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T Murate

Publications and source records attributed to T Murate.

At least 37 records · Page 2Linked to original sources
PubMed1999

Multiple functions of tissue inhibitors of metalloproteinases (TIMPs): new aspects in hematopoiesis.

The extracellular matrix (ECM), the product of stromal cells, is now thought to make a dynamic network in tissues. Stromal cells can support other cells not only by direct contact but also via this ECM network. The regulated turnover and remodeling of ECM needs both ECM degrading enzymes named matrix metalloproteinases (MMPs) and their inhibitors called tissue inhibitors of metalloproteinases (TIMPs). Through an understanding of their molecular structure, the nature of the enzymic activity of MMPs and the inhibitory action of TIMPs against MMPs have been well elucidated. Considering their potent inhibitory action against MMPs, TIMPs are thought to play an important role in maintaining ECM. However, other unique functions of TIMPs have been reported, such as erythroid potentiating activity, cell growth-promoting activity, embryogenesis-stimulating activity, steroidogenesis-stimulating activity and so on. This review covers this new field, and discusses what role TIMPs can play in controlling life. In the second part, we briefly introduce our recent date on TIMPs and hematopoiesis. Because TIMPs have a dual function, i.e. a potent inhibitory action against MMPs and cell growth promoting action, TIMPs are good candidates for tissue fibrosis. Our recent measurements of TIMP-1 and TIMP-2 levels using serum and plasma from patients with platelet number disorders and cultured medium from various leukemia cell lines, shows that platelets are a rich source of TIMPs and that TIMP-1 is secreted in large amounts by megakaryoblastic- and erythro-leukemia cell lines. Proliferation of bone marrow fibroblasts can be stimulated by TIMP-1 and TIMP-2. Taken together, TIMPs might be one of the important factors for the process of myelofibrosis in some pathological conditions.

Journal Article↗
PubMed1999

Identification and mapping of novel tumor suppressor loci on 6p in diffuse large B-cell non-Hodgkin's lymphoma.

Allelic deletions have been thought to be indicators of the presence of tumor suppressor genes (TSGs). As indicated by this allelotype study using 39 highly informative microsatellite markers distributed among all autosomal chromosomes, frequent loss of heterozygosity (LOH) has been found at 6p in B-cell non-Hodgkin's lymphoma. To identify the commonly deleted regions (CDRs), we performed fine deletion mapping using 26 highly polymorphic microsatellite markers on 6p. The most frequent LOH occurred at D651721, where 9 of 18 of the informative cases (50%) had allelic losses. Seventeen of 32 cases (53%) exhibited LOH at least at one locus on 6p. Ten of these 17 cases showed interstitial deletions, and their LOH patterns indicated two CDRs on 6p; one between D6S1721 and D6S260 (at 6p23-24), and the other between D6S265 and D6S291 (at 6p21). The genetic distance of both CDRs was 6 cM. The CDKN1A (p21) gene is reported to be located within the interval of the CDR at 6p21, but no mutation of the gene was found in these 32 patients. These data suggested that these two loci might harbor novel putative TSGs responsible for the pathogenesis of malignant lymphoma. We have constructed a contig of yeast artificial chromosome (YAC) clones spanning the most frequent CDR at 6p23-24. This YAC contig can be used for fine physical mapping of the region and cloning of candidate TSGs.

Adolescent↗
PubMed1999

Clonality analysis of granulocytes and T lymphocytes in healthy females by the PCR-based HUMARA method.

Clonality analysis utilizing X-chromosome inactivation has been used in the study of various diseases, including hematological malignancies. The human androgen receptor gene (HUMARA) assay is the newest of such methods, and the majority of the female population can be assessed by this relatively simple procedure. One problem in using these clonality analysis methods, however, is that there may be significant variation in Lyonization in blood cells in normal individuals. To determine the diversity in X-chromosome methylation patterns, which reflect Lyonization, assessed by the HUMARA assay in the supposedly normal population, we analyzed granulocytes and T cells from 97 relatively young (18- to 35-year-old) healthy female volunteers. We found that the methylation patterns in the two HUMARA alleles were distributed even more widely, both in granulocytes and in T cells, than previously reported with other methods. We also found that the deviation of methylation in granulocytes and T cells was well correlated. Thus, we conclude that appropriate controls from the same individuals, such as T cells in the case of stem cell disorders, should always be employed to conclusively determine whether certain cells of hematopoietic origin are clonal.

