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T Taki

Publications and source records attributed to T Taki.

At least 127 records · Page 7Linked to original sources
PubMed1996

Motility-related protein-1 (MRP-1/CD9) reduction as a factor of poor prognosis in breast cancer.

The application of reliable markers is of major importance for predicting the prognosis of and instituting the appropriate postsurgical treatment of patients with breast cancer. Previously we showed that motility-related protein-1 (MRP-1), which is identical to CD9, regulates cell motility, and that cultured tumor cells transfected with MRP-1/CD9 cDNA have low motility and low metastatic potential. In addition, MRP-1/CD9 immunoblotting and immunohistochemical study with breast cancer revealed that MRP-1/CD9 expression diminished as the clinical stage of a given breast cancer advanced and that the MRP-1/CD9 gene and protein expression in the metastatic lymph nodes was strikingly lower than in the primary breast cancers. In this study, we also investigated the expression of MRP-1/CD9 by immunoblotting and immunohistochemical analysis in 143 freshly resected invasive ductal carcinomas of the breast: 52 tumors were stage I, 61 were stage II, and 30 were stage III. Tumors were classified as MRP-1/CD9 positive when a band intensity of >30% compared with positive control cells, ZR-75-30 were evaluated with the antibody M31-15, and those with intensities <30% as negative. Moreover, these results were ascertained by immunostaining. Tumor specimens classified as MRP-1/CD9 positive using Western blotting had >50% of the cancer cells immunostained with M31-15, and those classified as MRP-1/CD9 reduced had <50% of the cancer cells immunostained with M31-15. There were 97 patients with MRP-1/CD9 positive tumors and 46 patients whose tumors had reduced MRP-1/CD9 levels. The disease-free rate of the former group of patients was strikingly higher than that of the latter (84.7% versus 51.4%, P<0.001). Similarly, the overall survival rate was also significantly different between the two groups (93.6% versus 69.6%, P=0.004). Multivariate analysis with the Cox regression model indicated that MRP-1/CD9 positively correlated better with disease-free survival (P<0.001) than estrogen receptor, tumor, and lymph node status. Our data suggest that low MRP-1/CD9 expression by tumors of the breast may be associated with poor prognosis. It is conceivable that testing for MRP-1/CD9 may identify node-negative breast cancer patients who are at high risk for early disease recurrence.

Antigens, CD↗
PubMed1996

Gene expression of neural cell adhesion molecule L1 in malignant gliomas and biological significance of L1 in glioma invasion.

Neural cell adhesion molecule L1 is a member of the immunoglobulin superfamily that is expressed in the nervous system. Its functions have been mainly studied in vitro using premature neuronal cells. We show that all glioma cells tested, as well as normal glia cells, express a short type of L1, L1cs mRNA. The expression of L1 protein in glioma cells was confirmed by Western blotting and flow cytometric analysis. Migration assay showed that C6 glioma cells were stimulated to migrate to soluble L1 and L1cs released from L1- or L1cs-transfected fibroblast cells. The L1-stimulated migration was significantly inhibited by antibody that recognizes the immunoglobulin C2-like domain of L1. However, antibodies that recognize the fibronectin type III-like domain and the cytoplasmic (IC) domain of L1 had no effect on migration. Our in vivo migration study demonstrated the migration of L1 on C6 glioma cells that had been transfected in rat brains. These results suggest that L1cs expressed on glioma cells may play an important role in the adhesion and migration of glioma cells by homophilic binding (probably through the extracellular immunoglobulin C2 domain of L1) and that L1cs participates in tumor invasion along neuronal fibers.

Animals↗
PubMed1996

The mouse and human homologs of DMC1, the yeast meiosis-specific homologous recombination gene, have a common unique form of exon-skipped transcript in meiosis.

