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Koshi Mimori

Publications and source records attributed to Koshi Mimori.

At least 37 records · Page 2Linked to original sources
PubMed2005

Somatic mutations of epidermal growth factor receptor in colorectal carcinoma.

PURPOSE: Somatic mutations of the epidermal growth factor receptor (EGFR) gene may predict the sensitivity of non-small cell lung carcinoma to gefitinib. However, no mutations have been reported for colorectal carcinoma. We therefore analyzed EGFR mutations in colorectal adenocarcinomas by the combined use of laser microdissection and sequencing of genomic DNA. EXPERIMENTAL DESIGN: We examined 11 representative colorectal adenocarcinoma cell lines and 33 clinical samples of colorectal carcinoma. In the clinical cases, we carefully dissected only carcinoma cells from frozen sections by laser microdissection. After DNA extraction and PCR, we examined EGFR mutations by sequencing genomic DNA. RESULTS: None of 11 colorectal carcinoma cell lines exhibited somatic mutations, but 4 of 33 clinical tumors (12%) exhibited mutations in the EGFR kinase domain. This may be the first report of somatic mutations in colorectal adenocarcinoma. CONCLUSIONS: Our findings suggest that a distinct minority of colorectal adenocarcinomas exhibit somatic mutations of EGFR, and these tumors may be susceptible to gefitinib treatment.

Base Sequence↗
PubMed2005

Identification of molecular markers for metastasis-related genes in primary breast cancer cells.

Comparing differential gene expression profiles established by cDNA microarray between normal cells (N), primary carcinoma cells (T), and metastatic carcinoma cells (M) may determine those critical genes directly associated with progression and metastasis of breast cancer. Total RNA was extracted by laser microdissection (LMD) from 20 slices of T, N and M from 6 cases. After amplification by a T7-based system, differentially expressed genes between T, N and M were identified by cDNA microarray. In addition, to clarify the mechanism for altered gene expression, we determined the methylation status by sequencing after bisulfite treatment for intriguing genes. As a result, the expression of motility related protein-1 (MRP-1/CD9), peripheral myelin protein-22 (PMP-22), and caspase 3 (CASP-3) were down-regulated in M compared to T. We focused especially on MRP-1 and found that the expression status of MRP-1 was significantly inversely associated with stage of disease in 56 cases of breast cancer (P<0.05), and the relapse free survival in 5 years was significantly higher in MRP-1 positive cases than those negative cases (P<0.05). Conversely, overexpression, by 11-fold, of signal transduction and translation factors were observed in T compared to N. The cancer specific methylation was observed only in CASP-3 in a case. In conclusion, the establishment of the present assay allows us to detect genes directly associated with each cell population within tumor tissue and gives us clues to identify metastasis-related genes comprehensively in clinical breast cancer cases.

Antigens, CD↗
PubMed2005

Differential roles of E-type cyclins during transformation of murine E2F-1-deficient cells.

Deregulation of retinoblastoma gene product (pRB) is a hallmark of cancer, which acts as a transcriptional repressor by targeting E2F transcription factors. A transcription factor E2F-1 is not only important for S phase entry of cell cycle, but also stimulates gene expression of pro-apoptotic molecules. To investigate roles of E2F-1 and its target genes in cellular transformation, we studied murine E2F-1-deficient embryonic fibroblasts. Compared with control wild-type cells, E2F-1-deficient cells at early passages were less sensitive to exposure to gamma-radiation and showed an increase of colony formation, while their growth was slow. After sequential passages, the growth of E2F-1-deficient cells reached closely to that of wild-type cells. Immunoblot study of E2F target genes showed that multiple passages of E2F-1-deficient cells resulted in preferential increase of cyclin E2 expression. Furthermore, carcinogenicity study using N-nitrosomethylbenzylamine demonstrated that, compared to wild-type mice, fore-stomach tumors in E2F-1-deficient mice expressed an increased amount of cyclin E2, but not cyclin E1. Taken together, the present study shows that differential roles of E-type cyclins are involved at least partially in the process of cellular transformation, supporting the concept of important roles of the E2F regulatory pathway in carcinogenesis.