Adolescent↗
PubMed1999

Molecular evaluation of bone marrow involvement in peripheral T-cell lymphoma with a PCR-mediated RNase protection assay.

Bone marrow (BM) involvement in peripheral T-cell lymphoma was assessed by polymerase chain reaction (PCR)-mediated RNase protection assay. The sensitivity of this assay was approximately 10(-4) to 10(-5). In 16 of 30 patients (53.3%) with peripheral T-cell malignancies, consensus primers for the T-cell receptor (TCR)-gamma gene amplified the rearranged V(N)J region. Using the PCR products of diagnostic lymph nodes of the patients as probes, we analyzed the BM involvement of lymphoma cells in eight patients: four with peripheral T-cell lymphoma, unspecified; two with adult T-cell leukemia/lymphoma; and two with angioimmunoblastic T-cell lymphoma. BM involvement was detected by PCR-mediated RNase protection assay in four patients from BM smear and/or histo-pathological examination of clotted BM. Moreover, in two of four patients in whom BM involvement was not evident from morphological examination, BM involvement was detected by PCR-mediated RNase protection assay. Our results indicate that the PCR-mediated RNase protection assay targeting the TCR-gamma gene is useful in detecting minimal residual disease in about half of all T-cell lymphoma cases. In addition, in some patients with peripheral T-cell lymphoma, morphologically unproven BM involvement was found using the method.

Adult↗
PubMed1998

Sulfated glycoglycerolipid from archaebacterium inhibits eukaryotic DNA polymerase alpha, beta and retroviral reverse transcriptase and affects methyl methanesulfonate cytotoxicity.

A sulfated glycoglycerolipid, 1-O-(6'-sulfo-alpha-D-glucopyranosyl)-2,3-di-O-phytanyl- sn-glycerol (KN-208), a derivative of the polar lipid isolated from an archaebacterium, strongly inhibited DNA polymerase (pol) alpha and pol beta in vitro among 5 eukaryotic DNA polymerases (alpha, beta, gamma, delta, and epsilon). It also inhibited Escherichia coli DNA polymerase I Klenow fragment (E. coli pol I) and human immunodeficiency virus reverse transcriptase (HIV RT). The mode of inhibition of these polymerases was competitive with the DNA template primer and was non-competitive with the substrate dTTP. KN-208 inhibited pol beta most strongly, with a Ki value of 0.05 microM, 10-fold lower than that for pol alpha (0.5 microM) and 60- or 140-fold lower than that for HIV RT (3 microM) or for E. coli pol I (7 microM), respectively. The loss of sulfate on the 6'-position of glucopyranoside of this compound completely abrogated inhibition. However, the hydrophilic part of KN-208, glucose 6-sulfate alone, showed no inhibition. Other sulfated compounds containing different hydrophobic structures, such as dodecyl sulfate and cholesterol sulfate, exhibited a much weaker inhibition. Our results suggest that the whole molecular structure of KN-208 is required for inhibition. KN-208 was shown to be modestly cytotoxic for the human leukemic cell line K562. Interestingly, a subcytotoxic dose of KN-208 increased the sensitivity of the human leukemic cells to an alkylating agent, methyl methanesulfonate, while it did not potentiate the effects of ultraviolet light or of cisplatin.

Archaea↗
PubMed1998

A high dose chemoradiotherapy and peripheral blood stem cell support combined with the CD34(+)-selection method in cyclin D1(+)-mantle cell lymphoma.