Genetic recombination in meiosis plays an important role in generating diversity of genetic information. In yeast an Escherichia coli RecA-like gene, DMC1, is expressed in meiotic prophase and its product co-localizes with Rad51 protein on zygotene chromosomes. We have cloned the mouse and human homologs of the yeast DMC1 gene. The predicted human and mouse DMC1 proteins showed 54.1% sequence identity with yeast Dmc1 protein. The domain II region, highly conserved in the E.coli RecA-like protein family, was also found in the mammalian DMC1 proteins, including the two ATP binding motifs and DNA binding sites with the region. In situ hybridization analysis revealed expression of the mouse Dmc1 gene in testicular germ cells in meiosis; RT-PCR showed expression in embryonal ovaries. These findings suggest that DMC1 plays an important role in meiotic homologous recombination. From both the man and mouse we have isolated an alternative spliced form of Dmc1 cDNA (Dmc1-d), which is deleted for a region between the two motifs involved in nucleotide binding. Since the alternatively spliced Dmc1-d transcript was detected in both male and female germ cells, the encoded protein DMC1-D may have a novel role in mammalian genetic recombination in meiosis.

Adenosine Triphosphatases↗
PubMed1996

Establishment of spontaneously immortalized rat type 1 astroglial cell lines: the role of p53 in astroglial carcinogenesis.

We established five spontaneously immortalized cell lines using purified rat type 1 astroglia on a rigid transfer schedule. All the cell lines maintained their polygonal shape, regular pavement growth, low saturation density, positive glial fibrillary acidic protein expression, and serum requirements, while none were tumorigenic in nude mice. We then obtained a spontaneously transformed cell line by maintaining the cells for 6 months at a high cell density. Since alterations of the tumor suppressor p53 gene have been reported in the immortalization of some cell lines and in transformation of others, we characterized p53 in immortalized, spontaneously transformed, and 5 Nethyl-N-nitrosourea (ENU)-transformed cell lines. While each of the ENU-induced or the spontaneously transformed cell lines exhibited p53 gene mutations that resulted in amino acid alterations, no alterations in the p53 gene were observed in any of the immortalized cell lines. Thus, alterations of the p53 protein correlate more strongly with transformation than with immortalization of type 1 astroglia. Immortalization may be regulated by gene(s) other than p53. Spontaneously immortalized type 1 astroglial cell lines may provide a new tool to investigate an initial step of astroglial carcinogenesis.

Animals↗
PubMed1996

Microscale analysis of glycosphingolipids by TLC blotting/secondary ion mass spectrometry: a novel blood group A-active glycosphingolipid and changes in glycosphingolipid expression in rat mammary tumour cells with different metastatic potentials.

The glycosphingolipid compositions of rat mammary tumour cell lines with different metastatic potentials for the lung [a parental tumour cell line (MTC) and its subclones MTLn2 (a non metastatic subclone) and MTLn3 (a subclone with high metastatic potential to the lung)] were studied using a newly developed TLC blotting/secondary ion mass spectrometry system and crude glycosphingolipids obtained from 0.5-1 x 10(7) cells of each cell line. GM3 and GM2 were the major components of the MTC cell line, but they were very minor components in the MTLn2 and MTLn3 cell lines, GDla being the major ganglioside HexNAc-fucosyl-GMla was found in the MTLn2 cells by the TLC blotting/SIMS method, and the terminal sugar linkage was shown to be a blood group A-type structure by immunostaining. These findings suggest that the ganglioside is a novel type of blood group A-active ganglioside, GalNAc alpha 1-3(fuc alpha 1 -2)GMla. No blood group A-active lipid was present in MTLn3 cells, whereas Hex-GMla and neutral glycosphingolipids with more than 5 sugar residues were.

ABO Blood-Group System↗
PubMed1996

Antibody to GalNAc-GD1a and GalNAc-GM1b in Guillain-Barré syndrome subsequent to Campylobacter jejuni enteritis.

