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Biomedical subjects

K Matsumoto

Publications and source records attributed to K Matsumoto.

At least 19 recordsLinked to original sources
PubMed1992

Negative regulation of hepatocyte growth factor gene expression in human lung fibroblasts and leukemic cells by transforming growth factor-beta 1 and glucocorticoids.

Hepatocyte growth factor (HGF), a mesenchymal-derived factor which regulates growth, motility, and morphogenesis of epithelial and endothelial cells, functions as a hepatotrophic and renotrophic factor for regeneration of the liver and kidney. We have now obtained evidence that transforming growth factor-beta 1 (TGF-beta 1) and glucocorticoids are negative regulators for HGF gene expression. When TGF-beta 1 or dexamethasone was added to cultures of MRC-5 human embryonic lung fibroblasts and HL-60 human promyelocytic leukemic cells, the amount of HGF secreted into the culture medium was inhibited to 30-40% of that of control cultures by 10 ng/ml TGF-beta 1 and to 40-50% by 10(-6) M dexamethasone. The inhibitory effect of TGF-beta 1 and dexamethasone on HGF synthesis in MRC-5 cells was additive, thereby suggesting that TGF-beta 1 and dexamethasone exert effects through distinct mechanisms. Hydrocortisone also inhibited HGF synthesis with the same potency as dexamethasone; however, testosterone, estriol, and beta-estradiol had no effect. The rate of HGF synthesis in MRC-5 cells, as measured by pulse labeling with [35S]methionine and subsequent immunoprecipitation, was suppressed to 30-40% of the control with 10 ng/ml TGF-beta 1, and to 30-45% by 10(-6) M dexamethasone. HGF mRNA levels in MRC-5 cells and HL-60 cells were dose-dependently suppressed by TGF-beta 1 and dexamethasone; 10 ng/ml TGF-beta 1 suppressed HGF mRNA levels to 32% and 35% of control culture, respectively, in MRC-5 cells and HL-60 cells, and 10(-6) M dexamethasone suppressed to 43% and 38%, respectively. Thus, TGF-beta 1 and glucocorticoids seem to inhibit HGF synthesis by suppressing the expression of the HGF gene. We propose that a negative regulation of HGF gene expression by TGF-beta 1 or glucocorticoids may be involved in physiological or pathological processes during tissue regeneration.

Animals↗
PubMed1992

Recombinant variants of tissue-type plasminogen activator containing amino acid substitutions in the finger domain.

Tissue-type plasminogen activator (t-PA) is a fibrin-specific agent which has been used to treat acute myocardial infarction. In an attempt to clarify the determinants for its rapid clearance in vivo and high affinity for fibrin clots, we produced five variants containing amino acid substitutions in the finger domain, at amino acid residues 7-9, 10-14, 15-19, 28-33, and 37-42. All the variants had a prolonged half-life and a decreased affinity for fibrin of various degrees. The 37-42 variant demonstrated about a 6-fold longer half-life with a lower affinity for fibrin. Human plasma clot lysis assay estimated the fibrinolytic activity of the 37-42 variant to be 1.4-fold less effective than that of the wild-type rt-PA. In a rabbit jugular vein clot lysis model, doses of 1.0 and 0.15 mg/kg were required for about 70% lysis in the wild-type and 37-42 variant, respectively. Fibrinogen was degraded only when the wild-type rt-PA was administered at a dose of 1.0 mg/kg. These findings suggest that the 37-42 variant can be employed at a lower dosage and that it is a more fibrin-specific thrombolytic agent than the wild-type rt-PA.

Amino Acids↗
PubMed1992

Developmental changes in hepatocyte growth factor mRNA and its receptor in rat liver, kidney and lung.