Mantle cell lymphoma (MCL) is currently regarded as one of the most incurable lymphomas, although reliable prognostic indicators are not yet to be defined. In a previous report, it was indicated that most of the patients with immunohistochemically cyclin D1(+)-MCL pursued the lethal clinical course within 7 years, not having achieved complete remission (CR). Recently, a high dose chemoradiotherapy was carried out, this was supported by peripheral blood stem cell transplantation (PBSCT) using the CD34(+)-selection method in a 48-year-old female patient with cyclin D1(+)-MCL. The tumor cells were detected in her peripheral blood despite four courses of combination chemotherapy using CHOP regimen. Soon after the pre-conditioning of total body irradiation (TBI) and high dose melphalan, she received the PBSCT of 1.8 x 10(6)/kg CD34+ cells and showed rapid hematological recovery without life-threatening complications. The patient achieved CR and was alive, without disease, 730 days after PBSCT. Thus, CD34+ selected PBSCT appears to provide further insight into the effective treatment and possible cure of this aggressive disease, i.e. cyclin D1(+)-MCL.

Antigens, CD34↗
PubMed1998

Feasibility and pharmacokinetic study of a chimeric anti-CD20 monoclonal antibody (IDEC-C2B8, rituximab) in relapsed B-cell lymphoma. The IDEC-C2B8 Study Group.

BACKGROUND: In clinical trials in the USA, IDEC-C2B8 (a mouse-human chimeric anti-CD20 monoclonal antibody) has demonstrated high response rates with only mild toxic effects in relapsed B-cell lymphoma at a dose of four weekly 375 mg/m2 infusions. The aim of the present trial was to determine whether or not this dose is practically applicable to Japanese patients with relapsed B-cell lymphoma with respect to safety, pharmacokinetics and efficacy. PATIENTS AND METHODS: Patients with relapsed CD20+ B-cell lymphoma received intravenous infusions of IDEC-C2B8 once a week for four weeks. A total of 12 patients (four at 250 mg/m2 and eight at 375 mg/m2) were enrolled. RESULTS: All 11 eligible patients treated with either dose level tolerated IDEC-C2B8 well. Commonly observed adverse drug reactions were grades 1 or 2 non-hematologic toxicities during the infusion, consisting mostly of flu-like symptoms and skin reactions. All of the observed hematologic toxicities were of grade 3 or less, and transient. A rapid and sustained B-cell decrease in peripheral blood was observed, but no infectious episodes were encountered. Human anti-mouse and anti-chimeric antibodies were not detected. Of the 11 eligible patients (eight with follicular, two with diffuse large-cell and one with mantle cell lymphoma), two showed a complete response and five showed a partial response, and all of the seven responders had lymphoma with follicular histology. A pharmacokinetic analysis showed that the elimination half-life (T1/2) of IDEC-C2B8 was 445 +/- 361 hours, and that the serum antibody levels increased in parallel with the course of infusions, and in most patients was still measurable at three months. CONCLUSIONS: The dose of four weekly 375 mg/m2 infusions of IDEC-C2B8 is safe and effective in Japanese patients with relapsed B-cell lymphoma. Further studies evaluating IDEC-C2B8 are warranted.

Adult↗
PubMed1998

Mutational analysis of the PTEN/MMAC1 gene in non-Hodgkin's lymphoma.

The PTEN/MMAC1 gene at 10q23.3, which has dual specific phosphatase activity, is a novel tumor suppressor gene candidate. Various kinds of tumors have mutations in this gene, including glioblastoma, endometrial carcinoma and prostate cancer. We examined 29 cases of primary non-Hodgkin's lymphoma (NHL) for mutations in the PTEN/MMAC1 gene. One case of diffuse large B cell lymphoma had an 11 bp deletion, but the remaining 28 cases showed no mutations in the genome. Two of these 28 cases showed missense mutations in the PTEN/MMAC1 transcripts, but no alterations in the genomic DNA. These mRNA missense variants are similar to PTEN/MMAC1 transcript aberrations which have been reported in patients with breast cancer. These findings suggest that alterations in the PTEN/MMAC1 gene play a role in the pathogenesis of NHL.

