A method for suppressing tumor metastasis, in which an effective amount of a compound of formula (I) is administered to a subject in need thereof. Also disclosed is a method of treating cancer, in which an effective amount of a chemotherapy agent and an effective amount of a compound of formula (I) is administered to a subject in need thereof. Further disclosed are pharmaceutical compositions for suppressing tumor metastasis and for treating cancer, each of the compositions containing a compound of formula (I).