Animals↗
PubMed2005

Differentially expressed genes in endothelial differentiation.

By screening differentially expressed genes in mouse embryonic stem (ES) cells by subtractive hybridization, we identified three conserved but uncharacterized genes encoding bromodomain containing 3 (BRD3), protein lysine methyltransferase (PLM), and kelch domain containing 2 (KLHDC2), which were downregulated during endothelial differentiation. An RNA blot study showed that these genes were markedly expressed in undifferentiated ES cells, whereas the expression was reduced upon endothelial differentiation; a study of mouse endothelium showed a significant reduction in the expression of BRD3. A study of human BRD3, located on chromosome 9 at q34, a region susceptible to genomic rearrangement, showed an altered expression in 4 of 12 patients with bladder cancer, compared with adjacent noncancerous tissues. Taken together with the result of siRNA inhibition showing the positive regulation of cell proliferation by BRD3, it is suggested that this molecule plays a role in allowing cells to enter the proliferative phase of the angiogenic process.

Animals↗
PubMed2005

Components of DNA damage checkpoint pathway regulate UV exposure-dependent alterations of gene expression of FHIT and WWOX at chromosome fragile sites.

Common chromosome fragile sites are highly recombinogenic and susceptible to deletions during the development of environmental carcinogen-induced epithelial tumors. Previous studies showed that not only genetic but also epigenetic alterations in cancerous cells are involved in inactivation of the genes FHIT and WWOX at chromosome fragile sites, reported to be potential tumor suppressor genes. Here we investigated the effect of UV light on the gene expression. After exposure to UV, the mRNA and protein of the two genes in murine embryonic fibroblasts (MEF) were unstable, apparently at the G1-S phase of the cell cycle, which was consistent with nuclear run-on assay. A study of MEFs synchronized via a double thymidine block indicated that, after the exposure, the expression of Fhit and Wwox was reduced in E2f-1-deficient cells and markedly in wild-type cells, whereas the reduction was partially inhibited in Trp53-deficient cells; cells at the S phase seemed to be sensitive to exogenous FHIT, suggesting a role of the checkpoint at the G1-S phase in the stability of gene expression and a possible involvement of FHIT function at the S phase. The transfection experiment showed that the UV-induced decrease in expression was partially inhibited by transfection of kinase-dead Atr (ataxia telangiectasia mutated and Rad3 related), which is a sensor of UV-induced damage. Taken together, the present study showed that UV-induced alterations of the fragile site gene expression are involved at least partially in the checkpoint function, suggesting the role in the process of carcinogenesis after exposure to UV.

Acid Anhydride Hydrolases↗
PubMed2005

Detection of occult cancer cells in peripheral blood and bone marrow by quantitative RT-PCR assay for cytokeratin-7 in breast cancer patients.

The clinical significance of occult micrometastasis (O.M) remains unknown. We investigated it in peripheral blood (P.B.) and bone marrow (B.M.) in breast cancer patients with surgery. First, we investigated the expression levels of 7 representative molecular markers for detecting O.M (CEA, CK-7, CK-18, CK-19, CK-20, MAM and MUC-1) in 27 cancer and 8 non-epithelial cell lines using quantitative RT-PCR (QRT-PCR), and showed that the expression level of CK-7 was higher in every cancer cell line than in the non-epithelial cell lines. Next, we studied the clinical significance of O.M in P.B. and B.M. by QRT-PCR for CK-7 in breast cancer patients with surgery. Based on comparison with 17 non-cancer controls, 37 (18.0%) and 100 (48.5%) of the 206 patients were positive for CK-7 in P.B. and B.M., respectively. In 98 cases observed over 24 months after surgery, the CK-7-positive group in P.B. had poorer disease-free survival (DFS) than the negative group (p<0.01). The CK-7-positive group in P.B. showed poorer DFS than the negative group in 132 lymph node-negative cases (p=0.01), and moreover, in 61 lymph node-negative cases observed over 24 months after surgery, the CK-7-positive group in P.B. showed poorer DFS than the negative group (p<0.0001). In B.M., no significant difference in DFS was found between the CK-7-positive and CK-7-negative groups. QRT-PCR for CK-7 could be a useful and universal method for detecting O.M, and the quantitative detection of CK-7 in P.B. would have a prognostic value as a marker of early recurrence in breast cancer patients with surgery.