Chromosomes, Human, Pair 10↗
PubMed1998

Truncated c-Myb expression in the human leukemia cell line TK-6.

The c-MYB proto-oncogene encodes a transcription factor which plays an important role in hematopoiesis. We detected truncated c-MYB mRNA (2.0 kb) and c-Myb protein (55 kDa) in the TK-6 cell line, which was established from a patient with chronic myelogenous leukemia in T cell blast crisis. Mutated c-MYB cDNA clone (WTK-1) was isolated from a TK-6 cell cDNA library and sequenced in its entirety. Compared with the wild-type human c-MYB sequence, the WTK-1 sequence diverged at the 3' ends of exons 9. A termination codon was present as the second codon downstream from the point of divergence and was followed by a previously unknown rearranged sequence. The conceptual protein encoded by WTK-1 (Myb(TK-6)) comprises 402 amino acids and lacks the negative regulatory domain of the normal c-Myb, reminiscent of the activated form of Myb protein. Luciferase reporter assay in NIH3T3 cells showed that the expression vector encoding Myb(TK-6) stimulated Myb-regulated mim-1 promoter more effectively than that encoding wild-type human c-Myb, suggesting that Myb(TK-6) is functional as a transcription factor, and thus as a potential transforming protein. Southern blot and mutant allele-specific polymerase chain reaction analyses showed that the same rearrangement of the c-MYB gene in TK-6 was present in late, but not in early, specimens obtained from the patient, indicating that this mutation had been acquired during disease progression.

Adult↗
PubMed1998

Lithocholic acid, a putative tumor promoter, inhibits mammalian DNA polymerase beta.

Lithocholic acid (LCA), one of the major components in secondary bile acids, promotes carcinogenesis in rat colon epithelial cells induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), which methylates DNA. Base-excision repair of DNA lesions caused by the DNA methylating agents requires DNA polymerase beta (pol beta). In the present study, we examined 17 kinds of bile acids with respect to inhibition of mammalian DNA polymerases in vitro. Among them, only LCA and its derivatives inhibited DNA polymerases, while other bile acids were not inhibitory. Among eukaryotic DNA polymerases alpha, beta, delta, epsilon, and gamma, pol beta was the most sensitive to inhibition by LCA. The inhibition mode of pol beta was non-competitive with respect to the DNA template-primer and was competitive with the substrate, dTTP, with the Ki value of 10 microM. Chemical structures at the C-7 and C-12 positions in the sterol skeleton are important for the inhibitory activity of LCA. This inhibition could contribute to the tumor-promoting activity of LCA.

Animals↗
PubMed1998

CDKN2 (MTS1/p16INK4A) gene alterations in adult T-cell leukemia/lymphoma.

p16INK4A is a cyclin-dependent kinase inhibitor (CDKI), and regulates the cell cycle negatively. Recently, p16INK4A protein was shown to be encoded by the CDKN2 gene, which is identical to multiple tumor suppressor gene 1 (MTS1) on chromosome 9p21, where genetic alterations occur frequently in many malignant tumors. As the loss of p16INK4A function by genetic alterations leads to inappropriate progression of the cell cycle, the CDKN2 gene has been investigated intensively as a new candidate tumor suppressor gene in many malignant tumors. Adult T-cell leukemia/lymphoma (ATLL) is a peripheral T-cell malignancy associated with human T-cell lymphotrophic virus type 1 (HTLV-1). As the development to ATL is believed to require not only HTLV-1 infection but also accumulation of genetic alterations, we investigated the relationship between alterations in the CDKN2 gene and ATL. Alterations in the CDKN2 gene were detected in approximately 15 to 20% of ATL patients. Interestingly, most of the patients with CDKN2 gene alterations had the aggressive form of ATL. The CDKN2 gene appears to be the major tumor suppressor gene on chromosome 9p21, and alteration in this gene may play an important role during late stages in the transformation process induced by HTLV-1.

