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A Shinagawa

Publications and source records attributed to A Shinagawa.

35 records · Page 2Linked to original sources
PubMed1996

Expression of membrane-type matrix metalloproteinase 1 (MT1-MMP) in tumor cells enhances pulmonary metastasis in an experimental metastasis assay.

Membrane-type matrix metalloproteinase 1 (MT1-MMP) is a member of the recently identified unique membrane-type subgroup in the matrix metalloproteinase (MMP) family. MT1-MMP has proteolytic activity against components in the extracellular matrix and activates progelatinase A (72-kDa type IV procollagenase/proMMP-2) on the cell surface. Because MT1-MMP is frequently expressed in a variety of tumors, we examined its contribution to their metastatic potential. The mouse lung carcinoma cell line Madison 109 was transiently transfected with a MT1-MMP expression plasmid and inoculated into the tail vein of BALB/c mouse. Fate of the transfected cells was monitored by the neo(r) gene in the plasmid using the quantitative PCR method. The survival rate of the parental cells in lung was 0.7% of the inoculated cells. It was increased by 3-fold with the MT1-MMP transfected cells and the number of the lung nodules increased accordingly. Immunostaining of the consecutive tissue sections revealed that lung nodules expressing MT1-MMP were positive for gelatinase A as well, whereas MT1-MMP-negative cells were not stained for gelatinase A at all. Thus, MT1-MMP-expressing cells acquire specific ability to bind exogenous progelatinase A.

Animals↗
PubMed1996

Tyrosine phosphorylation is crucial for growth signaling by tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2).

[3H]Thymidine (TdR) incorporation by human osteosarcoma cell line MG-63 was significantly stimulated at as early as 3 h after the addition of either TIMP-1 or TIMP-2 alone. Maximum stimulation was attained at a concentration of either 20 ng/ml (0.71 nM) TIMP-1 or 1.0 ng/ml (46 pM) TIMP-2. Tyrosine kinase inhibitors such as genistein, erbstatin, and herbimycin A almost completely inhibited the [3H]TdR incorporation stimulated by either of the TIMPs. However, essentially no effect was observed with H-89, H-7, bisindolylmaleimide and K-252a. These inhibition studies suggest a crucial role for tyrosine kinase in the signal transduction of TIMPs. Phosphotyrosine-containing proteins were significantly elevated by the treatment with both TIMPs. We also found that either TIMP stimulated an increase in mitogen-activated protein (MAP) kinase activity, suggesting that MAP kinase plays a role in TIMP-dependent growth signaling.

Benzoquinones↗
PubMed1996

Location and behavior of dorsal determinants during first cell cycle in Xenopus eggs.

In Xenopus eggs, removal of small volumes of cytoplasm along with the surface (2-10% of the entire egg volume) causes very severe dorsal reduction (average DAI=1.4) when made at a site ventrally 30 degrees off the vegetal pole at 20% time of first cell cycle (0.2 NT). The greatest dorsal reduction (average DAI=1.1) occurs when removal is done at the vegetal pole at 0.3 NT, and intermediate reductions (average DAI=2.2-2.6) when done at sites dorsally, dorsolaterally or laterally 30 degrees off the vegetal pole at 0.4 NT. Removal at sites dorsally, dorsolaterally or laterally 60 degrees off the vegetal pole provokes slight dorsal reduction (average DAI=3.5-3.9) when made at 0.4-0.5 NT. Removal at all sites after 0.4 NT causes a steady decrease in the extent of dorsal reduction. By contrast, removal of larger volumes of dorsal cytoplasm (16-50% of the entire egg volume) causes a steady increase in the extent of dorsal reduction during first cell cycle with its maximum effect at 1.0 NT (average DAI=3.1). The surgery for the cytoplasmic removal does not affect cortical rotation. We conclude from these results that dorsal determinants are concentrated first in a small region ventrally 30 degrees off the vegetal pole by 0.2 NT, then move toward the vegetal pole during the period 0.2-0.3 NT and disperse to a broad region spanning over both the presumptive dorsal and ventral, but mainly the dorsal, hemispheres during the period 0.3-0.8 NT.

Animals↗
PubMed1996

Experimental intraperitoneal administration of cisplatin-activated carbon for rat ovarian adenocarcinomas.