Adult↗
PubMed2005

Genomic screens for genes upregulated by demethylation in colorectal cancer: possible usefulness for clinical application.

Inactivation of tumor suppressor genes may result in clinically aggressive tumors and poor prognoses for cancer patients. This study was conducted to investigate the clinical significance of genomic screens for genes upregulated by demethylation in colorectal cancer. We performed a comprehensive survey of commonly inactivated genes in colorectal cancer through the functional reactivation of epigenetically silenced genes by 5-Azacytidine, using cDNA microarrays containing 12,814 genes. We then investigated the clinical significance of the identified gene in colorectal cancer patients. Among 41 candidate genes identified by this microarray analysis, 31 (76%) harbored CpG islands, and many of the genes were associated with cancer-testis antigens, Wnt inhibitors, growth factors, and cell cycle regulators. Subsequent analysis by quantitative RT-PCR confirmed the reliability of our microarray strategy. In order to elucidate the potential clinical significance of these identified genes, we selected one of these genes, apolipoprotein D (apo D), and investigated its mRNA expression in 63 colorectal cancer patients using quantitative real-time RT-PCR. The mean expression level of Apo D mRNA was significantly lower in cancerous tissues than in non-cancerous tissues (p < 0.01), and a lower expression of Apo D was significantly correlated with lymph node metastasis (p < 0.05), advanced stages (p < 0.05) and poorer overall survival (p < 0.05). These results indicated that a genomic screen for genes upregulated by demethylation may be a useful approach for the identification of genes that are of clinical significance in colorectal cancer patients.

Aged↗
PubMed2004

Coexpression of matrix metalloproteinase-7 (MMP-7) and epidermal growth factor (EGF) receptor in colorectal cancer: an EGF receptor tyrosine kinase inhibitor is effective against MMP-7-expressing cancer cells.

PURPOSE: Matrix metalloproteinase-7 (MMP-7) plays an important role in carcinoma invasion and metastasis of cancer. Recent studies focus on diverse roles of MMP-7, other than as a protease, during cancer progression. MMP-7 activates the epidermal growth factor (EGF) receptor by releasing an EGF ligand, tumor growth factor (TGF)-alpha. EXPERIMENTAL DESIGN: We examined expression of MMP-7 and EGF receptor in an immunohistochemical study of 40 colorectal cancer (CRC) cases. To determine the relationship between the EGF receptor and MMP-7, with a potential curative application, we compared the antitumor activity of the EGF receptor tyrosine kinase inhibitor (gefitinib) between MMP-7 transfectant, KYSE150 and HT29, and control cells. RESULTS: We found a statistically significant correlation (P = 0.04) between MMP-7 and activated (phosphorylated) EGF receptor expression, both being positive in six (15%) cases. Gefitinib reduced the cell number ratio more for MMP-7 transfectant than mock cells, and the proportion of apoptotic cells was 1.5 times higher in MMP-7 transfectant than mock cells by annexin/propidium iodide staining. This was mediated by activation of a TGF-beta signal as confirmed by the abundant expression of TGF-beta protein, the cytoplasmic to nuclear translocation of Smad4 protein by the administration of gefitinib, and the quantitative assay of the plasminogen activator inhibitor-1 promoter/luciferase construction. CONCLUSIONS: We propose that there are some cancers with up-regulated MMP-7 expression that leads to the activation of apoptotic activity of TGF-beta, which is susceptible to treatment with EGF receptor tyrosine kinase inhibitor.

