Biomedical subjects

Hiroshi Handa

Publications and source records attributed to Hiroshi Handa.

98 records · Page 6Linked to original sources

PubMed2002

Genome-wide analysis of changes in early gene expression induced by oestrogen.

BACKGROUND: The sex hormone 17beta-oestradiol (E2) has profound effects on many aspects of reproduction, development, as well as behaviour. Although the oestrogen receptor is well characterized on a molecular level, relatively few genes affected by E2 have been identified, and the mechanisms underlying the physiological changes caused by E2 are largely unknown. In order to identify oestrogen-regulated genes in vivo, early uterine gene expression profiles were developed using DNA microarrays. RESULTS: Ovariectomized mice were exposed to 17beta-oestradiol for 6 h, and mRNA expression analysis for 9977 genes was performed. Although a large number of genes was affected by oestrogen administration, the genes that showed higher reproducibility in repetitive experiments were selected and further examined. For most of the selected genes, expression was induced in a dose-dependent manner, and gene expression was not altered following oestrogen treatment in oestrogen receptor-alpha (ER(alpha))-deficient mice. In combination with the estimation of gene expression levels using quantitative PCR, it was revealed that multiple genes related to sterol biosynthesis, tRNA synthesis, RNA processing, and growth signalling were activated. Based on the microarray data, we selected additional genes related to sterol biosynthesis and tRNA synthesis and confirmed that these genes are also activated by oestrogen. CONCLUSION: Genes suggesting a basis for the drastic uterotrophic effect observed several days following oestrogen administration were identified. These findings not only reveal the diverse effect of oestrogen signalling on transcript levels in vivo but also demonstrate the ability of DNA microarrays to identify cellular pathways affected by oestrogen.

Animals↗

PubMed2002

Evidence that negative elongation factor represses transcription elongation through binding to a DRB sensitivity-inducing factor/RNA polymerase II complex and RNA.

Negative elongation factor (NELF) is a human transcription factor complex that cooperates with DRB sensitivity-inducing factor (DSIF)/hSpt4-hSpt5 to repress elongation by RNA polymerase II (RNAPII). NELF activity is associated with five polypeptides, including NELF-A, a candidate gene product for Wolf-Hirschhorn syndrome, and NELF-E, a putative RNA-binding protein with arginine-aspartic acid (RD) dipeptide repeats. Here we report several important findings regarding the DSIF/NELF-dependent elongation control. First, we have established an effective method for purifying the active NELF complex using an epitope-tagging technique. Second, the five polypeptides each are important and together are sufficient for its function in vitro. Third, NELF does not bind to either DSIF or RNAPII alone but does bind to the preformed DSIF/RNAPII complex. Fourth, NELF-E has a functional RNA-binding domain, whose mutations impair transcription repression without affecting known protein-protein interactions. Taken together, we propose that NELF causes RNAPII pausing through binding to the DSIF/RNAPII complex and to nascent transcripts. These results also have implications for how DSIF and NELF are regulated in a gene-specific manner in vivo.

Chromatography, Affinity↗

PubMed2002

CD7+ and CD56+ myeloid/natural killer cell precursor acute leukemia treated with idarubicin and cytosine arabinoside.

We describe a 69-year-old Japanese male with acute leukemia with a CD7+ and CD56+ immunophenotype presenting with multiple lymphadenopathy. He was treated with idarubicin and cytosine arabinoside. Although the leukemia showed partial response, the patient did not achieve complete remission. He died of sepsis due to severe neutropenia after the third course of chemotherapy. His autopsy revealed blast infiltration in the lymph nodes, liver, spleen and vertebral bone marrow. Recently, CD7+ and CD56+ myeloid/natural killer precursor acute leukemia has been associated with a poor prognosis. Our case illustrates that myeloid/natural killer cell precursor acute leukemia shows some response to intensive chemotherapy for acute myeloid leukemia, but such therapy is insufficient to effect a cure. To overcome the resistance of this disease to chemotherapy, further studies should explore other treatment strategies.

Acute Disease↗

PubMedDate not supplied

Total analysis and purification of cellular proteins binding to cisplatin-damaged DNA using submicron beads.