Hepatocyte growth factor (HGF) is a mesenchymal-derived factor which induces mitosis, cell movement and morphogenesis of tissue-like structure. We analyzed changes in HGF mRNA and its receptor, the c-met proto-oncogene product, in the liver, kidney and lung during late fetal and postnatal development in rats. In the liver, the HGF-mRNA level was very low during late gestation and in neonates, it increased remarkably and reached a maximum two weeks postnatally, to be followed by a decrease to 33% of the maximum. HGF mRNA in the kidney and lung was either undetectable or very low during late gestation and the neonatal period and increased markedly to reach a maximum, respectively, 3-4 weeks postnatally. HGF-mRNA level in the adult rat lung was fivefold higher than that in the liver and kidney. The number of HGF receptors on plasma membranes of these tissues was low in neonates but there was a rapid increase after birth and a maximum was reached within three weeks. The number of HGF receptors/ng plasma membrane protein at the maximal level was highest in the liver and lowest in the lung. c-met/HGF-receptor mRNA in the liver was also low during late-gestation or in early neonatal periods and increased postnatally. Since HGF-mRNA and HGF-receptor levels changed differently in liver, kidney and lung, the expression of HGF and its receptor may be independently regulated in each organ. However, in these organs, HGF mRNA and the HGF receptor increased within a few weeks of birth, HGF may play roles in organ growth, organ maturation and the maintenance of tissue homeostasis during the postnatal period, presumably through its potential to act as mitogen, motogen and morphogen.

Aging↗
PubMed1992

Crystal structure of papain-E64-c complex. Binding diversity of E64-c to papain S2 and S3 subsites.

In order to investigate the binding mode of E64-c (a synthetic cysteine proteinase inhibitor) to papain at the atomic level, the crystal structure of the complex was analysed by X-ray diffraction at 1.9 A (1 A is expressed in SI units as 0.1 nm) resolution. The crystal has a space group P2(1)2(1)2(1) with a = 43.37, b = 102.34 and c = 49.95 A. A total of 21,135 observed reflections were collected from the same crystal, and 14811 unique reflections of up to 1.9 A resolution [Fo > 3 sigma(Fo)] were used for the structure solution and refinement. The papain structure was determined by means of the molecular replacement method, and then the inhibitor was observed on a (2 magnitude of Fo-magnitude of Fc) difference Fourier map. The complex structure was finally refined to R = 19.4% including 207 solvent molecules. Although this complex crystal (Form II) was polymorphous as compared with the previously analysed one (Form I), the binding modes of leucine and isoamylamide moieties of E64-c were significantly different from each other. By the calculation of accessible surface area for each complex atom, these two different binding modes were both shown to be tight enough to prevent the access of solvent molecules to the papain active site. With respect to the E64-c-papain binding mode, molecular-dynamics simulations proposed two kinds of stationary states which were derived from the crystal structures of Forms I and II. One of these, which corresponds to the binding mode simulated from Form I, was essentially the same as that observed in the crystal structure, and the other was somewhat different from the crystal structure of Form II, especially with respect to the binding of the isoamylamide moiety with the papain S subsites. The substrate specificity for the papain active site is discussed on the basis of the present results.

Amino Acid Sequence↗
PubMed1992

Up-regulation of hepatocyte growth factor gene expression by interleukin-1 in human skin fibroblasts.

Hepatocyte growth factor (HGF) functions as a hepatotrophic and renotrophic factor for regeneration of the liver and kidney. When 1 ng/ml of interleukin-1 alpha (IL-1 alpha) or interleukin-1 beta (IL-1 beta) was added to cultures of human skin fibroblasts, the production of HGF was 5-6 fold higher than levels in the controls. HGF mRNA level in the cells was increased to 4-fold higher levels at 6 h after exposure to IL-1 alpha. Tumor necrosis factor-alpha and interferon-gamma but no other cytokine tested had slightly stimulatory effects on HGF production. The tumor promoter, tetradecanoylphorbol 13-acetate (TPA) markedly enhanced the stimulatory effect of IL-1 alpha and IL-1 beta on the production of HGF. The stimulatory effect of both IL-1 alpha and IL-1 beta and the synergistical stimulation with TPA were completely abrogated by 10 ng/ml TGF-beta 1 or 1 microM dexamethasone. These results suggest that IL-1 alpha and IL-1 beta are positive regulators for expression of the HGF gene and are likely have a role in regeneration of tissues following the occurrence of inflammatory diseases.

Animals↗
PubMed1992

Hepatocyte growth factor increases urokinase-type plasminogen activator (u-PA) and u-PA receptor expression in Madin-Darby canine kidney epithelial cells.

