Publications by authors named "Seitaro Nakazawa"

Oral frailty is defined as a decrease in oral function accompanied by a decrease in mental and physical functions. Studies showing that people with oral frailty are at high risk of physical frailty, sarcopenia, severe conditions requiring nursing care and death have been reported in Japan. An increase in life expectancy and maintenance of teeth result in a decrease in the effect of the number of teeth.

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Background/aim: Malignant pleural mesothelioma (MPM) is an intractable cancer, and causes of its malignant transformation are not well known. Adenosine deaminase acting on RNA (ADAR) is an RNA-editing enzyme that converts adenosine into inosine in double-stranded RNAs potentially involved in malignant development.

Materials And Methods: To examine the role of ADAR1 and ADAR2 in MPM, small interfering RNAs (siRNAs) against ADAR1 or ADAR2 were used.

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The tumor suppressor gene TP53 (gene) codes for a transcription factor which transactivates its target genes responsible for cell cycle arrest, DNA repair, apoptosis, and senescence. TP53 is well known to be the most frequent target of genetic mutations in nearly half of human cancers including oral squamous cell carcinoma (OSCC). Many p53 mutants including R248Q and R248W not only lose its tumor-suppressor activities, but also interfere with the functions of wild-type p53; this is so-called dominant-negative (DN) mutation.

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In this study, we examined the effects of hypoxia on the malignancy of human malignant pleural mesothelioma (MPM) cell lines, and found (1) hypoxia enhanced motility and invasiveness of human malignant pleural mesothelioma (MPM) cells; (2) this phenomenon resulted from increased expression of sialylated MUC1 through the activation of HIF-1 pathway; (3) two HIF-binding sites located in the promoter region of MUC1 were important for MUC1 transactivation under hypoxia. These findings are useful for better understanding molecular mechanisms of aggressive behavior of MPM cells and for targeting them in the clinical therapies for MPM patients.

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Sex determining region Y-box 2 (SOX2) is well known as one of the "stemness" factors and is often expressed in cancers including breast cancer. In this study, we developed a reporter system using fluorescent protein driven by the promoter for SOX2 gene to detect and isolate living SOX2-positive cells. Using this system, we determined that SOX2 promoter activities were well correlated with SOX2 mRNA expression levels in 5 breast cancer cell lines, and that the cell population with positive SOX2 promoter activity (pSp-T(+)) isolated from one of the 5 cell lines, MCF-7 cells, showed a high SOX2 protein expression and high sphere-forming activity compared with very low promoter activity (pSp-T(low/-)).

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