N-Acetylgalactosaminyl GD1a (GalNAc-GD1a) is a proposed target molecule for serum antibody in some patients with Guillain-Barré syndrome (GBS) (Kusunoki et al., 1994). We examined autoantibody to GalNAc-GD1a in sera from 58 GBS patients. Eight GBS patients had high IgG anti-GalNAc-GD1a antibody titers, 3 of whom also had high IgM anti-GalNAc-GD1a antibody titers. These 8 patients had experienced gastrointestinal infection before the onset of their neurological symptoms. Campylobacter jejuni was isolated from 4 of them. An absorption test indicated the presence of the GalNAc-GD1a epitope in lipopolysaccharides of C. jejuni. Sera that had anti-GalNAc-GD1a antibody reacted with several acidic glycolipids in bovine peripheral nerve, one of which was identified as N-acetylgalactosaminyl GM1b (GalNAc-GM1b). Serum binding to GalNAc-GM1b was decreased by absorption with GalNAc-GD1a. The presence of GalNAc-GM1b as well as GalNAc-GD1a has been reported in human peripheral nerves. We assume that C. jejuni, which bears the [GalNAc beta 1-4 (NeuAc alpha 2-3) Gal beta 1-3 GalNAc beta 1-] epitope, is the immunogen and that the glycoconjugates with the epitope are target molecules for the autoantibody in peripheral nerves of some GBS patients.

Animals↗
PubMed1996

Lysophosphatidic acid and bFGF control different modes in proliferating myoblasts.

Myogenic cells provide excellent in vitro models for studying the cell growth and differentiation. In this study we report that lysophosphatidic acid (LPA), a bioactive phospholipid contained in serum, stimulates the growth and inhibits the differentiation of mouse C2C12 myoblast cells, in a distinct manner from basic fibroblast growth factor (bFGF) whose mitotic and anti-differentiation actions have been well investigated. These actions of LPA were both blocked by pertussis toxin, suggesting the involvement of Gi class of G proteins, whereas bFGF acts through receptor tyrosine kinases. Detailed analysis revealed that LPA and bFGF act differently in regulating the myogenic basic helix-loop-helix (bHLH) proteins, the key players in myogenic differentiation process. LPA stimulates the proliferation of undifferentiated myoblasts allowing the continued expression of MyoD, but in contrast, bFGF does so with the MyoD expression suppressed at the mRNA level. Both compounds maintain the myf-5 expression, and suppress the myogenin expression. In addition, while LPA did not inhibit cell-cell contact-induced differentiation, bFGF strongly inhibited this process. Furthermore, LPA and bFGF act cooperatively in their mitogenic and anti-differentiation abilities. These findings indicate that LPA and bFGF differently stimulate intracellular signaling pathways, resulting in proliferating myoblasts each bearing a distinct expression pattern of myogenic bHLH proteins and distinct differentiation potentials in response to cell-cell contact, and illustrate the biological significance of Gi-mediated and tyrosine kinase-mediated signals.

Animals↗
PubMed1996

[Cancer-associated alterations of glycoconjugates--special reference to glycosphingolipids].

Glycoconjugates show the dramatic alterations of the carbohydrate structures in association with oncogenic transformation of the cells. Since glycoconjugates on the cell surfaces are involved in the cellular recognition and response, the structural changes of the carbohydrate in the cancer cells seemed to be closely related to the cell-cell adhesion, cell growth, cell behavior and metastatic property. One of the characteristic changes of glycosphingolipids in association with the oncogenic transformation is oncofetal change, and the other is the molecular mimicry of the glycosphingolipids to those in the cells of immune system. These phenomena indicate how the cancer cells smartly escape the immune surveillance system of the host. In this chapter, cancer-associated changes of glycosphingolipids together with glycolipid synthetase are summarized, and also our recent work on glycosphingolipids in metastatic tumor cells is introduced.

Carbohydrate Sequence↗
PubMed1996

Frequency and clinical significance of the MLL gene rearrangements in infant acute leukemia.