We have recently demonstrated that fibroblast-conditioned medium induces Madin-Darby canine kidney (MDCK) epithelial cells to form branching tubules when grown in three-dimensional collagen or fibrin gels (Montesano, R., Schaller, G., and Orci, L. (1991) Cell 66, 697-711), and that this morphogenetic effect is mediated by hepatocyte growth factor (HGF), also known as scatter factor (Montesano, R., Matsumoto, K., Nakamura, T., and Orci, L. (1991) Cell 67, 901-908). In fibrin gels, this effect is inhibited by addition of exogenous serine protease inhibitors, which suggests a role for plasminogen activators (PAs) in the matrix remodeling required for tubulogenesis. In the studies reported in this paper, we have investigated the effect of fibroblast-conditioned medium (CM) and HGF on the production of PAs by MDCK cells. We have found that urokinase-type PA (u-PA) activity and mRNA are increased 4.9-fold by CM from human MRC-5 fibroblasts, which has tubulogenic activity, but not by CM from human Detroit-550 fibroblasts, which lacks tubulogenic activity. The u-PA inductive property of MRC-5 CM was completely inhibited by preincubation with antibodies to recombinant human HGF (rhHGF). Exogenously added rhHGF also increased u-PA activity and mRNA 5.9-fold in MDCK cells, with an optimal effect at approximately 10 ng/ml. MRC-5 CM also increased u-PA receptor mRNA 34.9-fold in MDCK cells, an effect which was inhibited by 71% by preincubating the CM with antibodies to rhHGF, and which was mimicked by exogenously added rhHGF (31.3-fold increase). These results demonstrate that HGF, which induces tubulogenesis by MDCK cells in vitro, also increases u-PA and u-PA receptor expression in these cells. Taken together with our previous observations, this suggests that the resulting increase in extracellular proteolysis, appropriately localized to the cell surface, is required for epithelial morphogenesis.

Animals↗
PubMed1992

Cloning and characterization of an androgen-induced growth factor essential for the androgen-dependent growth of mouse mammary carcinoma cells.

An androgen-dependent mouse mammary carcinoma cell line (SC-3) requires androgen for growth stimulation. We have shown previously that androgen acts on SC-3 cells to induce secretion of a fibroblast growth factor (FGF)-like growth factor, which in turn stimulates growth of the cells in an autocrine manner. In this study, the androgen-induced growth factor (AIGF) was purified from a conditioned medium of SC-3 cells stimulated with testosterone. cDNA cloning of AIGF by use of its partial amino acid sequence data revealed that AIGF is a distinctive FGF-like growth factor. An AIGF cDNA (pSC17) encodes a 215-amino acid protein with a putative signal peptide, which shares 30-40% homology with known members of the FGF family. The AIGF mRNA was markedly induced by 10 nM testosterone in Northern blot analysis. Expression of AIGF cDNA in mammalian cells clearly showed remarkable stimulatory effects of AIGF on growth of SC-3 cells in the absence of androgen. Thus, it is clear that the androgen-induced growth of SC-3 cells is mediated in an autocrine manner by AIGF, which is secreted by the tumor cells themselves in response to hormonal stimuli.

Amino Acid Sequence↗
PubMed1992

Phosphorylation of the retinoblastoma protein by cdk2.

The retinoblastoma gene product (the RB protein) is phosphorylated in a cell cycle-dependent manner and this modification is believed to be important for cells to progress through the cell cycle. We found that purified cdk2 (cyclin-dependent kinase/cell division kinase 2) can phosphorylate the RB protein in vitro at the sites phosphorylated in the cell. The timing of activation of cdk2 in the cell cycle was similar to that of the onset of phosphorylation of the RB protein. The kinase coprecipitated with the RB protein also exhibited a similar substrate specificity to cdk2 and a similar time course of activation during the cell cycle. We further showed that cdk2 formed a complex with the RB protein in vitro and that its formation was not competitively inhibited by the simian virus 40 large T antigen. These observations suggest that cdk2 or a cdk2-related protein is involved in the cell cycle-dependent phosphorylation of the RB protein.

