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Takahiro Taguchi

Publications and source records attributed to Takahiro Taguchi.

18 recordsLinked to original sources
PubMed2006

ZD6474 induces growth arrest and apoptosis of GIST-T1 cells, which is enhanced by concomitant use of sunitinib.

ZD6474 (Zactima, AstraZeneca, Macclesfield, UK) is an orally available, small-molecule inhibitor of vascular endothelial growth factor receptor-2 and epidermal growth factor receptor tyrosine kinases, with additional activity versus rearranged during transfection (RET). This study explored the effect of ZD6474 in gastrointestinal stromal tumor-T1 (GIST-T1) cells that possess a gain of function mutation in exon 11 of the c-KIT gene. ZD6474 induced growth arrest and apoptosis of GIST-T1 cells in association with blockade of c-Kit and its downstream effectors, including Akt and extracellular signal-regulated kinase (ERK). ZD6474 treatment also blocked the mammalian target of rapamycin (mTOR), which lies downstream of Akt and ERK. Interestingly, when ZD6474 was combined with sunitinib (SU11248; Sutent, Pfizer, Kalamazoo, MI, USA), a class III and V receptor tyrosine kinase inhibitor, the ZD6474-mediated growth inhibition was potentiated in association with further down-regulation of the mTOR targets p-p70S6K and p-4E-BP-1. The combination of ZD6474 and sunitinib should be investigated further.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Therapeutic effect of imatinib in gastrointestinal stromal tumors: AKT signaling dependent and independent mechanisms.

Most gastrointestinal stromal tumors (GISTs) possess a gain-of-function mutation in c-KIT. Imatinib mesylate, a small-molecule inhibitor against several receptor tyrosine kinases, including KIT, platelet-derived growth factor receptor-alpha, and BCR-ABL, has therapeutic benefit for GISTs both via KIT and via unknown mechanisms. Clinical evidence suggests that a potential therapeutic benefit of imatinib might result from decreased glucose uptake as measured by positron emission tomography using 18-fluoro-2-deoxy-d-glucose. We sought to determine the mechanism of and correlation to altered metabolism and cell survival in response to imatinib. Glucose uptake, cell viability, and apoptosis in GIST cells were measured following imatinib treatment. Lentivirus constructs were used to stably express constitutively active AKT1 or AKT2 in GIST cells to study the role of AKT signaling in metabolism and cell survival. Immunoblots and immunofluorescent staining were used to determine the levels of plasma membrane-bound glucose transporter Glut4. We show that oncogenic activation of KIT maximizes glucose uptake in an AKT-dependent manner. Imatinib treatment markedly reduces glucose uptake via decreased levels of plasma membrane-bound Glut4 and induces apoptosis or growth arrest by inhibiting KIT activity. Importantly, expression of constitutively active AKT1 or AKT2 does not rescue cells from the imatinib-mediated apoptosis although glucose uptake was not blocked, suggesting that the potential therapeutic effect of imatinib is independent of AKT activity and glucose deprivation. Overall, these findings contribute to a clearer understanding of the molecular mechanisms involved in the therapeutic benefit of imatinib in GIST and suggest that a drug-mediated decrease in tumor metabolism observed clinically may not entirely reflect therapeutic efficacy of treatment.

Apoptosis↗
PubMed2006

STI571 (Glivec) suppresses the expression of vascular endothelial growth factor in the gastrointestinal stromal tumor cell line, GIST-T1.

AIM: To estimate whether STI571 inhibits the expression of vascular endothelial growth factor (VEGF) in the gastrointestinal stromal tumor (GIST) cells. METHODS: We used GIST cell line, GIST-T1. It has a heterogenic 57-bp deletion in exon 11 to produce a mutated c-KIT, which results in constitutive activation of c-KIT. Cells were treated with/without STI571 or stem cell factor (SCF). Transcription and expression of VEGF were determined by RT-PCR and flow cytometry or Western blotting, respectively. Activated c-KIT was estimated by immunoprecipitation analysis. Cell viability was determined by MTT assay. RESULTS: Activation of c-KIT was inhibited by STI571 treatment. VEGF was suppressed at both the transcriptional and translational levels in a temporal and dose-dependent manner by STI571. SCF upregulated the expression of VEGF and it was inhibited by STI571. STI571 also reduced the cell viability of the GIST-T1 cells, as determined by MTT assay. CONCLUSION: Activation of c-KIT in the GIST-T1 regulated the expression of VEGF and it was inhibited by STI571. STI571 has antitumor effects on the GIST cells with respect to not only the inhibition of cell growth, but also the suppression of VEGF expression.

