| Summary: | 碩士 === 中山醫學大學 === 醫學研究所 === 99 === In Taiwan, the incidence and mortality of oral cancer have increased gradually. Oral cancer may affect every part of the oral cavity, including the lips, tongue, mouth, and throat and the main mortality cause is metastasis. Dioscorea nipponica was a popular folk medicine with several proven biological benefits including reducing blood pressure and anti-cough activities, together with abilities of oxidation resistance, anti-allergy, anti-inflammation and anti-tumor. However, the detailed effects and mechanisms of this medicine on cancer cell invasion and metastasis were still unclear. First of all, HSC-3 cells were treated with ethanol extracts of Dioscorea nipponica and then subjected to MTT assays. Results suggested that Dioscorea nipponica have no effect on cell viability of HSC-3 cells. The modified Boyden chamber assays revealed that a treatment of Dioscorea nipponica significantly inhibited the cell motility/invasion capacities of HSC-3 cells. Since that tumor metastasis is accompanied with proteolytic degradation of the extracellular matrix and changed cell motility, MMP-2 and MMP-9 activity were also studied via gelatin zymography assay to show that they all were inhibited by Dioscorea nipponica. Furthermore, results from western blot showed that Dioscorea nipponica extract may suppress the protein expression of proteinase MMP-2 and their proteinase inhibitor TIMP-2. Dioscorea nipponica extract also inhibited the signal transduction protein expression of PI3K and phosphorylation of ERK and Akt while the expression of nuclear protein CREB-1, c-Jun and c-Fos were inhibited as well. The CHIP assay also revealed that the DNA binding activity with AP-1 and CREB-1 was also decreased by Dioscorea nipponica extract. In conclusion, Dioscorea nipponica may be a powerful candidate for a preventive agent against oral cancer development and metastasis.
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