Induction of apoptosis and regulation of the MAPK pathway by ursolic acid in human leukemia K562 cells.

Ursolic acid (UA) is a pentacyclic triterpene acid naturally occurring in a number of foods and medicinal plants. It is one of the most promising chemopreventive agents and has been reported to induce apoptosis in many cancer cells. Here, we report that treatment with UA induces apoptosis in human leukemia K562 cells and down-regulates protein levels of bcl-xL. Treatment also increases phospho-JNK in a dose- and time-dependent manner but does not alter phospho-Erk1/2 and phospho-P38. These results suggest that JNK may participate in UA-induced apoptosis in K562 cells.