Antineoplastic Agents↗
PubMed2006

In vitro Epstein-Barr virus-immortalized lymphoma cell line carrying t(9;14)(p13;q32) chromosome abnormality, derived from splenic lymphoma with villous lymphocytes.

We herein describe splenic lymphoma with villous lymphocytes (SLVL) carrying t(9;14)(p13;q32). The t(9;14)(p13;q32) is a rare reciprocal chromosome translocation found in a subset of B-cell malignancies, mainly in low-grade non-Hodgkin's lymphomas. In t(9;14)(p13;q32), PAX-5 gene on 9p13 is involved with the immunoglobulin heavy-chain gene on 14q32. It has been thought that the deregulated expression of PAX-5 as a result of t(9;14)(p13;q32) may contribute to abnormal cell proliferation. Although continuous cell lines are invaluable tools for studying lymphomagenesis in the t(9;14)(p13;q32)-bearing lymphomas, establishment of such cell lines is extremely difficult since they are usually mature B-cell malignancies. In an attempt to transform the SLVL cells into a proliferating cell line, we examined the responses of the cells to infection by Epstein-Barr virus (EBV). SLVL cells were found to be susceptible to immortalization by EBV, resulting in a permanent cell line. The cell line, designated SL-15, possessed the t(9;14)(p13;q32). Genotype analysis and immunophenotype profiles confirmed that the cell line arose from the primary lymphoma cells. The cells had characteristic cytoplasmic villi. SL-15 cells has been growing over 2 years equivalent to 350-400 population doubling levels without proliferative crisis that is often observed in EBV-positive lymphoblastoid cell lines. Furthermore, SL-15 cells, when inoculated into nude mice, formed t(9;14)(p13;q32)-bearing tumors with cytoplasmic villi. The validated SLVL-derived cell line provide a useful model system to study molecular biology of t(9;14)(p13;q32)-bearing B-cell malignancies as well as lymphomagenesis of SLVL in vitro and in vivo.

Animals↗
PubMed2006

Effect of SU11248 on gastrointestinal stromal tumor-T1 cells: enhancement of growth inhibition via inhibition of 3-kinase/Akt/mammalian target of rapamycin signaling.

SU11248 is an orally available type III and V receptor tyrosine kinase inhibitor. Clinical studies have shown the efficacy of SU11248 in individuals with gastrointestinal stromal tumors (GIST); however, the molecular mechanisms by which SU11248 inhibits the proliferation of these tumor cells remains to be fully elucidated. Taking advantage of GIST-T1 cells, which possess an activating mutation in exon 11 of the c-KIT gene, we examined the medicinal action of SU11248 in GIST cells. Clonogenic and MTT assays showed that SU11248 potently inhibited the proliferation of GIST-T1 cells with IC50 of approximately 1 nM and 40 nM, respectively. SU11248 (10 or 20 nM, 48 h) activated caspase-3 and induced apoptosis of GIST-T1 cells as measured by caspase assay, annexin V staining and cleavage of poly (ADP-ribose) polymerase. Western blot analyses found that SU11248 blocked autophosphorylation of c-KIT in association with inhibition of its downstream effectors, including Akt and extracellular signal-regulated kinase, but not signal transducers and activators of transcription. Interestingly, when phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin signaling was blocked simultaneously by either LY294002 or rapamycin, growth inhibition mediated by SU11248 was potentiated. Taken together, this study supports clinical studies of SU11248 for individuals with GIST, and the combination of SU11248 and inhibitors of 3-kinase/Akt/mammalian target of rapamycin signaling represents a promising novel treatment strategy.