CDC2-CDC28 Kinases↗
PubMed1992

In vitro activation of distinct molecular and cellular phenotypes after induction of differentiation in a human neuroblastoma cell line.

In this report we provide evidence for the activation of distinct differentiation pathways during treatment of the neuroblastoma cell line SMS-KCNR with 1 mM dibutyryl cyclic AMP (dbcAMP) and/or 5 microM retinoic acid (RA). Our results show that the adrenal gland specific gene pG2 is induced only during dbcAMP treatment, while RA induces a neuronal phenotype and expression of all neural related genes while decreasing the expression of many chromaffin related genes. Furthermore dbcAMP does not affect the DNA content distribution of SMS-KCNR [G1 = 61.8 +/- 4.1% (SD); S = 20.3 +/- 6.3%; G2-M = 18 +/- 5.4%] despite morphological and molecular signs of cellular differentiation. Conversely, RA arrests cell growth causing a decrease in cells in the growth fraction (S + G2 + M = 15.6 +/- 6.1%) and an increase in cells in G1 (G1 = 84.3 +/- 5%). Using cyclic AMP and RA in combination, we found that RA inhibited expression of adrenal gland specific gene pG2 and induced a neuronal phenotype. Since dbcAMP does not cause a significant G1 block in SMS-KCNR cells we propose that this agent may be able to induce SMS-KCNR only to an intermediate stage of chromaffin differentiation in which cells retain their proliferative potential.

Bucladesine↗
PubMed1992

Detection of large cell component in small cell lung carcinoma by combined cytologic and histologic examinations and its clinical implication.

BACKGROUND: In the classification recently proposed by the Pathology Committee of International Association for the Study of Lung Cancer, small cell lung carcinoma (SCLC) was divided into three subtypes: pure SCLC, mixed small cell/large cell carcinoma (mixed SC/LC), and combined SCLC. METHODS: To examine the clinical utility of this classification, histologic specimens, cytologic specimens obtained by brushing or fine-needle aspiration, and sputum cytologic specimens from 430 patients with SCLC were reviewed. RESULTS: When the subtype of SCLC was determined from the biopsy specimen, cytologic specimen obtained by brushing or fine-needle aspiration, and sputum cytologic specimen, the frequency of mixed SC/LC was 25 of 299 (8.4%), 75 of 400 (18.8%), and 8 of 232 (3.4%), respectively. Whatever the diagnostic method, patients with mixed SC/LC showed a poorer response to treatment and worse prognosis than those with pure SCLC: a median survival of 144 days versus 285 days when classified with the use of biopsy specimens; 160 days versus 275 days with cytologic specimens obtained by brushing or fine-needle aspiration; and 47 days versus 259 days with sputum cytologic specimens, respectively. CONCLUSIONS: These findings showed that mixed SC/LC should be separated from pure SCLC as a distinctive group and that cytologic studies of specimens obtained by brushing or fine-needle aspiration were sensitive and useful procedures for this purpose.

Adult↗
PubMed1992

Marked induction of hepatocyte growth factor mRNA in intact kidney and spleen in response to injury of distant organs.

Hepatocyte growth factor (HGF) is a potent mitogen for various epithelial cells, including mature hepatocytes and renal tubular cells. Here, HGF mRNA was found to be markedly increased in non-injured kidney and spleen, when the liver or kidney in rats was injured by 70% partial hepatectomy or unilateral nephrectomy. HGF mRNA increased to 3-4 fold higher level than the normal in the kidney and spleen as well as in the remnant liver after partial hepatectomy. Similarly, HGF mRNA markedly increased in the spleen as well as in the remnant kidney after unilateral nephrectomy. These results suggest that the onset of injury to the liver or kidney may be recognized by distal non-injured organs by the signalling of a humoral factor and that HGF derived from these organs may be involved in the regeneration of liver or kidney, through an endocrine mechanism.

Animals↗
PubMed1992

IL-2 and EGF receptors stimulate the hematopoietic cell cycle via different signaling pathways: demonstration of a novel role for c-myc.