Selective delivery of a high level of cisplatin (CDDP) to the omentum, intraperitoneal disseminated tumors and lymph nodes was studied using a dosage form of CDDP-activated carbon. Although intraperitoneal CDDP-activated carbon delivered much higher levels of CDDP to the omentum, tumors and lymph nodes, a primary burst phenomenon of CDDP occurred just after administration. This indicates that activated carbon is an unsuitable particle to provide a slow steady release of CDDP.

Adenocarcinoma↗
PubMed1996

[Appearance of cytoplasmic processes of megakaryocytes in the peripheral blood in a Munchausen syndrome with factitious anemia].

Many cytoplasmic processes of megakaryocytes were seen in a 45-year-old male patient of Munchausen syndrome with sustained severe anemia due to repeated self-blood drawing. He had a past history of repeated infection and removal of skin-graft transplanted for giant congenital melanocytic nevus due to self-infliction (later confessed by the patient). On the admission, he presented with high fever (39 approximately 40 degrees C) and severe sustained anemia refractory to repeated blood transfusions. Any specific clinical data indicating bleeding or hemolysis were not found. Self-blood drawing was discovered by a nurse on his 27th hospital day. Syringes and needles for blooddrawing were also found. He recovered from anemia under intensive watching without any specific treatment. He confessed that the high fever was artificial. It was of interest that cytoplasmic processes of megakaryocytes were seen in the peripheral blood film until he recovered from anemia for one month. The serum level of erythropoietin was elevated (1540 mU/ml), but not significantly was that of thrombopoietin (1.54 fmol/ml). This case was considered to be valuable to understand the mechanism of platelet-production by megakaryocytes at persistent bleeding.

Anemia↗
PubMed1995

Identification of the second membrane-type matrix metalloproteinase (MT-MMP-2) gene from a human placenta cDNA library. MT-MMPs form a unique membrane-type subclass in the MMP family.

Membrane-type matrix metalloproteinase (MT-MMP), which we have identified recently, is unique in its transmembrane (TM) domain at the C terminus and mediates activation of pro-gelatinase A on the cell surface (Sato, H., Takino, T., Okada, Y., Cao, J., Shinagawa, A., Yamamoto, E., and Seiki, M. (1994) Nature 370, 61-65; Takino, T., Sato, H., Yamamoto, E., and Seiki, M. (1995) Gene (Amst.) 115, 293-298). In addition to MT-MMP, a novel MMP-related cDNA of 2.1 kilobases was isolated from a human placenta cDNA library. The cDNA contains an open reading frame for a new MMP. The deduced protein composed of 604 amino acids was closely related to MT-MMP in the amino acid sequence (66% homology at the catalytic domains) and has a potential TM domain at the C terminus. Monoclonal antibodies raised against the synthetic peptide recognized a 64-kDa protein as the major product in the transfected cells. TIMP-1 fused with the potential TM domain was localized on the cell surface while native TIMP-1 is in the culture medium. Thus, we called the second membrane-type MMP, MT-MMP-2 and renamed MT-MMP, MT-MMP-1. MT-MMP-1 and -2 are thought to form a distinct membrane-type subclass in the MMP family since all the others are secreted as soluble forms. Like MT-MMP-1, expression of MT-MMP-2 induced processing of pro-gelatinase A (68-kDa in gelatin zymography) into the activated form of 62-kDa fragments through a 64-kDa intermediate form. Expression of MT-MMP-2 mRNA was at the highest levels in the brain where MT-MMP-1 was at the lowest level compared to other tissues. MT-MMP-1 and -2 are thought to be utilized for extracellular matrix turnover on the surface of cells under different genetic controls.

Amino Acid Sequence↗
PubMed1995

White matter microglia produce membrane-type matrix metalloprotease, an activator of gelatinase A, in human brain tissues.

Membrane-type matrix metalloprotease (MT-MMP) is an activator of gelatinase A (MMP-2), which has previously been found in carcinoma cells. We examined non-neurological and Alzheimer's disease brain tissues for MT-MMP by immunohistochemistry and in situ hybridization. The anti-MT-MMP antibodies gave positive staining of brain microglial cells in all the brain tissues. Positively stained microglia were found only in the white matter. The cells producing MT-MMP protein were also shown to be white matter microglia. These results provide further evidence that activated gelatinase A, which may be a processing enzyme for degradation of beta-amyloid protein, may be produced in white matter microglia.

Aged↗
PubMed1995

Detection of a proteinaceous toxin in the brackishwater clam (Corbicula japonica).