Antineoplastic Agents↗
PubMed2006

STI571 (Glivec) induces cell death in the gastrointestinal stromal tumor cell line, GIST-T1, via endoplasmic reticulum stress response.

STI571 is a specific inhibitor of tyrosine kinases, such as BCR-ABL, platelet-derived growth factor receptor, and c-KIT, and has recently been approved for the treatment of chronic myeloid leukemia and gastrointestinal stromal tumors (GISTs). This study demonstrated that STI571 induces cell death in the gastrointestinal stromal tumor cell line, GIST-T1. In these cells, STI571 induced pro-caspase-12 or pro-caspase-7 cleavage and it affected caspase-3 activity and induced the endoplasmic reticulum (ER)-resident chaperone, glucose-regulated protein 78. The STI571-induced cell death was blocked by the protein synthesis inhibitor, cycloheximide. Together, these results suggest that STI571 induces cell death in GIST-T1 cells, at least in part, via the ER stress response.

Antineoplastic Agents↗
PubMed2005

Overexpression of carbonic anhydrase-related protein XI promotes proliferation and invasion of gastrointestinal stromal tumors.

Three isoforms of carbonic anhydrase-related protein (CA-RP) are evolutionally well conserved among the CA gene family but lack classical CA activity. Although the biological function of CA-RPs is unknown, overexpression of CA-RP VIII has been reported in certain tumor types. Based on the finding that CA-RPs are commonly expressed in the neuronal cells, we investigated expression of all three CA-RPs in gastrointestinal stromal tumor (GIST). In contrast to no detectable signal of any of the three CA-RPs in intestinal cells of Cajal, immunohistochemical analysis showed distinct cytoplasmic expressions of CA-RPs VIII and XI in 13 (59%) and 20 (91%) of 22 GIST tissue specimens, respectively. The positive signals for both CA-RPs VIII and XI were more intense in the periphery than in the central part of GISTs, whereas no significant signal for CA-RP X expression was observed in any of the GISTs. These expression patterns of CA-RPs were consistently observed by reverse transcription-polymerase chain reaction-Southern blot and immunocytochemistry in the cultured GIST cell line GIST-T1. Ectopic expression of CA-RP XI in GIST-T1 cells induced cell proliferation and invasion in vitro. These findings indicate that CA-RP XI plays a role in the development of GIST.

Biomarkers, Tumor↗
PubMed2005

Genetic changes in localized prostate cancer of Japanese patients shown by comparative genomic hybridization.

To search for additional amplification and deletion sites that may serve as a starting point for the discovery of new oncogenes or tumor suppressor genes, 30 Japanese localized prostate cancers were analyzed by comparative genomic hybridization (CGH) in this study. CGH was used to search for changes in DNA sequence copy-number in a series of 30 primary prostate adenocarcinomas, consisting of 22 cases of pT2N0 (organ confined; without capsular invasion) and 8 cases of pT3N0 (with capsular invasion), removed by radical prostatectomy. CGH revealed that the shortest regions of overlap (SRO) of gains in pT2N0 were at 8q22.2 approximately q24.2, 11q13.1 approximately q14.1, and 12q23 approximately q24.2, whereas the SRO of losses were seen at 8p23.3 approximately p22, 13q21.2 approximately p22, and 18q21 approximately q22. The SRO of gains in pT3N0 were noted at 5q32 approximately q34, 8q22.3 approximately q24.1, 11q14.1 approximately q22.3, and 12q22 approximately q24.2, whereas the SRO of losses were seen at 18q21.2 approximately q23. These results suggest that gains or losses of DNA in these regions are important for prostate cancer progression. The detection of the SRO may serve as a starting point to discover novel oncogenes and tumor suppressor genes involved in prostate cancer progression.

Adenocarcinoma↗
PubMed2005

Eradication of Epstein-Barr virus episome and associated inhibition of infected tumor cell growth by adenovirus vector-mediated transduction of dominant-negative EBNA1.

Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1), a latent viral protein consistently expressed in infected proliferating cells, is essentially required in trans to maintain EBV episomes in cells. We constructed a mutant (mt) EBNA1 and examined whether it exerted dominant-negative effects on maintenance of the viral episome thereby leading to abrogation of EBV-infected tumor cell growth. Using lymphocyte and epithelial cell lines converted with neomycin-resistant recombinant EBV (rEBV) as models, adenovirus vector-mediated transduction of mtEBNA1, but not LacZ, brought about rapid and striking reductions in rEBV-derived wild-type EBNA1 levels and viral genomic loads in converted lines of three major viral latencies. This outcome was further validated at the single-cell level by cellular loss of G418 resistance and viral signals in situ. The mtEBNA1 transduction significantly impaired growth of naturally EBV-harboring Burkitt lymphoma cells in vitro and in vivo, largely in association with the eradication of viral episomes. Expression of mtEBNA1 per se caused no detectable cytotoxicity in EBV-uninfected cells. These results indicate that mtEBNA1 can act as a dominant-negative effector that efficiently impedes the EBV-dependent malignant phenotypes in cells regardless of viral latency or tissue origin. The mutant will afford an additional therapeutic strategy specifically targeting EBV-associated malignancies.

Adenoviridae↗
PubMed2005

STI571 (Glivec) inhibits the interaction between c-KIT and heat shock protein 90 of the gastrointestinal stromal tumor cell line, GIST-T1.

The gastrointestinal stromal tumor cell line, GIST-T1, has a heterogenic 57-base pair deletion in exon 11 of the c-kit mutation, and the c-KIT protein in the GIST-T1 cells constitutively activated. We report that STI571 (Glivec; Novartis, Basel, Switzerland), a specific inhibitor of c-KIT, inhibits the clustering of c-KIT at the cell membrane of the GIST-T1 cells. Furthermore, STI571 prevents the interaction between c-KIT and the molecular chaperone, heat shock protein 90 (Hsp90). Geldanamycin, an inhibitor of Hsp90, also prevents interaction between c-KIT and Hsp90, and inhibits tyrosine phosphorylation of c-KIT. Our results indicate that c-KIT molecules are assembled on the cell surface of the GIST-T1 cells, and that the interaction between c-KIT and Hsp90 plays an important role in c-KIT activation.

Benzamides↗
PubMed2004

Differential gene-expression profiling in the leukemia cell lines derived from indolent and aggressive phases of CD56+ T-cell large granular lymphocyte leukemia.

As a rule, T cell large granular lymphocyte (T-LGL) leukemia runs a chronic clinical course without need for therapy. Some cases, however, progress to an aggressive disease after the indolent clinical stage. The transformation mechanism into a high-grade malignancy has not been well studied. We have established 2 leukemia cell lines, MOTN-1 and PLT-2, derived from the same clone of CD56+ T-LGL leukemia in chronic and aggressive phases, respectively. The paired availability of such cell lines is valuable in biologic and genetic investigation of T-LGL leukemia. We used a microarray containing 406 cDNAs to elucidate alterations of gene expression between the 2 cell lines. We found a number of genes that were differentially expressed: 13 genes with increased expression and 3 genes with reduced expression in PLT-2 cells as compared to MOTN-1 cells. Increased expression of the dek, rac, Op18, CD6, CD58, CD106, Id2, ATF4, IRF5, ELL2 and D6 genes, and reduced expression of the GzmA and GzmK genes were confirmed by real-time quantitative reverse transcription-PCR, whose results paralleled the microarray data. These upregulated genes encode oncoproteins, cell surface antigens including molecules related to T cell proliferation, transcription factors, and a chemokine receptor. The two downregulated genes encode granzymes that play an important role for induction of cell death. These findings suggest that there is differential gene expression in different clinical phases of T-LGL leukemia and these differentially expressed genes would be potential targets for further studies to identify the genes involved in the transformation process of T-LGL leukemia.

CD56 Antigen↗
PubMed2004

Low-grade tubular-mucinous renal neoplasm with neuroendocrine differentiation: a histological, immunohistochemical and ultrastructural study.