Stimulation via cytokine receptors such as IL-2 and IL-3 receptors, but not by the EGF receptor (EGFR), induces cells of the BAF-B03 hematopoietic cell line to transit the cell cycle. We demonstrate that the IL-2 receptor beta chain (IL-2R beta) is linked to at least two intracellular signaling pathways. One pathway may involve a protein tyrosine kinase of the src family, which leads to the induction of the c-jun and c-fos genes, among others. A second pathway, involving an as yet unknown mechanism, leads to c-myc gene induction. Stimulation of the EGFR, expressed following transfection of an appropriate recombinant construct, can activate the former, but not the latter, pathway in this cell line and cause the cells to enter S phase but not progress further. This deficiency can be rescued by ectopic expression of the c-myc gene, indicating a novel role for this proto-oncogene in the S to G2/M transition of the cell cycle.

Animals↗
PubMed1992

New human gene encoding a positive modulator of HIV Tat-mediated transactivation.

The human immunodeficiency virus-1 (HIV-1) protein Tat is a potent activator of virus gene expression. Tat functions through a sequence known as TAR, located immediately downstream of the transcription start site in the long terminal repeat. Several observations suggest that cellular factors cooperate with Tat in the overall transactivating process. We have isolated a human complementary DNA from the new gene MSS1, which may encode such a cellular factor, by transcomplementation of a yeast sgv1- mutant. The MSS1 protein shares 42% sequence identity with the human TBP-1 protein, which binds Tat in vitro and suppresses Tat-mediated transactivation in vivo (ref. 6). We report here that the levels of HIV activation by Tat correlate with endogenous levels of MSS1 messenger RNA. Furthermore, we provide evidence that expression of MSS1 enhances the Tat-mediated transactivation. Our results suggest that MSS1 has a key role in activation of HIV genes regulated by Tat.

ATPases Associated with Diverse Cellular Activitie↗
PubMed1992

[Hormones and growth of cancer].

Estrogen and androgen play essential roles in the development of breast cancer and prostate cancer, respectively. However, only 30% of breast cancer mass and 70% of prostate cancer mass are found to be hormone-dependent when they have been treated clinically. These findings show that hormone dependency of cancer disappears rather easily. Recently, it has been found that the growth of hormone-dependent cancer is mediated through sex steroid-induced growth factors in an autocrine manner. Future studies on sex steroid-induced growth factor(s) will play important roles in order to understand the molecular mechanisms of the development and growth of breast cancer and prostate cancer.

Adult↗
PubMed1992

Elevation of metallothionein gene expression associated with hepatic copper accumulation in Long-Evans Cinnamon mutant rat.

The mechanism of the metallothionein (MT) gene expression was investigated in a mutant rat, LEC, which exhibits an abnormal accumulation of copper in hepatocytes. The levels of MT mRNA were extremely high and correlated with the hepatic copper concentrations in LEC rat liver. Gel retardation assays in nuclear extracts from LEC rat liver showed an increase in the copper-dependent binding proteins, which bind to the metal responsive element (MRE) of the MT gene. These results suggest that the high intracellular copper accumulation results in the elevation of the MT gene expression through increasing a putative trans-activating factor in LEC rat.

Aging↗
PubMed1992

Biological activities and quantitative structure-activity relationships of spiro[imidazolidine-4,4'(1'H)-quinazoline]-2,2',5(3'H)-triones as aldose reductase inhibitors.

A series of spiro[imidazolidine-4,4'(1'H)-quinazoline]- 2,2'5(3'H)-triones were prepared and tested for aldose reductase inhibitory activity. The 6'-halogenated derivatives were found to be highly potent in vitro inhibitors of male rabbit lens aldose reductase and in vivo inhibitors of polyol accumulation in the sciatic nerves of galactosemic rats. Of these, (4R)-6'-chloro-3'-methylspiro[imidazolidine-4,4'(1'H)-quinazoline] -2,2',5(3'H)-trione (67) showed the most potent in vitro and in vivo activities. An oral dose of 3 g/kg of compound 67 caused neither death nor behavioral abnormality in the preliminary acute toxicity study using mice and rats. Compound 67 was selected as a candidate for further evaluation. The quantitative structure-activity relationships in this series are also discussed.

Aldehyde Reductase↗