• Preventive Nutrition and Food Science
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• v.20 no.1
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• pp.73-77
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• 2015

As an approach to search for chemopreventive agents, we tested p-coumaric acid, 3-methoxy-p-coumaric acid (ferulic acid), and 3,5-dimethoxy-p-coumaric acid (sinapic acid) in B16/F10 melanoma cells. Intracellular melanin contents were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and cytotoxicity of the compounds were examined by lactate dehydrogenase (LDH) release. p-Coumaric acid showed inhibitory effect on melanogenesis, but ferulic acid increased melanin content, and sinapic acid had almost no effect on melanogenesis. Treatment with ferulic acid resulted in a 2 to 3 fold elevation in the production of melanin. Correlatively, cell viability decreased in a dose-dependent manner when treated with ferulic acid. However, ferulic acid did not affect the LDH release from the cells. Treatment with sinapic acid resulted in a 50~60% elevation in the release of LDH when treated with a $200{\mu}g/mL$ concentration and showed neither cytostasis nor increase of melanin synthesis in a dose-dependent manner. Taken together, p-coumaric acid inhibits melanogenesis, ferulic acid induces melanogenesis, and sinapic acid exerts cytotoxic effects in B16/F10 murine melanoma cells. The results indicate that the addition of methoxy groups to p-coumaric acid shows the melanogenic or cytotoxic effects in melanoma cells compared to the original compound. Therefore, this study suggests the possibility that methoxylated p-coumaric acid, ferulic acid can be used as a chemopreventive agent.

• BMB Reports
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• v.50 no.12
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• pp.599-600
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• 2017

Many studies have focused on the tumor suppressive role of $TGF-{\beta}$ signaling during the early stages of tumorigenesis by activating the target genes involved in cytostasis and apoptosis. We investigated the effects of $TGF-{\beta}$ inhibition on early tumorigenesis in the liver, by employing diverse inhibitory methods. Strikingly, $TGF-{\beta}$ inhibition consistently suppressed hepatic tumorigenesis that was induced either by activated RAS plus p53 downregulation or by the co-activation of RAS and TAZ signaling; this demonstrates the requirements for canonical $TGF-{\beta}$ signaling in tumorigenesis. Moreover, we found that Snail is the target gene of the $TGF-{\beta}$ signaling pathway that promotes hepatic carcinogenesis. The knockdown of Snail suppressed the early tumorigenesis in the liver, as did the $TGF-{\beta}$ inhibition, while the ectopic expression of Snail restored tumorigenesis that was suppressed by the $TGF-{\beta}$ inhibition. Our findings establish the oncogenic $TGF-{\beta}$-Smad-Snail signaling axis during the early tumorigenesis in the liver.

• Archives of Pharmacal Research
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• v.26 no.11
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• pp.960-966
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• 2003

Macrophages play an important role in host defenses by killing tumors and virus infections and producing secretory products. High mannuronic acid (HMA) containing alginate was examined to determine the mechanisms by which HMA-activated macrophages resist infection with HSV-1 and inhibit the growth of tumor cells. The ability of macro phages to resist infection with HSV-1 or to inhibit the growth of tumor cells was assessed following treatment with HMA alginate in the presence of either antibodies to various cytokines or inhibitors/scavengers of toxic macrophage products. Only antibodies to IFN-$\alpha$/$\beta$ were able to abrogate the protective effects of HMA alginate in macrophages infected with HSV-1, suggesting that the antiviral activity induced by this immunomodulator was mediated by the production of IFN-$\beta$. In contrast, anti-TNF-$\alpha$, anti-IFN and inhibitors of nitric oxide and reactive oxygen species were all able to partially abrogate HMA-induced cytostatic activity, suggesting that multiple mechanisms are involved in macrophage cytostasis. These results indicate that the HMA-induced intrinsic antiviral and extrinsic cytotoxic activites are mediated by different mechanisms.

• Restorative Dentistry and Endodontics
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• v.27 no.5
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• pp.543-551
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• 2002

Nitric oxide (NO) is a small molecule (mol. wt. 30 Da) and oxidative free radical. It is uncharged and can therefore diffuse freely within and between cells across membrane. Such characteristics make it a biologically important messenger in physiologic processes such as neurotransmission and the control of vascular tone. NO is also highly toxic and is known to acts as a mediator of cytotoxicity during host defense. NO is synthesized by nitric oxide synthase (NOS) through L-arginine/nitric oxide pathway which is a dioxygenation process. NO synthesis involves several participants, three co-substrates, five electrons, five co-factors and two prosthetic groups. Under normal condition, low levels of NO are synthesized by type I and III NOS for a short period of time and mediates many physiologic processes. Under condition of oxidant stress, high levels of NO are synthesized by type II NOS and inhibits a variety of metabolic processes and can also cause direct damage to DNA. Such interaction result in cytostasis, energy depletion and ultimately cell death. NO has the potential to interact with a variety of intercellular targets producing diverse array of metabolic effects. It is known that NO is involved in hemodynamic regulation, neurogenic inflammation, re-innervation, management of dentin hypersensitivity on teeth. Under basal condition of pulpal blood flow, NO provides constant vasodilator tone acting against sympathetic vasoconstriction. Substance P, a well known vasodilator, was reported to be mediated partly by NO, while calcitonin-gene related peptide has provided no evidence of its relation with NO. This review describes the roles of NO in dental pulp in addition to the known general roles of it.