A high-performance affinity purification technique has been developed for cisplatin (CDDP)-damaged DNA binding proteins directly from crude nuclear extracts of HeLaS3 cell using novel submicron beads synthesized by copolymerization of styrene and glycidyl methacrylate (GMA). The beads dramatically decreased both nonspecific protein adsorption on solid surfaces and elution volume and simplified the handling procedure. Preparation of the beads for purification was carried out by immobilization of telomeric repeats, (TTAGGG)(n), on the surface after the reaction with CDDP. At least nine proteins clearly showed higher affinity to CDDP-DNA and were identified by amino acid sequence analysis including HMGB (high mobility group), hUBF (human upstream binding factor), and Ku autoantigen, which were previously reported to be components of CDDP-damaged DNA binding proteins.

Amino Acid Sequence↗

PubMedDate not supplied

Development of polymer latex particles for selective cleavage of mismatched DNA and their application for DNA diagnosis.

We developed functional polymer latex particles that can catch and cleave mismatched DNA selectively and propose a new mismatch detection system using the functional particles. The aimed particles possess two functional units composed of mismatch binding protein (MutS) and an anthraquinone derivative (AQ), a light-activated agent that photocleaves dsDNA. Use of the functional particles made it possible to discriminate complementary and mismatched DNAs and photocleave mismatched DNA selectively. The efficiency of photocleavage of mismatched DNA by the functional particles increased with UV irradiation time. It was also found that the functional particles were reusable and had dissociation constants (K(d)) of 1000 and 68.5 nM for G/C homoduplex and G/T heteroduplex, respectively. Using the functional particles and a dsDNA-binding fluorescent dye, SYBR-Gold, we could construct the system for detection of mismatched DNA that was 40 base pairs. The functional particles prepared in this study will be an absolutely new tool for mismatch detection in DNA diagnosis.

Adenosine Triphosphatases↗

PubMedDate not supplied

Ribosome-lamella complex of leukemic cells in a patient with aggressive NK cell leukemia.

A 36-year-old male was admitted to the hospital with anemia and leukopenia. A bone marrow specimen revealed the proliferation of leukemic cells with flower-like nuclei observed in adult T-cell leukemia. The leukemic cells were positive for HLA-DR, CD2, CD7, and CD56. A diagnosis of aggressive NK cell leukemia was made, the patient was treated with induction chemotherapy and cord blood stem cell transplantation, and he is well now. Seen with electron microscopy, some leukemic cells had ribosome-lamella complexes (RLC). This is the first reported case of leukemic cells with flower-like nuclei seen with light microscopy and RLC seen with electron microscopy.

Adult↗

PubMedDate not supplied

Redox regulation of NF-kappaB activation: distinct redox regulation between the cytoplasm and the nucleus.

Reduction/oxidation (redox) regulation mediates numerous cellular responses and contributes to several physiological diseases. The transcription factor nuclear factor kappaB (NF-kappaB) is known to be a redox-sensitive factor. NF-kappaB plays a central role in immune responses and inflammation, through regulation of the gene expression of a large number of cytokines and other immune response genes. NF-kappaB is trapped in the cytoplasm in stimulated cells and translocates into the nucleus in response to several stimuli, including oxidative stress. Reactive oxygen species enhance the signal transduction pathways for NF-kappaB activation in the cytoplasm and translocation into the nucleus. In contrast, the DNA binding activity of oxidized NF-kappaB is significantly diminished, and that activity is restored by reducing enzymes, such as thioredoxin or redox factor 1. This review describes the signal transduction pathways for NF-kappaB activation and redox regulation of NF-kB activation in the cytoplasm and nucleus.

Animals↗

PubMedDate not supplied

A celecoxib derivative potently inhibits proliferation of colon adenocarcinoma cells by induction of apoptosis.

BACKGROUND: Celecoxib, a selective cyclooxygenase (COX)-2 inhibitor, has a pro-apoptotic effect on colon adenocarcinoma cells via COX-independent mechanisms. MATERIALS AND METHODS: The pro-apoptotic effect of N-(2-Aminoethyl)-4-[5- (4-tolyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl] benzenesulfonamide (TT101), a new derivative of celecoxib, was investigated on the HT-29 and SW480 colon adenocarcinoma cells. Cell proliferation and viability were assessed by incorporation of 5-bromo-2'-deoxyuridine and by the 2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium monosodium salt assay, respectively. Apoptosis was detected by identifying DNA fragmentation. Production of prostaglandin E2 by the HT-29 cells was analyzed. RESULTS: TT101 inhibited the proliferation of HT-29 and SW480 cells by inducing apoptosis more potently than celecoxib in a concentration-dependent manner. The COX-2 inhibitory effect of TT101 was weaker than that of celecoxib. CONCLUSION: A slight modification of celecoxib enhanced the pro-apoptotic effect on colon adenocarcinoma cells.

Adenocarcinoma↗