We have analyzed the frequency and clinical significance of the MLL gene rearrangements in 42 cases of infant acute leukemias; including 37 cases of acute lymphoblastic leukemia (ALL) and five cases of acute myeloid leukemia (AML). MLL gene rearrangements were found in 27 of the 37 ALL cases (73 percent), and in all five AML cases. Cytogenetic studies showed 11q23 abnormalities in 24 of 27 ALL cases with MLL gene rearrangements. MLL gene rearrangements were significantly correlated with absence of CD10 expression and poor prognosis, but not with age under 6 months, hyperleukocytosis, myeloid-associated antigen expression, or CNS leukemia. The 3-year overall survival rate for ALL cases with MLL gene rearrangements was 5.3 +/- 5.2 percent, compared with 88.9 +/- 10.5 percent for cases with germline MLL (P=0.0001). Absence of CD10 expression was also associated with poor prognosis (9.9 +/- 6.6 percent vs 85.7 +/- 13.2 percent, P = 0.0003). Of the five AML cases, three have remained alive for 27 months to 67 months. These findings suggest that infant ALL with MLL gene rearrangement is strongly associated with poor prognosis. We consider that infant ALL should be treated on different chemotherapy protocols according to the presence or absence of MLL gene rearrangement.

Antigens, CD↗
PubMed1995

Reduced motility related protein-1 (MRP-1/CD9) gene expression as a factor of poor prognosis in non-small cell lung cancer.

Motility related protein-1 (MRP-1) is a transmembrane glycoprotein that is identical to the CD9 antigen. In previous studies, we showed that various types of cultured tumor cells transfected with MRP-1/CD9 cDNA have low motility and diminished metastatic potential to the lung. More recently we used immunohistochemical procedures, immunoblotting, and reverse transcription-PCR to demonstrate that the level of MRP-1/CD9 expression was inversely related to the clinical stage of a given carcinoma of the breast. In addition, we found that the primary tumors of almost 50% of the patients had higher MRP-1/CD9 levels than their respective metastatic lymph nodes. In consideration of these findings, we have now applied reverse transcription-PCR to determine MRP-1/CD9 gene expression in lung cancer. We analyzed tumor tissues of 109 patients: 49 tumors were stage I; 15 were stage II; and 45 were stage III. We found that 67 patients had MRP-1/CD9-positive tumors, and that gene expression was reduced in the tumors of the remaining 42 individuals. The overall rate of survival was strikingly higher among patients with positive tumors than in those whose tumors had reduced gene expression (62.3 versus 34.9%; P < 0.001). This also pertained to patients with adenocarcinomas of the lung (55.4 versus 26.0%; P < 0.001). Multivariate analysis with the Cox regression model indicated that MRP-1/CD9 positivity correlated better with overall survival rate than did other variables, except lymph node status. Our data suggest that low MRP-1/CD9 expression by tumors of the lung may be associated with poor prognosis. It is conceivable that testing for MRP-1/CD9 may identify node-negative lung cancer patients and patients with adenocarcinomas who are at high risk for early disease recurrence.

Antigens, CD↗
PubMed1995

EWS-FLI-1 and EWS-ERG chimeric mRNAs in Ewing's sarcoma and primitive neuroectodermal tumor.

The t(11;22)(q24;q12) and t(21;22)(q22;q12) are specific chromosomal translocations found in the Ewing family of tumors including ES, PNET and Askin tumors. In these translocations, the amino-terminal portion of the EWS gene located in 22q12 fuses to the carboxyl-terminal portion of the FLI-1 gene located in 11q24 or the ERG gene located in 21q22, which belong to the ets oncogene superfamily of transcription activators. We investigated the chimeric mRNAs of 15 ESs (7 cell lines and 8 tumor samples) and 7 PNETs (3 cell lines and 4 tumor samples) using the RT-PCR method and sequencing. We detected 2 types of EWS-ERG chimeric mRNA in 2 ES cell lines and 1 PNET tumor sample in addition to 4 types of EWS-FLI-1 chimeric mRNA in 11 ESs (4 cell lines and 7 tumor samples) and 4 PNETs (2 cell lines and 2 tumor samples). There seemed to be no association between the type of chimeric mRNA and clinical features such as sex, age, primary site and histopathology of the patients. All of the chimeric mRNAs are generated from in-frame junctions and are thought to encode fusion proteins that may be the molecular mechanism involved in the Ewing family of tumors.

