Oral cancer mortality has increased during the last decade due to the difficulties in treating related metastasis. Dioscorea nipponica Makino, a popular folk medicine, exerts anti-obesity and anti-inflammation properties. However, the effect of this folk medicine on metastasis of oral cancer has yet to be fully elucidated. The present study demonstrates that D. nipponica extracts (DNE), at a range of concentrations (0-50 μg/mL), concentration-dependently inhibited migration/invasion capacities of human oral cancer cells, HSC-3, without cytotoxic effects. The anti-migration effect of DNE was also observed in two other OSCC cell lines, Ca9-22 and Cal-27. Zymography, real time PCR, and Western blotting analyses revealed that DNE inhibited matrix metalloproteinase-2 (MMP-2) enzyme activity, and RNA and protein expression. The inhibitory effects of DNE on MMP-2 proceeded by up-regulating tissue inhibitor of metalloproteinase-2 (TIMP-2), as well as suppressing nuclear translocation and DNA binding activity of cAMP response element-binding (CREB) and activating protein-1 (AP-1) on the MMP-2 promoter in HSC-3 cells. In conclusion, DNE inhibited the invasion of oral cancer cells and may have potential use as a chemopreventive agent against oral cancer metastasis.
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