Low-grade tubular-mucinous renal neoplasm (LGTMRN) was recently established as a distinct carcinoma classification. A 70-year-old, female traffic accident victim underwent a detailed examination that disclosed a huge mass in the lower pole of the left kidney. The patient underwent a nephrectomy based on a diagnosis of renal tumor. Macroscopically, the tumor was well demarcated and a whitish color with focal hemorrhage. Histological examination showed that tumor cells proliferated through tubular, trabecular, and solid growth patterns in the mucinous background. Focally, foci of clear cells or the proliferation of spindle cells was also observed. Nuclei were generally round and uniform in size. No abnormal mitotic figures were identified. Immunohistochemically, tumor cells were diffusely positive for AE1/AE3, vimentin and chromogranin A, and focally positive for cytokeratin (CK) 18, CK19, Ulex europaeus agglutinin-1, epithelial membrane antigen, neuron-specific enolase (NSE), CD9 and CD57. Ultrastructurally, tumor cells contained a moderate number of mitochondria, rough endoplasmic reticulum and dense-core granules. No renin granules or glycogen were observed. Microvilli were focally seen. Our results render further evidence that LGTMRN is a distinct entity from the hitherto established renal neoplasms. Foci of clear cells and neuroendocrine differentiation should be added to the histological spectrum of LGTMRN.

Adenocarcinoma, Mucinous↗
PubMed2003

A probe generated by chromosome microdissection, useful for analyzing Y chromosome evolution in Old World monkeys.

We isolated a DNA probe, designated MMDYZ1, using a chromosome microdissection technique from the Y chromosome of the Rhesus monkey. The probe obtained from eight whole Y chromosomes shows higher specificity for the Y short arm of the Rhesus monkey, which consists totally of constitutive heterochromatin. Two microclones (MMY#3 and MMY#4) were constructed from the Y-specific primary PCR products. Sequence analysis of these two microclones revealed that both were essentially identical to each other and the sizes were 870 and 686 bp, respectively. From alignment analysis using the Genbank database of primates, the alphoid DNA has the highest affinity with the probe. However, the total composition of this probe has extremely high homology with the Y short arm of the Rhesus monkey, as demonstrated by fluorescence in-situ hybridization (FISH). Comparative FISH-mapping disclosed that this DNA-sequence cluster was located at extremely different sites on the Y chromosome in several species of the Old World monkey. Accordingly, this probe seems to be a high-quality tool, now established for the first time, for investigating Y chromosome evolution of the Old World monkey.

Animals↗
PubMed2002

A novel t(16;20)(q22;p13) in polycythemia vera.

We report a patient with polycythemia vera whose bone marrow cells carried a novel t(16;20)(q22;p13) as detected by karyotype analysis using G- and Q-banding techniques. The reciprocal translocation was confirmed by fluorescence in situ hybridization (FISH) using DNA libraries of chromosomes 16 and 20. To our knowledge, t(16;20)(q22;p13) has not been reported previously. The core binding factor beta (CBFbeta) gene located on 16q22 is known to be frequently involved in acute myelocytic leukemia. On the other hand, the 20p13 locus contains a gene encoding protein kinase CK2alpha, which is closely related to cell proliferation and cell cycle regulation. The t(16;20)(q22;p13) may be one of the cytogenetic aberrations in myeloproliferative disorders, and therefore, our observation warrants further studies on a possible involvement of the genes resulting from this translocation.

Bone Marrow Cells↗
PubMed2002

Detection of genetic alterations in advanced prostate cancer by comparative genomic hybridization.