Adult↗
PubMed2004

N-cadherin is regulated by activin A and associated with tumor aggressiveness in esophageal carcinoma.

PURPOSE: Activin A is a member of the transforming growth factor beta superfamily and plays an important role in the differentiation of embryonic stem cells. We have reported previously that the expression of activin A is associated with lymph node metastasis in esophageal cancer, and our purpose in the current work is to clarify the molecular mechanism of the aggressive behavior of tumors that have high activin A expression. EXPERIMENTAL DESIGN: We have compared the gene expression profiles of human esophageal carcinoma cell lines that were stably transfected with activin beta A, which is a subunit of activin A, with those of control human esophageal carcinoma cell lines, using a cDNA microarray. RESULTS: We found that the expression level of neuronal cadherin (N-cadherin) was higher in the transfectants than in the control cells. N-cadherin was located on the cell surface of the transfectants, irrespective of the expression of epithelial cadherin (E-cadherin), and the expression of N-cadherin mRNA was significantly associated with that of activin beta A mRNA in clinical samples of esophageal carcinoma (n = 51; r = 0.855). A clinicopathologic analysis suggested that expression of N-cadherin mRNA was associated with the depth of tumor wall invasion, and a group of patients with high expression of N-cadherin mRNA showed a significantly poorer prognosis than a group of patients with low N-cadherin expression (P = 0.046). CONCLUSIONS: These results indicate that activin A might mediate the expression of N-cadherin and that this may be associated with depth of invasion and poor prognosis.

Activins↗
PubMed2004

Differential expression of MMP and uPA systems and prognostic relevance of their expression in esophageal squamous cell carcinoma.

Matrix metalloproteinase (MMP) is critical for carcinoma progression. In our study, we evaluated the prognostic significance of the major MMP family such as MMP-3, MMP-9, MMP-11 and MT1-MMP at the mRNA in 44 esophageal squamous cell carcinoma (ESCC) that were previously characterized for MMP-7, MMP-1 and MMP-2, and their relation to urokinase system (uPA and uPAR). MT1-MMP, MMP-11 and MMP-2 expressions are closely associated with each other, while MMP-9 and uPAR expressions are inversely associated with the former group. There is no MMP related to clinicopathological factors; however, patients with high MT1-MMP could show worse prognosis, as compared to those with low MT1-MMP expression (p=0.01), as well as MMP-11 did (p=0.02). Both MMP showed clear expression of carcinoma cells by immunohistochemistry. In patients with high MT1-MMP, recurrence was more prominent (23/26: 88.5%) than those with low MT1-MMP (7/18: 38.9%) (p=0.0016). In the 20 cases who died within 3 years, all 15 cases with high MT1-MMP showed initial recurrence of distant metastasis, and the other 5 cases with low MT1-MMP showed locoregional recurrence (p=0.000064). These results could indicate that there is a relevant mechanism of associated expression of clinically significant MMP and that among them, MT1-MMP plays the most critical role in ESCC progression.

Adult↗
PubMed2004

Effect of exogenous E2F-1 on the expression of common chromosome fragile site genes, FHIT and WWOX.

The expression of two tumor suppressor genes, fragile histidine triad (FHIT) and WW domain containing oxidoreductase (WWOX), encompassing common chromosome fragile regions, FRA3B at 3p14.2 and FRA16D at 16q23, is altered in many epithelial tumors. Since DNA sequence search shows that the FHIT gene has the E2F-1 recognition site in 5'] region, which regulates cell cycle, we tested the effect of E2F-1 overexpression in tumor cells. Ectopic E2F-1 expression led to an increase of Fhit and Wwox expression in allele remaining tumor cells and resulted in induction of apoptosis. Reporter assay showed that the E2F-1 site in FHIT 5' region was involved in the down-stream transcription after exogenous E2F-1 introduction. Chromatin immunoprecipitation detected exogenous E2F-1 binding to the recognition site in FHIT 5' region. The data suggest that E2F-1 overexpression plays a role in suppression of tumor, at least in part trough transcriptional regulation of FHIT and relevant activation of WWOX.