Cyclin-Dependent Kinase Inhibitor p16↗
PubMed1998

Production and effects of interleukin-6 and other cytokines in patients with non-Hodgkin's lymphoma.

Cytokines are regulatory molecules that are produced by a variety of cell types and are characterized by numerous biologic functions involved in the regulation of the immune system and hematopoiesis. This review summarizes the functions and regulation of cytokines in lymphomas and discusses the effect of a specific cytokine, interleukin-6 (IL-6), in B-cell lymphomas. IL-6 is a multipotent cytokine that can mediate the differentiation of B-cells into immunoglobulin-secreting cells, stimulate the autocrine or paracrine growth of myeloma cells, induce acute-phase proteins in liver cells, and may influence the pathogenesis of several diseases by autocrine or paracrine mechanisms. Patients with non-Hodgkin's lymphoma (NHL) have increased serum concentrations of IL-6; increased IL-6 levels can be associated with the presence of B-symptoms. Data presented in this review indicate that neoplastic cells from patients with NHL contained high concentrations of IL-6. Thus, elevated serum levels of IL-6 appear to originate from the lymphoma cells in patients with B-cell NHL, suggesting that the neoplastic cells may modulate the general status of patients with B-cell NHL. The inhibition or modification of the production of IL-6 in lymphoma cells may lead to a more effective control of the general status of patients with B-cell NHL.

Acute-Phase Reaction↗
PubMed1998

High-risk myelodysplastic syndromes and hypermethylation of the p15Ink4B gene.

Recent studies have elucidated that not only genetic alterations but also epigenetic changes may play an important role in carcinogenesis. In particular, de novo methylation of CpG islands within the promoter region associated with the inactivation of tumor suppressor genes (TSGs) has been demonstrated in various malignancies. Since de novo acute myelogenous leukemia shows frequent inactivation of the p15INK4B gene through the promoter methylation only, we investigated the methylation status of the p15INK4B gene in myelodysplastic syndrome (MDS). In MDS, the p15INK4B gene is also frequently hypermethylated at the promoter region located at the 5'-CpG island of exon 1. Association of frequent and strong methylation with high-risk MDS suggested that promoter methylation of the p15INK4B gene plays an important role as a late event during MDS progression. Since several TSGs and growth regulatory genes, including the p15INK4B gene, may be inactivated through promoter hypermethylation in hematological malignancies, modulation of the methylation status may be considered as a novel treatment modality in MDS.

Animals↗
PubMed1998

Analysis of bax protein in sphingosine-induced apoptosis in the human leukemic cell line TF1 and its bcl-2 transfectants.

Sphingosine, a sphingolipid breakdown product, has been proposed as an apoptosis-inducing agent. In this study, we examined the effect of sphingosine in bcl-2-overexpressing cells compared with cells that do not express the bcl-2 gene. The human erythroleukemic cell line TF1, which lacks bcl-2 expression, was easily induced to undergo apoptotic cell death by a variety of stimuli, including depletion of granulocyte-macrophage colony-stimulating factor (GM-CSF) or exposure to methylmethane sulfonate (MMS) (100 microg/mL), ultraviolet light (15 J/m2), X-ray irradiation (20 Gy), or sphingosine, a sphingolipid breakdown product (5 microM). In contrast, bcl-2 transfectants of TF1 (TF1-bcl2), which we established, were resistant to most of these treatments but remained sensitive to sphingosine. Neither C2- nor C6-ceramide (short-chain ceramide) induced apoptosis in TF1-mock and TF1-bcl2 cells. Sphingosine-induced apoptosis could not be inhibited by fumonisin B1, which can prevent conversion of sphingosine to ceramide, suggesting that sphingosine itself, not ceramide, possesses apoptosis-inducing capability. Western blotting, which revealed a 21-kDa bax protein in untreated cells, revealed the presence of an additional 18-kDa protein in GM-CSF-depleted and MMS- or sphingosine-treated TF1-mock cells. In TF1-bcl2 cells, this protein was not detected after GM-CSF depletion or MMS treatment, but was observed after sphingosine treatment. Immunoprecipitation with anti-bcl2 antibody, followed by immunoblotting with anti-bax antibody, showed that both the 21-kDa bax protein and the 18-kDa protein heterodimerized with bcl-2 protein. These results suggest that sphingosine is a unique reagent for apoptosis and that it can overcome bcl-2 gene expression. Furthermore, induction of 18-kDa bax-related protein may play an important role in apoptosis. Sphingosine, but not ceramide, may prove applicable as a reagent for future cytotoxic drugs used to treat intractable tumors overexpressing bcl-2.

