by GM-CSF, IL-3, TNF, and FMLP in monocytes, whereas all these signaling molecules were affected and/or utilized by GM-CSF in MO7e cells. In contrast to neutrophils, p38 was constitutively phosphorylated and agonist-dependent phosphorylation and activation was not detected in human monocytes. Superoxide release stimulated by FMLP was inhibited partially by PD98059 or SB203580, a specific inhibitor of ERK or p38 pathway, and was almost completely inhibited by the combination of both inhibitors, whereas PMA-induced superoxide release was resistant to these two inhibitors in monocytes. PD98059 inhibited GM-CSF-dependent proliferation of MO7e cells. Present results indicate trancriptional roles of STAT5 and functional roles of ERK and/or p38 in normal human monocytes stimulated by physiological receptor-mediated agonists GM-CSF and FMLP. Possible roles of ERK in proliferation of transformed cells were also suggested.

Adult↗