Acid Anhydride Hydrolases↗
PubMed2004

Analysis of gastric cancer with cDNA microarray.

Recent advances in cDNA microarray techniques have enabled us to study the expression of many genes simultaneously. As gastric cancer remains one of the most common cancers in Japan, we studied gene expression profiles in gastric cancer by cDNA microarray analysis to determine if it would be clinically useful. We demonstrated two points. First, cDNA microarray might be useful as a prognostic indicator. However, there remain several important problems to be solved and these are discussed. Second, laser microdissection plus cDNA microarray might be useful in determining the specific genes that correlate to cancer metastasis or histological subtype. We review the pros and cons for cDNA microarray analysis in the context of gastric cancer.

Gene Expression Profiling↗
PubMed2004

A gene-expression signature can quantify the degree of hepatic fibrosis in the rat.

BACKGROUNDS/AIMS: A more accurate and objective quantification of hepatic fibrosis would provide clinically useful information for the monitoring of chronic liver disease progression and therapy recommendation. METHODS: Using a cDNA microarray of 14,814 clones, we analyzed the gene-expression profiles of fibrotic livers in a rat model. RESULTS: We identified 750 up- and 345 down-regulated genes by combining a signal-to-noise score and a random permutation test (P<0.01). The functions of these genes provided insight into the underlying molecular mechanisms of both structural remodeling and functional deficits in cirrhosis. To quantify the extent of liver fibrosis, we have generated for the first time a 'genetic fibrosis index' based on gene-expression profiling of 95 genes by combining a Pearson correlation coefficient and a 'leave-one-out' cross-validation procedure. This technique based on a supervised learning analysis correctly quantified the various degrees of fibrosis in both 20 training samples (R(2)=0.829, P<0.001) and 6 test samples (R(2)=0.822, P<0.05). CONCLUSIONS: Our method will assist researchers in identifying rational targets for intervention and might help clinicians to objectively monitor the severity of liver fibrosis.

Animals↗
PubMed2004

Expression of cancer-testis antigen (CTA) genes in intrahepatic cholangiocarcinoma.

BACKGROUND: Cancer-testis antigens (CTA), such as MAGE, are selectively expressed in various types of human neoplasms but not in normal tissues other than testis. This characteristic feature of CTA makes them promising antigens for cancer-specific immunotherapy. METHODS: We investigated the expression of five genes, including MAGE-1, MAGE-3, NY-ESO-1, SCP-1, and SSX-4, in 20 surgical samples of intrahepatic cholangiocarcinomas (IHCC) using reverse transcription-polymerase chain reaction. To visualize the localization of MAGE proteins, we performed immunohistochemical studies. Furthermore, the correlation between the CTA expression and DNA methylation status was studied in three bile duct cancer cell lines. RESULTS: Expression of MAGE-1, MAGE-3, NY-ESO-1, SCP-1, and SSX-4 was recognized in 4, 4, 2, 6, and 3 of all 20 cases, respectively. In contrast, the expressions of five genes were not recognized at all in the corresponding normal tissues. In 10 cases (50%), the tumors expressed at least one of the five CTA. An immunohistochemical analysis of MAGE proteins demonstrated homogenous or focal distributions in cytoplasm of the IHCC. Using a demethylating agent, MAGE-1, NY-ESO-1, SCP-1, and SSX-4 were induced in two of three cell lines, whereas MAGE-3 was not. CONCLUSIONS: Half of the tumor tissues of IHCC expressed at least one of the CTA. Some of the patients with IHCC, therefore, should be candidates for potentially useful cancer-specific immunotherapy.