Apoptosis↗
PubMed1997

Hypermethylation of the p15INK4B gene in myelodysplastic syndromes.

Previous studies have shown that the cyclin-dependent kinase inhibitor (CDKI) genes p15INK4B and p16INK4A are frequently inactivated by genetic alterations in many malignant tumors and that they are candidate tumor-suppressor genes. Although genetic alterations in these genes may be limited to lymphoid malignancies, it has been reported that their inactivation by aberrant methylation of 5' CpG islands may be involved in various hematologic malignancies. In this study, we investigated the p15INK4B and p16INK4A genes to clarify their roles in the pathogenesis of myelodysplastic syndrome (MDS). Southern blotting analysis showed no gross genetic alterations in either of these genes. However, hypermethylation of the 5' CpG island of the p15INK4B gene occurred frequently in patients with MDS (16/32 [50%]). Interestingly, the p15INK4B gene was frequently methylated in patients with high-risk MDS (refractory anemia with excess blasts [RAEB], RAEB in transformation [RAEB-t], and overt leukemia evolved from MDS; 14/18 [78%]) compared with patients with low-risk MDS (refractory anemia [RA] and refractory anemia with ring sideroblast [RARS]; 1/12 [8%]). Furthermore, methylation status of the p15INK4B gene was progressed with the development of MDS in most patients examined. In contrast, none of the MDS patients showed apparent hypermethylation of the p16INK4A gene. These results suggest that hypermethylation of the p15INK4B gene is involved in the pathogenesis of MDS and is one of the important late events during the development of MDS.

Carrier Proteins↗
PubMed1997

Oncostatin M and leukemia inhibitory factor do not use the same functional receptor in mice.

Oncostatin M (OSM) and leukemia inhibitory factor (LIF) are members of the interleukin-6 (IL-6) subfamily of cytokines that use a common signal transducer gp130. Human OSM (hOSM) and LIF share a functional high-affinity receptor that is composed of gp130 and LIF receptor beta subunit (LIFRbeta). A second high-affinity receptor for hOSM was recently found to be formed by gp130 and the hOSM receptor beta subunit. However, the nature of murine OSM (mOSM) and its receptors has remained unknown. Using the recently cloned mOSM cDNA, we produced recombinant mOSM and studied its biological activity and receptor structure. Murine hematopoietic cell lines M1 and DA1.a, an embryonic stem cell line CCE, and Ba/F3 transfectants expressing gp130 and LIFRbeta responded to murine LIF (mLIF) and hOSM equally well, while these cells responded to mOSM only at a 30-fold to 100-fold higher concentration than those of mLIF and hOSM. In contrast, NIH3T3 cells responded to mOSM, but not to mLIF and hOSM. Scatchard plot analyses showed that mOSM bound to gp130 with low-affinity (kd = 2.8 to 4.2 nmol/L) and that the binding affinity did not increase in the presence of LIFRbeta. However, mOSM bound to NIH3T3 cells with high-affinity (kd = 660 pmol/L), whereas mLIF did not bind to NIH3T3 cells at all. These results indicate that unlike hOSM, mOSM and mLIF do not share the same functional receptor, and mOSM delivers signals only through its specific receptor complex. Further studies in mice will define the physiological roles of OSM.

Animals↗