In this study, we examined nine cases of advanced Japanese prostate cancer by comparative genomic hybridization (CGH) to detect chromosomal imbalances across the entire genome and to identify several new regions likely to contain genes important to the development and progression of this disease. These cases had been previously examined for numerical chromosomal aberrations by fluorescence in situ hybridization (FISH). By CGH, the following regions were found to be over-represented (gains), with fluorescence ratio values higher than the threshold: 4p, 6p, 8q, 11q, 12q, 15q, 16p, 17q, 20, and 21 (>4 cases); underrepresentation (losses) involved: 1q, 4q, 5q, 6q, 13q, 14q, and 22 (>4 cases). The shortest regions of overlap (SRO) of gains were noted at 8q24.1 through q24.3, 12q23, and 17q23 through q24 (>5 cases). The SRO of losses were seen at 5q14 through q21, 6q16.1 through q21, 13q21.3 through q22, and 14q21 (>5 cases). Notably, the gain of chromosomes 8 and 12 by CGH was in agreement with the FISH data, suggesting that the gain of chromosomes 8 and 12 may play an important role in prostate carcinogenesis. The genes on the SRO regions were also discussed in relation to oncogenes and bone metastases.

Aged↗
PubMed2002

Epstein-Barr virus (EBV)-positive pyothorax-associated lymphoma (PAL): chromosomal integration of EBV in a novel CD2-positive PAL B-cell line.

Pyothorax-associated lymphoma (PAL) is a clinico-pathological entity arising in the pleural cavity of patients with long-standing inflammatory pyothorax. PAL is closely associated with Epstein-Barr virus (EBV), but how this virus contributes to the development of the lymphoma is unknown. We have successfully obtained a novel EBV-infected PAL cell line, designated Pal-1. The cell line and its source coexpressed CD2 and CD20 molecules, but other representative B- and T-cell markers such as CD1, CD3, CD5, CD7, CD10 and CD19 were not found. The B-cell origin of Pal-1 cells was proven by rearrangement of the immunoglobulin heavy- and light-chain genes without rearranged T-cell receptor genes. Both the cell line and primary tumour cells carried monoclonal EBV genome. Although EBV genome is known to be maintained as circular extrachromosomal DNA, neither circular nor linear extrachromosomal EBV DNA was detectable in Pal-1 cells by in situ lysis gel analysis. Fluorescence in situ hybridization demonstrated viral integration at a marker chromosome mostly consisting of the centromere region of chromosome 1. The viral integration event may enhance a chromosomal instability at the insertion site. This cell line represents the first example of EBV integration in PAL and could enable the study of the potential role of integrated viral infection in the development of PAL as well as mechanism of the aberrant phenotype expression.

Aged↗
PubMed2002

Establishment and characterization of a new lung cancer cell line (MI-4) producing high levels of granulocyte colony stimulating factor.

We established a human lung cancer cell line, MI-4 from the pleural effusion of a 69-year-old male with advanced large cell undifferentiated carcinoma of the lung complicated by leukocytosis. The culture supernatant of MI-4 contained high levels of granulocyte colony stimulating factor (G-CSF). The intracellular localization of the G-CSF was identified by immunocytochemistry. Reverse transcription-polymerase chain reaction (RT-PCR) revealed G-CSF mRNA expression in this cell line. The cell line was successfully transplanted into nude mice. The transplanted nude mice also showed leukocytosis with a high serum G-CSF level. Southern blot analysis did not show amplification or rearrangement of the G-CSF gene in MI-4 cells. Spectral karyotyping (SKY) and fluorescence in situ hybridization (FISH) analyses revealed that this cell line has an additional chromosome 17 attached to a segment of chromosome 10 besides two intact chromosomes 17, and that each of these three chromosomes 17 has a G-CSF gene on chromosome 17q. Inflammatory cytokines, tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta, significantly enhanced G-CSF expression at both the protein and mRNA levels in MI-4. However, these cytokines did not stimulate the growth of MI-4 cells, regardless of abundant G-CSF production. TNF-alpha rather suppressed it, in a dose-dependent manner. Exogenous recombinant human G-CSF and anti-G-CSF antibody did not promote or inhibit the growth of MI-4 cells at any concentration examined. In addition, RT-PCR analysis did not show G-CSF receptor mRNA expression. These results suggest that this cell line does not have an autocrine growth loop for G-CSF. This cell line should be very useful for understanding the biological activity of G-CSF in G-CSF-overproducing lung cancer.

Aged↗