Aged↗
PubMed2004

Prediction of 5'-deoxy-5-fluorouridine sensitivity in colorectal cancer cases by thymidine phosphorylase activity and preliminary identification of susceptibility related genes.

We confirmed that the enzyme activity of thymidine phosphorylase (TP) can substitute for 5'-deoxy-5-fluorouridine (5'-dFUR) sensitivity in clinical colorectal cancer (CRC) tissues. Moreover, the idenfication of susceptible genes other than TP will be desired for prediction or treatment of 5'-dFUR. We initially established conditions for the MTT assay system in vivo to compare the growth inhibition rate and TP activity in 18 cases of CRC. TP activity levels were concordant with 5'-dFUR sensitivity in the CRCs (p<0.05). In 18 CRC cases, 4 cases of high sensitivity and 3 cases of low sensitivity to 5'-dFUR were compared to analyze expression profiles of 9437 genes on cDNA microarray chips. As a result, a cluster of genes related to the sensitivity were identified and another cluster of genes related to the insensitivity of 5'-DFUR were also listed. We determined that TP expression can precisely predict 5'-dFUR sensitivity in CRCs and found susceptibility related genes.

Aged↗
PubMed2003

A tumor-suppressive role for trypsin in human cancer progression.

Trypsin is a serine protease family member with a potential role in cancer invasion. We investigated trypsinogen expression at the RNA level in 49 esophageal squamous cell carcinomas (ESCCs) and 72 gastric adenocarcinomas. Almost all primary ESCC tissues (95%) showed reduced expression, and 9 of 13 ESCC cell lines were silenced for trypsinogen expression. Absent expression correlated with promoter hypermethylation of trypsinogen-4 by bisulfite DNA sequence. Moreover, we detected promoter hypermethylation in 50% of primary ESCCs by methylation-specific PCR. A subset of gastric adenocarcinomas (71%) also showed reduced trypsinogen accompanied by reduction in PAR2, a G protein activated by trypsin, and a propensity to penetrate beyond the gastric wall (P = 0.001). Our results support the notion that trypsin plays a tumor-suppressive role in human carcinoma.

Adenocarcinoma↗
PubMed2003

MAL gene expression in esophageal cancer suppresses motility, invasion and tumorigenicity and enhances apoptosis through the Fas pathway.

We isolated the MAL (T-lymphocyte maturation associated protein) gene from differentially expressed products of esophageal epithelium relative to esophageal carcinoma tissues. The Mal protein has been demonstrated as being a component of the protein machinery for apical transport in epithelial polarized cells. In this study, we describe the reduced expression of MAL in all 39 cases of esophageal carcinoma tested and 60 other human carcinomas. MAL gene transcription was induced in three out of 13 esophageal carcinoma cell lines by treatment with the demethylating agent 5-aza-2'-deoxycytidine (DAC), and in nine additional cell lines by simultaneous treatment with trichostatin A, an inhibitor of deacetylation, and DAC. We established a stable MAL gene transfectant whose expression was regulated by subcutaneous doxycycline injection in nude mice. Tumor growth was suppressed in cells expressing TE3-MAL compared with TE3 parent cells or cells not expressing TE3-MAL with doxycycline injection (20 microg/body) (P<0.01). Additionally, the TE3-MAL transfectant cells exhibited decreased cellular motility, a G1/S transition block and increased levels of apoptosis, concomitant with increased expression of Fas receptor in vitro. The apoptotic staining in MAL-expressing tumors was confirmed by TUNEL assay. Therefore, we conclude that expression of MAL was frequently decreased or diminished in gastrointestinal tract cancers, and that Mal expression confers reduced tumorigenicity in vivo to tumor TE3 cells through the induction of apoptosis via the Fas signaling pathway.

Animals↗