6-(methylsulfinyl)hexyl isothiocyanate isolated from wasabi (Wasabia japonica MATSUM) suppresses tumor progression in an experimental mouse system

We examined the anti-metastatic effect of 6-(methylsulfinyl)hexyl isothiocyanate (6-MITC) isolated from wasabi (Wasabia japonica MATSUM). Pulmonary micrometastasis was quantified using a dependable method to detect the human c-Ha-ras gene, which was carried in the tumor cell line. Mice belonging to the S-I group were administered 6-MITC continuously for 35 days from the time of tumor cell inoculation, and S-2 group mice were administered 6-MITC for 21 days from the day of amputation. Oral administration of 200 muM 6-MITC solution was effective in preventing metastasis of the experimental tumor. In the S-1 group, 7 out of ten experimental mice have lungs carrying no detectable human c-Ha-ras gene. Amplified human c-Ha-ras bands were detected in only the lungs of three mice; in these, the metastatic indexes of the lungs were respectively 0.60, 0.70 and 0.90. In the S-2 group, the bands were detected in four lungs of 5 experiments, with the metastatic indexes of the lungs in the range 0.36-0.72. Starting the treatment at the time of tumor cell inoculation was more effective in preventing metastasis than beginning the treatment on the day of amputation.