Adolescent↗
PubMed1995

Homozygous deletions of p16INK4A/MTS1 and p15INK4B/MTS2 genes in glioma cells and primary glioma tissues.

The p16INK4A/MTS1 (p16) and p15INK4B/MTS2 (p15) genes map to 9p21 where genetic alterations have been frequently reported in various human tumors. Using the polymerase chain reaction (PCR), we investigated the loss of these genes on primary glioma samples and cultured glioma cells. All or any of three exons of the p16 gene were homozygously delted in 11 (35.5%) of 31 glioblastomas, none of 9 anaplastic astrocytomas and 5 astrocytomas, and in all 6 human glioma cell lines. Exon 2 of the p15 gene was homozygously deleted in 4 (12.9%) of 31 glioblastomas, but not in lower grade gliomas. It was homozygously deleted in 5 (83.3%) of 6 glioma cell lines. In 12 short-term cultures of cells derived from primary glioma samples, 5 (41.7%) and 2 (16.7%) glioblastoma-derived cells had homozygous deletion of all or any of the three exons of the p16 gene and exon 2 of the p15 gene, respectively. The deletion pattern of these genes in cultured cells was completely consistent with that seen in the primary tumors. Furthermore, two long-term cultures retained both genes that were identical to those in the original tumor tissues. Our results indicate that loss of the p16 and p15 genes may be involved in tumor progression in human gliomas, especially in the development of glioblastoma, that this loss may give growth advantage to the cells in culture, and that it is not the result of culture artifacts.

Base Sequence↗
PubMed1995

Specific recognition of N-acetylneuraminic acid in the GM2 epitope by human GM2 activator protein.

GM2 Activator is a low molecular weight protein cofactor that stimulates the enzymatic conversion of GM2 into GM3 by human beta-hexosaminidase A and also the conversion of GM2 into GA2 by clostridial sialidase (Wu, Y.-Y., Lockyer, J.M., Sugiyama, E., Pavlova, N.V., Li, Y.-T., and Li, S.-C. (1994) J. Biol. Chem. 269, 16276-16283). Among the five known activator proteins for the enzymatic hydrolysis of glycosphingolipids, only GM2 activator is effective in stimulating the hydrolysis of GM2. However, the mechanism of action of GM2 activator is still not well understood. Using a unique disialosylganglioside, GalNAc-GD1a, as the substrate, we were able to show that in the presence of GM2 activator, GalNAc-GD1a was specifically converted into GalNAc-GM1a by clostridial sialidase, while in the presence of saposin B, a nonspecific activator protein, GalNAc-GD1a was converted into both GalNAc-GM1a and GalNAc-GM1b. Individual products generated from GalNAc-GD1a by clostridial sialidase were identified by thin layer chromatography, negative secondary ion mass spectrometry, and immunostaining with a monoclonal IgM that recognizes the GM2 epitope. Our results clearly show that GM2 activator recognizes the GM2 epitope in GalNAc-GD1a. Thus, GM2 activator may interact with the trisaccharide structure of the GM2 epitope and render the GalNAc and NeuAc residues accessible to beta-hexosaminidase A and sialidase, respectively.

Base Sequence↗
PubMed1995

New methods using polyvinylidene difluoride membranes to detect enzymes involved in glycosphingolipid metabolism.

