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Takaaki Masuda

Publications and source records attributed to Takaaki Masuda.

5 recordsLinked to original sources
PubMed2006

[Occult micrometastasis].

The concept of occult micrometastasis has been recognized for several decades. Recently, the balance of evidence favours the hypothesis that micrometastatic cells impacts on survival in spite of few clinical large-scale trials. Immunocytochemistry using anti-cytokeratin monoclonal antibodies is often used to detect micrometastatic cells. The strategy for detection of micrometastasis would help in the design of "tailor-made treatment". Furthermore, the genomic analyses of micrometastatic cells will contribute to the development of more effective strategies to treat cancer patients as well as the clarification of the carcinogenesis and the mechanism of clinical metastasis which is the leading cause of cancer-related death.

Biomarkers, Tumor↗
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↗
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↗
PubMed2002

Localization of thymidine phosphorylase expression in colorectal carcinoma tissues by in situ RT-PCR assay.

Abundant expression of thymidine phosphorylase (TP) mRNA and protein was observed in human carcinoma tissues relative to the corresponding normal tissues. However, the distribution of cells that express TP has not yet been determined. In this study, we examined enzyme activity of TP in 24 primary colorectal carcinoma tissues and the corresponding normal tissue. Using in situ reverse-transcription polymerase chain reaction (RT-PCR), a new methodology to determine the localization of genes of interest objectively and clearly, cell distribution was compared. The expression of TP mRNA is observed in normal infiltrating cells adjacent to colon carcinoma cells by in situ RT-PCR. Similar to the protein activity, the average TP mRNA expression (amplified products/x400 field) in cases of Dukes C and D is 76.8, while that of Dukes A and B is 42.5, being significantly different (p = 0.001). Moreover, the number of amplified products in colon carcinoma tissues showed a significant correlation with the enzyme activity evaluated by high-performance liquid chromatography (p < 0.01, R = 0.76). In conclusion, the expression of TP mRNA is localized in stromal tissues as determined by in situ RT-PCR and can reflect the level of TP enzyme activity.

Adenocarcinoma↗