Water extracts from the brackishwater clam (Corbicula japonica) were found to be lethal to mice upon i.v. injection. Muscular tissues (foot muscle, adductor muscle, mantle muscle, mantle and siphon) were all toxic while gill and viscera (mid-gut gland, testis and ovary) were nontoxic; the highest toxicity was observed with foot muscle. The toxin was judged to be a thermolabile, basic protein with a mol. wt. of about 13,000.

Animals↗
PubMed1995

Megakaryopoiesis in patients with cyclic thrombocytopenia.

Megakaryopoiesis was examined in 10 patients (eight females and two males) with cyclic thrombocytopenia (CT) to investigate the underlying pathogenesis. Numbers of CFU-Meg and megakaryocytes and the mean cytoplasmic area (mean area) of megakaryocytes at the peak, nadir, ascent mid phase, and descent mid phase of the platelet cycle were determined. The patients were classified as female cases group I (cases 1-4; previously diagnosed as ITP and CT occurred during remission), female cases group II (cases 5-8; persistent CT from initial diagnosis), and male CT (cases 9 and 10). In three of the four female cases in group I, numbers of CFU-Meg and megakaryocytes were normal or increased persistently during the platelet cycle, whereas the mean area fluctuated in synchrony with the platelet cycle, suggesting failure of cyclic production rather than platelet destruction. In the female cases in group II and one female case in group I, numbers of CFU-Meg and megakaryocytes were also normal or increased at four phases of the cycle, but the mean area did not fluctuate, remaining large during the cycle, suggesting cyclic destruction or platelet clearance. In contrast, in the male patients values for numbers of CFU-Meg, megakaryocytes and mean cytoplasmic area fluctuated during the platelet cycle, indicating that cyclic changes in megakaryopoiesis generated the platelet cycle. These findings indicate that the measurement of cytoplasmic area is useful for distinguishing cyclic platelet production from cyclic destruction or clearance in CT.

Adult↗
PubMed1994

A matrix metalloproteinase expressed on the surface of invasive tumour cells.

Gelatinase A (type-IV collagenase; M(r) 72,000) is produced by tumour stroma cells and is believed to be crucial for their invasion and metastasis, acting by degrading extracellular matrix macro-molecules such as type IV collagen. An inactive precursor of gelatinase A (pro-gelatinase A) is secreted and activated in invasive tumour tissue as a result of proteolysis which is mediated by a fraction of tumour cell membrane that is sensitive to metalloproteinase inhibitors. Here we report the cloning of the complementary DNA encoding a new matrix metalloproteinase with a potential transmembrane domain. Expression of the gene product on the cell surface induces specific activation of pro-gelatinase A in vitro and enhances cellular invasion of the reconstituted basement membrane. Tumour cells of invasive lung carcinomas, which contain activated forms of gelatinase A, were found to express the transcript and the gene product. The new metalloproteinase may thus trigger invasion by tumour cells by activating pro-gelatinase A on the tumour cell surface.

3T3 Cells↗
PubMed1994

Cell growth-promoting activity of tissue inhibitor of metalloproteinases-2 (TIMP-2).

Human tissue inhibitor of metalloproteinases-2 (TIMP-2) has a potent growth-promoting activity for wide range of human, bovine and mouse cells, having an optimal concentration (10 ng/ml, 0.46 nM) that is ten-times lower than that of TIMP-1 (Hayakawa et al. (1992) FEBS Lett. 298, 29). Neither TIMP-1 complexed with progelatinase B nor TIMP-2 complexed with progelatinase A, both of which have full inhibitory activity against active forms of matrix metalloproteinases (MMPs), showed any cell growth-promoting activity. On the contrary, both reductively alkylated TIMPs had no MMP inhibitory activity, but significantly stimulated cell proliferation. These facts clearly indicate that the cell-proliferation. These facts clearly indicate that the cell-proliferating activity of TIMPs is independent of MMP inhibitory activity. We also demonstrated that [3H]thymidine was significantly incorporated into Raji cells, a Burkitt lymphoma cell line, in the presence of either 4 ng/ml of TIMP-1 or 0.1 ng/ml of TIMP-2. Under steady-state conditions at 4 degrees C, high-(Kd = 0.15 nM) and low-(35 nM) affinity binding sites for TIMP-2 were identified on Raji cells with 20,000 and 1.4 x 10(5) sites/cell, respectively. Both high- and low-affinity binding of 125I-TIMP-2 to Raji cells were competitively inhibited by unlabeled TIMP-2 but not by unlabeled TIMP-1, suggesting the presence of receptors for TIMP-2 independent from those for TIMP-1. TIMP-2 seems to be another new TIMP cell-growth factor in serum, besides TIMP-1.

