Antimetastatic effects of licochalcone A on oral cancer via regulating metastasis-associated proteases

Licochalcone A, a major phenolic constituent of the licorice species Glycyrrhiza inflata, has been proven to possess various biological benefits including anti-cancer activity. However, the detailed effects and molecular mechanisms of licochalcone A on the invasiveness and metastasis of oral cancer cells have not been fully understood. Thus, SCC-25 oral cancer cells were subjected to a treatment with licochalcone A at indicated concentrations (25, 50, and 100 mu g/mL) for 36 h and then analyzed for the effect of licochalcone A on the cell migration and invasion. In vitro assays, including wound healing, cell adhesion, and cell invasion/migration assays, revealed that licochalcone A treatment significantly inhibited the cell migration/invasion capacities of SCC-25 cells. Also, results of zymography and Western blotting showed that activity and protein level of matrix metalloproteinase-2 (MMP-2) was suppressed, but TIMP-2 level was increased, indicating the important role of MMP-2 and TIPM-2 in anti-metastatic regulation of SCC-25 cells. Furthermore, licochalcone A was shown to suppress the nuclear factor-kappa B (NF-kappa B) signal, as evidenced by the decreased expression of phosphorylated p65 (p-65) protein in licochalcone A-treated SCC-25 cells. Notably, we also found that licochalcone A treatment increased the expression of the epithelial marker E-cadherin and decreased the expression of mesenchymal markers N-cadherin in SCC-25 cells. This is the first report describing the effects and possible mechanisms of licochalcone A on tumor invasion and metastasis of SCC-25 cells. Taken together, our findings support that licochalcone A can be developed to a potent anti-metastatic candidate for oral cancer therapy.