Abstract
We previously demonstrated that the motility of highly metastatic murine osteosarcoma cells is significantly reduced by serum from a mouse after intake of maoto and that spontaneous metastasis in tumor-bearing mice is suppressed by oral administration of maoto. Since it is important to evaluate the efficacy of maoto against human metastatic tumors, we investigated the inhibitory effect of maoto on human serum (HS)-induced motility of a human breast cancer cell line, MDA-MB-231. To determine an efficient concentration of HS to induce cell motility, we tested several concentrations of human serum. Motility was induced by HS in a concentration-dependent manner and reached a plateau at 1%. Therefore, the concentration of HS adequate for a serum-induced cell motility assay was determined to be 1%. We investigated the effect of maoto, juzentaihoto, or shikunshito on HS-induced cell motility using the assay. Cell motility was reduced by the addition of maoto in a concentration-dependent manner; 100 μg/ml of maoto caused an 83% reduction of cell motility. In contrast, no significant changes were observed following the addition of juzentaihoto or shikunshito. Maoto had no effect on the cell growth at the concentration of 6.25 to 100 μg/ml, indicating that maoto suppressed HS-induced motility without cytotoxicity. These results indicate that maoto suppresses not only murine cancer cell motility but also human cancer cell motility and suggest that maoto will be important for clinical application for the prevention of cancer metastasis.