Alkylation↗
PubMed1986

Periodic changes in the rigidity of activated anuran eggs depend on germinal vesicle materials.

The eggs of Xenopus laevis and Bufo bufo japonicus matured in vitro by progesterone were denuded and activated by electrical shock or pricking, and their diameters were determined periodically until the postactivation time equivalent to the 8- to 16-cell stage. Normally matured eggs showed a quick rounding-up and flattening immediately after activation (activation response), followed by a periodic flattening and rounding-up (postactivation response) corresponding to the intervals of early cleavage cycles. When denuded eggs that were induced to mature after removal of the germinal vesicle (GV) were activated, they showed a normal activation response, but retained the rounded-up state without exhibiting the periodic postactivation changes. Injection of GV materials back into enucleated Bufo oocytes and determination of the postactivation flattening 120 min after activation revealed that the extent of flattening correlated well with the amount of GV materials injected, provided injection was made before the first polar body was emitted. Thus, postactivation flattening, but not activation flattening, is an active property of eggs established under the influence of the GV and is linked to the periodical changes of rigidity during early cleavage cycles.

Animals↗
PubMed1985

Localization of the factors producing the periodic activities responsible for synchronous cleavage in Xenopus embryos.

This paper investigates the localization within the Xenopus egg of the factors responsible for the periodic activities such as the cyclic rounding-up and flattening, related to the cleavage cycle. Denuded eggs were bisected along the boundary line between the animal and the vegetal hemispheres immediately after being rotated through 90 degrees off the vertical axis (Early Bisection). The resulting animal halves, though prevented from cell division by colchicine, showed typical periodic rounding-up as previously observed in enucleated egg fragments, whereas the vegetal halves did not. This result indicates that the factors inducing the periodic rounding-up are not distributed uniformly throughout the egg but localized mostly in the animal hemisphere. Furthermore, the distribution of these factors between the cortex and endoplasm of the animal hemisphere was investigated. Eggs were separated into animal and vegetal halves following incubation for 30 min after the 90 degrees-off axis rotation (Late Bisection). During this incubation the endoplasmic components become relocated in the rotated egg under the force of gravity. After the rotation, the Late-Bisected vegetal halves showed typical cyclic rounding-up in contrast to those formed by Early Bisection. These results suggest that the factors inducing the periodic rounding-up (and probably also many other cyclic activities, closely linked with the rounding-up movement) are localized in endoplasmic components which can be displaced by gravity from the animal to the vegetal hemisphere of the Xenopus egg.

Animals↗
PubMed1983

Cyclic cytoplasmic activity of non-nucleate egg fragments of Xenopus controls the morphology of injected sperms.

Triton X-100-treated sperms were injected into non-nucleate egg fragments of Xenopus laevis to determine whether the structure of the injected sperm nucleus is affected by the cyclic activity of the cytoplasm. Swollen vesicular nuclei were very frequently observed when the sperms were injected and incubated during the 'rounding-up' phase of the recipient fragment, whereas no such structures were found when they were incubated during the 'relaxing' phase.

Animals↗
PubMed1983

The interval of the cytoplasmic cycle observed in non-nucleate egg fragments is longer than that of the cleavage cycle in normal eggs of Xenopus laevis.

Non-nucleate fragments of animal eggs are known to show a cyclic change in rigidity similar to the change observed in the cleavage of normal eggs. The interval of cyclic change was compared with that of the cleavage cycle in Xenopus eggs. Procedures employed by both Hara and co-workers and Sakai & Kubota to obtain non-nucleate fragments were carefully repeated. Non-nucleate fragments produced by either of those procedures had a longer duration of cycle than the normal cleavage cycle (about 30%). By injection of colchicine or vinblastine the cycle of the nucleate fragment was lengthened to coincide with that of the non-nucleate partner. It is suggested that the basic cycle length intrinsic to egg cytoplasm is modulated by assembly-disassembly of the mitotic apparatus, as demonstrated by Sluder in the chromosome cycle of sea urchin eggs.

Animals↗