Two new methods are described using polyvinylidene difluoride (PVDF) membranes to detect enzymes involved in glycosphingolipid metabolism. One is the detection of enzymes on a PVDF membrane to which glycosphingolipids have been transferred from an HPTLC-plate by TLC blotting. The glycosphingolipids on the membrane were incubated with an enzyme preparation, and the resulting product was detected by immunostaining with a monoclonal antibody directed to the product. IV(3)NeuAc(alpha)Lc(4)Cer that had been transferred to a PVDF membrane was incubated with Clostridium perfringens sialidase. Lc(3)Cer then was transferred to the membrane, and the whole incubated with bovine milk beta1-4 galactosyltransferase, after which the product, nLc(4)Cer, was detected by immunostaining with the monoclonal antibody H11 that recognizes the GAl(beta)1-4GlcNAc(beta)1-3Gal structure of neolactoseries glycosphingolipids. This method detects glycosphingolipid-metabolizing enzymes that produce the same epitope. The second method is the detection of enzymes located on a polyacrylamide gel. A sialidase preparation from C. perfringens was subjected to native polyacrylamide electrophoresis then transferred to a PVDF membrane impregnated with IV(3)NeuAc(alpha)nLc(4)Cer as the enzyme substrate. The membrane then was incubated, and the resulting product, nLc(4)Cer, detected by immunostaining with the monoclonal antibody H11. The area stained shows the location of the sialidase on the polyacrylamide gel. The method is effective for determining the apparent molecular weight(s) of the enzyme(s) in the crude enzyme preparation. This was demonstrated by using crude sialidase preparation from C. perfringens.

Chromatography, Thin Layer↗
PubMed1995

Motility related protein 1 (MRP-1/CD9) expression: inverse correlation with metastases in breast cancer.

In our previous studies we showed that motility related protein 1 (MRP-1) is a glycoprotein recognized by mAb M31-15, and that the sequence of MRP-1 is identical to that of CD9, a WBC differentiation antigen. Transfection of MRP-1/CD9 cDNA into cultured nonhematopoietic cells suppresses cell motility. The extent of suppression is directly related to the level of MRP-1/CD9 expression. In addition, the metastatic potential of MRP-1/CD9-transfected melanoma BL6 cells is lower than that of control BL6 cells. To determine whether these experimental results are of relevance with respect to actual human tumors, we investigated MRP-1/CD9 expression in 143 invasive ductal carcinomas of the breast. Of 97 patients with MRP-1/CD9-positive tumors, only 36 (37.1%) had lymph node involvement. In contrast, 21 of 39 (53.8%) patients whose tumors had reduced MRP-1/CD9 immunoreactivity and 5 of 7 patients whose primary carcinomas were not stained by the anti-MRP-1/CD9 MAb had lymph node metastases. The comparison of protein expression by 62 primary tumors and their respective metastatic lymph nodes revealed that in almost 50% of the cases, the latter had lower MRP-1/CD9 levels than the former. Moreover, reverse transcriptase-PCR-based analysis disclosed that MRP-1/CD9 gene expression in the metastatic lymph nodes of 17 of 32 patients was strikingly lower than in the primary invasive ductal carcinomas. Gene overexpression was not observed in any of the samples studied. Our data suggest that low MRP-1/CD9 expression may be associated with the metastatic potential of certain human tumors.

Adult↗
PubMed1995

EVI-1 zinc finger protein works as a transcriptional activator via binding to a consensus sequence of GACAAGATAAGATAAN1-28 CTCATCTTC.

Previously, the DNA-binding consensus sequences for domains 1 (GACAAGATAAGATAA) and 2 (GAAGATGAG) of the EVI-1 protein were identified using GST fusion proteins of each domain in binding and amplification reactions. We have utilized full-length EVI-1 protein to confirm these consensus sequences and determine the spacial and orientation requirements for binding. Our data demonstrate that full-length EVI-1 can independently bind the consensus sequences in gel mobility shift assays. In binding and amplification reactions only the domain 1 consensus sequence (D1-CONS) was obtained with full-length EVI-1 protein. However, by using constructs in which D1-CONS was anchored, products were obtained in which the domain 2 consensus sequence (D2-CONS) was observed with the spacing and orientation of GACAAGATAATATAAN1-28 CTCATCTTC. Using this consensus sequence we show that EVI-1 can activate transcription from reporter constructs. No transcriptional activation was seen with the reporter construct containing D1-CONS alone while activation was seen with the construct-containing D2-CONS alone. These results indicate that the EVI-1 protein works as a transcriptional activator and the binding of the domain 2 with D2-CONS is essential for its activation.

3T3 Cells↗